A brief summary of the CMS discovery potential for the Standard Model Higgs boson in the H->gamma+gamma channel is presented. We review both a standard cut-based search and a more optimized analysis that takes advantage of the wide range of signal/background expectations as function of the possible selection cuts. As the Higgs discovery in this channel will rely heavily on performance of the CMS electromagnetic calorimeter, the relevant aspects of its design and operation in situ at the LHC are also briefly discussed.
Latest results on inclusive top-quark pair production cross-sections are presented using collision data collected by ATLAS and CMS experiments at the LHC. Inclusive and differential measurements of top-quark pair production cross-sections from ATLAS and CMS are presented in the resolved and boosted kinematic regions. The cross-sections are measured as a function of various kinematic observables of the top quarks, the jets and leptons of the event final state.
Multiple searches for supersymmetry have been performed at the CMS experiment. Of these, inclusive searches aim to remain as sensitive as possible to the widest range of potential new physics scenarios. The results presented in this talk use the latest 19.5 fb$^{-1}$ of 8 TeV data from the 2012 LHC run. Interpretations are given within the context of Simplified Model Spectra for a variety of both hadronic and leptonic signatures.
Measurements performed by the CMS experiment of the cross section for inclusive $b$-quark production in proton-proton collisions at $\sqrt{s}= 7$ TeV are presented. The measurements are based on different methods, such as inclusive jet measurements with secondary vertex tagging or selecting a sample of events containing jets and at least one muon, where the transverse momentum of the muon with respect to the closest jet axis discriminates $b$-events from the background. The results are compared with predictions based on perturbative QCD calculations at leading and next-to-leading order.
Measurements performed by the CMS experiment of the cross section for inclusive b-quark production in proton-proton collisions at sqrt(s) = 7 TeV are presented. The measurements are based on different methods, such as inclusive jet measurements with secondary vertex tagging or selecting a sample of events containing jets and at least one muon, where the transverse momentum of the muon with respect to the closest jet axis discriminates b events from the background. The results are compared with predictions based on perturbative QCD calculations at leading and next-to-leading order.
The measurement of the $t\bar{t}$ inclusive production cross section $σ_{t\bar{t}}$ is crucial to probe QCD predictions, constrain new physic scenarios, proton PDFs, top quark pole mass, $α_S$ and many other parameters from the SM. The CMS Collaboration has measured this quantity in different final states and at different centre-of-mass energies, probing QCD calculations and deriving several constraints. In this document a summary of the latest results at each channel and centre-of-mass energy is presented.
Natural SUSY suggests the existence of light stop quarks, accessible at the LHC, which are the focus of a dedicated CMS search program. I present two inclusive CMS searches that look for TeV scale colored sparticles in final states with jets, b-tagged jets and missing transverse energy performed using up to 19.4fb-1 of 8TeV LHC proton-proton data. No deviation from the Standard Model was observed in these searches, and the implications for this was shown for several simplified model scenarios and phenomenological MSSM.
At the LHC, the production cross sections of W/Z bosons are tens to hundreds of nanobarns. The production mechanism of these processes is well established in the Standard Model and these processes can be used as "standard candles" to help commission the CMS detector for physics. Leptonic decays of W/Z bosons are expected to have very high trigger efficiency and signal to background ratio. Therefore they are ideal channels to study the properties of W/Z bosons in detail, such as cross sections and charge asymmetry. In this paper early CMS results on inclusive W/Z production at 10 TeV center-of-…
In this paper, selected CMS measurements sensitive to low-x QCD are presented: inclusive cross-sections for forward-central jets production at \sqrt{s}=7 TeV, inclusive cross-sections for forward jets production at 7 TeV and 8 TeV, inclusive to exclusive dijets production cross-sections ratios and correlations of Mueller-Navelet dijets at 7 TeV. Results for data are compared to predictions of theoretical models.
