Jay Dittmann

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, MW, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

We present new measurements of the inclusive forward-backward ttbar production asymmetry, AFB, and its dependence on several properties of the ttbar system. The measurements are performed with the full Tevatron data set recorded with the CDF II detector during ppbar collisions at sqrt(s) = 1.96 TeV, corresponding to an integrated luminosity of 9.4 fb^(-1). We measure the asymmetry using the rapidity difference Delta-y=y_(t)-y_(tbar). Parton-level results are derived, yielding an inclusive asymmetry of 0.164+/-0.047 (stat + syst). We observe a linear dependence of AFB on the top-quark pair mass M(ttbar) and the rapidity difference |Delta-y| at detector and parton levels. Assuming the standard model, the probabilities to observe the measured values or larger for the detector-level dependencies are 7.4*10^(-3) and 2.2*10^(-3) for M(ttbar) and |Delta-y| respectively. Lastly, we study the dependence of the asymmetry on the transverse momentum of the ttbar system at the detector level. These results are consistent with previous lower-precision measurements and provide additional quantification of the functional dependencies of the asymmetry.

This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$^{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B^{+}\to J/\psi K^{+}$ and $B^{0}\to J/\psi K^{*0}(892)$, where $J/\psi \to \mu^+\mu^-$ and $K^{*0} \to K^+ \pi^-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.

Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to as $B(5970)$, found simultaneously in the ${B}^{0}{\ensuremath{\pi}}^{+}$ and ${B}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ mass distributions with a significance of 4.4 standard deviations. We further report the first study of resonances consistent with orbitally excited ${B}^{+}$ mesons and an updated measurement of the properties of orbitally excited ${B}^{0}$ and ${B}_{s}^{0}$ mesons. We measure the masses and widths of all states, as well as the relative production rates of the ${B}_{1}$, ${B}_{2}^{*}$, and $B(5970)$ states and the branching fraction of the ${B}_{s2}^{*0}$ state to either ${B}^{*+}{K}^{\ensuremath{-}}$ and ${B}^{+}{K}^{\ensuremath{-}}$. Furthermore, we measure the production rates of the orbitally excited ${B}^{0,+}$ states relative to the ${B}^{0,+}$ ground state. The masses of the new $B(5970)$ resonances are $5978\ifmmode\pm\else\textpm\fi{}5(\text{stat})\ifmmode\pm\else\textpm\fi{}12(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ for the neutral state and $5961\ifmmode\pm\else\textpm\fi{}5(\text{stat})\ifmmode\pm\else\textpm\fi{}12(\text{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ for the charged state, assuming that the resonance decays into $B\ensuremath{\pi}$ final states. The properties of the orbitally excited and the new $B(5970{)}^{0,+}$ states are compatible with isospin symmetry.

For comparison of inclusive jet cross sections measured at hadron-hadron colliders to next-to-leading order (NLO) parton-level calculations, the energy deposited in the jet cone by spectator parton interactions must first be subtracted. The assumption made at the Tevatron is that the spectator parton interaction energy is similar to the ambient level measured in minimum bias events. In this paper, we test this assumption by measuring the ambient charged track momentum in events containing large transverse energy jets at $\sqrt{s}=1800$ GeV and $\sqrt{s}=630$ GeV and comparing this ambient momentum with that observed both in minimum bias events and with that predicted by two Monte Carlo models. Two cones in $\eta$--$\phi$ space are defined, at the same pseudo-rapidity, $\eta$, as the jet with the highest transverse energy ($E_T^{(1)}$), and at $\pm 90^o$ in the azimuthal direction, $\phi$. The total charged track momentum inside each of the two cones is measured. The minimum momentum in the two cones is almost independent of $E_T^{(1)}$ and is similar to the momentum observed in minimum bias events, whereas the maximum momentum increases roughly linearly with the jet $E_T^{(1)}$ over most of the measured range. This study will help improve the precision of comparisons of jet cross section data and NLO perturbative QCD predictions. %this is new The distribution of the sum of the track momenta in the two cones is also examined for five different $E_T^{(1)}$ bins. The HERWIG and PYTHIA Monte Carlos are reasonably successful in describing the data, but neither can describe completely all of the event properties.

The Run II jet physics group includes the Jet Algorithms, Jet Shape/Energy Flow, and Jet Measurements/Correlations subgroups. The main goal of the jet algorithm subgroup was to explore and define standard Run II jet finding procedures for CDF and DO. The focus of the jet shape/energy flow group was the study of jets as objects and the energy flows around these objects. The jet measurements/correlations subgroup discussed measurements at different beam energies; strong coupling constant measurements; and LO, NLO, NNLO, and threshold jet calculations. As a practical matter the algorithm and shape/energy flow groups merged to concentrate on the development of Run II jet algorithms that are both free of theoretical and experimental difficulties and able to reproduce Run I measurements. Starting from a review of the experience gained during Run I, the group considered a variety of cone algorithms and KT algorithms. The current understanding of both types of algorithms, including calibration issues, are discussed in this report along with some preliminary experimental results. The jet algorithms group recommends that CDF and DO employ the same version of both a cone algorithm and a KT algorithm during Run II. Proposed versions of each type of algorithm are discussed. The group also recommends the use of full 4-vector kinematic variables whenever possible. The recommended algorithms attempt to minimize the impact of seeds in the case of the cone algorithm and preclustering in the case of the KT algorithm. Issues regarding precluster definitions and merge/split criteria require further study.

The MEGA experiment, which searched for the muon- and electron-number violating decay ${\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\gamma},$ is described. The spectrometer system, the calibrations, the data taking procedures, the data analysis, and the sensitivity of the experiment are discussed. The most stringent upper limit on the branching ratio, $\mathcal{B}({\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\gamma})&lt;1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$ with $90%$ confidence, is derived from a likelihood analysis.

We report on measurements of the $\ensuremath{\Upsilon}(1S)$, $\ensuremath{\Upsilon}(2S)$, and $\ensuremath{\Upsilon}(3S)$ differential, ${(\frac{{d}^{2}\ensuremath{\sigma}}{d{P}_{t}\mathrm{dy}})}_{y=0}$, and integrated cross sections in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of 16.6 \ifmmode\pm\else\textpm\fi{} 0.6 ${\mathrm{pb}}^{\ensuremath{-}1}$ collected by the Collider Detector at Fermilab. The three resonances were reconstructed through the decay $\ensuremath{\Upsilon}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. Comparison is made to a leading order QCD prediction.

We present a measurement of the mass of the W boson using data collected with the CDF detector during the 1992-93 collider run at the Fermilab Tevatron.A t to the transverse mass spectrum of a sample of 3268 W ! events recorded in an integrated luminosity of 19.7 pb 1 gives a mass M W = 80:310 0:205 (stat.)0:130 (syst.)GeV/c 2 .A t to the transverse mass spectrum of a sample of 5718 W ! e events recorded in 18.2 pb 1 gives a mass M e W = 80:490 0:145 (stat.)0:175 (syst.)GeV/c 2 .Combining the electron and muon results, accounting for correlated uncertainties, yields a mass M W = 80:410 0:180 GeV/c 2 .

We report final measurements of direct $\mathit{CP}$--violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete $\sqrt{s}=1.96$ TeV proton-antiproton collisions data set, corresponding to 9.3 fb$^{-1}$ of integrated luminosity, we measure $\mathcal{A}(\Lambda^0_b \rightarrow p\pi^{-}) = +0.06 \pm 0.07\mathrm{(stat)} \pm 0.03\mathrm{(syst)}$ and $\mathcal{A}(\Lambda^0_b \rightarrow pK^{-}) = -0.10 \pm 0.08\mathrm{(stat)} \pm 0.04\mathrm{(syst)}$, compatible with no asymmetry. In addition we measure the $\mathit{CP}$--violating asymmetries in $B^0_s \rightarrow K^{-}\pi^{+}$ and $B^0 \rightarrow K^{+}\pi^{-}$ decays to be $\mathcal{A}(B^0_s \rightarrow K^{-}\pi^{+}) = +0.22 \pm 0.07\mathrm{stat)} \pm 0.02\mathrm{(syst)}$ and $\mathcal{A}(B^0 \rightarrow K^{+}\pi^{-}) = -0.083\pm 0.013 \mathrm{(stat)} \pm 0.004\mathrm{(syst)}$, respectively, which are significantly different from zero and consistent with current world averages.

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions and decaying to final states that contain two charged leptons (electrons or muons). The data are collected with the Collider Detector at Fermilab and correspond to an integrated luminosity of 9.1 fb(-1). We measure the leptonic forward-backward asymmetry, A(FB)(ℓ), to be 0.072 ± 0.060 and the leptonic pair forward-backward asymmetry, A(FB)(ℓℓ), to be 0.076 ± 0.082. The measured values can be compared with the standard model predictions of A(FB)(ℓ) = 0.038 ± 0.003 and A(FB)(ℓℓ) = 0.048 ± 0.004, respectively. Additionally, we combine the A(FB)(ℓ) result with a previous determination from a final state with a single lepton and hadronic jets and obtain A(FB)(ℓ) = 0.090(-0.026)(+0.028).

A search for the exotic meson $X(5568)$ decaying into the $B^0_s \pi^{\pm}$ final state is performed using data corresponding to $9.6 \textrm{fb}^{-1}$ from $p{\bar p}$ collisions at $\sqrt{s} = 1960$ GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7\% at the 95\% confidence level is set on the fraction of $B^0_s$ produced through the $X(5568) \rightarrow B^0_s \, \pi^{\pm}$ process.

