Unki Yang

The NuTeV Collaboration has extracted the electroweak parameter sin(2)theta(W) from the measurement of the ratios of neutral current to charged current nu and (-)nu cross sections. Our value, sin(2)theta((on-shell))(W) = 0.2277 +/- 0.0013(stat) +/- 0.0009(syst), is 3 standard deviations above the standard model prediction. We also present a model independent analysis of the same data in terms of neutral-current quark couplings.

We present measurements of the semi-inclusive cross sections for νμ- and ν¯μ-nucleon deep inelastic scattering interactions with two oppositely charged muons in the final state. These events dominantly arise from the production of a charm quark during the scattering process. The measurement was obtained from the analysis of 5102 νμ-induced and 1458 ν¯μ-induced events collected with the NuTeV detector exposed to a sign-selected beam at the Fermilab Tevatron. We also extract a cross-section measurement from a reanalysis of 5030 νμ-induced and 1060 ν¯μ-induced events collected from the exposure of the same detector to a quad-triplet beam by the Chicago Columbia Fermilab Rochester (CCFR) experiment. The results are combined to obtain the most statistically precise measurement of neutrino-induced dimuon production cross sections to date. These measurements should be of broad use to phenomenologists interested in the dynamics of charm production, the strangeness content of the nucleon, and the Cabibbo-Kobayashi-Maskawa matrix element Vcd. Received 21 February 2001DOI:https://doi.org/10.1103/PhysRevD.64.112006©2001 American Physical Society

We study a new production mechanism for heavy neutrinos at the LHC, which dominates over the usually considered $s$-channel $W$-exchange diagram for heavy-neutrino masses larger than 100 - 200 GeV. The new mechanism is infrared-enhanced by $t$-channel $W\gamma$-fusion processes. This has important implications for experimental tests of the seesaw mechanism of neutrino masses, and in particular, for the ongoing heavy neutrino searches at the LHC. We find that the direct collider limits on the light-to-heavy neutrino mixing can be significantly improved, when this new production channel is properly taken into account. The scope of this new mechanism can equally well be extended to other exotic searches at the LHC.

Received 17 April 2003DOI:https://doi.org/10.1103/PhysRevLett.90.239902©2003 American Physical Society

We present a new measurement of the difference between the nucleon strange and antistrange quark distributions from dimuon events recorded by the NuTeV experiment at Fermilab. This analysis is the first to use a complete next to leading order QCD description of charm production from neutrino scattering. Dimuon events in neutrino deep inelastic scattering allow direct and independent study of the strange and antistrange content of the nucleon. We find a positive strange asymmetry with a significance of 1.6σ. We also report a new measurement of the charm mass.Received 25 March 2007DOI:https://doi.org/10.1103/PhysRevLett.99.192001©2007 American Physical Society

The NuTeV Collaboration recently reported a value of ${\mathrm{sin}}^{2}{\ensuremath{\theta}}_{W}$ measured in neutrino-nucleon scattering that is 3 standard deviations above the standard model prediction. This result is derived assuming that (1) the strange sea is quark-antiquark symmetric, $s(x)=\overline{s}(x),$ and (2) up and down quark distributions are symmetric under the simultaneous interchange of $u\ensuremath{\leftrightarrow}d$ and $p\ensuremath{\leftrightarrow}n.$ We report the impact of violations of these symmetries on ${\mathrm{sin}}^{2}{\ensuremath{\theta}}_{W}$ and discuss the theoretical and experimental constraints on such asymmetries.

We report on the extraction of the structure functions F2 and DeltaxF(3) = xF(nu)(3)-xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe differential cross sections. The extraction is performed in a physics model-independent (PMI) way. This first measurement of DeltaxF(3), which is useful in testing models of heavy charm production, is higher than current theoretical predictions. The ratio of the F2 (PMI) values measured in nu(mu) and mu scattering is in agreement (within 5%) with the predictions of next-to-leading-order parton distribution functions using massive charm production schemes, thus resolving the long-standing discrepancy between the two sets of data.

A re-analysis of the NMC and SLAC data leads to a great improvement in our knowledge of the valence d and u parton distribution functions at high x. Standard parton distributions with our modifications are in good agreement with QCD predictions for d/u at x=1, and with the CDHSW nu p and nubar p data, the HERA charged current cross section data, the collider high-P_t jet data, and the CDF W asymmetry data. With the inclusion of target mass and higher twist corrections, the modified PDF's also describe all DIS data up to x = 0.98 and down to Q^2 = 1 GeV^2.