The results of the most recent measurements of the inclusive $\mathrm{t\bar{t}}$ cross section performed by the ATLAS and CMS experiments at the CERN LHC are summarized. These include results obtained in proton-proton collisions at different centre-of-mass energies, and the first observation of $\mathrm{t\bar{t}}$ production in proton-lead collisions. A new result at $\sqrt{s} = 13~\mathrm{TeV}$ by the CMS Collaboration is presented for the first time at this conference. In this analysis, the total cross section is determined both for a fixed top quark mass value in the simulation of $m_{\math…
Several electroweak precision measurements are performed by the ATLAS and CMS collaborations at the LHC. The main ones are carried out using Drell-Yan production of single W and Z boson. They regard the measurement of the production cross sections of W and Z bosons, the mass of the W boson, and $\sin^2θ_W$. The results of the $\sin^2θ_W$ measurements have an accuracy of approximately twice that reached at LEP and SLD. Other measurements reported are about the Drell-Yan differential production cross section.
We report on potential for measurement of inclusive W and Z boson production cross section using initial data from the LHC. We have designed W and Z triggers, selection algorithms, and event reconstruction techniques for both muon and electron decay modes, for low luminosity operation of the LHC integrating up to about 10 pb-1. Initial calibrations and alignment accuracies are assumed. While the accuracy of the cross section extracted will be dominated by the integral luminosity measurement, ratios of W and Z production, and asymmetry distributions will be important early measurements from LHC…
Measurements of the muon charge asymmetry in inclusive $pp \rightarrow WX$ production at $\sqrt{s}=7$ TeV are presented. The data sample corresponds to an integrated luminosity of 4.7 $\mathrm{fb^{-1}}$ recorded with the CMS detector at the LHC. With a sample of more than twenty million $W \rightarrow μν$ events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable $x$ from $10^{-3}$ to $10^{-1}$. These measurements ar…
Inclusive and normalised differential cross sections measurements are presented for the production of single top quarks in association with a W boson, in proton-proton collisions at a centre-of-mass energy of 13 TeV. Events containing one muon and one electron in the final state are analysed. For the inclusive measurement, a multivariate discriminant, exploiting the kinematic properties of the events, is used to separate the signal from the dominant t$\bar{\mathrm{t}}$ background. For the differential measurements, a fiducial region is defined according to the detector acceptance, and the requ…
The Compact Muon Solenoid (CMS) Experiment is a general purpose particle detector experiment located at the Large Hadron Collider (LHC) at CERN. In 2008, the LHC beam was commissioned and successfully steered through the CMS detector. First results from CMS with beam data are described, focusing on detector commissioning with beam data, from beam halo studies with the endcap muon system to displays of "beam splash" events, in which the proton beam was stopped by an upstream collimator.
This paper describes latest results on lepton (electron, muon and tau) and photon particle identification at the ATLAS and CMS experiments, with emphasis on how the particle identification can be validated and its performance determined using early LHC data.
Charm physics has been established at the LHC based on several high-precision measurements. The future of charm physics at the LHC experiments is discussed in detail. The bulk of the charm physics programme will be performed by LHCb and the LHCb upgrade. In particular, the impact of the LHCb upgrade on mixing and \CP violation measurements is presented.
A brief review of the discovery potential of the ATLAS and CMS experiments to search for signals from extra dimensions in different luminosity scenarios is given.
