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  1. Abstract

    Computing demands for large scientific experiments, such as the CMS experiment at the CERN LHC, will increase dramatically in the next decades. To complement the future performance increases of software running on central processing units (CPUs), explorations of coprocessor usage in data processing hold great potential and interest. Coprocessors are a class of computer processors that supplement CPUs, often improving the execution of certain functions due to architectural design choices. We explore the approach of Services for Optimized Network Inference on Coprocessors (SONIC) and study the deployment of this as-a-service approach in large-scale data processing. In the studies, we take a data processing workflow of the CMS experiment and run the main workflow on CPUs, while offloading several machine learning (ML) inference tasks onto either remote or local coprocessors, specifically graphics processing units (GPUs). With experiments performed at Google Cloud, the Purdue Tier-2 computing center, and combinations of the two, we demonstrate the acceleration of these ML algorithms individually on coprocessors and the corresponding throughput improvement for the entire workflow. This approach can be easily generalized to different types of coprocessors and deployed on local CPUs without decreasing the throughput performance. We emphasize that the SONIC approach enables high coprocessor usage and enables the portability to run workflows on different types of coprocessors.

     
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  2. Abstract

    This paper describes theCombinesoftware package used for statistical analyses by the CMS Collaboration. The package, originally designed to perform searches for a Higgs boson and the combined analysis of those searches, has evolved to become the statistical analysis tool presently used in the majority of measurements and searches performed by the CMS Collaboration. It is not specific to the CMS experiment, and this paper is intended to serve as a reference for users outside of the CMS Collaboration, providing an outline of the most salient features and capabilities. Readers are provided with the possibility to runCombineand reproduce examples provided in this paper using a publicly available container image. Since the package is constantly evolving to meet the demands of ever-increasing data sets and analysis sophistication, this paper cannot cover all details ofCombine. However, the online documentation referenced within this paper provides an up-to-date and complete user guide.

     
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  3. The first observation of the concurrent production of twoJ/ψmesons in proton-nucleus collisions is presented. The analysis is based on a proton-lead (pPb) data sample recorded at a nucleon-nucleon center-of-mass energy of 8.16 TeV by the CMS experiment at the CERN LHC and corresponding to an integrated luminosity of174.6nb1. The twoJ/ψmesons are reconstructed in theirμ+μdecay channels with transverse momentapT>6.5GeVand rapidity|y|<2.4. Events where one of theJ/ψmesons is reconstructed in the dielectron channel are also considered in the search. ThepPbJ/ψJ/ψ+Xprocess is observed with a significance of 5.3 standard deviations. The measured inclusive fiducial cross section, using the four-muon channel alone, isσ(pPbJ/ψJ/ψ+X)=22.0±8.9(stat)±1.5(syst)nb. A fit of the data to the expected rapidity separation for pairs ofJ/ψmesons produced in single (SPS) and double (DPS) parton scatterings yieldsσSPSpPbJ/ψJ/ψ+X=16.5±10.8(stat)±0.1(syst)nbandσDPSpPbJ/ψJ/ψ+X=5.4±6.2(stat)±0.4(syst)nb, respectively. This latter result can be transformed into a lower bound on the effective DPS cross section, closely related to the squared average interparton transverse separation in the collision, ofσeff>1.0mbat 95% confidence level.

    © 2024 CERN, for the CMS Collaboration2024CERN 
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  4. The first search for soft unclustered energy patterns (SUEPs) is performed using an integrated luminosity of138fb1of proton-proton collision data ats=13TeV, collected in 2016–2018 by the CMS detector at the LHC. Such SUEPs are predicted by hidden valley models with a new, confining force with a large ’t Hooft coupling. In events with boosted topologies, selected by high-threshold hadronic triggers, the multiplicity and sphericity of clustered tracks are used to reject the background from standard model quantum chromodynamics. With no observed excess of events over the standard model expectation, limits are set on the cross section for production via gluon fusion of a scalar mediator with SUEP-like decays.