We present a measurement of $\sigma \cdot B(W \to e \nu)$ and $\sigma \cdot B(Z^0 \to e^+e^-)$ in proton - antiproton collisions at $\sqrt{s} =1.8$ TeV using a significantly improved understanding of the integrated luminosity. The data represent an integrated luminosity of 19.7 pb$^{-1}$ from the 1992-1993 run with the Collider Detector at Fermilab (CDF). We find $\sigma \cdot B(W \to e \nu) = 2.49 \pm 0.12$~nb and $\sigma \cdot B(Z^0 \to e^+e^-) = 0.231 \pm 0.012$~nb.

We have used $19{\mathrm{pb}}^{\ensuremath{-}1}$ of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at 95% confidence level models containing the following new particles: axigluons with mass between 200 and 870 GeV/ ${c}^{2}$, excited quarks with mass between 80 and 570 GeV/ ${c}^{2}$, and color octet technirhos with mass between 320 and 480 GeV/ ${c}^{2}$.

Using data from proton-antiproton collisions at Ecms=1.96 TeV recorded by the CDF II detector at the Fermilab Tevatron, evidence for the excited resonance state Lambda_b* is presented in its Lambda_b0 pi+ pi- decay, followed by the Lambda_b0 -->Lambda_c+ (-->proton K- pi+) pi- decays. The analysis is based on a data sample corresponding to an integrated luminosity of 9.6/fb collected by an online event selection based on charged-particle tracks displaced from the proton-antiproton interaction point. The significance of the observed signal is 3.5 Gaussian sigmas. The mass of the observed state is found to be 5919.22 +- 0.76 MeV in agreement with similar findings in proton-proton collision experiments.

We present a measurement of the total decay width of the top quark using events with top-antitop-quark pair candidates reconstructed in the final state with one charged lepton and four or more hadronic jets. We use the full Tevatron Run II data set of $\sqrt{s} = 1.96$ TeV proton-antiproton collisions recorded by the CDF II detector. The top-quark mass and the mass of the hadronically-decaying $W$ boson are reconstructed for each event and compared with distributions derived from simulated signal and background samples to extract the top-quark width (\gmt) and the energy scale of the calorimeter jets with {\it in-situ} calibration. For a top-quark mass $\mtop = \gevcc{172.5}$, we find $1.10<\gmt<\gev{4.05}$ at 68% confidence level, which is in agreement with the standard-model expectation of \gev{1.3} and is the most precise direct measurement of the top-quark width to date.

This Letter reports a measurement of the cross section for producing pairs of central prompt isolated photons in proton-antiproton collisions at a total energy of 1.96 TeV using data corresponding to 9.5/fb integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. The measured differential cross section is compared to three calculations derived from the theory of strong interactions. These include a prediction based on a leading order matrix element calculation merged with parton shower, a next-to-leading order, and a next-to-next-to-leading order calculation. The first and last calculations reproduce most aspects of the data, thus showing the importance of higher-order contributions for understanding the theory of strong interaction and improving measurements of the Higgs boson and searches for new phenomena in diphoton final states.

We measure the asymmetry in the charge-weighted rapidity of the lepton in semileptonic ttbar decays recorded with the CDF II detector using the full Tevatron Run II sample, corresponding to an integrated luminosity of 9.4/fb. A parametrization of the asymmetry as a function of the charge-weighted rapidity is used to correct for the finite acceptance of the detector and recover the production-level asymmetry. The result of afb(lep) = 0.094 +0.032 -0.029 is to be compared to the standard model next-to-leading-order prediction of afb(lep) = 0.038 +-0.003.

We study charged particle production in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta-phi space; toward, away, and transverse. The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the underlying event. The transverse region is divided into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event are studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.

The Run II jet physics group includes the Jet Algorithms, Jet Shape/Energy Flow, and Jet Measurements/Correlations subgroups. The main goal of the jet algorithm subgroup was to explore and define standard Run II jet finding procedures for CDF and DO. The focus of the jet shape/energy flow group was the study of jets as objects and the energy flows around these objects. The jet measurements/correlations subgroup discussed measurements at different beam energies; strong coupling constant measurements; and LO, NLO, NNLO, and threshold jet calculations. As a practical matter the algorithm and shape/energy flow groups merged to concentrate on the development of Run II jet algorithms that are both free of theoretical and experimental difficulties and able to reproduce Run I measurements. Starting from a review of the experience gained during Run I, the group considered a variety of cone algorithms and KT algorithms. The current understanding of both types of algorithms, including calibration issues, are discussed in this report along with some preliminary experimental results. The jet algorithms group recommends that CDF and DO employ the same version of both a cone algorithm and a KT algorithm during Run II. Proposed versions of each type of algorithm are discussed. The group also recommends the use of full 4-vector kinematic variables whenever possible. The recommended algorithms attempt to minimize the impact of seeds in the case of the cone algorithm and preclustering in the case of the KT algorithm. Issues regarding precluster definitions and merge/split criteria require further study.

Direct limits are set on W W Z and W W three-boson couplings in a search for W W and W Z production with high transverse momentum in pp collisions at p s = 1:8 TeV, using the Collider Detector at Fermilab.The results are in agreement with the SU(2) U(1) model of electroweak interactions.Assuming Standard Model W W couplings, the limits are interpreted as direct evidence for a non-zero W W Z coupling at subprocess energies near 500 GeV.Alternatively, assuming identical W W Z and W W couplings, bounds

We measure the time dependence of the ratio of decay rates for ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ to the Cabibbo-favored decay ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. The charge conjugate decays are included. A signal of $3.3\ifmmode\times\else\texttimes\fi{}{10}^{4}$ ${D}^{*+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{D}^{0}$, ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays is obtained with ${D}^{0}$ proper decay times between 0.75 and 10 mean ${D}^{0}$ lifetimes. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of $9.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ for $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. Assuming $CP$ conservation, we search for ${D}^{0}$-${\overline{D}}^{0}$ mixing and measure the mixing parameters to be ${R}_{D}=(3.51\ifmmode\pm\else\textpm\fi{}0.35)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, ${y}^{\ensuremath{'}}=(4.3\ifmmode\pm\else\textpm\fi{}4.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, and ${x}^{\ensuremath{'}2}=(0.08\ifmmode\pm\else\textpm\fi{}0.18)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. We report Bayesian probability intervals in the ${x}^{\ensuremath{'}2}$-${y}^{\ensuremath{'}}$ plane and find that the significance of excluding the no-mixing hypothesis is equivalent to 6.1 Gaussian standard deviations, providing the second observation of ${D}^{0}$-${\overline{D}}^{0}$ mixing from a single experiment.

We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant production via an intermediate gluon as well as resonant production via a distinct nonstandard-model intermediate strongly interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at √[s]=1.96 TeV corresponding to an integrated luminosity of 6.6 fb(-1). We find the data to be consistent with nonresonant production. We report limits on σ(pp[over ¯]→jjjj) as a function of the masses of the hypothetical intermediate particles. Upper limits on the production cross sections for nonstandard-model particles in several resonant and nonresonant processes are also derived.

This Letter reports a search for a narrow resonant state decaying into two W bosons and two b quarks where one W boson decays leptonically and the other decays into a quark-antiquark pair. The search is particularly sensitive to top-antitop resonant production. We use the full data sample of proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, corresponding to an integrated luminosity of 9.45 fb(-1). No evidence for resonant production is found, and upper limits on the production cross section times branching ratio for a narrow resonant state are extracted. Within a specific benchmark model, we exclude a Z' boson with mass, M(Z'), below 915 GeV/c(2) decaying into a top-antitop pair at the 95% credibility level assuming a Z' boson decay width of Γ(Z') = 0.012 M(Z'). This is the most sensitive search for a narrow qq-initiated tt resonance in the mass region below 750 GeV/c(2).

The first observation of the production of a W boson with a single charm quark (c) jet in pp[over ¯] collisions at √s=1.96 TeV is reported. The analysis uses data corresponding to 4.3 fb(-1), recorded with the CDF II detector at the Fermilab Tevatron. Charm quark candidates are selected through the identification of an electron or muon from charm-hadron semileptonic decay within a hadronic jet, and a Wc signal is observed with a significance of 5.7 standard deviations. The production cross section σ(Wc)(p(Tc)>20 GeV/c,|η(c)|<1.5)×B(W→ℓν) is measured to be 13.6(-3.1)(+3.4) pb and is in agreement with theoretical expectations. From this result the magnitude of the quark-mixing matrix element V(cs) is derived, |V(cs)|=1.08±0.16 along with a lower limit of |V(cs)|>0.71 at the 95% confidence level, assuming that the Wc production through c to s quark coupling is dominant.

Abstract As part of its HL-LHC upgrade program, the CMS collaboration is developing a High Granularity Calorimeter (CE) to replace the existing endcap calorimeters. The CE is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic (CE-E) and hadronic (CE-H) compartments. The calorimeter will be built with ∼30,000 hexagonal silicon modules. Prototype modules have been constructed with 6-inch hexagonal silicon sensors with cell areas of 1.1 cm 2 , and the SKIROC2-CMS readout ASIC. Beam tests of different sampling configurations were conducted with the prototype modules at DESY and CERN in 2017 and 2018. This paper describes the construction and commissioning of the CE calorimeter prototype, the silicon modules used in the construction, their basic performance, and the methods used for their calibration.