This paper presents combinations of inclusive and differential measurements of the charge asymmetry ($A_{\mathrm{C}}$) in top quark pair ($\mathrm{t}\overline{\mathrm{t}}$) events with a lepton+jets signature by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at centre-of-mass energies of 7 and 8 TeV corresponding to integrated luminosities of about 5 and 20 fb$^{-1}$ for each experiment, respectively. The resulting combined LHC measurements of the inclusive charge asymmetry are $A_{\mathrm{C}}^{\mathrm{LHC7}} = 0.005 \pm0.007 \text{ (stat)}\pm0.006 \text{ (syst)…
We present the first search for the standard model Higgs boson (H) produced with large transverse momentum ($\mathrm{p_{T}}$) via gluon fusion and decaying to a bottom quark-antiquark pair ($\mathrm{b\overline{b}}$). The search is performed using a data set of pp collisions at $\sqrt{s}=13$ TeV collected with the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb$^{\mathrm{-1}}$. A highly Lorentz-boosted Higgs boson decaying to $\mathrm{b\overline{b}}$ is reconstructed as a single, large radius jet and is identified using jet substructure and dedicated b tagging te…
Selected results of searches for neutral long-lived particles with displaced and delayed jets, trackless jets and emerging jets, as well as displaced muons, obtained with data recorded at a centre-of-mass energy of 13 TeV by the ATLAS and CMS Collaborations during LHC's Run 2 are presented, as well as challenges and techniques.
A clear evidence of inclusive diffraction observed by the CMS detector at the Large Hadron Collider in minimum bias events at $\sqrt{s}=$0.9 TeV, 2.36 TeV is presented. The observed diffractive signal is dominated by inclusive single-diffractive dissociation and can be identified by the presence of a Large Rapidity Gap that extends over the forward region of the CMS detector. A comparison of the data with Monte Carlo predictions provided by PYTHIA6 and PHOJET generators is given. In addition, first observation of the single-diffractive production of di-jets at $\sqrt{s}=$7 TeV is presented.
Photon bremsstrahlung is studied for identifying elastic proton-proton interactions in the CMS experiment at the LHC. In addition to measurement of the elastic pp cross section (assuming that the elastic slope is known) the bremsstrahlung photons will allow evaluation of the total pp cross section, luminosity and alignment of the Zero Degree Calorimeters (ZDCs).
The physics reach of the CMS detector achievable with 300(0) inverse femtobarns of proton-proton collisions recorded at sqrt(s)=14 TeV is presented. Ultimate precision on measurements of Higgs boson properties, top quark physics, and electroweak processes are discussed, as well as the discovery potential for new particles beyond the standard model. In addition, the potential for future heavy ion physics is presented. This document has been submitted as a white paper to the Snowmass process, an exercise initiated by the American Physical Society's Division of Particles and Fields to assess the …
Physical possibility for bending the LHC protons (or ions) a huge angle of 1-20 degrees in the energy range of 0.45 to 7 TeV by means of a bent channeling crystal of Silicon or Germanium is demonstrated. Such an application can be useful for calibration of CMS (or ATLAS) calorimeters in situ by the LHC beam of precisely known energy. We show by simulations that such an application would be feasible at the LHC, and report the experience of IHEP Protvino in bending 70 GeV protons by 9 degrees (150 mrad) during 10 years in 1994-2004 experiments.
We report on the status and history of the CMS commissioning, together with selected results from cosmic-ray muon data. The second part focuses on strategies for optimizing the reconstruction of jets, missing transverse energy and photons for early standard model measurements at ATLAS and CMS with the first collision data from the Large Hadron Collider at CERN.
Measurements of the top quark mass are presented, obtained from CMS data collected in proton proton collisions at the LHC at centre-of-mass energies of 7 TeV and 8 TeV. The mass of the top quark is measured using several methods and channels, including the reconstructed invariant mass distribution of the top quark as well as measurements based on charged particle information. The dependence of the mass measurement on the kinematic phase space is investigated. The results of the various channels are combined and compared to the world average. The top mass is extracted from the inclusive top qua…
In January 2007 the CERN director general announced the plan for the staged upgrade of the LHC luminosity. The plan foresees a phase 1 upgrade reaching a peak luminosity of $3 \times 10^{34}$ cm$^{-2}$s$^{-1}$ followed by phase reaching up to $ 10^{35}$ cm$^{-2}$s$^{-1}$. We discuss the physics potential and the experimental challenges of an upgraded LHC running. The detector R&D needed to operate ATLAS and CMS in a very high radiation environment and the expected detector performance are also discussed.
