M. Narain

Abstract Colliders are essential research tools for particle physics. Numerous future collider proposal were discussed in the course of the US high energy physics community strategic planning exercise Snowmass'21 . The Implementation Task Force (ITF) has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This article describes the metrics and approaches, and presents evaluations of future colliders performed by the ITF.

This biennial Review summarizes much of Particle Physics. Using data from previous editions plus new measurements from papers we list evaluate and average measured properties of gauge bosons leptons quarks mesons and baryons. We also summarize searches for hypothetical particles such as Higgs bosons heavy neutrinos and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables gures formulae and reviews of topics such as the Standard Model particle detectors probability and statistics. Among the reviews are many that are new or heavily revised including those on neutrino mixing CP violation in K D and B mesons Vcb the new exotic  particle extra dimensions grand unified theories cosmic background radiation dark matter cosmological parameters and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables listings and reviews and errata are also available on the Particle Data Group website https://pdg.lbl.gov.

This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $CP$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).

We describe the construction of end-to-end jet image classifiers based on simulated low-level detector data to discriminate quark- vs. gluon-initiated jets with high-fidelity simulated CMS Open Data. We highlight the importance of precise spatial information and demonstrate competitive performance to existing state-of-the-art jet classifiers. We further generalize the end-to-end approach to event-level classification of quark vs. gluon di-jet QCD events. We compare the fully end-to-end approach to using hand-engineered features and demonstrate that the end-to-end algorithm is robust against the effects of underlying event and pile-up.

Using the Columbia University--Stony Brook (CUSB-II) detector we have studied the inclusive photon spectrum from 2.9\ifmmode\times\else\texttimes\fi{}${10}^{4}$ \ensuremath{\Upsilon}(5S) decays. We observe a strong signal due to ${\mathit{B}}^{\mathrm{*}}$\ensuremath{\rightarrow}B\ensuremath{\gamma} decays. From this we obtain (i) the average ${\mathit{B}}^{\mathrm{*}}$-B mass difference, 46.7\ifmmode\pm\else\textpm\fi{}0.4 MeV, (ii) the photon yield per \ensuremath{\Upsilon}(5S) decay, 〈\ensuremath{\gamma}/\ensuremath{\Upsilon}(5S)〉=1.09\ifmmode\pm\else\textpm\fi{}0.06, and (iii) the average velocity of the ${\mathit{B}}^{\mathrm{*}}$'s, 〈\ensuremath{\beta}〉=0.156\ifmmode\pm\else\textpm\fi{}0.010, for a mix of nonstrange (B) and strange (${\mathit{B}}_{\mathit{s}}$) ${\mathit{B}}^{\mathrm{*}}$ mesons from \ensuremath{\Upsilon}(5S) decays. From the shape of the photon line, we find that both B and ${\mathit{B}}_{\mathit{s}}$ mesons are produced with nearly equal values for the hyperfine splitting of the B and ${\mathit{B}}_{\mathit{s}}$ meson systems.

Z' bosons that couple preferentially to the third generation fermions can arise in models with extended weak (SU(2)xSU(2)) or hypercharge (U(1)xU(1)) gauge groups. We show that existing limits on quark-lepton compositeness set by the LEP and Tevatron experiments translate into lower bounds of order a few hundred GeV on the masses of these Z' bosons. Resonances of this mass can be directly produced at the Tevatron. Accordingly, we explore in detail the limits that can be set at Run II using the process p pbar -> Z' -> tau tau -> e mu. We also comment on the possibility of using hadronically-decaying taus to improve the limits.

This document describes the simulation framework used in the Snowmass Energy Frontier studies for future Hadron Colliders. An overview of event generation with Madgraph5 along with parton shower and hadronization with Pythia6 is followed by a detailed description of pile-up and detector simulation with Delphes3. Details of event generation are included in a companion paper cited within this paper. The input parametrization is chosen to reflect the best object performance expected from the future ATLAS and CMS experiments; this is referred to as the "Combined Snowmass Detector". We perform simulations of pp interactions at center-of-mass energies √s = 14, 33, and 100 TeV with 0, 50, and 140 additional pp pile-up interactions. The object performance with multi-TeV pp collisions are studied for the first time using large pile-up interactions.

This document describes the novel techniques used to simulate the common Snowmass 2013 En- ergy Frontier Standard Model backgrounds for future hadron colliders. The purpose of many Energy Frontier studies is to explore the reach of high luminosity data sets at a variety of high energy collid- ers. The generation of high statistics samples which accurately model large integrated luminosities for multiple center-of-mass energies and pile-up environments is not possible using an unweighted event generation strategy | an approach which relies on event weighting was necessary. Even with these improvements in e ciency, extensive computing resources were required. This document de- scribes the speci c approach to event generation using Madgraph5 to produce parton-level processes, followed by parton showering and hadronization with Pythia6, and pile-up and detector simulation with Delphes3. The majority of Standard Model processes for pp interactions at √s = 14, 33, and 100 TeV with 0, 50, and 140 additional pile-up interactions are publicly available.

This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $CP$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).

As the heaviest known fundamental particle, the top quark has taken a central role in the study of fundamental interactions. Production of top quarks in pairs provides an important probe of strong interactions. The top quark mass is a key fundamental parameter which places a valuable constraint on the Higgs boson mass and electroweak symmetry breaking. Observations of the relative rates and kinematics of top quark final states constrain potential new physics. In many cases, the tests available with study of the top quark are both critical and unique. Large increases in data samples from the Fermilab Tevatron have been coupled with major improvements in experimental techniques to produce many new precision measurements of the top quark. The first direct evidence for electroweak production of top quarks has been obtained, with a resulting direct determination of V tb . Several of the properties of the top quark have been measured. Progress has also been made in obtaining improved limits on potential anomalous production and decay mechanisms. This review presents an overview of recent theoretical and experimental developments in this field. We also provide a brief discussion of the implications for further efforts.

Snowmass is a US long-term planning study for the high-energy community by the American Physical Society's Division of Particles and Fields. For its simulation studies, opportunistic resources are harnessed using the Open Science Grid infrastructure. Late binding grid technology, GlideinWMS, was used for distributed scheduling of the simulation jobs across many sites mainly in the US. The pilot infrastructure also uses the Parrot mechanism to dynamically access CvmFS in order to ascertain a homogeneous environment across the nodes. This report presents the resource usage and the storage model used for simulating large statistics Standard Model backgrounds needed for Snowmass Energy Frontier studies.