Drell-Yan lepton pairs are produced in the process $p\overline{p}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}+X$ through an intermediate ${\ensuremath{\gamma}}^{*}/Z$ boson. The lepton angular distributions are used to provide information on the electroweak-mixing parameter ${sin}^{2}{\ensuremath{\theta}}_{W}$ via its observable effective-leptonic ${sin}^{2}{\ensuremath{\theta}}_{W}$, or ${sin}^{2}{\ensuremath{\theta}}_{\mathrm{eff}}^{\mathrm{lept}}$. A new method to infer ${sin}^{2}{\ensuremath{\theta}}_{W}$ or, equivalently, the $W$-boson mass ${M}_{W}$ in the on-shell scheme, is developed and tested using a previous CDF Run II measurement of angular distributions from electron pairs in a sample corresponding to $2.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity from $p\overline{p}$ collisions at a center-of-momentum energy of 1.96 TeV. The value of ${sin}^{2}{\ensuremath{\theta}}_{\mathrm{eff}}^{\mathrm{lept}}$ is found to be $0.2328\ifmmode\pm\else\textpm\fi{}0.0011$. Within a specified context of the standard model, this results in ${sin}^{2}{\ensuremath{\theta}}_{W}=0.2246\ifmmode\pm\else\textpm\fi{}0.0011$, which corresponds to a $W$-boson mass of $80.297\ifmmode\pm\else\textpm\fi{}0.055\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, in agreement with previous determinations in electron-position collisions and at the Tevatron collider.

We report a measurement of the differential cross section $d\ensuremath{\sigma}/d(\mathrm{cos}{\ensuremath{\theta}}_{t})$ for top-quark pair production as a function of the top-quark production angle in proton-antiproton collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. This measurement is performed using data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of $9.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We employ the Legendre polynomials to characterize the shape of the differential cross section at the parton level. The observed Legendre coefficients are in good agreement with the prediction of the next-to-leading-order standard-model calculation, with the exception of an excess linear-term coefficient ${a}_{1}=0.40\ifmmode\pm\else\textpm\fi{}0.12$, compared to the standard-model prediction of ${a}_{1}={0.15}_{\ensuremath{-}0.03}^{+0.07}$.

We present a measurement of the $W$-boson mass, $M_W$, using data corresponding to 2.2/fb of integrated luminosity collected in ppbar collisions at $\sqrt{s}$ = 1.96 TeV with the CDF II detector at the Fermilab Tevatron. The selected sample of 470126 $W\to e\nu$ candidates and 624708 $W\to\mu\nu$ candidates yields the measurement $M_W = 80387\pm 12$ (stat) $\pm 15$ (syst)$ = 80387 \pm 19$ MeV$/c^2$ . This is the most precise single measurement of the $W$-boson mass to date.

We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of sqrt[s]=1.96 TeV proton-antiproton collisions corresponding to 9.1 fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|<1.0, a heavy-quark-jet transverse momentum pTjet>20 GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions.

Differential cross sections for the production of $Z$ bosons or off-shell photons $\gamma^*$ in association with jets are measured in proton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96$ TeV using the full data set collected with the Collider Detector at Fermilab in Tevatron Run II, and corresponding to 9.6 fb$^{-1}$ of integrated luminosity. Results include first measurements at CDF of differential cross sections in events with a $Z/\gamma^*$ boson and three or more jets, the inclusive cross section for production of $Z/\gamma^*$ and four or more jets, and cross sections as functions of various angular observables in lower jet-multiplicity final states. Measured cross sections are compared to several theoretical predictions.

We report evidence for s-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy sqrt[s] = 1.96 TeV using a data set that corresponds to an integrated luminosity of 9.4 fb(-1) collected by the Collider Detector at Fermilab. We select events consistent with the s-channel process including two jets and one leptonically decaying W boson. The observed significance is 3.8 standard deviations with respect to the background-only prediction. Assuming a top-quark mass of 172.5 GeV/c(2), we measure the s-channel cross section to be 1.41(-0.42)(+0.44) pb.

We report on measurements of differential µ -b cross sections, where the muon is from a semi-leptonic b decay and the b is identified using precision track reconstruction in jets.The semi-differential correlated cross sections, dσ/dE b T , dσ/dp b T , and dσ/dδφ(µ -b) for p µ T > 9 GeV/c, |η µ | < 0.6, E b T > 10 GeV, |η b | < 1.5, are presented and compared to next-to-leading order QCD calculations.

We report on a search for \bsmm\ and \bdmm\ decays using proton-antiproton collision data at $\sqrt{s}=1.96$ TeV corresponding to $10 \fb$ of integrated luminosity collected by the CDF detector at the Fermilab Tevatron collider. The observed number of \bd\ candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of $\brbdmm < 4.6\times 10^{-9}$ at 95% confidence level. We observe an excess of \bs\ candidates. The probability that the background processes alone could produce such an excess or larger is 0.94%. The probability that the combination of background and the expected standard model rate of \bsmm\ could produce such an excess or larger is 6.8%. These data are used to determine a branching fraction $\brbsmm = (1.3^{+0.9}_{-0.7}) \times 10^{-8} $ and provide an upper limit of $\brbsmm < 3.1\times 10^{-8}$ at 95% confidence level.

We measure the polarization of $W$ bosons from top-quark ($t$) decays into final states with a charged lepton and jets, $t\overline{t}\ensuremath{\rightarrow}{W}^{+}b{W}^{\ensuremath{-}}\overline{b}\ensuremath{\rightarrow}\ensuremath{\ell}\ensuremath{\nu}bq{\overline{q}}^{\ensuremath{'}}\overline{b}$, using the full Run II data set collected by the CDF II detector, corresponding to an integrated luminosity of $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. A model-independent method simultaneously determines the fraction of longitudinal (${f}_{0}$) and right-handed (${f}_{+}$) $W$ bosons to yield ${f}_{0}=0.726\ifmmode\pm\else\textpm\fi{}0.066(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.067(\mathrm{syst})$ and ${f}_{+}=\ensuremath{-}0.045\ifmmode\pm\else\textpm\fi{}0.044(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.058(\mathrm{syst})$ with a correlation coefficient of $\ensuremath{-}0.69$. Additional results are presented under various standard model assumptions. No significant discrepancies with the standard model are observed.

We report on a measurement of the top-quark electric charge in $t\overline{t}$ events in which one $W$ boson originating from the top-quark pair decays into leptons and the other into hadrons. The event sample was collected by the CDF II detector in $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ proton-antiproton collisions and corresponds to $5.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We find the data to be consistent with the standard model and exclude the existence of an exotic quark with $\ensuremath{-}4/3$ electric charge and mass of the conventional top quark at the 99% confidence level.

We report a measurement of the indirect $CP$-violating asymmetries (${A}_{\mathrm{\ensuremath{\Gamma}}}$) between effective lifetimes of anticharm and charm mesons reconstructed in ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}$ and ${D}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays. We use the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab experiment and corresponding to $9.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity. The strong-interaction decay ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$ is used to identify the meson at production as ${D}^{0}$ or ${\overline{D}}^{0}$. We statistically subtract ${D}^{0}$ and ${\overline{D}}^{0}$ mesons originating from $b$-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure ${A}_{\mathrm{\ensuremath{\Gamma}}}({K}^{+}{K}^{\ensuremath{-}})=(\ensuremath{-}0.19\ifmmode\pm\else\textpm\fi{}0.15(\text{stat})\ifmmode\pm\else\textpm\fi{}0.04(\text{syst}))%$ and ${A}_{\mathrm{\ensuremath{\Gamma}}}({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=\phantom{\rule{0ex}{0ex}}(\ensuremath{-}0.01\ifmmode\pm\else\textpm\fi{}0.18(\text{stat})\ifmmode\pm\else\textpm\fi{}0.03(\text{syst}))%$. The results are consistent with the hypothesis of $CP$ symmetry and their combination yields ${A}_{\mathrm{\ensuremath{\Gamma}}}=(\ensuremath{-}0.12\ifmmode\pm\else\textpm\fi{}0.12)%$.

We present a combination of searches for the standard model Higgs boson using the full CDF run II data set, which corresponds to an integrated luminosity of $9.45--10.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected from $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ $p\overline{p}$ collisions at the Fermilab Tevatron. The searches consider Higgs boson production from gluon-gluon fusion, vector-boson fusion, and associated production with either a $W$ or $Z$ boson or a $t\overline{t}$ pair. Depending on the production mode, Higgs boson decays to ${W}^{+}{W}^{\ensuremath{-}}$, $ZZ$, $b\overline{b}$, ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$, and $\ensuremath{\gamma}\ensuremath{\gamma}$ are examined. We search for a Higgs boson with masses (${m}_{H}$) in the range $90--200\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. In the absence of a signal, we expect based on combined search sensitivity to exclude at the 95% credibility level the mass regions $90&lt;{m}_{H}&lt;94\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, $96&lt;{m}_{H}&lt;106\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, and $153&lt;{m}_{H}&lt;175\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. The observed exclusion regions are $90&lt;{m}_{H}&lt;102\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ and $149&lt;{m}_{H}&lt;172\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. A moderate excess of signal-like events relative to the background expectation at the level of 2.0 standard deviations is present in the data for the ${m}_{H}=125\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ search hypothesis. We also present interpretations of the data within the context of a fermiophobic model and an alternative standard model incorporating a fourth generation of fermions. Finally, for the hypothesis of a new particle with mass $125\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, we constrain the coupling strengths of the new particle to ${W}^{\ifmmode\pm\else\textpm\fi{}}$ bosons, $Z$ bosons, and fermions.

Abstract The Compact Muon Solenoid collaboration is designing a new high-granularity endcap calorimeter, HGCAL, to be installed later this decade. As part of this development work, a prototype system was built, with an electromagnetic section consisting of 14 double-sided structures, providing 28 sampling layers. Each sampling layer has an hexagonal module, where a multipad large-area silicon sensor is glued between an electronics circuit board and a metal baseplate. The sensor pads of approximately 1.1 cm 2 are wire-bonded to the circuit board and are readout by custom integrated circuits. The prototype was extensively tested with beams at CERN's Super Proton Synchrotron in 2018. Based on the data collected with beams of positrons, with energies ranging from 20 to 300 GeV, measurements of the energy resolution and linearity, the position and angular resolutions, and the shower shapes are presented and compared to a detailed Geant4 simulation.