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 evidence for the diffractive processes νμFe→μ−D+S(D*S)Fe and ¯νμFe→μ+D−S(D*S)Fe using the Fermilab SSQT neutrino beam and the Lab E neutrino detector. The data are consistent with standard model production of the neutrino trident reactions νμFe→νμμ−μ+Fe and ¯νμFe→¯νμμ+μ−Fe. We see no evidence for neutral-current production of J/ψ via either diffractive or deep inelastic scattering mechanisms.Received 24 September 1999DOI:https://doi.org/10.1103/PhysRevD.61.092001©2000 American Physical Society

The NuTeV collaboration recently reported a value of sin2thetaW measured in neutrino-nucleon scattering that is 3 standard deviations above the standard model prediction. This result is derived assuming that (1) the strange sea is quark-antiquark symmetric, s(x)=sbar(x), and (2) up and down quark distributions are symmetric under the simultaneous interchange of u<->d and p<->n. We report the impact of violations of these symmetries on sin2thetaW and discuss the theoretical and experimental constraints on such asymmetries.

This Expression of Interest (EoI) describes the motivation for and the feasibility studies of a long baseline neutrino oscillation experiment (LBNO) with a new conventional neutrino beamline facility (CN2PY). The beam will be aimed at a next generation deep-underground neutrino observatory comprising a double phase liquid argon (LAr) detector and a magnetized iron calorimeter, located at the Pyhasalmi (Finland) mine at a distance of 2300~km. The double phase LAr Large Electron Multiplier Time Projection Chamber (LAr LEM-TPC) is known to provide excellent tracking and calorimetry performance that can outperform other techniques. An initial 20~kton LAr fiducial volume, as considered here, comparable to the fiducial mass of SuperKamiokande and NOvA, offers a new insight and an increase in sensitivity reach for many physics channels. A magnetized iron calorimeter with muon momentum and charge determination collects an independent neutrino sample, and serves as a tail catcher for CERN beam events occurring in the LAr target. The long baseline physics objectives comprise the precise investigation of all flavor oscillations ($\nu_\mu\rightarrow \nu_\mu$, $\nu_\mu\rightarrow \nu_\tau$, $\nu_\mu\rightarrow \nu_e$) with neutrinos and antineutrinos, exploiting the energy spectrum information of the oscillation probability ($L/E$ method) in appearance and disappearance modes, to provide unambiguous sensitivity to oscillation parameters, and a stringent test of the 3-generation mixing. The existence of CP-violation will be tested explicitly, which is different from simply extracting the $\delta_{CP}$ violating phase from global fits of all available data. With an exposure of $2.25\times 10^{20}$~p.o.t. from the SPS at 400~GeV, a conclusive determination ($>5\sigma$~C.L.) of the neutrino mass hierarchy is possible for \emph{any} value of $\delta_{CP}$. Although limited by statistics in the initial configuration, the $L/E$ method also yields a clean measurement of the CP-violating phase. With $1\times 10^{21}$~p.o.t., the existence of CP-violation (CPV) can be demonstrated at the 90\%C.L. for $\sim 60\%$ of the $\delta_{CP}$ parameter space. This CPV-sensitivity is achievable in $\sim$12~years at the upgraded SPS. It improves further with the increased exposure resulting from longer running periods and/or an increase in beam power and far detector mass. With the chosen location in the deepest mine in Europe at $-1440$~m ($\sim$4000~m.w.e.), the already very large initial target mass provides an unique opportunity to observe new rare phenomena, independently of the CERN beam events. In the GeV range, evidence for Grand Unified Theories (GUT) can be searched for with nucleon decay signals. From 100~MeV to tens of GeV, the collection of thousands of atmospheric electron and muon neutrinos with good energy resolution and particle identification over a very large range of energies (SubGeV and MultiGeV) improves our understanding of this source and yields information on subleading oscillation effects, which provide additional and complementary sensitivity to the oscillation phenomenology including $\theta_{13}$, matter effects and possibly the CP-phase. At high energy, it allows an identification with high statistical significance and a study of $\nu_\tau$ appearance in atmospheric events. Below 100~MeV, neutrinos from a new galactic supernova burst would be recorded with large statistics, addressing the astrophysics of the supernova and neutrino flavor oscillations through the SN and Earth matter. Neutrinos from relic supernovae could also be potentially detected, depending on their flux and prevailing backgrounds. LBNO can also potentially detect as-of-yet unknown sources of astrophysical neutrinos, like for instance those that could arise from annihilation processes of WIMP particles in astrophysical objects, and study their flavor composition. The plan described so far is augmented with a concrete upgrade path to evolve towards an ultimate volume observatory by additional units of increasingly larger masses. With a three-fold increase in exposure (defined as the product neutrino beam power $\times$ far detector target mass), CPV becomes accessible at $>3\sigma$~C.L. for 75\% of the $\delta_{CP}$ parameter space, assuming that all systematic errors can be controlled below the 5\% level. The LBNO far site at 2300~km from CERN could also represent the first step towards a Neutrino Factory project based on the decays of muons in the straight sections of a storage ring. Based on the expertise present at CERN and in European and in international research groups, and building upon the results of several years of EU-funded design studies, we are confident that the technology for the beam and detectors is sufficiently mature to allow for an early start to realizing the facility. We are calling on CERN to promptly support and engage in the prototyping of the near and far detector components, to investigate options for campaigns of detector performance characterization and calibration with test beams in the North Area, and engage in a collaborative effort with the LBNO Collaboration that should lead to a full engineering design of the CN2PY beam and to an LBNO Proposal by the end of 2014.