We present an overview of the High-Luminosity (HL-LHC) program at the Large Hadron Collider (LHC), its scientific potential and technological challenges for both the accelerator and detectors. The HL-LHC program is expected to start circa 2027 and aims to increase the integrated luminosity delivered by the LHC by an order of magnitude at the collision energy of 14 TeV. This requires upgrades to the injector system, accelerator complex and luminosity levelling. The two experiments, ATLAS and CMS, require substantial upgrades to most of their systems in order to cope with the increased interaction rate, and much higher radiation levels than at the current LHC. We present selected examples based on novel ideas and technologies for applications at a hadron collider. Both experiments will replace their tracking systems. We describe the ATLAS pixel detector upgrade featuring novel tilted modules, and the CMS Outer Tracker upgrade with a new module design enabling use of tracks in the level-1 trigger system. CMS will also install state-of-the-art highly segmented calorimeter endcaps. Finally, we describe new picosecond precision timing detectors of both experiments. In addition, we discuss how the upgrades will enhance the physics performance of the experiments, and solve the computing challenges posed by the expected large data sets. The physics program of the HL-LHC is focused on precision measurements probing the limits of the Standard Model (SM) of particle physics and discovering new physics. We present a selection of studies that have been carried out to motivate the HL-LHC program. A central topic of exploration will be the characterization of the Higgs boson. The large HL-LHC data samples will extend the sensitivity of searches for new particles or new interactions whose existence has been hypothesized in order to explain shortcomings of the SM. Finally, we comment on the nature of large scientific collaborations.

A study of radiative decays from 400 000 ϒ (9460)'s in the partially upgraded CUSB detector is presented. We find evidence against the existence of gluinos of mass 0 6(GeV/c2)<m<2.2(GeV/c2) from a search for radiative ϒ (9460) decays into bound states of gluinos.

Jet substructure techniques are playing an essential role in exploring the TeV scale at the Large Hadron Collider (LHC), since they facilitate the efficient reconstruction and identification of highly-boosted objects. Both for the LHC and for future colliders, there is a growing interest in using jet substructure methods based only on charged-particle information. The reason is that silicon-based tracking detectors offer excellent granularity and precise vertexing, which can improve the angular resolution on highly-collimated jets and mitigate the impact of pileup. In this paper, we assess how much jet substructure performance degrades by using track-only information, and we demonstrate physics contexts in which calorimetry is most beneficial. Specifically, we consider five different hadronic final states—W bosons, Z bosons, top quarks, light quarks, gluons—and test the pairwise discrimination power with a multi-variate combination of substructure observables. In the idealized case of perfect reconstruction, we quantify the loss in discrimination performance when using just charged particles compared to using all detected particles. We also consider the intermediate case of using charged particles plus photons, which provides valuable information about neutral pions. In the more realistic case of a segmented calorimeter, we assess the potential performance gains from improving calorimeter granularity and resolution, comparing a CMS-like detector to more ambitious future detector concepts. Broadly speaking, we find large performance gains from neutral-particle information and from improved calorimetry in cases where jet mass resolution drives the discrimination power, whereas the gains are more modest if an absolute mass scale calibration is not required.

We consider the production at the LHC of exotic quarks ${U}^{+}$ of charge $Q=+(5/3)e$ and ${D}^{\ensuremath{-}}$ of charge $Q=\ensuremath{-}(4/3)e$ of mass ${m}_{*}$ arising in a composite fermion scenario characterized by a compositeness scale $\mathrm{\ensuremath{\Lambda}}$. Such states are predicted in composite models of higher isospin multiplets (${I}_{W}=1$ or ${I}_{W}=3/2$). Given their exotic charges (such as $5/3$), their decays proceed through the electroweak interactions. We compute decay widths and rates for resonant production of the exotic quarks at the LHC. Partly motivated by the recent observation of an excess by the CMS collaboration in the $e{\overline{)p}}_{T}jj$ final state signature we focus on $pp\ensuremath{\rightarrow}{U}^{+}j\ensuremath{\rightarrow}{W}^{+}+jj\ensuremath{\rightarrow}{\ensuremath{\ell}}^{+}{\overline{)p}}_{T}jj$ and then perform a fast simulation of the detector reconstruction based on Delphes. We then scan the parameter space of the model (${m}_{*}=\mathrm{\ensuremath{\Lambda}}$) and study the statistical significance of the signal against the relevant standard model background ($Wjj$ followed by leptonic decay of the $W$ gauge boson) providing the luminosity curves as function of ${m}_{*}$ for discovery at 3- and $5\text{\ensuremath{-}}\ensuremath{\sigma}$ level.

Using the CUSB-II detector at the Cornell Electron Storage Ring, we have made precision measurements of the electric dipole transition rates from \ensuremath{\Upsilon}\ensuremath{''} to${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}}^{\ensuremath{'}}$, which are in excellent agreement with theory. The fine-structure splitting is found to beM(${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}2}^{\ensuremath{'}}$)-M(${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}1}^{\ensuremath{'}}$=13.5\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.5 MeV and(${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}1}^{\ensuremath{'}}$)-M(${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}0}^{\ensuremath{'}}$)=23.2\ifmmode\pm\else\textpm\fi{}0.7\ifmmode\pm\else\textpm\fi{}0.7 MeV, leading to a ratioR=0.584\ifmmode\pm\else\textpm\fi{}0.024\ifmmode\pm\else\textpm\fi{}0.02. The fine structure measures the relative contributions of the spin-orbit interaction a=9.5\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}0.1 MeV and tensor interaction b=2.3\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\pm\else\textpm\fi{}0.1 MeV. We also find that the long-range confining potential transforms as a Lorentz scalar.\textcopyright{} 1991 The American Physical Society

This report summarizes the work of the Energy Frontier New Physics working group of the 2013 Community Summer Study (Snowmass).

The 2021-22 High-Energy Physics Community Planning Exercise (a.k.a. ``Snowmass 2021'') was organized by the Division of Particles and Fields of the American Physical Society. Snowmass 2021 was a scientific study that provided an opportunity for the entire U.S. particle physics community, along with its international partners, to identify the most important scientific questions in High Energy Physics for the following decade, with an eye to the decade after that, and the experiments, facilities, infrastructure, and R&D needed to pursue them. This Snowmass summary report synthesizes the lessons learned and the main conclusions of the Community Planning Exercise as a whole and presents a community-informed synopsis of U.S. particle physics at the beginning of 2023. This document, along with the Snowmass reports from the various subfields, will provide input to the 2023 Particle Physics Project Prioritization Panel (P5) subpanel of the U.S. High-Energy Physics Advisory Panel (HEPAP), and will help to guide and inform the activity of the U.S. particle physics community during the next decade and beyond.