    © 2024 CERN, for the CMS Collaboration2024CERN 
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  5. A<sc>bstract</sc>

    A search for Higgs boson pair (HH) production in association with a vector boson V (W or Z boson) is presented. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb1. Both hadronic and leptonic decays of V bosons are used. The leptons considered are electrons, muons, and neutrinos. The HH production is searched for in the$$ \textrm{b}\overline{\textrm{b}}\textrm{b}\overline{\textrm{b}} $$bb¯bb¯decay channel. An observed (expected) upper limit at 95% confidence level of VHH production cross section is set at 294 (124) times the standard model prediction. Constraints are also set on the modifiers of the Higgs boson trilinear self-coupling,kλ, assumingk2V= 1, and vice versa on the coupling of two Higgs bosons with two vector bosons,k2V. The observed (expected) 95% confidence intervals of these coupling modifiers are37.7 <kλ< 37.2 (30.1 <kλ< 28.9) and12.2 <k2V< 13.5 (7.2 <k2V< 8.9), respectively.

     
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  6. The first search for theZboson decay toττμμat the CERN LHC is presented, based on data collected by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of138fb1. The data are compatible with the predicted background. For the first time, an upper limit at the 95% confidence level of 6.9 times the standard model expectation is placed on the ratio of theZττμμtoZ4μbranching fractions. Limits are also placed on the six flavor-conserving four-lepton effective-field-theory operators involving two muons and two tau leptons, for the first time testing all such operators.

    <supplementary-material><permissions><copyright-statement>© 2024 CERN, for the CMS Collaboration</copyright-statement><copyright-year>2024</copyright-year><copyright-holder>CERN</copyright-holder></permissions></supplementary-material></sec> </div> <a href='#' class='show open-abstract' style='margin-left:10px;'>more »</a> <a href='#' class='hide close-abstract' style='margin-left:10px;'>« less</a> <div class="actions" style="padding-left:10px;"> <span class="reader-count"> Free, publicly-accessible full text available October 1, 2025</span> </div> </div><div class="clearfix"></div> </div> </li> <li> <div class="article item document" itemscope itemtype="http://schema.org/TechArticle"> <div class="item-info"> <div class="title"> <a href="https://par.nsf.gov/biblio/10556766-measurement-differential-zz-jets-production-cross-sections-pp-collisions-sqrt-tev" itemprop="url"> <span class='span-link' itemprop="name">Measurement of differential ZZ + jets production cross sections in pp collisions at $$ \sqrt{s} $$ = 13 TeV</span> </a> </div> <div> <strong> <a class="misc external-link" href="https://doi.org/10.1007/JHEP10(2024)209" target="_blank" title="Link to document DOI">https://doi.org/10.1007/JHEP10(2024)209  <span class="fas fa-external-link-alt"></span></a> </strong> </div> <div class="metadata"> <span class="authors"> <span class="author" itemprop="author">Hayrapetyan, A</span> <span class="sep">; </span><span class="author" itemprop="author">Tumasyan, A</span> <span class="sep">; </span><span class="author" itemprop="author">Adam, W</span> <span class="sep">; </span><span class="author" itemprop="author">Andrejkovic, J W</span> <span class="sep">; </span><span class="author" itemprop="author">Bergauer, T</span> <span class="sep">; </span><span class="author" itemprop="author">Chatterjee, S</span> <span class="sep">; </span><span class="author" itemprop="author">Damanakis, K</span> <span class="sep">; </span><span class="author" itemprop="author">Dragicevic, M</span> <span class="sep">; </span><span class="author" itemprop="author">Escalante_Del_Valle, A</span> <span class="sep">; </span><span class="author" itemprop="author">Hussain, P S</span> <span class="sep">; </span><span class="author">et al</span></span> <span class="year">( <time itemprop="datePublished" datetime="2024-10-01">October 2024</time> , Journal of High Energy Physics) </span> </div> <div style="cursor: pointer;-webkit-line-clamp: 5;" class="abstract" itemprop="description"> <title>A<sc>bstract</sc>

    Diboson production in association with jets is studied in the fully leptonic final states, pp → (Z/γ*)(Z/γ*) + jets → 22′ + jets, (,′ = e orμ) in proton-proton collisions at a center-of-mass energy of 13 TeV. The data sample corresponds to an integrated luminosity of 138 fb1collected with the CMS detector at the LHC. Differential distributions and normalized differential cross sections are measured as a function of jet multiplicity, transverse momentumpT, pseudorapidityη, invariant mass and ∆ηof the highest-pTand second-highest-pTjets, and as a function of invariant mass of the four-lepton system for events with various jet multiplicities. These differential cross sections are compared with theoretical predictions that mostly agree with the experimental data. However, in a few regions we observe discrepancies between the predicted and measured values. Further improvement of the predictions is required to describe the ZZ+jets production in the whole phase space.