We report on the extraction of R = sigma(L)/sigma(T) from CCFR nu(mu)-Fe and nu(mu)-Fe differential cross sections. The CCFR differential cross sections do not show the deviations from the QCD expectations that are seen in the CDHSW data at very low and very high x. R as measured in nu(mu) scattering is in agreement with R as measured in muon and electron scattering. All data on R for Q(2)>1 GeV(2) are in agreement with a NNLO QCD calculation which uses NNLO parton distribution functions and includes target mass effects. We report on the first measurements of R in the low x and Q(2)<1 GeV(2) region (where an anomalous large rise in R for nuclear targets has been observed by the HERMES Collaboration).

A surprisingly large charge symmetry violation of the sea quarks in the nucleon has been proposed in a recent article by Boros et al. as an explanation of the discrepancy between neutrino and muon nucleon structure function data at low $x$. We show that these models are ruled out by the published CDF $W$ charge asymmetry measurements, which strongly constrain the ratio of $d$ and $u$ quark momentum distributions in the proton over the $x$ range of $0.006$ to $0.34$. This constraint also limits the systematic error from possible charge symmetry violation in the determinations of ${sin}^{2}{\ensuremath{\theta}}_{W}$ from $\ensuremath{\nu}N$ scattering experiments.

The first measurements of $\ensuremath{\Delta}{\mathrm{xF}}_{3}$ are higher than current theoretical predictions. We investigate the sensitivity of these theoretical predictions upon a variety of factors including the renormalization scheme and scale, quark mass effects, higher twist, isospin violation, and PDF uncertainties.

We construct a model for inelastic neutrino- and electron-nucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable $ξ_w$. Non-perturbative effects are well described using the $ξ_w$ scaling variable, in combination with multiplicative $K$ factors at low $Q^2$.Our model describes all inelastic charged lepton-nucleon scattering (including resonance) data (HERA/NMC/BCDMS/SLAC/JLab) ranging from very high $Q^2$ to very low $Q^2$ and down to the photo-production region. The model describes existing inelastic neutrino-nucleon scattering measurements, and has been developed to be used in analysis of neutrino oscillation experiments in the few GeV region.

NuTeV measures sin2 θW by comparing neutral and charged current cross-sections on a heavy nuclear target, and finds a value of sin2 θW(on-shell) = 0.2277 ± 0.0013(stat) ± 0.0009(syst), approximately 3σ from the predicted value. We discuss the possibility that nuclear effects on parton distribution functions or cross-sections may be responsible for the discrepancy.

After the Phase-2 high-luminosity upgrade to the Large Hadron Collider (LHC), the collision rate and therefore the background rate will significantly increase, particularly in the high $\eta$ region. To improve both the tracking and triggering of muons, the Compact Muon Solenoid (CMS) Collaboration plans to install triple-layer Gas Electron Multiplier (GEM) detectors in the CMS muon endcaps. Demonstrator GEM detectors were installed in CMS during 2017 to gain operational experience and perform a preliminary investigation of detector performance. We present the results of triple-GEM detector performance studies performed in situ during normal CMS and LHC operations in 2018. The distribution of cluster size and the efficiency to reconstruct high $p_T$ muons in proton--proton collisions are presented as well as the measurement of the environmental background rate to produce hits in the GEM detector.

The NuTeV experiment at Fermilab has obtained a unique high statistics sample of neutrino and antineutrino interactions using a novel high-energy sign-selected neutrino beam. Recent results from this sample are presented including a precision measurement of the electroweak parameter sin2≡W, which is observed to be three standard deviations above the standard model prediction.

We construct a model for inelastic neutrino‐ and electron‐nucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable ξw. Non‐perturbative effects are well described using the ξw scaling variable, in combination with multiplicative K factors at low Q2. Our model describes all inelastic charged lepton‐nucleon scattering (including resonance) data (HERA/NMC/BCDMSS/LACJ/Lab) ranging from very high Q2 to very low Q2 and down to the photo‐production region. The model describes existing inelastic neutrino‐nucleon scattering measurements, and is currently used in analyses of neutrino oscillation experiments in the few GeV region.