B-meson semileptonic decay spectra have been obtained at the \ensuremath{\Upsilon}(4S) and at the \ensuremath{\Upsilon}(5S) at the Cornell Electron Storage Ring with the Columbia University--Stony Brook detector. The branching ratio for B\ensuremath{\rightarrow}e\ensuremath{\nu}X at the \ensuremath{\Upsilon}(4S) is found to be (10.0\ifmmode\pm\else\textpm\fi{}0.5)%. The electron spectrum of B\ensuremath{\rightarrow}e\ensuremath{\nu}X at the \ensuremath{\Upsilon}(5S) is observed for the first time and the average branching ratio of B,${\mathit{B}}_{\mathit{s}}$\ensuremath{\rightarrow}e\ensuremath{\nu}X is consistent with that for B's from \ensuremath{\Upsilon}(4S) decays. The shape of the electron spectrum at the \ensuremath{\Upsilon}(5S) indicates production of B mesons which are heavier than nonstrange B's, presumably strange B's.

Using the Columbia University--Stony Brook detector at the Cornell Electron Storage Ring, we have measured ${B}_{\ensuremath{\mu}\ensuremath{\mu}}$, the branching fraction into muons, of the 1S, 2S, and 3S \ensuremath{\Upsilon} mesons. We obtain ${\mathit{B}}_{\mathrm{\ensuremath{\mu}}\mathrm{\ensuremath{\mu}}}$(1S)=(2.61\ifmmode\pm\else\textpm\fi{}0.09\ifmmode\pm\else\textpm\fi{}0.11)%, ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{tot}}$(1S)=51.1\ifmmode\pm\else\textpm\fi{}3.2 keV, ${\mathit{B}}_{\mathrm{\ensuremath{\mu}}\mathrm{\ensuremath{\mu}}}$(2S)=(1.38\ifmmode\pm\else\textpm\fi{}0.25\ifmmode\pm\else\textpm\fi{}0.15)%, ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{tot}}$(2S)=42.3\ifmmode\pm\else\textpm\fi{}9.2 keV, ${\mathit{B}}_{\mathrm{\ensuremath{\mu}}\mathrm{\ensuremath{\mu}}}$(3S)=(1.73\ifmmode\pm\else\textpm\fi{}0.15\ifmmode\pm\else\textpm\fi{}0.11)%, and ${\ensuremath{\Gamma}}_{\mathrm{tot}(3\mathrm{S})=27.7\ifmmode\pm\else\textpm\fi{}3.7}$ kev. We also derive, from these results, ${\ensuremath{\alpha}}_{s}$=0.174 and ${\ensuremath{\Lambda}}_{\mathrm{MS}\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}=157}$ MeV, where MS\ifmmode\bar\else\textasciimacron\fi{} denotes the modified minimal-subtraction scheme.

With an expected 10-fold increase in luminosity in S-LHC, the radiation environment in the tracker volumes will be considerably harsher for silicon-based detectors than the already harsh LHC environment. Since 2006, a group of CMS institutes, using a modified CMS DAQ system, has been exploring the use of Magnetic Czochralski silicon as a detector element for the strip tracker layers in S-LHC experiments. Both p+/n-/n+ and n+/p-/p+ sensors have been characterized, irradiated with proton and neutron sources, assembled into modules, and tested in a CERN beamline. There have been three beam studies to date and results from these suggest that both p+/n-/n+ and n+/p-/p+ Magnetic Czochralski silicon are sufficiently radiation hard for the R>25cm regions of S-LHC tracker volumes. The group has also explored the use of forward biasing for heavily irradiated detectors, and although this mode requires sensor temperatures less than −50 °C, the charge collection efficiency appears to be promising.

The Snowmass 2021 Implementation Task Force has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This report documents the metrics and processes, and presents evaluations of future colliders performed by Implementation Task Force.

This report, as part of the 2021 Snowmass Process, summarizes the current status of collider physics at the Energy Frontier, the broad and exciting future prospects identified for the Energy Frontier, the challenges and needs of future experiments, and indicates high priority research areas.

Using the CUSB-II detector at CESR we have observed electric dipole transitions between the $\ensuremath{\Upsilon}$ and ${\ensuremath{\chi}}_{b}$ states, both in exclusive and inclusive channels. We have measured their branching ratios and find $B(\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}{\ensuremath{\chi}}_{b}(2{P}_{2,1,0})\ensuremath{\gamma})=(11.1\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.4)%,(11.5\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.5)%,(6.0\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.6)%$. We have measured the center of gravity of the ${\ensuremath{\chi}}_{b}(2P)$ states to be (10259.5\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}1.0) MeV and their fine-structure mass splittings to be (13.5\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.5) MeV between the $J=2$ and $J=1$ states and (23.5\ifmmode\pm\else\textpm\fi{}0.7\ifmmode\pm\else\textpm\fi{}0.7) MeV between $J=1$ and $J=0$, leading to a fine-structure ratio of 0.574\ifmmode\pm\else\textpm\fi{}0.024\ifmmode\pm\else\textpm\fi{}0.02. The measured fine-structure splitting implies that the spin-orbit interaction dominates over the tensor interaction and that the long-range confining potential is due to an effective scalar exchange. From the measured branching ratios we infer the hadronic widths of the ${\ensuremath{\chi}}_{b}(2P)$ states and find them to be consistent with QCD predictions. We use them to derive values of ${\ensuremath{\alpha}}_{s}$. We have observed the suppressed transition $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}{\ensuremath{\chi}}_{b}(1P)\ensuremath{\gamma}$ and the ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ transitions from the $\ensuremath{\Upsilon}(3S)$. We find $B(\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\Upsilon}(1S){\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(2.2\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.3)%$ and $B(\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\Upsilon}(2S){\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(1.7\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.2)%$. We also present a measurement of the dipion invariantmass spectrum from the transition $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\Upsilon}(1S){\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$.

We have studied the decay chain \ensuremath{\Upsilon}\ensuremath{''}\ensuremath{\rightarrow}${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}}^{\ensuremath{'}}$(${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}}$)\ensuremath{\gamma}\ensuremath{\rightarrow}\ensuremath{\Upsilon}\ensuremath{'}(\ensuremath{\Upsilon})\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{\mu}(ee)\ensuremath{\gamma}\ensuremath{\gamma}with the CUSB II detector at the Cornell Electron Storage Ring. For a sample of 1.33\ifmmode\times\else\texttimes\fi{}${10}^{6}$ \ensuremath{\Upsilon}\ensuremath{''}'s we find \ensuremath{\approx}400 events. We measure branching ratios for${\mathrm{\ensuremath{\chi}}}_{\mathrm{bJ}}^{\ensuremath{'}}$\ensuremath{\rightarrow}\ensuremath{\Upsilon}\ensuremath{'}(\ensuremath{\Upsilon})\ensuremath{\gamma} and, using calculated E1 rates, we derive total and hadronic widths of the${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}}^{\ensuremath{'}}$ states. From these widths we obtain values of ${\mathrm{a}}_{\mathrm{s}}$ in the range between 0.13 and 0.21, in agreement with other determinations. We observe the suppressed decay \ensuremath{\Upsilon}\ensuremath{''}\ensuremath{\rightarrow}${\mathrm{\ensuremath{\chi}}}_{\mathrm{b}}$\ensuremath{\gamma}. The measured branching ratio suggests that relativistic effects are important. We also determine the branching ratios for \ensuremath{\Upsilon}\ensuremath{''}\ensuremath{\rightarrow}\ensuremath{\Upsilon}\ensuremath{'}${\mathrm{\ensuremath{\pi}}}^{0}$${\mathrm{\ensuremath{\pi}}}^{0}$ to be (1.3\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.2)% and\ensuremath{\Upsilon}\ensuremath{''}\ensuremath{\rightarrow}\ensuremath{\Upsilon}${\mathrm{\ensuremath{\pi}}}^{0}$${\mathrm{\ensuremath{\pi}}}^{0}$ to be (1.8\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}0.2)%. \textcopyright{} 1991 The American Phsyical Society