Identifying outlier behavior among sensors and subsystems is essential for discovering faults and facilitating diagnostics in large systems. At the same time, exploring large systems with numerous multivariate data sets is challenging. This study presents a lightweight interconnection and divergence discovery mechanism (LIDD) to identify abnormal behavior in multi-system environments. The approach employs a multivariate analysis technique that first estimates the similarity heatmaps among the sensors for each system and then applies information retrieval algorithms to provide relevant multi-level interconnection and discrepancy details. Our experiment on the readout systems of the Hadron Calorimeter of the Compact Muon Solenoid (CMS) experiment at CERN demonstrates the effectiveness of the proposed method. Our approach clusters readout systems and their sensors consistent with the expected calorimeter interconnection configurations, while capturing unusual behavior in divergent clusters and estimating their root causes.

We report on a search for supersymmetry using dilepton events which complements the classic missing ${E}_{T}$ plus multijet analyses. Using $19{\mathrm{pb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ recorded with the Collider Detector at Fermilab we have searched for squarks and gluinos decaying into charginos and producing events with two leptons. We observe one candidate event. In comparison, the expected number of background events from standard model processes is $2.39\ifmmode\pm\else\textpm\fi{}0.63(\mathrm{stat}{)}_{\ensuremath{-}0.42}^{+0.77}(\mathrm{syst})$. Hence we set limits on gluino and squark production based on predictions from the supergravity inspired minimal supersymmetric extension of the standard model.

We use a neural-network technique to search for standard model single-top-quark production in the $106{\mathrm{pb}}^{\ensuremath{-}1}$ dataset accumulated by the Collider Detector at Fermilab detector during the 1992--1995 collider run (``run I''). Using a sample of 64 $W+1,$ 2, 3 jets events, we set a 95% confidence level upper limit of 24 pb on the W-gluon and ${W}^{*}$ combined single-top cross section.

We present a measurement of the isolated direct photon cross section in p-pbar collisions at sqrt(s) = 1.8 TeV and |eta| < 0.9 using data collected between 1994 and 1995 by the Collider Detector at Fermilab (CDF). The measurement is based on events where the photon converts into an electron-positron pair in the material of the inner detector, resulting in a two-track event signature. To remove pi0 -> gamma gamma and eta -> gamma gamma events we use a new background subtraction technique which takes advantage of the tracking information available in a photon conversion event. We find that the shape of the cross section as a function of pT is poorly described by next-to-leading-order QCD predictions, but agrees with previous CDF measurements.

The first search for single-top-quark production from the exchange of an $s$-channel virtual $W$ boson using events with an imbalance in the total transverse energy, $b$-tagged jets, and no identified leptons is presented. Assuming the electroweak production of top quarks of mass $172.5\text{ }\text{ }\mathrm{GeV}/{\mathit{c}}^{2}$ in the $s$ channel, a cross section of $1.1{2}_{\ensuremath{-}0.57}^{+0.61}$ ($\text{stat}+\text{syst}$) pb with a significance of 1.9 standard deviations is measured. This measurement is combined with the result obtained from events with an imbalance in total transverse momentum, $b$-tagged jets, and exactly one identified lepton, yielding a cross section of $1.3{6}_{\ensuremath{-}0.32}^{+0.37}$ ($\text{stat}+\text{syst}$) pb, with a significance of 4.2 standard deviations.

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96 TeV using a data set corresponding to 7.5 fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t→Wb→ℓνb by requiring the presence of an electron or muon, a large imbalance of transverse momentum indicating the presence of a neutrino, and two or three jets including at least one originating from a bottom quark. An artificial neural network is used to discriminate the signal from backgrounds. We measure a single top quark production cross section of 3.04(-0.53)(+0.57) pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |Vtb|>0.78 at the 95% credibility level.

We present a measurement of the ratio of the top-quark branching fractions $R=\mathcal{B}(t\rightarrow Wb)/\mathcal{B}(t\rightarrow Wq)$, where $q$ represents quarks of type $b$, $s$, or $d$, in the final state with a lepton and hadronic jets. The measurement uses $\sqrt{s}$ = 1.96 TeV proton--antiproton collision data from 8.7 fb$^{-1}$ of integrated luminosity collected with the Collider Detector at Fermilab during Run II of the Tevatron. We simultaneously measure $R=0.94 \pm 0.09$ (stat+syst), the $t\bar{t}$ production cross section $\sigma_{t \bar t} = 7.5 \pm 1.0$ (stat+syst) pb. The magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, $|V_{tb}| = 0.97 \pm 0.05$ (stat+syst) is extracted assuming three generations of quarks, and a lower limit of $|V_{tb}|>0.89$ at 95% credibility level is set.

We present a study of W+multijet events that compares the kinematics of the observed events with expectations from direct QCD W+jet production and from production and decay of top quark pairs. The data were collected in the 1992--93 run with the Collider Detector at Fermilab (CDF) from 19.3 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of proton-antiproton collisions at \ensuremath{\surd}s =1.8 TeV. A W+\ensuremath{\ge}2 jet sample and a W+\ensuremath{\ge}3 jet sample are selected with the requirement that at least the two or three jets have energy transverse with respect to the beam axis in excess of 20 GeV. The jet energy distributions for the W+\ensuremath{\ge}2 jet sample agree well with the predictions of direct QCD W production. From the W+\ensuremath{\ge}3 jet events, a ``signal sample'' with an improved ratio of tt\ifmmode\bar\else\textasciimacron\fi{} to QCD produced W events is selected by requiring each jet to be emitted centrally in the event center of mass frame. This sample contains 14 events with unusually hard jet ${\mathit{E}}_{\mathit{T}}$ distributions not well described by expectations for jets from direct QCD W production and other background processes. Using expected jet ${\mathit{E}}_{\mathit{T}}$ distributions, a relative likelihood is defined and used to determine if an event is more consistent with the decay of tt\ifmmode\bar\else\textasciimacron\fi{} pairs, with ${\mathit{M}}_{\mathrm{top}}$=170 GeV/${\mathit{c}}^{2}$, than with direct QCD W production. Eight of the 14 signal sample events are found to be more consistent with top-quark than direct QCD W production, while only 1.7 such top-quark--like events are expected in the absence of tt\ifmmode\bar\else\textasciimacron\fi{}.The probability that the observation is due to an upward fluctuation of the number of background events is found to be 0.8%. The robustness of the result was tested by varying the cuts defining the signal sample, and the largest probability for such a fluctuation found was 1.9%. Good agreement in the jet spectra is obtained if jet production from tt\ifmmode\bar\else\textasciimacron\fi{} pair decays is included. For those events kinematically more consistent with tt\ifmmode\bar\else\textasciimacron\fi{} we find evidence for a b-quark content in their jets to the extent expected from top quark decay, and larger than expected for background processes. For events with four or more jets, the discrepancy with the predicted jet distributions from direct QCD W production, and the associated excess of b-quark content, is more pronounced.

We have measured the azimuthal angular correlation of $b\overline{b}$ production, using $86.5\text{ }\text{ }\mathrm{p}{\mathrm{b}}^{\ensuremath{-}1}$ of data collected by Collider Detector at Fermilab (CDF) in $p\overline{p}$ collisions at $\sqrt{s}=1.8\text{ }\text{ }\mathrm{TeV}$ during 1994--1995. In high-energy $p\overline{p}$ collisions, such as at the Tevatron, $b\overline{b}$ production can be schematically categorized into three mechanisms. The leading-order (LO) process is ``flavor creation,'' where both $b$ and $\overline{b}$ quarks substantially participate in the hard scattering and result in a distinct back-to-back signal in final state. The ``flavor excitation'' and the ``gluon splitting'' processes, which appear at next-leading-order (NLO), are known to make a comparable contribution to total $b\overline{b}$ cross section, while providing very different opening angle distributions from the LO process. An azimuthal opening angle between bottom and antibottom, $\ensuremath{\Delta}\ensuremath{\phi}$, has been used for the correlation measurement to probe the interaction creating $b\overline{b}$ pairs. The $\ensuremath{\Delta}\ensuremath{\phi}$ distribution has been obtained from two different methods. One method measures the $\ensuremath{\Delta}\ensuremath{\phi}$ between bottom hadrons using events with two reconstructed secondary vertex tags. The other method uses $b\overline{b}\ensuremath{\rightarrow}(J/\ensuremath{\psi}X)(\ensuremath{\ell}{X}^{\ensuremath{'}})$ events, where the charged lepton ($\ensuremath{\ell}$) is an electron ($e$) or a muon ($\ensuremath{\mu}$), to measure $\ensuremath{\Delta}\ensuremath{\phi}$ between bottom quarks. The $b\overline{b}$ purity is determined as a function of $\ensuremath{\Delta}\ensuremath{\phi}$ by fitting the decay length of the $J/\ensuremath{\psi}$ and the impact parameter of the $\ensuremath{\ell}$. Both methods quantify the contribution from higher-order production mechanisms by the fraction of the $b\overline{b}$ pairs produced in the same azimuthal hemisphere, ${f}_{\mathrm{toward}}$. The measured ${f}_{\mathrm{toward}}$ values are consistent with both parton shower Monte Carlo and NLO QCD predictions.