Forward physics with CMS at the LHC covers a wide range of physics subjects, including very low-x QCD, underlying event and multiple interactions characteristics, gamma-mediated processes, shower development at the energy scale of primary cosmic ray interactions with the atmosphere, diffraction in the presence of a hard scale and even MSSM Higgs discovery in central exclusive production. We describe the forward detector instrumentation around the CMS interaction point and present selected feasibility studies to illustrate their physics potential.
Preliminary results on a variety of jet analyses are presented using pp collision data collected by the CMS experiment at $\sqrt{s}$=7 TeV. We report on measurements of the inclusive jet cross sections, the ratio of the inclusive three-jet over two-jet cross sections, the hadronic event shapes, the jet structure and the dijet azimuthal decorrelations. The data distributions are compared with the predictions of Monte Carlo event generators and with perturbative QCD calculations.
This note presents selected measurements of W and Z boson production, carried out with the CMS experiment at the LHC, based on samples of events collected during 2015-2018 physics runs. W boson events were selected containing an isolated, energetic electron or muon, while Z boson events were selected containing a pair of isolated, energetic electrons or muons. Presented results include searches for rare decays of W bosons to pions.
We present an overview of measurements of electroweak vector boson pair production and anomalous Triple Gauge Couplings (aTGC), with semileptonic and fully leptonic final states. The data analyzed were taken at center of mass energy of 7 & 8 TeV by the CMS detector at the Large Hadron Collider. The cross-section measurements are important because they are test of the Standard Model predictions, while these processes serve as background for Higgs searches and various other processes.
The measurement of the inclusive cross section for Wgamma production is presented based on 36/ pb of data acquired with the CMS detector from 7 TeV LHC collisions in 2010. Comparisons are made with the predictions of the standard model. The W bosons are identified through their leptonic decays to electrons and muons. The Wgamma cross section is sensitive to anomalous triple-gauge couplings and hence this measurement probes physics beyond the standard model.
Searches for high-mass resonances decaying to pairs of standard model bosons using ATLAS and CMS detectors are presented. The searches use 15 - 36 $\textrm{fb}^{-1}$ of proton-proton collision data collected at the centre-of-mass energy of 13 TeV at the LHC. Many different final states have been considered and the results are interpreted in a range of theories beyond the standard model of particle physics, most common being heavy vector triplet and warped extra dimensions.
In this paper, a brief outlook on the measurements of the total and differential cross-sections of vector bosons production associated with heavy flavor quarks performed using CMS proton-proton collision data taken at center of mass energies of 7, 8, and 13 TeV is presented. Obtained results are compared with predictions of various state-of-the-art Monte-Carlo generators.
A search for central exclusive production of top quark pairs ($\mathrm{t}\bar{\mathrm{t}}$) is presented using collision data collected by CMS and the CMS-TOTEM Precision Proton Spectrometer in 2017. A data-driven method to estimate the background from coincidences of inclusive events and pileup protons is described, as well as the development of a Boosted Decision Tree classifier to separate the exclusive $\mathrm{t}\bar{\mathrm{t}}$ signal from the inclusive $\mathrm{t}\bar{\mathrm{t}}$ background. The first-ever upper limits on the cross section of exclusive $\mathrm{t}\bar{\mathrm{t}}$ are…
The latest results on searches for production of two Higgs bosons with the CMS detector using the 2016 CERN LHC dataset are presented, as shown at the LHCP 2017 conference.