Theoretical progress in Higgs boson production and background processes is discussed with particular emphasis on QCD corrections at and beyond next-to-leading order as well as next-to-leading order electroweak corrections. The residual theoretical uncertainties of the investigated processes are estimated in detail. Moreover, recent investigations of the MSSM Higgs sector and other extensions of the SM Higgs sector are presented. The potential of the LHC and a high-energy linear e+e- collider for the measurement of Higgs couplings is analyzed.

We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high pT leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the "New Physics'' working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 11-29 June, 2007).

We describe a novel application of the end-to-end deep learning technique to the task of discriminating top quark-initiated jets from those originating from the hadronization of a light quark or a gluon. The end-to-end deep learning technique combines deep learning algorithms and low-level detector representation of the high-energy collision event. In this study, we use lowlevel detector information from the simulated CMS Open Data samples to construct the top jet classifiers. To optimize classifier performance we progressively add low-level information from the CMS tracking detector, including pixel detector reconstructed hits and impact parameters, and demonstrate the value of additional tracking information even when no new spatial structures are added. Relying only on calorimeter energy deposits and reconstructed pixel detector hits, the end-to-end classifier achieves a ROC-AUC score of 0.975±0.002 for the task of classifying boosted top quark jets. After adding derived track quantities, the classifier ROC-AUC score increases to 0.9824±0.0013, serving as the first performance benchmark for these CMS Open Data samples.

A large scale scintillating fiber tracker using visible light photon counter (VLPC) readout was built as a prototype far the upgraded DO central tracker. This prototype has been under test at Fermilab for six months using cosmic rays. A description of the components of the tracker including the photodetector, fibers, lightguides, ribbons, and DAQ is given. Preliminary results on detected photon yield, position resolution, efficiency and VLPC performance are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

With the CUSB-II detector at CESR we have studied the processes γ(3S) → γ(1S)π+γ− and γ(3S) → γ(2S)π+π−, where the final state γ(1S or 2S) decays into a pair of leptons. We have found 451 γ(3S) → γ(1S)π+π− events and 138 γ(3S) → γ(2S)π+π− events. The corresponding branching ratios are (4.46 ± 0.34 ± 0.50)% and (4.82 ± 0.65 ± 0.53) % respectively, where the first error is statistical and the second systematic. The properties of the π+π− system have been studied and compared with several models.

We investigate the prospects for discovery or exclusion of additional Higgs scalars at the 14 TeV and 33 TeV LHC in the context of theories with two Higgs doublets. We focus on the modes with the largest production rates at hadron colliders, namely gluon fusion production of a heavy CP-even scalar H or a heavy CP-odd pseudoscalar A. We consider the sensitivity of the decay channels H to ZZ to 4l, and A to Zh with Z to ll and h to bb or h to tautau.

The precise measurement of physics observables and the test of their consistency within the standard model (SM) are an invaluable approach, complemented by direct searches for new particles, to determine the existence of physics beyond the standard model (BSM). Studies of massive electroweak gauge bosons (W and Z bosons) are a promising target for indirect BSM searches, since the interactions of photons and gluons are strongly constrained by the unbroken gauge symmetries. They can be divided into two categories: (a) Fermion scattering processes mediated by s- or t-channel W/Z bosons, also known as electroweak precision measurements; and (b) multi-boson processes, which include production of two or more vector bosons in fermion-antifermion annihilation, as well as vector boson scattering (VBS) processes. The latter categories can test modifications of gauge-boson self-interactions, and the sensitivity is typically improved with increased collision energy. This report evaluates the achievable precision of a range of future experiments, which depend on the statistics of the collected data sample, the experimental and theoretical systematic uncertainties, and their correlations. In addition it presents a combined interpretation of these results, together with similar studies in the Higgs and top sector, in the Standard Model effective field theory (SMEFT) framework. This framework provides a model-independent prescription to put generic constraints on new physics and to study and combine large sets of experimental observables, assuming that the new physics scales are significantly higher than the EW scale.

Abstract The design of a processor to trigger on long-lived particles (e.g. b-quarks) for the DO experiment at the Fermilab Tevatron is presented. This device reconstructs the trajectory of the charged particles in the DO tracking system, which consists of a central fiber tracker and a silicon microstrip tracker. The r-φ impact parameter resolution of the fitted tracks is about 40 μm. This enables the identification of the long-lived b-quarks produced in the decays of various particles, e.g. the top quarks, Higgs Boson, techni-particles and other exotic particles produced in p p collisions at the Tevatron. In this report we describe the design of the architecture and algorithms for the Silicon Track Trigger.

The increase in instantaneous luminosity anticipated in Run IIb of the Tevatron collider at Fermilab requires increased background rejection capabilities from the trigger system of the DO detector. A set of upgrades is under way to improve triggering at level 1 in the calorimeter and tracker, and at level 2 in the silicon track trigger and software triggers. Reductions of up to a factor of ten on the rates of high transverse momentum triggers are anticipated with the upgrades described.

We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high p{sub T} leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 11-29 June, 2007).

These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 3, on the Energy Frontier, discusses the program of research with high-energy colliders. This area includes experiments on the Higgs boson, the electroweak and strong interactions, and the top quark. It also encompasses direct searches for new particles and interactions at high energy.

Characterization of a large number of visible light photon counters (VLPC) is an integral part of the scintillating fiber system test for the DO upgrade, currently underway at Fermilab. We report results from our investigation of 4200 channels of HISTE IV VLPC's, for use in a cosmic ray test. We have studied the dependence of critical device characteristics like quantum efficiency, gain, and noise as a function of operating temperature and VLPC bias voltage, and the variation of these characteristics over the large sample. We also discuss the general operation of the devices and the problems encountered during the characterization.