The polarization of the $W$ boson in $t\ensuremath{\rightarrow}Wb$ decay is unambiguously predicted by the standard model of electroweak interactions and is a powerful test of our understanding of the $tbW$ vertex. We measure this polarization from the invariant mass of the $b$ quark from $t\ensuremath{\rightarrow}Wb$ and the lepton from $W\ensuremath{\rightarrow}l\ensuremath{\nu}$ whose momenta measure the $W$ decay angle and direction of motion, respectively. In this paper we present a measurement of the decay rate (${f}_{V+A}$) of the $W$ produced from the decay of the top quark in the hypothesis of $\mathrm{V}+\mathrm{A}$ structure of the $tWb$ vertex. We find no evidence for the nonstandard $\mathrm{V}+\mathrm{A}$ vertex and set a limit on ${f}_{V+A}$ $&lt;$ 0.80 at $95%$ confidence level. By combining this result with a complementary observable in the same data, we assign a limit on ${f}_{V+A}$ $&lt;$ 0.61 at $95%$ CL. This corresponds to a constraint on the right-handed helicity component of the W polarization of ${f}_{+}&lt;0.18$ at $95%$ CL. This limit is the first significant direct constraint on ${f}_{V+A}$ in top decay.

We present a measurement of the top-quark mass using the full data set of Tevatron $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ proton-antiproton collisions recorded by the CDF II detector, corresponding to an integrated luminosity of $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The analysis uses events with one semileptonic $t$ or $\overline{t}$ decay, but without detection of the electron or muon. We select events with significant missing transverse energy and multiple jets. We veto events containing identified electrons or muons. We obtain distributions of the top-quark masses and the invariant mass of the two jets from $W$-boson decays from data and compare these to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. A likelihood fit of the templates from signal and background events to the data yields the top-quark mass, ${M}_{\mathrm{top}}=173.93\ifmmode\pm\else\textpm\fi{}1.64(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.87(\mathrm{syst})\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. This result is the most precise measurement to date of the mass of the top quark in this event topology.

At the Fermilab Tevatron proton-antiproton ($p\bar{p}$) collider, Drell-Yan lepton pairs are produced in the process $p \bar{p} \rightarrow e^+e^- + X$ through an intermediate $\gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $e^-$ as a function of the $e^+e^-$-pair mass is used to obtain $\sin^2\theta^{\rm lept}_{\rm eff}$, the effective leptonic determination of the electroweak-mixing parameter $\sin^2\theta_W$. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4~fb$^{-1}$ of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $\sin^2\theta^{\rm lept}_{\rm eff}$ is found to be $0.23248 \pm 0.00053$. The combination with the previous CDF measurement based on $\mu^+\mu^-$ pairs yields $\sin^2\theta^{\rm lept}_{\rm eff} = 0.23221 \pm 0.00046$. This result, when interpreted within the specified context of the standard model assuming $\sin^2 \theta_W = 1 - M_W^2/M_Z^2$ and that the $W$- and $Z$-boson masses are on-shell, yields $\sin^2\theta_W = 0.22400 \pm 0.00045$, or equivalently a $W$-boson mass of $80.328 \pm 0.024 \;{\rm GeV}/c^2$.

We report on a search for the flavor-changing neutral current decays ${B}_{d,s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{K}^{+}$, and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{K}^{*0}$ using data from $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$, collected with the Collider Detector at Fermilab during the 1992--1993 running period. We find no indication of such decays, and we set the following 90% confidence level upper limits on branching ratios: $B({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})&lt;1.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})&lt;8.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{K}^{+})&lt;1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, and $B({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}{K}^{*0})&lt;2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$.

We present a study of the production of ${K}_{S}^{0}$ and ${\ensuremath{\Lambda}}^{0}$ in inelastic $p\overline{p}$ collisions at $\sqrt{s}=1800$ and 630 GeV using data collected by the CDF experiment at the Fermilab Tevatron. Analyses of ${K}_{S}^{0}$ and ${\ensuremath{\Lambda}}^{0}$ multiplicity and transverse momentum distributions, as well as of the dependencies of the average number and $⟨{p}_{T}⟩$ of ${K}_{S}^{0}$ and ${\ensuremath{\Lambda}}^{0}$ on charged particle multiplicity, are reported. Systematic comparisons are performed for the full sample of inelastic collisions, and for the low and high momentum transfer subsamples, at the two energies. The ${p}_{T}$ distributions extend above $8\text{ }\text{ }\mathrm{GeV}/c$, showing a $⟨{p}_{T}⟩$ higher than previous measurements. The dependence of the mean ${K}_{S}^{0}({\ensuremath{\Lambda}}^{0})$ ${p}_{T}$ on the charged particle multiplicity for the three samples shows a behavior analogous to that of charged primary tracks.

The experiments at Run 2 of the Tevatron have each accumulated over 1 inverse femtobarn of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focussed on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.

We present an updated search for the Higgs boson produced in association with a vector boson in the final state with missing transverse energy and two jets. We use the full CDF data set corresponding to an integrated luminosity of 9.45 fb${}^{-1}$ at a proton-antiproton center-of-mass energy of $\sqrt{s}=1.96$ TeV. New to this analysis is the inclusion of a $b$-jet identification algorithm specifically optimized for $H\to b\bar{b}$ searches. Across the Higgs boson mass range $90 \le m_H \le 150$ GeV$/c^2$, the expected 95% credibility level upper limits on the $V H$ production cross section times the $H\to b\bar{b}$ branching fraction are improved by an average of 14% relative to the previous analysis. At a Higgs boson mass of 125 GeV$/c^2$, the observed (expected) limit is 3.06 (3.33) times the standard model prediction, corresponding to one of the most sensitive searches to date in this final state.

We present a measurement of the top-quark pair production cross section in proton-antiproton collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. The data were collected at the Fermilab Tevatron by the CDF II detector and correspond to an integrated luminosity of $8.8\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, representing the complete CDF Run II data set. We select events consistent with the production of top-quark pairs by requiring the presence of two reconstructed leptons, an imbalance in the total event transverse momentum, and jets. At least one jet is required to be identified as consistent with the fragmentation of a bottom quark using a secondary-vertex-finding algorithm. The 246 candidate events are estimated to have a signal purity of 91%. We measure a cross section of ${\ensuremath{\sigma}}_{t\overline{t}}=7.09\ifmmode\pm\else\textpm\fi{}0.84\text{ }\text{ }\mathrm{pb}$, assuming a top-quark mass of $172.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. The results are consistent with the standard model as predicted by next-to-leading-order calculations.

We present a measurement of the ZZ boson-pair production cross section in 1.96 TeV center-of-mass energy ppbar collisions. We reconstruct final states incorporating four charged leptons or two charged leptons and two neutrinos from the full data set collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.7 fb-1 of integrated luminosity. Combining the results obtained from each final state, we measure a cross section of 1.04(+0.32)(-0.25) pb, in good agreement with the standard model prediction at next-to-leading order in the strong-interaction coupling.

Abstract The CMS experiment at the CERN LHC will be upgraded to accommodate the 5-fold increase in the instantaneous luminosity expected at the High-Luminosity LHC (HL-LHC) [1]. Concomitant with this increase will be an increase in the number of interactions in each bunch crossing and a significant increase in the total ionising dose and fluence. One part of this upgrade is the replacement of the current endcap calorimeters with a high granularity sampling calorimeter equipped with silicon sensors, designed to manage the high collision rates [2]. As part of the development of this calorimeter, a series of beam tests have been conducted with different sampling configurations using prototype segmented silicon detectors. In the most recent of these tests, conducted in late 2018 at the CERN SPS, the performance of a prototype calorimeter equipped with ≈12,000 channels of silicon sensors was studied with beams of high-energy electrons, pions and muons. This paper describes the custom-built scalable data acquisition system that was built with readily available FPGA mezzanines and low-cost Raspberry Pi computers.

We report on the reconstruction of the decay mode B0→J/ψKS0 using 19.3pb−1 of data collected by the Collider Detector at Fermilab in p¯p collisions at s=1.8TeV. A signal of 41.8±6.9 events, with a signal-to-background ratio of 9:1, is observed. Three additional decay modes B+→J/ψK+, B0→J/ψK*(892)0, and B+→J/ψK*(892)+ are reconstructed. We measure three ratios of branching ratios, each one relative to the B+→J/ψK+ mode. We also report the ratio of decay rates, γ(B→J/ψK*)/γ(B→J/ψK), for the vector-vector relative to the vector-pseudoscalar modes, to be 1.32±0.23(stat)±0.16(syst).Received 15 November 1995DOI:https://doi.org/10.1103/PhysRevLett.76.2015©1996 American Physical Society

We present a detailed examination of the heavy flavor content of the $W $ + jet data sample collected with the CDF detector during the 1992-1995 collider run at the Fermilab Tevatron. Jets containing heavy flavor quarks are selected via the identification of secondary vertices or semileptonic decays of $b$ and $c$ quarks. There is generally good agreement between the rates of secondary vertices and soft leptons in the data and in the standard model simulation including single and pair production of top quarks. An exception is the number of events in which a single jet has both a soft lepton and a secondary vertex tag. In $W +$ 2,3 jet data, we find 13 such events where we expected 4.4 $\pm$ 0.6 events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.

We present an analysis of top-antitop quark production and decay into a tau lepton, tau neutrino, and bottom quark using data from $9\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity at the Collider Detector at Fermilab. Dilepton events, where one lepton is an energetic electron or muon and the other a hadronically decaying tau lepton, originating from proton-antiproton collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$, are used. A top-antitop quark production cross section of $8.1\ifmmode\pm\else\textpm\fi{}2.1\text{ }\text{ }\mathrm{pb}$ is measured, assuming standard-model top quark decays. By separately identifying for the first time the single-tau and the ditau components, we measure the branching fraction of the top quark into the tau lepton, tau neutrino, and bottom quark to be $(9.6\ifmmode\pm\else\textpm\fi{}2.8)%$. The branching fraction of top quark decays into a charged Higgs boson and a bottom quark, which would imply violation of lepton universality, is limited to be less than 5.9% at a 95% confidence level [for $\mathcal{B}({\mathrm{H}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\tau}\overline{\ensuremath{\nu}})=1$].