We propose a novel experimental scheme, called DAMSA (Dump-produced Aboriginal Matter Searches at an Accelerator), for searching for dark-sector particles, using rare nuclear isotope accelerator facilities that provide high-flux proton beams to produce a large number of rare nuclear isotopes. The high-intensity nature of their beams enables the investigation of dark-sector particles, including axionlike particles (ALPs) and dark photons. By contrast, their typical beam energies are not large enough to produce the backgrounds such as neutrinos resulting from secondary charged particles. The detector of DAMSA is then placed immediate downstream of the proton beam dump to maximize the prompt decay signals of dark-sector particles, which are often challenging to probe in other beam-dump-type experiments featuring a longer baseline, at the expense of an enormous amount of the beam-related neutron background. We demonstrate that beam-related neutrons can be significantly suppressed if the signal accompanies multiple, correlated visible particles in the final state. We show that the close proximity of the detector to the ALP production dump makes it possible to probe a high-mass region of ALP parameter space that the existing experiments have never explored.

This paper presents the inaugural investigation of beyond the Standard Model (BSM) radiation processes, framed as a generalized, process- and model-independent parton shower algorithm within Herwig 7, based on direct translations of Universal FeynRules Output (UFO) constructed via Herwig's ufo2herwig module. Leveraging the fact that shower kinematics are dictated by the spins of involved particles, we calculate comprehensive helicity-dependent branching kernels for all feasible splittings of scalars, fermions, and vector bosons, tailored to Herwig 7's angular-ordering (AO) parton shower algorithm. Utilizing these kernels, we derive BSM splitting functions in the quasi-collinear limit, ensuring compatibility with the Standard Model (SM) and supersymmetry (SUSY) splitting functions when analogous parameter conditions are applied. These newly derived functions have been integrated into the Herwig 7 event generator framework. Comparative analyses with fixed-order matrix element calculations show good agreement for single radiation events. Moreover, the results showcase the influence of BSM radiation at the Large Hadron Collider (LHC) and envisage its implications for future collider endeavours. This research augments our comprehension of BSM radiation effects, with significant bearings on present and prospective collider-based inquiries.

We propose a novel experimental scheme, called DAMSA (Dump-produced Aboriginal Matter Searches at an Accelerator), for searching for dark-sector particles, using rare nuclear isotope accelerator facilities that provide high-flux proton beams to produce a large number of rare nuclear isotopes. The high-intensity nature of their beams enables the investigation of dark-sector particles, including axion-like particles (ALPs) and dark photons. By contrast, their typical beam energies are not large enough to produce the backgrounds such as neutrinos resulting from secondary charged particles. The detector of DAMSA is then placed immediate downstream of the proton beam dump to maximize the prompt decay signals of dark-sector particles, which are often challenging to probe in other beam-dump-type experiments featuring a longer baseline, at the expense of an enormous amount of the beam-related neutron (BRN) background. We demonstrate that BRN can be significantly suppressed if the signal accompanies multiple, correlated visible particles in the final state. As an example physics case, we consider ALPs interacting with the Standard Model photon and their diphoton decay signal at DAMSA implemented at a rare nuclear isotope facility similar to the Rare isotope Accelerator complex for ON-line experiment under construction in South Korea. We show that the close proximity of the detector to the ALP production dump makes it possible to probe a high-mass region of ALP parameter space that the existing experiments have never explored.

We report on the first observation of open charm production in neutral current deep inelastic neutrino scattering as seen in the NuTeV detector at Fermilab. The production rate is shown to be consistent with a pure gluon-Z 0 boson production model, and the observed level of charm production is used to determine the effective charm mass.

The NuTeV experiment obtained high statistics samples of neutrino and antineutrino charged current events during the 1996-1997 Fermilab fixed target run. The experiment combines sign-selected neutrino and antineutrino beams and the upgraded CCFR iron-scintillator neutrino detector. A precision continuous calibration beam was used to determine the muon and hadron energy scales to a precision of 0.7% and 0.43% respectively. The structure functions F 2 (x, Q 2 ) and xF 3 (x, Q 2 ) obtained by fitting the y-dependence of the sum and the difference of the ν and [Formula: see text] differential cross sections are presented.

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation ($b$-jets) by selecting online proton-antiproton ($p\overline{p}$) collisions with a vertex displaced from the $p\overline{p}$ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of 1.96 TeV, and corresponding to an integrated luminosity of $5.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, is used to measure the $Z$-boson production cross section times branching ratio into $b\overline{b}$. The number of $Z\ensuremath{\rightarrow}b\overline{b}$ events is determined by fitting the dijet-mass distribution, while constraining the dominant $b$-jet background, originating from QCD multijet events, with data. The result, $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}Z)\ifmmode\times\else\texttimes\fi{}\mathcal{B}(Z\ensuremath{\rightarrow}b\overline{b})=\phantom{\rule{0ex}{0ex}}1.11\ifmmode\pm\else\textpm\fi{}0.08(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.14(\mathrm{syst})\text{ }\text{ }\mathrm{nb}$, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive $p\overline{p}\ensuremath{\rightarrow}H\ensuremath{\rightarrow}b\overline{b}$ process at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ is set, corresponding to 33 times the expected standard-model cross section, or $\ensuremath{\sigma}=40.6\text{ }\text{ }\mathrm{pb}$, at the 95% confidence level.

