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.
Results on analyses involving WGamma and ZGamma production from the CDF and D0 experiments at the Fermilab Tevatron Collider at Sqrt(s) = 1.96 TeV are presented here. Using 1-2 fb^-1 of data, cross sections, anomalous coupling limits, and the WGamma Radiation Amplitude Zero are reviewed.
We present results from a study of p-pbar -> W(gamma) + X events utilizing data corresponding to 0.7 fb^{-1} of integrated luminosity at sqrt(s) = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We set limits on anomalous WWgamma couplings at the 95% C.L. The one dimensional 95% C.L. limits are 0.49 < kappa_{gamma} < 1.51 and -0.12 < lambda_{gamma} < 0.13. We make the first study of the charge-signed rapidity difference between the lepton and the photon and find it to be indicative of the standard model radiation-amplitude zero in the Wgamma system.
The WWgamma triple gauge boson coupling parameters are studied using p-pbar -> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were collected with the DO detector from an integrated luminosity of 162 pb^{-1} delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum) pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gam…
We present final searches of the anomalous gammaWW and ZWW trilinear gauge boson couplings from WW and WZ production using lepton plus dijet final states and a combination with results from Wgamma, WW, and WZ production with leptonic final states. The analyzed data correspond to up to 8.6/fb of integrated luminosity collected by the D0 detector in pp-bar collisions at sqrt{s}=1.96 TeV. We set the most stringent limits at a hadron collider to date assuming two different relations between the anomalous coupling parameters Deltaκ_γ, lambda, and Delta g_1^Z for a cutoff energy scale Lambda=2 TeV. …
We present studies of W and Z bosons with associated high energy photons produced in pp collisions at sqrt(s)=7 TeV. The analysis uses 35 pb-1 of data collected by the ATLAS experiment in 2010. The event selection requires W and Z bosons decaying into high pT leptons (electrons or muons) and a photon with ET>15 GeV separated from the lepton(s) by a distance Delta_R(l,gamma)>0.7 in eta-phi space. A total of 95 (97) pp->e nu gamma + X (pp->mu nu gamma + X) and 25 (23) pp->e+ e- gamma + X (pp->mu+ mu- gamma + X) event candidates are selected. The kinematic distributions of the leptons and photons…
The integrated and differential fiducial cross sections for the production of a W or Z boson in association with a high-energy photon are measured using pp collisions at sqrt{s} = 7 TeV. The analyses use a data sample with an integrated luminosity of 4.6 fb^{-1} collected by the ATLAS detector during the 2011 LHC data-taking period. Events are selected using leptonic decays of the W and Z bosons (W(e nu,mu nu) and Z(e+ e-, mu+ mu-, nu nubar)) with the requirement of an associated isolated photon. The data are used to test the electroweak sector of the Standard Model and search for evidence for…
We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W -> lnu+gamma production in egamma and mugamma final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the cross section multiplied by the branching fraction for the process ppbar -> Wgamma+X -> lnugamma+X, measured to be 15.8 +/- 0.8 (stat.) +/- 1.2 (syst.) pb, and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These…
Tevatron diboson measurements are reviewed, and new or recent results reported for Wgamma, Zgamma, and ZZ production in the leptonic decay modes, and for WW/WZ production in the lepton plus jets decay mode. The most stringent limits on anomalous triple gauge couplings are reported for each final state.
We present the latest results on the production of WW, WZ, Wgamma, Zgamma and ZZ events at the Fermilab Tevatron Collider. The results are based on the analyses of 0.2 -- 2 /fb of data collected in p pbar collisions at sqrt(s) = 1.96 TeV by CDF and DO experiments during the Tevatron Run II. Analyses of the diboson production processes provide crucial test of the Standard Model, directly probing its predictions on the Trilinear Gauge Couplings.
We consider the production of $Wγ$ and $Zγ$ pairs at hadron colliders. We report on the complete fully differential computation of radiative corrections at next-to-next-to-leading order (NNLO) in QCD perturbation theory. The calculation includes the leptonic decay of the vector boson with the corresponding spin correlations, off shell effects and final-state photon radiation. We present numerical results for $pp$ collisions at 7 and 8 TeV and we compare them with available LHC data. In the case of $Zγ$ production, the impact of NNLO corrections is generally moderate, ranging from 8% to 18%, de…
Measurements of electroweak gauge-boson pair-production in sqrt(s) = 7 and 8 TeV pp collisions at the LHC probe self-couplings and interference effects to an accuracy of O(10%) or better. ATLAS measurements of ZZ and WZ production at both center of mass energies, and of WW, Zgamma and Wgamma production at sqrt(s) = 7 TeV, are presented. Total, fiducial, and differential cross sections are given, along with limits on anomalous triple-gauge couplings.