We present the results of the Model Unspecific Search in CMS (MUSiC), which systematically scans the data taken by the CMS detector for deviations from the Standard Model predictions. Due to the minimal theoretical bias this approach is sensitive to a variety of models for new physics. Events containing at least one electron or muon are classified according to their content of reconstructed objects (muons, electrons, photons, jets and missing transverse energy). A broad scan of three kinematic distributions in those classes is performed by identifying deviations from Standard Model expectation…
The top quark pair production cross section is measured in proton-proton collisions at a center-of-mass energy of 5.02 TeV. The data collected in 2017 by the CMS experiment at the LHC corresponding to an integrated luminosity of 304 pb$^{-1}$ are analyzed. The measurement is performed using events with one electron and one muon of opposite sign, and at least two jets. The measured cross section is found to be $σ_{\mathrm{t}\bar{\mathrm{t}}}~=~60.3~\pm5.0~\mathrm{(stat)}\pm2.8~\mathrm{(syst)}\pm0.9~\mathrm{(lumi)}$ pb. To reduce the statistical uncertainty, a combination with the result in the …
The Large Hadron Collider (LHC), scheduled to start operation in 2006, is foreseen to provide in the first year of running a total of $\sim 10^{12}$ $τ$ leptons. CMS (Compact Muon Solenoid) is a general-purpose experiment designed to study proton-proton and heavy-ion collisions at LHC. Even if the Susy particles and Higgs searches togheter with the B-physics present its main goal, the large amount of $τ$-lepton, could allow a systematic study of tau-physics. We have performed a full simulation of CMS using GEANT 3 package and the object-oriented reconstruction program ORCA to study the sensiti…
State-of-the-art theoretical predictions accurate to next-to-leading order QCD interfaced with {\sc pythia} and {\sc herwig} are tested by comparing the unfolded $t\bar{t}$ differential data collected with the CMS detector at 8 TeV and 13 TeV. These predictions are also compared with the measurements of underlying event activity distributions accompanying ${\rm t\bar{t}}$ events. Furthermore, predictions of beyond NLO accuracy in QCD are compared with the data.
The possibility to observe a Higgs boson having a mass between 300 and 600 GeV and to measure its couplings to vector bosons and top quark with CMS at the LHC is studied. Six different signatures are analyzed. The possibility to separate the Higgs events produced through weak boson fusion from the Higgs produced through gluon fusion using the forward going jets emitted in the weak boson fusion process is discussed for each of these different channels. The results are then used to determine the possible statistical errors on the ratio between the two Higgs decay branching fractions when it deca…
Leptonic decays of W/Z bosons provide the first electroweak precision measurements at the Large Hadron Collider (LHC). The results of measurements of inclusive W and Z boson production cross sections in pp collisions at $\sqrt{s}=7 \mathrm{TeV}$ are presented, based on 2.9 pb$^{-1}$ of data recorded by the Compact Muon Solenoid (CMS) detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give $σ(\mathrm{pp} \rightarrow \mathrm{W}X) \times {\cal{B}}(\mathrm{W} \rightarrow \ell ν) = 9.95\pm0.07\,{\textrm{(stat.)}}\pm 0.28\,{\textrm{(syst.)}}\pm1…
Results are presented for the search for invisible Higgs boson production using the full LHC dataset corresponding to integrated luminosity of 5.1 fb^-1 and 19.6 fb^-1 of proton-proton collision data at sqrt(s)= 7 TeV and 8 TeV (respectively) collected by the CMS detector. The invisible Higgs is searched for in final states of missing transverse energy, with two leptons from a recoiling Z boson. No significant excess is found beyond standard model predictions, and limits are obtained on the branching fraction of the Higgs boson to invisible particles.
The latest measurements of the top quark mass obtained by the ATLAS and CMS experiments at the LHC for centre-of-mass energies of 7 and 8 TeV are presented. The mass of the top quark is measured using several methods and channels, including the reconstructed invariant mass distribution of the top quark and shapes of top quark decay distributions. Measurements based on the inclusive tt-bar cross section and novel observables based on the differential cross section in the tt-bar + 1 jet channel are also discussed. The results of the various channels are combined and compared to the world average…
Results are summarized from searches for the standard model Higgs boson in pp collisions at sqrt(s) = 7 and 8 TeV in the CMS experiment at the LHC. The measurements of mass, cross section, and properties of the narrow resonance recently observed are presented. The searches beyond standard model Higgs boson, in the CMS experiment at the LHC, are highlighted.