Charm production by neutrino charged-current interactions produces two muon (dimuon) events which are easily identified. This signal provides an important method to measure the strange sea and the mass of the charm quark. Several experiments, including CCFR, CDHS and CHARM II, have performed analyses of such events. The results of these analyses are summarized with emphasis on CCFR and improvements made by NuTeV.

The NuTeV experiment has performed precision measurements of the ratio of neutral-current to charged-current cross-sections in high rate, high energy neutrino and anti-neutrino beams on a dense, primarily steel, target. The separate neutrino and anti-neutrino beams, high statistics, and improved control of other experimental systematics, allow the determination of electroweak parameters with significantly greater precision than past neutrino-nucleon scattering experiments. Our null hypothesis test of the standard model prediction measures sin2thetaW=0.2277+/-0.0013(stat)+/-0.0009(syst), a value which is 3.0 standard deviations above the prediction. We discuss possible explanations for and implications of this discrepancy.

We report an updated measurement of the top quark mass in the lepton plus jets channel of t{bar t} events from p{bar p} collisions at {radical}s = 1.96 TeV. This measurement uses a dataset with integrated luminosity of 680 pb{sup -1}, containing 360 t{bar t} candidates separated into four subsamples. A top quark mass is reconstructed for each event by using energy and momentum constraints on the top quark pair decay products. We also employ the reconstructed mass of hadronic W boson decays W {yields} jj to constrain in situ the largest systematic uncertainty of the top quark mass measurement: the jet energy scale. Monte Carlo templates of the reconstructed top quark and W boson mass are produced as a function of the true top quark mass and the jet energy scale. The distribution of reconstructed top quark and W boson mass in the data are compared to the Monte Carlo templates using a likelihood fit to obtain: M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}.

An estimate of environmental background hit rate on triple-GEM chambers is performed using Monte Carlo (MC) simulation and compared to data taken by test chambers installed in the CMS experiment (GE1/1) during Run-2 at the Large Hadron Collider (LHC). The hit rate is measured using data collected with proton-proton collisions at 13 TeV and a luminosity of 1.5$\times10^{34}$ cm$^{-2}$ s$^{-1}$. The simulation framework uses a combination of the FLUKA and Geant4 packages to obtain the hit rate. FLUKA provides the radiation environment around the GE1/1 chambers, which is comprised of the particle flux with momentum direction and energy spectra ranging from $10^{-11}$ to $10^{4}$ MeV for neutrons, $10^{-3}$ to $10^{4}$ MeV for $\gamma$'s, $10^{-2}$ to $10^{4}$ MeV for $e^{\pm}$, and $10^{-1}$ to $10^{4}$ MeV for charged hadrons. Geant4 provides an estimate of detector response (sensitivity) based on an accurate description of detector geometry, material composition and interaction of particles with the various detector layers. The MC simulated hit rate is estimated as a function of the perpendicular distance from the beam line and agrees with data within the assigned uncertainties of 10-14.5%. This simulation framework can be used to obtain a reliable estimate of background rates expected at the High Luminosity LHC.

The NuTeV experiment uses neutrino deep-inelastic scattering from separate neutrino and anti-neutrino beams to study the structure of the nucleon. Charged-current production of charm is sensitive to the strange content of the nucleon while neutral-current charm production probes the charm content. Preliminary analyses of both topics are presented along with discussion of possible momentum asymmetry in the strange sea.

Measurements of charged current neutrino and anti-neutrino nucleon interactions in the CCFR detector are used to extract the structure functions, F_2, xF_3(nu), xF_3(nubar) and R(longitudinal) in the kinematic region 0.01<x<0.6 and 1<Q^2<300 GeV^2. The new measurements of R in the x<0.1 region provide a constraint on the level of the gluon distribution. The x and Q^2 dependence of R is compared with a QCD based fit to previous data. The CKM matrix element |V_cs| is extracted from a combined analysis of xF_3 and dimuon data.

We construct a model for inelastic neutrino- and electron-nucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable $\xi_w$. Non-perturbative effects are well described using the $\xi_w$ scaling variable, in combination with multiplicative $K$ factors at low $Q^2$. Our model describes all inelastic charged lepton-nucleon scattering (including resonance) data (HERA/NMC/BCDMS/SLAC/JLab) ranging from very high $Q^2$ to very low $Q^2$ and down to the photo-production region. The model describes existing inelastic neutrino-nucleon scattering measurements, and is currently used in analyses of neutrino oscillation experiments in the few GeV region.