All therapeutic methods dealing with coronavirus (past and present) are based on chemicals.We test for it (positive or negative) chemically and hope to cure it with a future vaccine (some complicated chemical preparation).If and when the virus mutates, another set of chemical protocols for its testing and a hunt for new chemicals as a vaccine shall begin again and again.But the history of modern (western) medicine tells us that our biotechnology is not so limited.Copious scientific evidence for sonic and low energy electromagnetic signals produced by all biological elements (DNA, cells, bacteria, parasites, virus) exists; in turn, the biological elements are affected by these non-chemical signals as well.A careful analysis and a catalogue of the spectrum of these nonchemical signals are proposed here as a unique biophysical signature.

The performance of a large scale scintillating fiber tracker with VLPC readout has been studied in a cosmic-ray test. Approximately 9.6 photoelectrons per single layer per trigger were detected at a VLPC bias voltage of 6.5V. The doublet efficiency was nearly 100% at a 0.1% noise level and a position resolution of about 140μm was measured. We also studied the relationship between VLPC performance and VLPC bias voltage by measuring single fiber efficiency as a function of VLPC bias in the range 6.2V to 7.OV at a fixed temperature of 6.5 °K. We observed no significant variation in VLPC performance within this bias range.

Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. We describe ongoing R&D efforts to demonstrate functionality of components of such detectors. This includes the study of integrated 3D electronics with active edge sensors to produce "active tiles" which can be tested and assembled into arrays of arbitrary size with high yield.

We report on results of a cosmic ray test of a scintillating fiber tracker using Visible Light Photon Counter (VLPC) readout. Two different detector configurations have been constructed and operated, the first with a total of 3072 channels and the second with 1,785 channels. The 3072 channel system is a prototype for the DO detector tracking upgrade and represents a configuration that is similar to that in the final detector. The second, smaller test was specifically designed to study the position resolution capabilities of the fiber tracker. A description of the cosmic ray test including trigger, fiber configuration, undoped lightguides, VLPC cassettes and cryogenics, and calibration system is given. Final results from the 3072 channel test will be presented, including measurements of resolution, light yield per minimum ionizing particle, singlet and doublet efficiency, and long-term stability. Resolution results from the second, 1785 channel test will be compared to the predicted resolution from Monte Carlo studies.

This is a summary of the projects undertaken by the working group I on high energy and collider physics.

The luminosity goal for the Super-LHC is 1035/cm2/s. At this luminosity the number of proton-proton interactions in each beam crossing will be in the hundreds. This will stress many components of the CMS detector. One system that has to be upgraded is the trigger system. To keep the rate at which the level 1 trigger fires manageable, information from the tracker has to be integrated into the level 1 trigger. Current design proposals foresee tracking detectors that perform on-detector filtering to reject hits from low-momentum particles. In order to build a trigger system, the filtered hit data from different layers and sectors of the tracker will have to be transmitted off the detector and brought together in a logic processor that generates trigger tracks within the time window allowed by the level 1 trigger latency. This paper describes a possible architecture for the off-detector logic that accomplishes this goal.

Machine learning algorithms are gaining ground in high energy physics for applications in particle and event identification, physics analysis, detector reconstruction, simulation and trigger. Currently, most data-analysis tasks at LHC experiments benefit from the use of machine learning. Incorporating these computational tools in the experimental framework presents new challenges. This paper reports on the implementation of the end-to-end deep learning with the CMS software framework and the scaling of the end-to-end deep learning with multiple GPUs. The end-to-end deep learning technique combines deep learning algorithms and low-level detector representation for particle and event identification. We demonstrate the end-to-end implementation on a top quark benchmark and perform studies with various hardware architectures including single and multiple GPUs and Google TPU.

Transformative discovery in science is driven by innovation in technology. Our boldest undertakings in particle physics have at their foundation precision instrumentation. To reveal the profound connections underlying everything we see from the smallest scales to the largest distances in the Universe, to understand its fundamental constituents, and to reveal what is still unknown, we must invent, develop, and deploy advanced instrumentation. Investments in High Energy Physics (HEP) enabled by instrumentation have been richly rewarded with discoveries of the tiny masses of the neutrinos, the origin of mass itself: the enigmatic Higgs boson, and the surprising accelerating expansion of the Universe. What we have learned is remarkable, unexpected, exciting and mysterious; raising many new questions waiting to be answered. The quest to answer them drives innovation that improves the nation's health, wealth, and security, inspiring the public and drawing young people to science. Excellence and innovation come most effectively from diverse teams of people. Success, therefore, depends critically on attracting, engaging, and supporting a diverse cadre of young people to the field, and ensuring an inclusive environment at all levels. The program laid out in the 2014 Particle Physics Projects Prioritization Panel (P5) report "Building for Discovery - A Strategic Plan for U.S. Particle Physics in a Global Context" guides current and near future experiments to exploit these and other discoveries, and the instrumentation innovation they require, to push the frontiers of science into new territory. To explore this territory HEP will soon embark on planning the next generation of experiments. Realizing these experiments will require giant leaps in capabilities beyond the instrumentation of today. Accordingly, now is a pivotal moment to invest in the accelerated development of cost-effective instrumentation with greatly improved sensitivity and performance that will make measurable the unmeasurable, enabling a tool-driven revolution to open the door to future discoveries. Historic scientific opportunities await us, enabled by executing the instrumentation research plan outlined here.

This paper describes a novel algorithm for tagging jets originating from the hadronisation of strange quarks (strange-tagging) with the future International Large Detector (ILD) at the International Linear Collider (ILC). It also presents the first application of such a strange-tagger to a Higgs to strange ($h \rightarrow s\bar{s}$) analysis with the $P(e^-,e^+) = (-80\%,+30\%)$ polarisation scenario, corresponding to 900 fb$^{-1}$ of the initial proposed 2000 fb$^{-1}$ of data which will be collected by ILD during its first 10 years of data taking at $\sqrt{s} = 250$ GeV. Upper limits on the Standard Model Higgs-strange coupling strength modifier, $\kappa_s$, are derived at the 95% confidence level to be 7.14. The paper includes as well a preliminary study of a Ring Imaging Cherenkov (RICH) system capable of discriminating between kaons and pions at high momenta (up to 25 GeV), and thus enhancing strange-tagging performance at future Higgs factory detectors.