We report the measurement of the rates and asymmetries of inclusive and differential production of W and Z vector bosons in pp collision at $\sqrt{s}$=7 TeV. The data consists of 36 $pb^{-1}$ collected in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The measured inclusive cross sections are $σ(pp\to WX)\times B(W\to \ellν) = 10.31 \pm 0.02 (stat.) \pm 0.09 (syst.) \pm 0.10 (th.) \pm 0.41 (lumi.)$ nb and $σ(pp\to ZX)\times B(Z\to \ell\ell) = 0.975 \pm 0.007 (stat.) \pm 0.007 (syst.) \pm 0.018 (th.) \pm 0.039 (lumi.)$ nb. The measured inclusive cross sections and …
This article summarizes the first measurements of inclusive beauty production cross section in proton-proton collisions at sqrt(s)=7 TeV and central rapidities. The results are based on different techniques, such as the identification of semileptonic b-decays into muons and inclusive jet measurements with secondary vertex tagging. The measurements probe b-quark production in different regions of transverse momenta. The experimental results are compared with next-to-leading order QCD predictions and various Monte Carlo models.
We report on potential for measurement of W and Z boson production, as well as the production in association with jets. Of particular interest are jet multiplicity and $P_{\rm T}$ distributions. The 10 to $100 {\rm pb}^{-1}$ datasets expected in the startup year of operation of LHC are likely to already provide information beyond the reach of the Tevatron collider both in jet multiplicity and $P_{\rm T}$ range. We are especially interested in understanding the ratios of W+jets to Z+jets distributions by comparing them to next-to-leading order Monte Carlo generators, as these processes present …
A summary of the sensitivity of the ATLAS and CMS experiments at the LHC to discover a Standard Model Higgs boson is presented. Some prospects for Minimal Supersymmetric Standard Model Higgs searches at LHC are also included.
The path taken by the LHC team to reach 3.6 10$^{33}$ cm$^{-2}$ s$^{-1}$ instantaneous luminosity, and to deliver 5.6 fb$^{-1}$ per experiment is summarized. The main performances of the two experiments are highlighted, in particular the way they managed to cope with the already high level of "pile-up". Selected Standard Model and top physics results are given, and the status of the limits on the Higgs boson search by each experiment is summarized. A brief overview of the search for supersymmetry and exotic phenomena is made at the end.
When the LHC starts its operation, CMS will have a unique opportunity to study q uarkonium production in pp collisions and later in PbPb collisions. Here we report on the methods and plans for measuring the differential pT Jpsi->mu+mu- production cross section, using data to be collected in the first LHC run by the CMS detector. Furthermore we discuss the performance of the CMS detector for quarkonium measurements in PbPb collisions.
The expected SUSY discovery potential of the CMS experiment at LHC is described, both in the MSSM and in the more constrained framework of mSugra, with emphasis on inclusive searches, the MSSM Higgs sector, and one example of complete reconstruction of a SUSY decay chain.
The CMS detector at the LHC is in the final stages of preparation. The high resolution Electromagnetic Calorimeter, which consists of nearly 76000 lead tungstate crystals, will play a crucial role in the coming physics searches undertaken by CMS. The design, status, and initial performance of the calorimeter, in test beams and with cosmic rays, will be reviewed.
This document presents recent results of inclusive top-quark pair production cross section measurements at 7 and 8 TeV. The results are obtained analyzing the data collected by the CMS and ATLAS detectors at the LHC accelerator. Studies are performed in the dilepton channel, where the smallest uncertainty is reached, with different approaches. The most precise results of both experiments are combined and confronted with the most precise theoretical calculation (NNLO-NNLL).