We present a measurement of the mass difference between top ($t$) and antitop ($\overline{t}$) quarks using $t\overline{t}$ candidate events reconstructed in the final state with one lepton and multiple jets. We use the full data set of Tevatron $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ proton-antiproton collisions recorded by the CDF II detector, corresponding to an integrated luminosity of $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We estimate event by event the mass difference to construct templates for top pair signal events and background events. The resulting mass difference distribution in data compared to signal and background templates using a likelihood fit yields $\ensuremath{\Delta}{M}_{\mathrm{top}}={M}_{t}\ensuremath{-}{M}_{\overline{t}}=\ensuremath{-}1.95\ifmmode\pm\else\textpm\fi{}1.11(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.59(\mathrm{syst})\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ and is in agreement with the standard model prediction of no mass difference.

We present a measurement of the top-quark mass in events containing two leptons (electrons or muons) with a large transverse momentum, two or more energetic jets, and a transverse-momentum imbalance. We use the full proton-antiproton collision data set collected by the CDF experiment during the Fermilab Tevatron Run~II at center-of-mass energy $\sqrt{s} = 1.96$ TeV, corresponding to an integrated luminosity of 9.1 fb$^{-1}$. A special observable is exploited for an optimal reduction of the dominant systematic uncertainty, associated with the knowledge of the absolute energy of the hadronic jets. The distribution of this observable in the selected events is compared to simulated distributions of ${t\bar{t}}$ dilepton signal and background.We measure a value for the top-quark mass of $171.5\pm 1.9~{\rm (stat)}\pm 2.5~{\rm (syst)}$ GeV/$c^2$.

This Letter reports on measurements of the longitudinal polarization fractions in the decays ${B}_{d}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{*0}$ and ${B}_{s}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\varphi}$ using data collected with the Collider Detector at Fermilab. ${B}_{d}$ mesons are reconstructed through the decay chain ${B}_{d}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{*0}$, $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, ${K}^{*0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. A sample of $65\ifmmode\pm\else\textpm\fi{}10{B}_{d}$ events is used to obtain a longitudinal polarization fraction of ${\ensuremath{\gamma}}_{L}/\ensuremath{\gamma}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.65\ifmmode\pm\else\textpm\fi{}0.10(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{syst})$. ${B}_{s}$ mesons are reconstructed through the decay chain ${B}_{s}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\varphi}$, $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, $\ensuremath{\varphi}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}$. A sample of $19\ifmmode\pm\else\textpm\fi{}5{B}_{s}$ events is used to obtain the result ${\ensuremath{\gamma}}_{L}/\ensuremath{\gamma}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.56\ifmmode\pm\else\textpm\fi{}0.21(\mathrm{stat}{)}_{\ensuremath{-}0.04}^{+0.02}(\mathrm{syst})$.

We present the results of a search for second generation leptoquarks ${S}_{2}$ using $19.3{\mathrm{pb}}^{\ensuremath{-}1}$ of data collected at the Collider Detector at Fermilab (CDF) in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8$ TeV during the 1992--93 collider run. We have searched for ${S}_{2}\overline{{S}_{2}}$ pairs assuming that each leptoquark decays to a muon $+$ quark with a branching ratio $\ensuremath{\beta}$. We find two candidate events, consistent with an expected background of $1.11\ifmmode\pm\else\textpm\fi{}0.48$. We obtain upper limits on $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}{S}_{2}\overline{{S}_{2}}){\ensuremath{\beta}}^{2}$ as a function of ${M}_{{S}_{2}}$. Using a Monte Carlo prediction for ${S}_{2}\overline{{S}_{2}}$ pair production, we exclude ${M}_{{S}_{2}}&lt;131\phantom{\rule{0ex}{0ex}}\mathrm{GeV}/{c}^{2}$ for $\ensuremath{\beta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ and ${M}_{{S}_{2}}&lt;96\phantom{\rule{0ex}{0ex}}\mathrm{GeV}/{c}^{2}$ for $\ensuremath{\beta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.5$ at 95% C.L.

The top-quark mass M_top is measured using top quark-antiquark pairs produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV and decaying into a fully hadronic final state. The full data set collected with the CDFII detector at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.3 fb-1, is used. Events are selected that have six to eight jets, at least one of which is identified as having originated from a b quark. In addition, a multivariate algorithm, containing multiple kinematic variables as inputs, is used to discriminate signal events from background events due to QCD multijet production. Templates for the reconstructed top-quark mass are combined in a likelihood fit to measure M_top with a simultaneous calibration of the jet-energy scale. A value of M_top = 175.07+- 1.19(stat)+1.55-1.58(syst) GeV/c^2 is obtained for the top-quark mass.

We describe a measurement of the ratio of the cross sections times branching fractions of the ${B}_{c}^{+}$ meson in the decay mode ${B}_{c}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\mu}}^{+}\ensuremath{\nu}$ to the ${B}^{+}$ meson in the decay mode ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{+}$ in proton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. The measurement is based on the complete CDF Run II data set, which comes from an integrated luminosity of $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The ratio of the production cross sections times branching fractions for ${B}_{c}^{+}$ and ${B}^{+}$ mesons with momentum transverse to the beam greater than $6\text{ }\text{ }\mathrm{GeV}/c$ and rapidity magnitude smaller than 0.6 is $0.211\ifmmode\pm\else\textpm\fi{}0.012{(\mathrm{stat})}_{\ensuremath{-}0.020}^{+0.021}(\mathrm{syst})$. Using the known ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{+}$ branching fraction, the known ${B}^{+}$ production cross section, and a selection of the predicted ${B}_{c}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\mu}}^{+}\ensuremath{\nu}$ branching fractions, the range for the total ${B}_{c}^{+}$ production cross section is estimated.

We analyze a sample of W + jet events collected with the Collider Detector at Fermilab (CDF) in pp collisions at p s = 1.8 TeV to study tt production.We employ a simple kinematical variable H, de ned as the scalar sum of the transverse energies of the lepton, neutrino and jets.For events with a W boson and four or more jets, the shape of the H distribution deviates by 3.8 standard deviations from that expected from known backgrounds to tt production.However this distribution agrees well with a linear combination of background and tt events, the agreement being best for a top mass of 180 GeV/c 2 .

The lifetime of the $B_s$ meson is measured using the semileptonic decay $B_s \to D_s^- \ell^+ \nu X$. The data sample consists of 19.3 pb$^{-1}$ of $p \bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1993. There are $76 \pm 8$ $\ell^{+} D_s^{-}$ signal events where the $D_s$ is identified via the decay $D_s^{-} \to \phi \pi^{-}$,~$\phi \to K^+ K^-$. Using these events, the $B_s$ meson lifetime is determined to be $\tau_{s} = 1.42^{+ 0.27}_{- 0.23} {\rm (stat)} \pm 0.11 {\rm (syst)}$ ps. A measurement of the $B_s$ lifetime in a low statistics sample of exclusive $B_s \to J/\psi \phi$ decays is also presented in this paper.

We report the first largely model independent measurement of charged particle multiplicities in quark and gluon jets, ${N}_{q}$ and ${N}_{g}$, produced at the Fermilab Tevatron in $p\overline{p}$ collisions with a center-of-mass energy of 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies of 41 and 53 GeV by counting charged particle tracks in cones with opening angles of ${\ensuremath{\theta}}_{c}=0.28$, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness $Q={E}_{\mathrm{jet}}{\ensuremath{\theta}}_{c}$ varies in the range from 12 to 25 GeV. At $Q=19.2\text{ }\text{ }\mathrm{GeV}$, the ratio of multiplicities $r={N}_{g}/{N}_{q}$ is found to be $1.64\ifmmode\pm\else\textpm\fi{}0.17$, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with resummed perturbative QCD calculations.

We present a new search for ${H}^{0}V$ production, where ${H}^{0}$ is a scalar Higgs boson decaying into $b\overline{b}$ with branching ratio $\ensuremath{\beta}$, and $V$ is a ${Z}^{0}$ boson decaying into ${e}^{+}{e}^{\ensuremath{-}}$, ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, or $\ensuremath{\nu}\overline{\ensuremath{\nu}}$. This search is then combined with previous searches for ${H}^{0}V$ where $V$ is a ${W}^{\ifmmode\pm\else\textpm\fi{}}$ boson or a hadronically decaying ${Z}^{0}$. The data sample consists of $106\ifmmode\pm\else\textpm\fi{}4\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.8\text{ }\text{ }\mathrm{TeV}$ accumulated by the Collider Detector at Fermilab. Observing no evidence of a signal, we set 95% Bayesian credibility level upper limits on $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}{H}^{0}V)\ifmmode\times\else\texttimes\fi{}\ensuremath{\beta}$. For ${H}^{0}$ masses of 90, 110, and $130\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, the limits are 7.8, 7.2, and 6.6 pb, respectively.

We report on a search for charged massive resonances decaying to top ($t$) and bottom ($b$) quarks in the full data set of proton-antiproton collisions at center-of-mass energy of $\sqrt{s} = 1.96$ TeV collected by the CDF~II detector at the Tevatron, corresponding to an integrated luminosity of 9.5 $fb^{-1}$. No significant excess above the standard model (SM) background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged particle production cross section times branching ratio to $t b$. Using a SM extension with a $W^{\prime}$ and left-right-symmetric couplings as a benchmark model, we constrain the $W^{\prime}$ mass and couplings in the 300 to 900 GeV/$c^2$ range. The limits presented here are the most stringent for a charged resonance with mass in the range 300 -- 600 GeV/$c^2$ decaying to top and bottom quarks.