We present a search for anomalous triple gauge couplings (ATGC) in WW and WZ boson production. The boson pairs are produced in ppbar collisions at sqrt{s}=1.96 TeV, and the data sample corresponds to 350 pb-1 of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. In this search one W decays to leptons, and the other boson (W or Z) decays hadronically. Combining with a previously published CDF measurement of Wgamma boson production yields ATGC limits of -0.18 < lambda < 0.17 and -0.46 < Delta kappa < 0.39 at the 95% confidence level, using a cut-off scale Lambda=1…
The increasing size of the data samples recorded by the CDF and DO experiments at the Tevatron enables studies of a wide range of processes involving the electroweak bosons W and Z. Single boson production is now looked at in terms of differential cross sections such as rapidity or transverse momentum dependence. Diboson production cross-sections are several orders of magnitude smaller than single boson production cross-sections, but all combinations Wgamma, Zgamma, WW and WZ have been observed. ZZ production is expected at a rate just below the observation threshold with current data sample s…
This document gives an overview over the recent results on helicity measurement of W boson originated from top pair events. The results are obtained using data collected by the CMS detector at a center-of-mass energy of 8 TeV. The helicity measurements are confronted with the most precise theoretical predictions of the standard model.
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.
First searches for new physics phenomena using the LHC 7 TeV proton-proton collision data collected by the CMS detector in 2010 are reviewed. Results are presented of searches for new physics in events with hadronic jet pairs, and for heavy stable charged particles, including a dedicated search for long-lived particles that stop in the detector and decay in periods between beam crossings.
A search for the flavour-changing neutral current decay D0 to mu+mu- is performed in pp collisions at sqrt(s) = 7 TeV using 90 pb-1 of data collected by the CMS experiment at the LHC. No evidence is found for this decay mode. The upper limit on the branching fraction B(D0 to mu+mu-) is 5.4x10-7 at the 90% confidence level.
Measurements of inclusive jet and dijet production cross sections are presented. Data from LHC proton-proton collisions at sqrt(s) = 7 TeV, corresponding to 5.0 inverse femtobarns of integrated luminosity, have been collected with the CMS detector. Jets are reconstructed up to rapidity 2.5, transverse momentum 2 TeV, and dijet invariant mass 5 TeV, using the anti-kt clustering algorithm with distance parameter R = 0.7. The measured cross sections are corrected for detector effects and compared to perturbative QCD predictions at next-to-leading order, using five sets of parton distribution func…
We present a search for single production of heavy vector-like quarks (VLQs), carried out by the CMS collaboration analyzing LHC pp collisions at 13 TeV. The vector like quark is a massive top quark partner that is searched for in a mass range between 0.7 and 1.7 TeV and a width between $<$1\% and 30\%. Single production can be dominant over pair production, depending on the mass of the new quark. The search is performed in a variety of final states including boosted topologies that can increase the sensitivity of the analysis.
A search for narrow resonances with a mass of at least 1 TeV in the dijet mass spectrum is performed using pp collisions at sqrt(s)=7 TeV corresponding to an integrated luminosity of 1 inverse femtobarn, collected by the CMS experiment at the LHC. No resonances are observed. Upper limits at the 95% confidence level are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, and gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% confidence level: stri…
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.
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.
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.
Higher-order QCD predictions are used to extract the top quark mass, both in the pole and in the $\bar{\mathrm{MS}}$ scheme, from the top quark pair production cross section measured in the dilepton final state. The analysed dataset corresponds to an integrated luminosity of 1.14 fb$^{-1}$ collected by the CMS experiment in 2011 in proton-proton collisions at $\sqrt{s} = 7$ TeV.
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 of the angular correlations between beauty and anti-beauty hadrons produced in LHC pp collisions at $\sqrt{s}=7$ TeV are presented. These results probe for the first time the small angular separation region and show sensitivity to collinear particle emission. The results are compared with predictions based on perturbative QCD calculations at leading and next-to-leading order.
We present the first measurement of the top quark pair production cross section at the new LHC center-of-mass energy of $\sqrt{s} = 13.6 \, \mathrm{TeV}$, using $1.20 \, \mathrm{fb}^{-1}$ of data recorded at the CMS detector. We use a new method combining dilepton and lepton+jets decay channels, constraining several experimental uncertainties in situ. A cross section of $887^{+43}_{-41}(\mathrm{stat+syst}) \pm 53 (\mathrm{lumi}) \, \mathrm{pb}$ is measured, in agreement with the standard model. This result constitutes a first validation of the new data taken by CMS in LHC Run 3.