We report an analysis of the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} decay in a data sample collected by the CDF II detector at the Fermilab Tevatron corresponding to 2.4 fb{sup -1} of integrated luminosity. We reconstruct the currently largest samples of the decay modes {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2595){sup +}{pi}{sup -} (with {Lambda}{sub c}(2595){sup +} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}), {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}(2625){sup +}{pi}{sup -} (with {Lambda}{sub c}(2625){sup +} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}), {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455){sup ++}{pi}{sup -}{pi}{sup -} (with {Sigma}{sub c}(2455){sup ++} {yields} {Lambda}{sub c}{sup +}{pi}{sup +}), and {Lambda}{sub b}{sup 0} {yields} {Sigma}{sub c}(2455)0{pi}{sup +}{pi}{sup -} (with {Sigma}{sub c}(2455)0 {yields} {Lambda}{sub c}{sup +}{pi}{sup -}) and measure the branching fractions relative to the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} branching fraction. We measure the ratio {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})/ {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})=3.04 {+-} 0.33(stat){sub -0.55}{sup +0.70}(syst) which is used to derive {Beta}({Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})=(26.8{sub -11.2}{sup +11.9}) x 10{sup -3}.

We construct a model for inelastic neutrino- and electron-nucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable $\xi_w$. Non-perturbative effects are well described using the $\xi_w$ scaling variable, in combination with multiplicative $K$ factors at low $Q^2$. Our model describes all inelastic charged lepton-nucleon scattering (including resonance) data (HERA/NMC/BCDMS/SLAC/JLab) ranging from very high $Q^2$ to very low $Q^2$ and down to the photo-production region. The model describes existing inelastic neutrino-nucleon scattering measurements, and is currently used in analyses of neutrino oscillation experiments in the few GeV region.

We construct a model for inelastic neutrino- and electron-nucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable $\xi_w$. Non-perturbative effects are well described using the $\xi_w$ scaling variable, in combination with multiplicative $K$ factors at low $Q^2$. Our model describes all inelastic charged lepton-nucleon scattering (including resonance) data (HERA/NMC/BCDMS/SLAC/JLab) ranging from very high $Q^2$ to very low $Q^2$ and down to the photo-production region. The model describes existing inelastic neutrino-nucleon scattering measurements, and is currently used in analyses of neutrino oscillation experiments in the few GeV region.

Light charged Higgs boson searches for H+ to tau+ nu and H+ to c sbar in early LHC data at the ATLAS experiment

We report on an update (2021) of a phenomenological model for inelastic neutrino-and electronnucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable .Non-perturbative effects are well described using the scaling variable in combination with multiplicative factors at low 2 .The model describes all inelastic chargedlepton-nucleon scattering data (HERA/NMC/BCDMS/SLAC/JLab) ranging from very high 2 to very low 2 and down to the 2 = 0 photo-production region.The model has been developed to be used in analyses of neutrino oscillation experiments in the few GeV region.The 2021 update accounts for the difference between axial and vector structure functions which brings it into much better agreement with neutrino-nucleon total cross section measurements.The model has been developed primarily for hadronic final state masses above 1.8 GeV.However with additional parameters the model also describes the neutrino cross sections in the resonance region down to =1.4 GeV.

The experiments at LHC are implementing novel and challenging detector upgrades for the High Luminosity LHC, among which the tracking systems. This paper reports on performance studies, illustrated by an electron trigger, using a simplified pixel tracker. To achieve a real-time trigger (e.g. processing HL-LHC collision events at 40 MHz), simple algorithms are developed for reconstructing pixel-based tracks and track isolation, utilizing look-up tables based on pixel detector information. Significant gains in electron trigger performance are seen when pixel detector information is included. In particular, a rate reduction up to a factor of 20 is obtained with a signal selection efficiency of more than 95\% over the whole $\eta$ coverage of this detector. Furthermore, it reconstructs p-p collision points in the beam axis (z) direction, with a high precision of 20 $\mu$m resolution in the very central region ($|\eta| < 0.8$), and, up to 380 $\mu$m in the forward region (2.7 $< |\eta| <$ 3.0). This study as well as the results can easily be adapted to the muon case and to the different tracking systems at LHC and other machines beyond the HL-LHC. The feasibility of such real-time processing of the pixel information is mainly constrained by the Level-1 trigger latency of the experiment. How this might be overcome by the Front-End ASIC design, new processors, and embedded Artificial Intelligence algorithms is briefly tackled as well.

The NuTeV experiment at Fermilab presents a determination of the electroweak mixing angle. High purity, large statistics samples of muon-neutrino and muon-antineutrino events allow the use of the Paschos-Wolfenstein relation. This considerably reduces systematic errors associated with charm production and other sources. With Standard Model assumptions, this measurement of sin2thw indirectly determines the W boson mass to a precision comparable to direct measurements from high energy e+e- and p-pbar colliders. NuTeV measures sin^2theta_W (on-shell) = 0.2253 +/- 0.0019(stat) +/- 0.0010(syst) which implies M_W = 80.26 +/- 0.11 GeV.

