341 research outputs found

    Search for the lepton-flavor violating decay of the Higgs boson and additional Higgs bosons in the eőľe\mu final state at s=13\sqrt{s} = 13 TeV within CMS

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    The search for lepton-flavor violating decays of the Higgs boson to an electron-muon pair using data from proton-proton collisions at s=13\sqrt{s} = 13 TeV collected by the CMS experiment at the LHC is presented. The dataset corresponds to an integrated luminosity of 138fb‚ąí1138 fb^{-1}. No significant excess of events is observed for the 125 GeV Higgs. This analysis leads to the most stringent upper limits at 95\% confidence level so far on the branching fraction of the 125 GeV Higgs boson decaying into an electron and a muon, with an observed (expected) limit of 4.4 (4.7)√ó\times10‚ąí5^{-5}. A search for additional scalar resonances, X, in the same decay channel, leads to upper limits on the cross-section of pp‚Üí\rightarrowX‚Üí\rightarroweőľ\mu in the mass-range of 110-160 GeV. Here, an excess of events is observed at an electron-muon invariant mass of approximately 146 GeV with a local (global) significance of 3.8 (2.8) standard deviations. These results provide valuable insights into lepton-flavor-violating Higgs decays and contribute to our understanding of the Higgs boson sector and potential physics beyond the Standard Model

    First alignment of the Run 3 CMS tracker with cosmic rays and collision tracks

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    After the long shutdown preparing the CMS detector for Run 3, the tracker alignment constants, namely position, orientation, and curvature of each of the modules that compose the tracking system need to be derived again with a high precision in order to ensure a good performance of the detector for physics analysis. This process constitutes a major computational challenge due to the enormous number of degrees of freedom involved. The latest public results of the CMS tracker alignment performance corresponding to the very first alignment with collision data, derived after the work in the underground experimental cavern was finished, will be presented. The workflows, turnarounds, the so-called automated alignment, and the use of CMS CERN Analysis Facilities (CAF) for the derivation of the alignment conditions will also be discussed

    Exploring Lepton-Flavor Violation (LFV) in HeőľH e\mu. earch for the LFV decay of the Higgs boson and additional Higgs bosons in the eőľe\mu final state

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    This poster presents a search for lepton-flavor violating decays of the Higgs boson to an electron-muon pair using data from proton-proton collisions at ‚ąös = 13 TeV collected by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 138 fb‚ąí1. No significant excess of events is observed for the 125 GeV Higgs, leading to the most stringent upper limits so far on the branching fraction B(H ‚Üí e¬Ķ) at 95% confidence level, with an observed (expected) limit of 4.4 (4.7) √ó 10‚ąí5. Upper limits on the cross-section of pp->X->e¬Ķ are set on the mass-range of X of 110-160 GeV. Here, an excess of events is observed at an electron-muon invariant mass of approximately 146 GeV with a local (global) significance of 3.8 (2.8) standard deviations. These results provide valuable insights into lepton-flavor violating Higgs decays and contribute to our understanding of the Higgs sector and potential new physics beyond the Standard Model

    Alignment of the CMS tracker system and performance in Run3

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    The CMS tracker system is a state-of-the-art, fully silicon-based detector that consists of two subsystems: the Pixel and Strip detectors. With a remarkable resolution of less than 10 microns, the tracker is designed to accurately measure the trajectory of charged particles. Prior to the start of the latest data-taking period of the Large Hadron COllider, the innermost sub-detector of the tracker was upgraded to enhance its performance. To fully benefit on the excellent hit resolution and obtain the highest quality physics data, it is neccessary to measure the position and orientation of each module with precision beyond what mechanical alignment can provide (typically 100 microns). Additionally, fluctuations in the operating conditions may cause substructures to shift, needing regular corrections to ensure proper alignment, which are referred to as tracker alignment. This poster aims to present the alignment procedures adopted for the CMS tracker system and evaluate their impact on the overall performance of the detector

    Searches for additional heavy Higgs Bosons - Overview of Run2 analyses inspired by models involving an extended Higgs sector

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    Extensions of the Standard Model Higgs sector with a second Higgs doublet allow for the existence of charged Higgs bosons as well as heavy pseudoscalar Higgs bosons. The heavy pseudoscalars can decay into a Z boson and a lighter scalar Higgs boson, which could be either the established 125 GeV state, or a new heavier sibling. Charged Higgs bosons are probed in various final states, including decays to a W boson and another lighter scalar. This presentation discusses recent results from the CMS experiment based on the Run 2 dataset.Since the discovery of the Higgs boson in 2012 by the ATLAS and CMS experiments, investigating the detailed structure of the Higgs Sector is of highest importance. Models featuring two complex Higgs doublets, like generic two-Higgs-doublet models (2HDM) or models with additional singlets (2HDM+S) offer a rich phenomenology including additional neutral Higgs states. This talk will include results on searches for single heavy Higgs bosons in different final states, including ditau, WW, and diphoton final states. This presentation will report on recent results of the CMS experiment in this field, based on the data collected in LHC Run 2

    CMS tracker performance in Run3

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    The CMS silicon tracker consists of two tracking devices: the inner pixel and the outer strip detectors. The tracker occupies the region around the center of CMS, where the LHC beams collide, and therefore, operates in a high-occupancy and high-radiation environment produced by the particle collisions within the LHC tunnel.This poster summarizes the tracker performance during the ongoing Run 3 data-taking period. The operational challenges influencing the active fraction and read-out efficiency, the behaviour of local observables such as the hit reconstruction efficiency, as well as the radiation effects given the accumulated integrated luminosity are discussed

    Search for additional MSSM/2HDM H‚Üíbb with Run 2 CMS data

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    Some Beyond Standard Model (BSM) theories, like the Minimal Supersymmetric extension of the Standard Model (MSSM) or the Two-Higgs Doublet Model (2HDM), predict the existence of additional Higgs bosons with an enhanced coupling to bottom quarks. This talk focuses on the search for new neutral Higgs bosons decaying into b-quarks and produced in association with at least one b-quark. The analyzed data were collected by the CMS experiment at a centre-of-mass energy of 13 TeV, with the latest data reprocessing. First limits on the MSSM H->bb process using these data are shown

    Measurement of the double-differential inclusive jet cross section in proton-proton collisions at s\sqrt{s} = 5.02 TeV

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    International audienceThe inclusive jet cross section is measured as a function of jet transverse momentum pTp_\mathrm{T} and rapidity yy. The measurement is performed using proton-proton collision data at s\sqrt{s} = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb‚ąí1^{-1}. The jets are reconstructed with the anti-kTk_\mathrm{T} algorithm using a distance parameter of RR = 0.4, within the rapidity interval ‚ą£y‚ą£\lvert y\rvert<\lt 2, and across the kinematic range 0.06 <\ltpTp_\mathrm{T}<\lt 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling őĪS\alpha_\mathrm{S}

    Observation of four top quark production in proton-proton collisions at s\sqrt{s} = 13 TeV