To impart hands-on training in physics analysis, CMS experiment initiated the concept of CMS Data Analysis School (CMSDAS). It was born over three years ago at the LPC (LHC Physics Centre), Fermilab and is based on earlier workshops held at the LPC and CLEO Experiment. As CMS transitioned from construction to the data taking mode, the nature of earlier training also evolved to include more of analysis tools, software tutorials and physics analysis. This effort epitomized as CMSDAS has proven to be a key for the new and young physicists to jump start and contribute to the physics goals of CMS by looking for new physics with the collision data. With over 400 physicists trained in six CMSDAS around the globe, CMS is trying to engage the collaboration in its discovery potential and maximize physics output. As a bigger goal, CMS is striving to nurture and increase engagement of the myriad talents, in the development of physics, service, upgrade, education of those new to CMS and the career development of younger members. An extension of the concept to the dedicated software and hardware schools is also planned, keeping in mind the ensuing upgrade phase.

We have searched for photon signals in \ensuremath{\Upsilon}(4S) decays, indicative of large decay rates involving annihilation of the bb\ifmmode\bar\else\textasciimacron\fi{} pair rather than decays to BB\ifmmode\bar\else\textasciimacron\fi{} meson pairs. We do not observe any evidence for such signals. We also obtain a model-independent upper limit of (4.5--6.0)% for the branching ratio of \ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}ggX, for 0M(X)1.2 GeV, at 90% confidence level.

The design, construction and performance of a very compact precision electromagnetic spectrometer is described. The CUSB-II detector has been used to study ϒ spectroscopy, search for exotic particles and measure properties of the B and B∗ mesons at the Cornell Electron Storage Ring.

We discuss the experimental and theoretical uncertainties on precision electroweak observables and their relationship to the indirect constraints on the Higgs-boson mass, $\MH$, in the Standard Model (SM). The critical experimental measurements ($\MW$, $\sweff$, $\mt$, ...) are evaluated in terms of their present uncertainties and their prospects for improved precision at future colliders, and their contribution to the constraints on $\MH$. In addition, the current uncertainties of the theoretical predictions for $\MW$ and $\sweff$ due to missing higher order corrections are estimated and expectations and necessary theoretical improvements for future colliders are explored. The constraints from rare B decays are also discussed. Analysis of the present experimental and theoretical precisions yield a current upper bound on $\MH$ of $\sim 200$ GeV. Including anticipated improvements corresponding to the prospective situation at future colliders (Tevatron Run II, LHC, LC/GigaZ), we find a relative precision of about 25% to 8% (or better) is achievable in the indirect determination of $\MH$.

Z' bosons that couple preferentially to the third generation fermions can arise in models with extended weak (SU(2)xSU(2)) or hypercharge (U(1)xU(1)) gauge groups. We show that existing limits on quark-lepton compositeness set by the LEP and Tevatron experiments translate into lower bounds of order a few hundred GeV on the masses of these Z' bosons. Resonances of this mass can be directly produced at the Tevatron. Accordingly, we explore in detail the limits that can be set at Run II using the process p pbar -> Z' -> tau tau -> e mu. We also comment on the possibility of using hadronically-decaying taus to improve the limits.

The DØ experiment at the Fermilab pp¯ Tevatron collider (Batavia, IL, USA) has undergone significant upgrades in anticipation of high luminosity running conditions. As part of the upgrade, the capabilities of the Central Track Trigger (CTT) to make trigger decisions based on hit patterns in the Central Fiber Tracker (CFT) have been much improved. We report on the implementation, commissioning and operation of the upgraded CTT system.

Using the CUSB-II detector at the Cornell Electron Storage Ring, we have measured B\ensuremath{\mu}\ensuremath{\mu}, the branching fraction into muons, of the \ensuremath{\Upsilon}'' meson. We find ${\mathit{B}}_{\mathrm{\ensuremath{\mu}}\mathrm{\ensuremath{\mu}}}$(\ensuremath{\Upsilon}'')=(1.53\ifmmode\pm\else\textpm\fi{}0.33\ifmmode\pm\else\textpm\fi{}0.21)%, from which the \ensuremath{\Upsilon}'' total decay width is 25.5\ifmmode\pm\else\textpm\fi{}5.0 keV. From this result we obtain ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{s}}$=0.${170}_{\mathrm{\ensuremath{-}}0.012}^{+0.015}$, ${\ensuremath{\Lambda}}_{\mathrm{MS}\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}{=148}_{\mathrm{\ensuremath{-}}39}^{+56}}$ MeV. (MS\ifmmode\bar\else\textasciimacron\fi{} denotes the modified minimal-subtraction scheme).

Using the CUSB-II detector at CESR we have measured the B∗ cross section in the energy range from s = 10.61–10.65 GeV and 10.70 GeV to be 0.16±0.03 nb and 0.33±0.13 nb respectively. The photon energy for B∗→Bγ decays is measured to be 45.4±0.8 MeV, in agreement with our earlier determination. The implication of this measurement for future B factories is discussed.

This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers andCP -mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HLLHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).

In this note we study the prospect of high-precision measurements of W boson mass, top quark mass, and forward-backward asymmetry in Z-&gt;ee decays and the search for the Higgs boson during Run 2 to challenge the standard model.

In this paper, we present the results on top quark physics from the Tevatron and future prospects for studying the top quark properties during Run II of the Tevatron and at LHC. We discuss sensitivities of several measurements for the two machines. The enhanced capabilities of the CDF and DØ detectors, together with an integrated luminosity of at least 2 fb−1, will provide a measurement of the top quark mass of 2–3 GeV, and a W boson mass measurement of 40 MeV. These precision measurements will help constrain indirectly the mass of the elusive Higgs Boson.

We illustrate benefits to the U.S. economy and technological infrastructure of U.S. participation in accelerators overseas. We discuss contributions to experimental hardware and analysis and to accelerator technology and components, and benefits stemming from the involvement of U.S. students and postdoctoral fellows in global scientific collaborations. Contributed to the proceedings of the Snowmass 2013 Community Summer Study.

The Instrumentation Frontier was set up as a part of the Snowmass 2013 Community Summer Study to examine the instrumentation R&amp;D needed to support particle physics research over the coming decade. This report summarizes the findings of the Energy Frontier subgroup of the Instrumentation Frontier.

We illustrate benefits to the U.S. economy and technological infrastructure of U.S. participation in accelerators overseas. We discuss contributions to experimental hardware and analysis and to accelerator technology and components, and benefits stemming from the involvement of U.S. students and postdoctoral fellows in global scientific collaborations. Contributed to the proceedings of the Snowmass 2013 Community Summer Study.

We present the prospects for the discovery or exclusion of heavy vector-like charge 2/3 quarks, T, in proton-proton collisions at two center-of-mass energies, 14 and 33 TeV at the LHC. In this note, the pair production of T quark and its antiparticle, with decays to W boson and a b quark (Wb), a top quark and the Higgs boson (tH), and a top quark and Z boson (tZ) are investigated. Higgs boson decays to $b\bar b$ and $W^+W^-$ final states are selected for this study.