Received 21 October 2013DOI:https://doi.org/10.1103/PhysRevD.88.079905© 2013 American Physical Society

Production of the Upsilon(1S) meson in association with a vector boson is a rare process in the standard model with a cross section predicted to be below the sensitivity of the Tevatron. Observation of this process could signify contributions not described by the standard model or reveal limitations with the current non-relativistic quantum-chromodynamic models used to calculate the cross section. We perform a search for this process using the full Run II data set collected by the CDF II detector corresponding to an integrated luminosity of 9.4/fb. The search considers the Upsilon(1S) to di-muon decay and the decay of the W and Z bosons into muons and electrons. In these purely leptonic decay channels, we observe one Upsilon(1S)W candidate with an expected background of 1.2 +/- 0.5 events, and one Upsilon(1S)Z candidate with an expected background of 0.1 +/- 0.1 events. Both observations are consistent with the predicted background contributions. The resulting upper limits on the cross section for Upsilon(1S)+W/Z production are the most sensitive reported from a single experiment and place restrictions on potential contributions from non-standard-model physics.

We measure the forward--backward asymmetry of the production of top quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy $\sqrt{s} = 1.96~\mathrm{TeV}$ using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of $9.1~\rm{fb}^{-1}$. The asymmetry is characterized by the rapidity difference between top quarks and antiquarks ($\Delta y$), and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be $A_{\text{FB}}^{t\bar{t}} = 0.12 \pm 0.13$, consistent with the expectations from the standard-model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive $A_{\text{FB}}^{t\bar{t}}$ in both final states yields $A_{\text{FB}}^{t\bar{t}}=0.160\pm0.045$, which is consistent with the SM predictions. We also measure the differential asymmetry as a function of $\Delta y$. A linear fit to $A_{\text{FB}}^{t\bar{t}}(|\Delta y|)$, assuming zero asymmetry at $\Delta y=0$, yields a slope of $\alpha=0.14\pm0.15$, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of $A_{\text{FB}}^{t\bar{t}}(|\Delta y|)$ in the two final states is $\alpha=0.227\pm0.057$, which is $2.0\sigma$ larger than the SM prediction.

We present the first measurement of the A_2 and A_3 angular coefficients of the W boson produced in proton-antiproton collisions. We study W-> e+nu and W-> mu+nu candidate events produced in association with at least one jet at CDF, during Run Ia and Run Ib of the Tevatron at sqrt(s)=1.8 TeV. The corresponding integrated luminosity was 110 pb^-1. The jet balances the transverse momentum of the W and introduces QCD effects in W boson production. The extraction of the angular coefficients is achieved through the direct measurement of the azimuthal angle of the charged lepton in the Collins-Soper rest-frame of the W boson. The angular coefficients are measured as a function of the transverse momentum of the W boson. The electron, muon, and combined results are in good agreement with the Standard Model prediction, up to order alpha_s^2 in QCD.

We present a measurement of the coefficient alpha_2 of the leptonic polar-angle distribution from W boson decays, as a function of the W transverse momentum. The measurement uses an 80+/-4 pb^{-1} sample of proton-antiproton collisions at sqrt{s}=1.8 TeV collected by the CDF detector and includes data from both the W->e+nu and W->mu+nu decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the Standard Model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c.

We present a search for a standard model Higgs boson decaying to two $W$ bosons that decay to leptons using the full data set collected with the CDF II detector in $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ $p\overline{p}$ collisions at the Fermilab Tevatron, corresponding to an integrated luminosity of $9.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We obtain no evidence for production of a standard model Higgs boson with mass between 110 and $200\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, and place upper limits on the production cross section within this range. We exclude standard model Higgs boson production at the 95% confidence level in the mass range between 149 and $172\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, while expecting to exclude, in the absence of signal, the range between 155 and $175\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. We also interpret the search in terms of standard model Higgs boson production in the presence of a fourth generation of fermions and within the context of a fermiophobic Higgs boson model. For the specific case of a standard-model-like Higgs boson in the presence of fourth-generation fermions, we exclude at the 95% confidence level Higgs boson production in the mass range between 124 and $200\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, while expecting to exclude, in the absence of signal, the range between 124 and $221\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We report on a study of the dijet invariant-mass distribution in events with one identified lepton, a significant imbalance in the total event transverse momentum, and two jets. This distribution is sensitive to the possible production of a new particle in association with a $W$ boson, where the boson decays leptonically. We use the full data set of proton-antiproton collisions at 1.96 TeV center-of-mass energy collected by the Collider Detector at the Fermilab Tevatron, corresponding to an integrated luminosity of $8.9\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. The data are found to be consistent with standard model expectations, and a 95% confidence level upper limit is set on the production cross section of a $W$ boson in association with a new particle decaying into two jets.

We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons, each with pT > 11 GeV/c using a 107 pb(-1) sample of 1.8 TeV pp collisions collected by the CDF detector. We define a signal region containing low background from standard model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63(+0.84)(-0.07) events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tanbeta = 3) model.

A search for the direct production of Higgs bosons in the di-tau decay mode is performed with 86.3±3.5 pb−1 of data collected with the Collider Detector at Fermilab during the 1994–1995 data taking period of the Tevatron. We search for events where one tau decays to an electron plus neutrinos and the other tau decays hadronically. We perform a counting experiment and set limits on the cross section for supersymmetric Higgs boson production where tanβ is large and mA is small. For a benchmark parameter space point where mA0=100 GeV/c2 and tanβ=50, we limit the production cross section multiplied by the branching ratio to be less than 77.9 pb at the 95% confidence level compared to the theoretically predicted value of 11.0 pb. This is the first search for Higgs bosons decaying to tau pairs at a hadron collider.5 MoreReceived 13 June 2005DOI:https://doi.org/10.1103/PhysRevD.72.072004©2005 American Physical Society

The experiments at Run 2 of the Tevatron have each accumulated over 1 fb{sup -1} of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focused on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.

We present a measurement of the production cross section for ZW and ZZ boson pairs in final states with a pair of charged leptons, from the decay of a Z boson, and at least two jets, from the decay of a W or Z boson, using the full sample of proton-antiproton collisions recorded with the CDF II detector at the Tevatron, corresponding to 8.9 fb^(-1) of integrated luminosity. We increase the sensitivity to vector boson decays into pairs of quarks using a neural network discriminant that exploits the differences between the spatial spread of energy depositions and charged-particle momenta contained within the jet of particles originating from quarks and gluons. Additionally, we employ new jet energy corrections to Monte Carlo simulations that account for differences in the observed energy scales for quark and gluon jets. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three classes of events: events likely to contain jets with a heavy-quark decay, events likely to contain jets originating from light quarks, and events that fail these identification criteria. We determine the production cross section to be 2.5 +2.0 -1.0 pb (< 6.1 pb at the 95% confidence level), consistent with the standard model prediction of 5.1 pb.

We present a search for chargino-neutralino associated production using like electric charge dilepton events collected by the CDF II detector at the Fermilab Tevatron in proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV. One lepton is identified as the hadronic decay of a tau lepton, while the other is an electron or muon. In data corresponding to 6.0 fb$^{-1}$ of integrated luminosity, we obtain good agreement with standard model predictions, and set limits on the chargino-neutralino production cross section for simplified gravity- and gauge-mediated models. As an example, assuming that the chargino and neutralino decays to taus dominate, in the simplified gauge-mediated model we exclude cross sections greater than 300 fb at 95% credibility level for chargino and neutralino masses of 225 \gevcc. This analysis is the first to extend the LHC searches for electroweak supersymmetric production of gauginos to high $\tan\beta$ and slepton next-to-lightest supersymmetric particle scenarios.

We measure the particle-level forward-backward production asymmetry in $b\bar{b}$ pairs with masses $m(b\bar{b})$ larger than 150 GeV/$c^2$, using events with hadronic jets and employing jet charge to distinguish $b$ from $\bar{b}$. The measurement uses 9.5/fb of ppbar collisions at a center of mass energy of 1.96 TeV recorded by the CDF II detector. The asymmetry as a function of $m(b\bar{b})$ is consistent with zero, as well as with the predictions of the standard model. The measurement disfavors a simple model including an axigluon with a mass of 200 GeV/$c^2$ whereas a model containing a heavier 345 GeV/$c^2$ axigluon is not excluded.

We present a measurement of the $W$-boson-pair production cross section in $p\bar{p}$ collisions at 1.96 TeV center-of-mass energy and the first measurement of the differential cross section as a function of jet multiplicity and leading-jet energy. The $W^{+}W^{-}$ cross section is measured in the final state comprising two charged leptons and neutrinos, where either charged lepton can be an electron or a muon. Using data collected by the CDF experiment corresponding to $9.7~\rm{fb}^{-1}$ of integrated luminosity, a total of $3027$ collision events consistent with $W^{+}W^{-}$ production are observed with an estimated background contribution of $1790\pm190$ events. The measured total cross section is $\sigma(p\bar{p} \rightarrow W^{+}W^{-}) = 14.0 \pm 0.6~(\rm{stat})^{+1.2}_{-1.0}~(\rm{syst})\pm0.8~(\rm{lumi})$ pb, consistent with the standard model prediction.

An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF) and corresponding to 9.5 fb${}^{-1}$ of integrated luminosity from proton-antiproton collisions at 1.96 TeV center-of-mass energy. The events selected contain an imbalance in the total transverse energy, jets identified as originating from $b$ quarks, and no identified leptons. The sum of the $s$- and $t$-channel single top quark cross sections is measured to be $3.53_{-1.16}^{+1.25}$ pb and a lower limit on $V_{tb}$ of 0.63 is obtained at the 95% credibility level. These measurements are combined with previously reported CDF results obtained from events with an imbalance in total transverse energy, jets identified as originating from $b$ quarks, and exactly one identified lepton. The combined cross section is measured to be $3.02_{-0.48}^{+0.49}$ pb and a lower limit on $V{tb}$ of 0.84 is obtained at the 95% credibility level.