NuTeV is a neutrino-nucleon deep inelastic scattering experiment at Fermilab. The NuTeV detector is a traditional heavy target neutrino detector which consists of an iron/liquid scintillator sampling calorimeter followed by a muon spectrometer. The calorimeter response to hadrons, muons and electrons has been measured in an in situ calibration beam over the energy range from 4.5 to 190 GeV. The small non-linearity of the response to hadrons is compared to the expectation from the measured ratio of responses between electrons and hadrons combined with the energy dependence of the fractional electromagnetic energy deposition in the form of neutral pions in hadronic showers fπ0(Eπ). The predictions use fπ0(Eπ) from the Monte Carlo simulations by GHEISHA, GFLUKA and GCALOR and also from the parameterizations of Wigmans and Groom. In addition, a study based on the NuTeV hadron calibration data of the effectiveness of a thin calorimeter is presented. The results of this study have important consequences for the energy resolution of calorimeters used in other applications; for example, measuring the cosmic ray flux in space or with balloon-based experiments.

We present the results of a new scaling variable, ξw in modelling neutrino-and electronnucleon scattering cross sections using effective leading order PDFs.Our model desribes all deep inelastic scattering charged lepton-nucleon scattering data including resonance data (HERA/NMC/BCDMS/SLAC/JLab) from very high Q 2 to very low Q 2 (down to photo-productin region), as well as CCFR neutrino data.Non-perturbative QCD effects at low Q 2 region turn out to be well described by this new scaling variable.Our model is currently used for neutrino oscillation experiments at few GeV region.

We report a summary of the structure function working group which covers a wide range of the recent results from HERA, Tevatron, RHIC, and JLab experiments, and many theoretical issues from low x to high x.

We report on the extraction of the structure functions F_2 and Delta xF_3 = xF_3(nu)-xF_3(nubar) from CCFR nu_mu-Fe and nubar_mu-Fe different ial cross sections. The extraction is performed in a physics model independent (PMI) way. This first measurement of Delta xF_3, which is useful in testing models of heavy charm production, is higher than current theoretical predictios. The ratio of the F_2 (PMI) values measured in nu_mu and mu scattering is in agreement (within 5%) with the NLO predictions using massive charm production schemes, thus resolving the long-standing discrepancy between the two sets of data. In addition, measurements of F_L (or, equivalently, R) and 2xF_1 are reported in the kinematic region where anomalous nuclear effects in R are observed at HERMES.

We report on a search for flavor-changing neutral-currents (FCNC) in the production of heavy quarks in deep inelastic ν μ N and [Formula: see text] scattering by the NuTeV experiment at the Fermilab Tevatron. This measurement, made possible by the high-purity NuTeV sign-selected beams, probes for FCNC in heavy flavors at the quark level and is uniquely sensitive to neutrino couplings of potential FCNC mediators. All searches are consistent with zero, and limits on the effective mixing strengths |V us | 2 , |V db | 2 , and |V sb | 2 are obtained.

A search for the decay of long-lived neutral particles has been performed using an instrumented decay channel at the E815 (NuTeV) experiment at Fermilab. The data were examined for particles decaying into the muonic final states μμ, μe, and μπ. Three μμ events were observed over an expected background of 0.040±0.009 events; no events were observed in the other modes. No Standard Model process appears to be consistent with this observation.

The main focus of this working group was to investigate the different issues associated with the development of quantitative tools to estimate parton distribution functions uncertainties. In the conclusion, we introduce a Manifesto that describes an optimal method for reporting data.

In a recent comment, Miller and Thomas assert that differences in nuclear shadowing effects between neutrino neutral current (NC) and charged current (CC) interactions could explain the difference between NuTeV's measurement of the weak mixing angle and the prediction from other electroweak data. We argue that the proposed effect could have only a small impact on sin2thetaW derived from the Paschos-Wolfenstein R- and that such an effect is strongly disfavored by the neutrino and anti-neutrino NC-to-CC cross-section ratios also measured by NuTeV.

The NuTeV collaboration has performed precision measurements of the ratio of neutral current to charged current cross-sections in high rate, high energy neutrino and anti-neutrino beams on a dense, primarily steel, target. The separate neutrino and anti-neutrino beams, high statistics, and improved control of other experimental systematics, allow the determination of electroweak parameters with significantly greater precision than past neutrino-nucleon scattering experiments. Our null hypothesis test of the standard model prediction measures sin2thetaW=0.2277+/-0.0013(stat)+/-0.0009(syst), a value which is 3 sigma above the prediction. We discuss possible explanations for and implications of this discrepancy.