This document describes the novel techniques used to simulate the common Snowmass 2013 Energy Frontier Standard Model backgrounds for future hadron colliders. The purpose of many Energy Frontier studies is to explore the reach of high luminosity data sets at a variety of high energy colliders. The generation of high statistics samples which accurately model large integrated luminosities for multiple center-of-mass energies and pile-up environments is not possible using an unweighted event generation strategy -- an approach which relies on event weighting was necessary. Even with these improvements in efficiency, extensive computing resources were required. This document describes the specific approach to event generation using Madgraph5 to produce parton-level processes, followed by parton showering and hadronization with Pythia6, and pile-up and detector simulation with Delphes3. The majority of Standard Model processes for pp interactions at $\sqrt(s)$ = 14, 33, and 100 TeV with 0, 50, and 140 additional pile-up interactions are publicly available.

This document describes the simulation framework used in the Snowmass Energy Frontier studies for future Hadron Colliders. An overview of event generation with {\sc Madgraph}5 along with parton shower and hadronization with {\sc Pythia}6 is followed by a detailed description of pile-up and detector simulation with {\sc Delphes}3. Details of event generation are included in a companion paper cited within this paper. The input parametrization is chosen to reflect the best object performance expected from the future ATLAS and CMS experiments; this is referred to as the "Combined Snowmass Detector". We perform simulations of $pp$ interactions at center-of-mass energies $\sqrt{s}=$ 14, 33, and 100 TeV with 0, 50, and 140 additional $pp$ pile-up interactions. The object performance with multi-TeV $pp$ collisions are studied for the first time using large pile-up interactions.

We illustrate benefits to the U.S. economy and technological infrastructure of U.S. participation in accelerators overseas. We discuss contributions to experimental hardware and analysis and to accelerator technology and components, and benefits stemming from the involvement of U.S. students and postdoctoral fellows in global scientific collaborations. Contributed to the proceedings of the Snowmass 2013 Community Summer Study.

A large scale scintillating fiber tracker using visible light photon counter (VLPC) readout was built as a prototype for the upgraded DO central tracker. This prototype has been under test at Fermilab for six months using cosmic rays. A description of the components of the tracker including the photodetector, fibers, lightguides, ribbons, and DAQ is given. Preliminary results indicate a mean detected yield of about 10 photoelectrons per fiber, position resolution of 140 /spl mu/m for a fiber doublet, and a doublet efficiency greater than 99%.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

We describe a novel application of the end-to-end deep learning technique to the task of discriminating top quark-initiated jets from those originating from the hadronization of a light quark or a gluon. The end-to-end deep learning technique uses low-level detector representation of high-energy collision event as inputs to deep learning algorithms. In this study, we use low-level detector information from the simulated Compact Muon Solenoid (CMS) open data samples to construct the top jet classifiers. To optimize classifier performance we progressively add low-level information from the CMS tracking detector, including pixel detector reconstructed hits and impact parameters, and demonstrate the value of additional tracking information even when no new spatial structures are added. Relying only on calorimeter energy deposits and reconstructed pixel detector hits, the end-to-end classifier achieves an area under the receiver operator curve (AUC) score of $0.975\ifmmode\pm\else\textpm\fi{}0.002$ for the task of classifying boosted top quark jets. After adding derived track quantities, the classifier AUC score increases to $0.9824\ifmmode\pm\else\textpm\fi{}0.0013$, serving as the first performance benchmark for these CMS open data samples.

High Energy Particle Physics (HEP) faces challenges over the coming decades with a need to attract young people to the field and STEM careers, as well as a need to recognize, promote and sustain those in the field who are making important contributions to the research effort across the many specialties needed to deliver the science. Such skills can also serve as attractors for students who may not want to pursue a PhD in HEP but use them as a springboard to other STEM careers. This paper reviews the challenges and develops strategies to correct the disparities to help transform the particle physics field into a stronger and more diverse ecosystem of talent and expertise, with the expectation of long-lasting scientific and societal benefits.

The Snowmass 2021 Implementation Task Force has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This report documents the metrics and processes, and presents evaluations of future colliders performed by Implementation Task Force.

A description of Standard Model background Monte Carlo samples produced for studies related to future hadron colliders.

This report summarizes the work of the Energy Frontier Topical Group on EW Physics: Heavy flavor and top quark physics (EF03) of the 2021 Community Summer Study (Snowmass). It aims to highlight the physics potential of top-quark studies and heavy-flavor production processes (bottom and charm) at the HL-LHC and possible future hadron and lepton colliders and running scenarios.

investigation of the radiation levels in the SSC detectors was undertaken by D. Groom and colleagues, in the context of the ``task force on radiation levels in the SSC interaction regions.`` The method consisted essentially of an analytic approach, using standard descriptions of average events in conjunction with simulations of secondary processes. Following Groom`s work, extensive Monte Carlo simulations were performed to address the issues of backgrounds and radiation environments for the GEM and SD C3 experiments proposed at the SSC, and for the ATLAS and CMS experiments planned for the LHC. The purpose of the present article is to give a brief summary of some aspects of the methods, assumptions, and calculations performed to date (principally for the SSC detectors), and to stress the relevance of such calculations to the detectors proposed for the study of B-physics in particular.

Students from under-represented populations, including those at minority serving institutions have traditionally faced many barriers that have resulted in their being under-represented in High Energy Physics. These barriers include lack of research infrastructure and opportunities, insufficient mentoring, lack of support networks, and financial hardship, among many others. Recently the U.S. CMS Collaboration launched a pilot program U.S. CMS - PURSUE (Program for Undergraduate Research SUmmer Experience) to address these barriers. A 10-week paid internship program, the very first of its kind in an HEP experiment, was organised during the summer of 2022. Students were selected predominantly from Minority Serving Institutions with no research program in HEP. This pilot program provided a structured hands-on research experience under the mentor-ship of U.S. CMS scientists from several collaborating institutions. In addition to emphasis on hands-on research, the program offered a set of software training modules for the first few weeks. These were interleaved with a series of lectures every week covering a broad range of topics. The students were exposed to cutting-edge particle physics research and developed a broad set of skills in software, computing, data science, and machine learning. The modality of this program was virtual, due to the unknown circumstances following the pandemic. There is plan to continue the internship program annually, with in-person training and research participation. In this paper, we describe the experience with the pilot program U.S. CMS - PURSUE.

This is the Snowmass2021 Energy Frontier (EF) Beyond the Standard Model (BSM) report. It combines the EF topical group reports of EF08 (Model-specific explorations), EF09 (More general explorations), and EF10 (Dark Matter at Colliders). The report includes a general introduction to BSM motivations and the comparative prospects for proposed future experiments for a broad range of potential BSM models and signatures, including compositeness, SUSY, leptoquarks, more general new bosons and fermions, long-lived particles, dark matter, charged-lepton flavor violation, and anomaly detection.