We present measurements of the total inelastic pp cross section at 7 TeV obtained with the CMS detector. Two different methods are used. In runs with low event pile-up, we exploit the large pseudorapidity coverage (|η|<5.2) of the CMS calorimeters to obtain the cross section for events with any activity in the acceptance range. In addition, runs with high event pile-up are used by fitting a Poisson distribution with the total visible cross section as parameter to the number of reconstructed primary vertices. Both measurements are corrected to a hadron level definition of the inelastic cross se…
The observation of inclusive diffraction with the CMS detector at the LHC is presented for centre-of-mass energies \sqrt s = 0.9 TeV and 2.36 TeV. Diffractive events are selected by the presence of a Large Rapidity Gap in the forward region of the CMS detector and uncorrected data are compared with Monte Carlo simulations based on the event generators PYTHIA and PHOJET. The measurement of the forward energy flow, in the pseudorapidity region 3.15 < |η| < 4.9, is also presented at \sqrt s = 0.9 TeV, 2.36 TeV and 7 TeV. Uncorrected data are compared with Monte Carlo simulations based on PYTHIA.
The inclusive cross-section for tW production in proton-proton collisions at $\sqrt{s} = 13$ TeV is measured with a dataset corresponding to an integrated luminosity of 35.9 fb$^{-1}$ collected by the CMS experiment. The measurement is performed in events with one electron and one muon, and exploits kinematic differences between the signal and the dominating $t\bar{t}$ background through the use of multivariate discriminants designed to separate the two processes. The measured cross-section of $σ= 63.1 \pm 1.8~({\rm stat}) \pm 6.0~({\rm syst}) \pm 2.1~({\rm lumi})$ pb is in agreement with stan…
The identification of jets originating from b quarks is crucial both for the searches for new physics and for the measurement of standard model processes. The Compact Muon Solenoid (CMS) collaboration at the Large Hadron Collider (LHC) has developed a variety of algorithms to select b-quark jets based on variables such as the impact parameter of charged particle tracks, properties of reconstructed secondary vertices from heavy hadron decays, and the presence or absence of a lepton in the jet, or combinations thereof. Performance measurements of these b-jet identification algorithms are present…
Evidence is presented for standard model production of a Z boson in association with a single top quark. The analysis uses a data sample of proton-proton collisions at $\sqrt{s} = 13$ TeV recorded in 2016 by the CMS detector, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. Final states containing three leptons (electrons or muons) and at least two jets are investigated, and the measured cross section is $σ($pp $\rightarrow$ tZq $\rightarrow $Wb$\ell^{+}\ell^{-}$q) = 123$^{+44}_{-39}$ fb, where $\ell$ stands for electrons, muons or taus. The corresponding observed (expected) signif…
A search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9 inverse pb collected by the CMS experiment at the LHC. Upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% CL: string resonances, with mass less than 2.50 TeV, excited quarks, with mass less than 1.58 TeV, and axigl…
We present measurements of the inclusive jet production at centre-of-mass energies of 8 and 13 TeV, and of multijets at 8 TeV. These measurements allow to constrain PDFs and the strong coupling constant. Two measurements of the azimuthal correlations at 8 and 13 TeV are also presented, testing higher order 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.
I give an overview of recent results on top quark properties and interactions, obtained using data collected with the CMS experiment during the years 2010--2011 at sqrt(s)= 7 TeV. Measurements are presented for the inclusive top pair production cross section, using the dilepton, lepton plus jets, and hadronic channels. The mass of the top quark is measured using the dilepton and lepton plus jets samples. CMS also measures the cross section for electroweak production of single top quarks and constrains the CKM matrix element V_tb. Top quark results are compared with Standard Model predictions a…
Several theories beyond the Standard Model predict the existence of new heavy neutral bosons. Such particles could be produced in significant amounts at the LHC and their decay into a dilepton pair provides a clean signature with low background contamination. The results of the analysis of the whole 2012 dataset collected by the CMS experiment at a center of mass energy of 8 TeV are presented. No evidence for new physics is seen and upper limits on the cross section production of such particles are extracted. These results can be turned into lower limits on the mass of the heavy bosons, reachi…
A search for the standard model Higgs boson in the rare mu+mu- decay channel is presented. The data samples, recorded by the CMS experiment at the LHC, correspond to integrated luminosities of 5.0 +/- 0.1 inverse femtobarns at 7 TeV center-of-mass energy and of 19.7 +/- 0.5 inverse femtobarns at 8 TeV. To enhance the Higgs signal over the dominant Drell-Yan background, the events are categorized by topologies corresponding to different production processes. Upper limits on the production rate, with respect to the Standard Model prediction, are reported at the 95% confidence level for Higgs bos…
The electroweak production of single-top quarks in the $t$ channel can be changed by any deviation from the standard model, it is therefore an excellent opportunity to search for new physics. In this poster the recent cross-section measurement performed by the CMS collaboration is presented with the full 2015 dataset of the LHC Run II at a center-of-mass energy of 13 TeV. The cross section and the top/antitop ratio is extracted using a binned maximum likelihood fit to the distribution of a multivariate classifier in events containing one isolated muon in the final state.