     
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  7. A<sc>bstract</sc>

    The effective lifetime of the$$ {\textrm{B}}_{\textrm{s}}^0 $$Bs0meson in the decay$$ {\textrm{B}}_{\textrm{s}}^0\to \textrm{J}/{\uppsi \textrm{K}}_{\textrm{S}}^0 $$Bs0J/ψKS0is measured using data collected during 2016–2018 with the CMS detector in$$ \sqrt{s} $$s= 13 TeV proton-proton collisions at the LHC, corresponding to an integrated luminosity of 140 fb1. The effective lifetime is determined by performing a two-dimensional unbinned maximum likelihood fit to the$$ {\textrm{B}}_{\textrm{s}}^0 $$Bs0meson invariant mass and proper decay time distributions. The resulting value of 1.59 ± 0.07(stat) ± 0.03(syst) ps is the most precise measurement to date and is in good agreement with the expected value.

     
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  8. Abstract

    Using proton–proton collision data corresponding to an integrated luminosity of$$140\hbox { fb}^{-1}$$140fb-1collected by the CMS experiment at$$\sqrt{s}= 13\,\text {Te}\hspace{-.08em}\text {V} $$s=13TeV, the$${{{\Lambda }} _{\text {b}}^{{0}}} \rightarrow {{\text {J}/\uppsi }} {{{\Xi }} ^{{-}}} {{\text {K}} ^{{+}}} $$Λb0J/ψΞ-K+decay is observed for the first time, with a statistical significance exceeding 5 standard deviations. The relative branching fraction, with respect to the$${{{\Lambda }} _{\text {b}}^{{0}}} \rightarrow {{{\uppsi }} ({2\textrm{S}})} {{\Lambda }} $$Λb0ψ(2S)Λdecay, is measured to be$$\mathcal {B}({{{\Lambda }} _{\text {b}}^{{0}}} \rightarrow {{\text {J}/\uppsi }} {{{\Xi }} ^{{-}}} {{\text {K}} ^{{+}}} )/\mathcal {B}({{{\Lambda }} _{\text {b}}^{{0}}} \rightarrow {{{\uppsi }} ({2\textrm{S}})} {{\Lambda }} ) = [3.38\pm 1.02\pm 0.61\pm 0.03]\%$$B(Λb0J/ψΞ-K+)/B(Λb0ψ(2S)Λ)=[3.38±1.02±0.61±0.03]%, where the first uncertainty is statistical, the second is systematic, and the third is related to the uncertainties in$$\mathcal {B}({{{\uppsi }} ({2\textrm{S}})} \rightarrow {{\text {J}/\uppsi }} {{{\uppi }} ^{{+}}} {{{\uppi }} ^{{-}}} )$$B(ψ(2S)J/ψπ+π-)and$$\mathcal {B}({{{\Xi }} ^{{-}}} \rightarrow {{\Lambda }} {{{\uppi }} ^{{-}}} )$$B(Ξ-Λπ-).

     
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  9. A<sc>bstract</sc>

    A search for a new charged particle X with mass between 0.3 and 2.0 TeV decaying to a W boson and a photon is presented, using proton-proton collision data at a center-of-mass energy of 13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 138 fb1. Particle X has electric charge ±1 and is assumed to have spin 0. The search is performed using the electron and muon decays of the W boson. No significant excess above the predicted background is observed. The upper limit at 95% confidence level on the product of the production cross section of the X and its branching fraction to a W boson and a photon is found to be 94 (137) fb for a 0.3 TeV resonance and 0.75 (0.81) fb for a 2.0 TeV resonance, for an X width-to-mass ratio of 0.01% (5%). This search presents the most stringent constraints to date on the existence of such resonances across the probed mass range. A statistical combination with an earlier study based on the hadronic decay mode of the W boson is also performed, and the upper limit at 95% confidence level for a 2.0 TeV resonance is reduced to 0.50 (0.63) fb for an X width-to-mass ratio of 0.01% (5%).

     
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    Free, publicly-accessible full text available September 1, 2025