This report, as part of the 2021 Snowmass Process, summarizes the current status of collider physics at the Energy Frontier, the broad and exciting future prospects identified for the Energy Frontier, the challenges and needs of future experiments, and indicates high priority research areas.

This presentation covers the current status of measurements of top quark properties from about 350 pb -1 of data collected during the Tevatron Run II by both the CDF and Dzero collaborations.We discuss the measurements of the branching fraction of the top qaurk into a W boson and a b-quark, the searches for exotic decay modes of the top quark (t → H + b), the nature of the W -tb vertex.We also present the current status of the search of the single top quark signal by the Dzero experiment.This search currently sets the best 95% C.L. upper limit on the single top quark production cross section of 5.0pb in the s-channel and 4.4pb in the t-channel.

Many physics topics to be studied by the D0 experiment during Run II of the Fermilab Tevatron ppbar collider give rise to final states containing b--flavored particles. Examples include Higgs searches, top quark production and decay studies, and full reconstruction of B decays. The sensitivity to such modes has been significantly enhanced by the installation of a silicon based vertex detector as part of the DO detector upgrade for Run II. Interesting events must be identified initially in 100-200 microseconds to be available for later study. This paper describes custom electronics used in the DO trigger system to provide the real--time identification of events having tracks consistent with the decay of b--flavored particles.

Many physics topics to be studied by the D0 experiment during Run II of the Fermilab Tevatron ppbar collider give rise to final states containing b--flavored particles. Examples include Higgs searches, top quark production and decay studies, and full reconstruction of B decays. The sensitivity to such modes has been significantly enhanced by the installation of a silicon based vertex detector as part of the DO detector upgrade for Run II. Interesting events must be identified initially in 100-200 microseconds to be available for later study. This paper describes custom electronics used in the DO trigger system to provide the real--time identification of events having tracks consistent with the decay of b--flavored particles.

From particle identification to the discovery of the Higgs boson, deep learning algorithms have become an increasingly important tool for data analysis at the Large Hadron Collider (LHC). We present an innovative end-to-end deep learning approach for jet identification at the Compact Muon Solenoid (CMS) experiment at the LHC. The method combines deep neural networks with low-level detector information, such as calorimeter energy deposits and tracking information, to build a discriminator to identify different particle species. Using two physics examples as references: electron vs. photon discrimination and quark vs. gluon discrimination, we demonstrate the performance of the end-to-end approach on simulated events with full detector geometry as available in the CMS Open Data. We also offer insights into the importance of the information extracted from various sub-detectors and describe how end-to-end techniques can be extended to event-level classification using information from the whole CMS detector.

The DOslash experiment was upgraded in spring 2006 to harvest the full physics potential of the Tevatron accelerator at Fermi National Accelerator Laboratory, Batavia, Illinois, USA. It is expected that the peak luminosity delivered by the accelerator will increase to over 300 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . One of the upgraded systems is the central track trigger (CTT). The CTT uses the central fiber tracker (CFT) and preshower detectors to identify central tracks with p <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> > 1.5 GeV at the first trigger level. Track candidates are formed by comparing fiber hits to predefined track equations. In order to minimize latency, this operation is performed in parallel using combinatorial logic implemented in FPGAs. Limited hardware resources prevented the use of the full granularity of the CFT. This leads to a high fake track rate as the occupancy increases. In order to mitigate the problem, new track-finding hardware was designed and commissioned. We report on the upgrade and the improved performance of the CTT system.

We present the techniques used to identify electrons in the D0 detector. The D0 electron identification algorithm is based on the full covariance matrix of energy deposits in the calorimeter cells occupied by an electromagnetic shower and information from the central tracking system. The method exploits the fine longitudinal and transverse segmentation of the D0 calorimeter to achieve excellent pion rejection. Performance criteria are derived from test beam electron and pion data and from collider data.

We report the first results obtained by the Dzero Collaboration using data from Run II delivered by the Fermilab Tevatron. With the data sample collected until May 2002, we have commissioned and calibrated all of the detector components. Here we will present the current performance of all the detector subsystems. We also report the first physics signals, with emphasis on first measurements of production cross sections of W, Z bosons in proton anti-proton collisions at the new center of mass energy of 1.96 TeV and searches for particles predicted by theories beyond the Standard Model.

The COVID-19 pandemic has by-and-large prevented in-person meetings since March 2020. While the increasing deployment of effective vaccines around the world is a very positive development, the timeline and pathway to "normality" is uncertain and the "new normal" we will settle into is anyone's guess. Particle physics, like many other scientific fields, has more than a year of experience in holding virtual meetings, workshops, and conferences. A great deal of experimentation and innovation to explore how to execute these meetings effectively has occurred. Therefore, it is an appropriate time to take stock of what we as a community learned from running virtual meetings and discuss possible strategies for the future. Continuing to develop effective strategies for meetings with a virtual component is likely to be important for reducing the carbon footprint of our research activities, while also enabling greater diversity and inclusion for participation. This report summarizes a virtual two-day workshop on Virtual Meetings held May 5-6, 2021 which brought together experts from both inside and outside of high-energy physics to share their experiences and practices with organizing and executing virtual workshops, and to develop possible strategies for future meetings as we begin to emerge from the COVID-19 pandemic. This report outlines some of the practices and tools that have worked well which we hope will serve as a valuable resource for future virtual meeting organizers in all scientific fields.

Z 0 bosons that couple preferentially to the third generation fermions can arise in models with extended weak (SU(2)SU(2)) or hypercharge (U(1)U(1)) gauge groups. We show that existing limits on quarklepton compositeness set by the LEP and Tevatron experiments translate into lower bounds of order a few hundred GeV on the masses of these Z 0 bosons. Resonances of this mass can be directly produced at the Tevatron. Accordingly, we explore in detail the limits that can be set at Run II using the process pp ! Z 0 ! ! e. We also comment on the possibility of using hadronically-decaying taus to improve the limits.

The performance of a telescope of Micro-Strip Gas Chambers (MSGC) has been studied in a beam of minimum ionizing particles. Detectors of two different pitches have been studied. The position resolutions is obtained by reading out the cathodes and interpolating based on the amplitude of the signals. The position of the hit in the chamber is found to differ systematically from the cluster centroid position. A correction method is derived from the data and applied to improve the resolution. After correction, the spatial resolution of chambers with 200 /spl mu/m pitch is found to be 42 /spl mu/m, and for the 400 /spl mu/m pitch detectors the resolution is 42 /spl mu/m. The improved interpolation for the 400 /spl mu/m pitch chamber can be understood in terms of the better signal to noise observed for the 400 /spl mu/m pitch detectors. The degradation in resolution as a function of angle of track incidence is also expected to be less for the larger pitch chambers.