We report measurements of the inclusive transverse momentum (${p}_{T}$) distribution of centrally produced ${K}_{S}^{0}$, ${K}^{\ensuremath{\star}\ifmmode\pm\else\textpm\fi{}}(892)$, and ${\ensuremath{\phi}}^{0}(1020)$ mesons up to ${p}_{T}=10\text{ }\text{ }\mathrm{GeV}/c$ in minimum bias events, and ${K}_{S}^{0}$ and ${\ensuremath{\Lambda}}^{0}$ particles up to ${p}_{T}=20\text{ }\text{ }\mathrm{GeV}/c$ in jets with transverse energy between 25 and 160 GeV in $p\overline{p}$ collisions. The data were taken with the CDF II detector at the Fermilab Tevatron at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. We find that as ${p}_{T}$ increases, the ${p}_{T}$ slopes of the three mesons (${K}_{S}^{0}$, ${K}^{\ensuremath{\star}\ifmmode\pm\else\textpm\fi{}}$, and $\ensuremath{\phi}$) are similar. And using our previous ${\ensuremath{\Lambda}}^{0}$ results from minimum bias events, we show that the ratio of ${\ensuremath{\Lambda}}^{0}$ to ${K}_{S}^{0}$ as a function of ${p}_{T}$ in minimum bias events becomes similar to the fairly constant ratio in jets at ${p}_{T}\ensuremath{\sim}5\text{ }\text{ }\mathrm{GeV}/c$. This suggests that the particles with ${p}_{T}\ensuremath{\gtrsim}5\text{ }\text{ }\mathrm{GeV}/c$ in minimum bias events are from ``soft'' jets, and that the ${p}_{T}$ slope of particles in jets is insensitive to light quark flavor ($u$, $d$, or $s$) and to the number of valence quarks. We also find that for ${p}_{T}\ensuremath{\lesssim}4\text{ }\text{ }\mathrm{GeV}$ relatively more ${\ensuremath{\Lambda}}^{0}$ baryons are produced in minimum bias events than in jets.

We report the results of a study of multi-muon events produced at the Fermilab Tevatron collider and acquired with the CDF II detector using a dedicated dimuon trigger. The production cross section and kinematics of events in which both muon candidates are produced inside the beam pipe of radius 1.5 cm are successfully modeled by known processes which include heavy flavor production. In contrast, we are presently unable to fully account for the number and properties of the remaining events, in which at least one muon candidate is produced outside of the beam pipe, in terms of the same understanding of the CDF II detector, trigger, and event reconstruction.

A measurement of vector boson ($V$) production in conjunction with a $D^{*}(2010)^+$ meson is presented. Using a data sample corresponding to $9.7\, {\rm fb}^{-1}$ of ^Mproton-antiproton collisions at center-of-mass energy $\sqrt{s}=1.96\rm~ TeV$ produced by the Fermilab Tevatron, we reconstruct $V+D^{*+}$ samples with the CDF~II detector. The $D^{*+}$ is fully reconstructed in the $D^{*}(2010)^+ \rightarrow D^{0}(\to K^-\pi^+)\pi^+$ decay mode. This technique is sensitive to the associated production of vector boson plus charm or bottom mesons. We measure the ratio of production cross sections $\sigma(W+D^{*})/\sigma(W)$ = $[1.75\pm 0.13 {\rm (stat)}\pm 0.09 {\rm (syst)}]\% $ and $\sigma(Z+D^{*})/\sigma(Z)$ = $[1.5\pm 0.4 {\rm (stat)} \pm 0.2 {\rm (syst)}]\% $ and perform a differential measurement of $d\sigma(W+D^{*})/dp_T(D^{*})$. Event properties are utilized to determine the fraction of $V+D^{*}(2010)^+$ events originating from different production processes. The results are in agreement with the predictions obtained with the {\sc pythia} program, limiting possible contribution from non-standard-model physics processes.

We present the first signature-based search for delayed photons using an exclusive photon plus missing transverse energy final state. Events are reconstructed in a data sample from the CDF II detector corresponding to $6.3\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity from $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ proton-antiproton collisions. Candidate events are selected if they contain a photon with an arrival time in the detector larger than expected from a promptly produced photon. The mean number of events from standard model sources predicted by the data-driven background model based on the photon timing distribution is $286\ifmmode\pm\else\textpm\fi{}24$. A total of 322 events are observed. A $p$ value of 12% is obtained, showing consistency of the data with standard model predictions.

A search for a Higgs boson with suppressed couplings to fermions, ${h}_{f}$, assumed to be the neutral, lower-mass partner of the Higgs boson discovered at the Large Hadron Collider, is reported. Such a Higgs boson could exist in extensions of the standard model with two Higgs doublets, and could be produced via $p\overline{p}\ensuremath{\rightarrow}{H}^{\ifmmode\pm\else\textpm\fi{}}{h}_{f}\ensuremath{\rightarrow}{W}^{*}{h}_{f}{h}_{f}\ensuremath{\rightarrow}4\ensuremath{\gamma}+X$, where ${H}^{\ifmmode\pm\else\textpm\fi{}}$ is a charged Higgs boson. This analysis uses all events with at least three photons in the final state from proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected by the Collider Detector at Fermilab, corresponding to an integrated luminosity of $9.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. No evidence of a signal is observed in the data. Values of Higgs-boson masses between 10 and $100\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ are excluded at 95% Bayesian credibility.

We present a measurement of the total {\it WW} and {\it WZ} production cross sections in $p\bar{p}$ collision at $\sqrt{s}=1.96$ TeV, in a final state consistent with leptonic $W$ boson decay and jets originating from heavy-flavor quarks from either a $W$ or a $Z$ boson decay. This analysis uses the full data set collected with the CDF II detector during Run II of the Tevatron collider, corresponding to an integrated luminosity of 9.4 fb$^{-1}$. An analysis of the dijet mass spectrum provides $3.7\sigma$ evidence of the summed production processes of either {\it WW} or {\it WZ} bosons with a measured total cross section of $\sigma_{WW+WZ} = 13.7\pm 3.9$~pb. Independent measurements of the {\it WW} and {\it WZ} production cross sections are allowed by the different heavy-flavor decay-patterns of the $W$ and $Z$ bosons and by the analysis of secondary-decay vertices reconstructed within heavy-flavor jets. The productions of {\it WW} and of {\it WZ} dibosons are independently seen with significances of $2.9\sigma$ and $2.1\sigma$, respectively, with total cross sections of $\sigma_{WW}= 9.4\pm 4.2$~pb and $\sigma_{WZ}=3.7^{+2.5}_{-2.2}$~pb. The measurements are consistent with standard-model predictions.

We measure the mass of the B0s meson by reconstructing the decay chain B0s→J/ψφ, J/ψ→μ+μ−, and φ→K+K−. The data are obtained from 19.3 pb−1 of integrated luminosity of p¯p collisions at √s=1.8 TeV using the Collider Detector at Fermilab. A sample of 80 000 inclusive J/ψ→μ+μ− events is used to study systematic biases in track reconstruction and to calibrate the momentum scale. We reconstruct the kinematically similar decays B+→J/ψK+ and B0→J/ψK*0 to study the mass measurement technique used for the B0s meson. Based on the observation of 32 ± 6 candidates, the mass of the B0s meson is measured to be 5369.9 ± 2.3 ± 1.3 MeV/c2 and the mass difference between B0s and the average mass of B+ and B0 is determined to be 89.7 ± 2.7 ± 1.2 MeV/c2. © 1996 The American Physical Society.Received 27 September 1995DOI:https://doi.org/10.1103/PhysRevD.53.3496©1996 American Physical Society

Results of a study of the substructure of the highest transverse momentum (pT) jets observed by the CDF collaboration are presented. Events containing at least one jet with pT > 400 GeV/c in a sample corresponding to an integrated luminosity of 5.95 inverse fb, collected in 1.96 TeV proton-antiproton collisions at the Fermilab Tevatron collider, are selected. A study of the jet mass, angularity, and planar-flow distributions is presented, and the measurements are compared with predictions of perturbative quantum chromodynamics. A search for boosted top-quark production is also described, leading to a 95% confidence level upper limit of 38 fb on the production cross section of top quarks with pT > 400 GeV/c.

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for proton-antiproton collisions at sqrt{s}=1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and can be used to estimate the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 +/- 3(stat.)^{+207}_{-70}(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.

This is the first of a series of papers in which we present a brief introduction to the relevant mathematical and physical ideas that form the foundation of Particle Physics, including Group Theory, Relativistic Quantum Mechanics, Quantum Field Theory and Interactions, Abelian and Non-Abelian Gauge Theory, and the SU(3)xSU(2)xU(1) Gauge Theory that describes our universe apart from gravity. These notes are not intended to be a comprehensive introduction to any of the ideas contained in them. Among the glaring omissions are CPT theorems, evaluations of Feynman Diagrams, Renormalization, and Anomalies. The topics were chosen according to the authors preferences and agenda. These notes are intended for a student who has completed the standard undergraduate physics and mathematics courses. Furthermore, these notes should not and will not in any way take the place of the related courses, but rather provide a primer for detailed courses in QFT, Gauge Theory, String Theory, etc., which will fill in the many gaps left by this paper.

The CDF II eXtremely Fast Tracker (XFT) is the trigger processor which reconstructs charged particle tracks in the CDF II central outer tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers and are associated to electromagnetic clusters and muon stubs to generate trigger electron and muon candidates. The steady increase of the Tevatron instantaneous luminosity and the resulting higher occupancy of the chamber demanded an upgrade of the original system, which performed tracking only in the transverse plane of the chamber and was consequently affected by a significant level of fake tracks. In the upgraded XFT, tracking is reinforced by using additional data from the stereo layers of the chamber to reduce the level of fake tracks and to perform three-dimensional track reconstruction. A review of this upgrade is presented.