We extract the ratio of the down (d) and up (u) parton distribution functions (PDF's) from the ratio of NMC deuteron and proton structure function F_2(d)/F_2(p), using corrections for nuclear binding effects in the deuteron, which are extracted from the nuclear dependence of SLAC F_2 data. Significant corrections to the d quark distribution in standard PDF's are required, especially at high x. The corrected d/u ratio is in agreement with the QCD prediction of 0.2 at x=1. The predictions for the recent CDF W asymmetry data using PDF's with the corrected d/u ratio give much better agreement at large rapidity. Using the updated d/u ratio and the most recent world average for alpha_s, we perform a NLO global fit to all DIS data for F_2 and R, and estimate the size of the higher twist contributions using both a renormalon model and an empirical model. We find that with the updated value of alpha_s, the magnitude of the higher twist terms is half the value of previous analysis. With the inclusion of target mass and higher twist corrections, the standard NLO PDF's with the updated d/u ratio describe the SLAC F_2 data up to x=1.0. When the analysis is repeated in NNLO, we find that the additional NNLO contributions to R account for most of the higher twist effects extracted in the NLO fit. The analysis in NNLO indicates that the higher twist effects in R, F_2 and xF_3 (e.g. GLS sum rule) are very small.

Neutrino deep-inelastic scattering provides a means to study both the strange and charm content of the nucleon. The NuTeV experiment (Fermilab E-8Neutrino deep-inelastic scattering provides a means to study both the strange and charm content of the nucleon. The NuTeV experiment (Fermilab E-815) takes full advantage of separated neutrino and anti-neutrino beams to probe the nucleon. The strange sea is studied with charged-current charm production resulting in an opposite-signed two muon final state. The charm content of the nucleon is probed via neutral-current charm production creating an event with a single wrong-signed muon. Preliminary results are presented for both analyses.

We extract the ratio of the down (d) and up (u) parton distribution functions (PDF's) from the ratio of deuteron and proton structure function F_2(d)/F_2(p) measured by NMC. We use corrections for nuclear binding effects in the deuteron, which are extracted from the nuclear dependence of SLAC F_2 data. Significant corrections to the d quark distribution in standard PDF's are required, especially at high x. The corrected d/u ratio is in agreement with the QCD prediction of 0.2 at x=1. The predictions for the W asymmetry in hadron colliders using PDF's with the corrected d/u ratio are in much better agreement with recent CDF data at large rapidity. Using the updated d/u ratio and the most recent world average for alpha_s, we perform a NLO global fit to all DIS data for F_2 and R, and estimate the size of the higher twist contributions using both a renormalon model and an empirical model. We find that with the updated value of alpha_s, the magnitude of the higher twist terms is half the value of previous analysis. With the inclusion of target mass and higher twist corrections, the standard NLO PDF's with the updated d/u ratio describe the SLAC F_2 data up to x=1.0. When the analysis is repeated in NNLO, we find that the additional NNLO contributions to R account for most of the higher twist effects extracted in the NLO fit. The analysis in NNLO indicates that the higher twist effects in R, F_2 and xF_3 (e.g. GLS sum rule) are very small.

We extract a set of values for the Gross{endash}Llewellyn Smith sum rule at different values of 4-momentum transfer squared (Q{sup 2} ), by combining revised CCFR neutrino data with data from other neutrino deep-inelastic scattering experiments for 1{lt}Q{sup 2}{lt}15 GeV{sup 2}/c{sup 2} . A comparison with the order {alpha}{sup 3}{sub s} theoretical predictions yields a determination of {alpha}{sub s} at the scale of the Z -boson mass of 0.114{plus_minus}{sup 0.009}{sub 0.012} . This measurement provides a new and useful test of perturbative QCD at low Q{sup 2} , because of the low uncertainties in the higher order calculations. {copyright} {ital 1998} {ital The American Physical Society }

Measurements of charged current neutrino and anti-neutrino nucleon interactions in the CCFR detector are used to extract the structure functions, F_2, xF_3(nu), xF_3(nubar) and R(longitudinal) in the kinematic region 0.01

Measurements of neutrino - nucleon and antineutrino - nucleon differential cross sections using the CCFR neutrino detector at Fermilab have been used to extract preliminary values of in the kinematic region 0.01 < x < 0.6 and . The new data provide the first measurements of R in the region x < 0.1. The x and dependence of R is compared with a QCD-based fit to previous data. The QCD fit, which provides an estimate of R in the small-x region where R has not been previously measured, is in good agreement with the new CCFR data.

Measurements of neutrino-nucleon and antineutrino-nucleon differential cross sections using the CCFR neutrino detector at Fermilab have been used to extract preliminary values of $R ={\sigma_L}/{\sigma_T}$ in the kinematic region $0.01<x<0.6$, and $4<Q^2<300$ GeV$^2$. The new data provide the first measurements of $R$ in the $x<0.1$ region. The $x$ and $Q^2$ dependence of $R$ is compared with a QCD based fit to previous data. The QCD fit, which provides an estimate of $R$ in small $x$ region where $R$ has not been previously measured, is in good agreement with the new CCFR data.