In this note we present a measurement of the VZ (V=W,Z) production cross section in proton-proton collisions at $\sqrt{s}=$8 TeV in the VZ$\rightarrow$V$b\bar{b}$ decay mode with V$=$Z$\rightarrow (ν\barν$,$\ell\ell$), V$=$W$\rightarrow \ellν$, ($\ell=e,μ$). The results are based on data corresponding to an integrated luminosity of 18.9 fb$^{-1}$ collected with the CMS experiment. The process is observed for the first time in this particular final state with a significance exceeding six standard deviations ($σ$). The measured cross sections are consistent with the predictions of NLO calculatio…
The CMS Open Data project offers new opportunities to measure cross sections of standard model (SM) processes which have not been probed so far. In this work, we evaluate the challenges and the opportunities of the CMS Open Data project in the view of cross-section measurements. In particular, we reevaluate SM cross sections of the production of W bosons, Z bosons, top-quark pairs and WZ dibosons in several decay channels at a center of mass energy of 8 TeV with a corresponding integrated luminosity of 1.8 fb-1. Those cross sections have been previously measured by the ATLAS and CMS collaborat…
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.
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.
Forward (di)jet measurements are a useful tool to constrain the Parton Distribution Functions (PDFs) at low values of parton momentum fraction x, and to study the possible onset of BFKL or gluon saturation QCD evolutions in the proton. We present studies of jet reconstruction capabilities in the CMS Hadron Forward (HF) calorimeter (3<|eta|<5). The expected sensitivity of the inclusive forward jet p_T spectrum to the proton PDF, as well as the azimuthal decorrelation of Mueller-Navelet jets with a large rapidity separation are presented for p-p collisions at sqrt{s} = 14 TeV.
The forward physics program of the CMS experiment at the LHC spans a broad range of diverse physics topics including studies of low-x QCD and diffractive scattering, multi-parton interactions and underlying event structure, gamma-mediated processes and luminosity determination, Monte Carlo tuning and even MSSM Higgs discovery in central exclusive production. In this article, the forward detector instrumentation around the CMS interaction point is described and the prospects for diffractive and forward physics using the CMS forward detectors are summarized. In addition, first observation of for…
An overview of recent measurements of inclusive and differential single top quark cross sections at 13 TeV with the CMS experiment is given in this note. This includes measurements targeting the $t$-channel and tW production modes resulting in inclusive cross sections of $σ_{t\mathrm{\mbox{-}ch.}}=238\pm32~\mathrm{pb}$ and $σ_\mathrm{tW}=63.1\pm6.6~\mathrm{pb}$ respectively. In addition, the $t$-channel cross section has been measured differentially as a function of the top quark transverse momentum and rapidity. The results are found in agreement with the standard model expectations. Furtherm…
In this work, we present a search for the possible production of Dark Matter particles at the Large Hadron Collider alongside a new hypothetical gauge boson denoted by Z$^{\prime}$, which is governed by a model called Mono-Z$^{\prime}$. The topology of the studied events is dimuons plus large missing transverse momentum. The analyzed data were the CMS open data samples collected by the CMS detector, in addition to the CMS open Monte Carlo samples, for the proton-proton collisions at 8 TeV center of mass energy during 2012, which correspond to an integrated luminosity of 11.6 fb$^{-1}$. Two ben…
The inclusive cross-section for tW production in proton-proton collisions at $\sqrt{s} = 13$ TeV is measured for an integrated luminosity of 35.9 fb$^{-1}$ collected by the CMS experiment. The measurement is performed using events with one electron and one muon in the final state and at least one b-quark jet, and utilises kinematic differences between the signal and the dominating $t\bar{t}$ background using multivariant discriminants which is designed to disentangle the two processes. The measured cross-section of $σ= 63.1 \pm 1.8~({\rm stat}) \pm 6.4~({\rm syst}) \pm 2.1~({\rm lumi})$ pb is …
The CMS experiment has measured the electroweak production of top quark in different singly production modes: t-, tW- and s-channel. Recent results on inclusive and differential cross section measurements of t-channel at 13 TeV and of the fiducial cross section at 8 TeV are shown. The search for single top quark production in s-channel at 7 and 8 TeV as well as the search for associated production of Z boson and single top are presented. All measurements are in agreement with the Standard Model prediction and no sign of new physics is observed.
At hadron colliders, top quarks are dominantly produced in pairs ($t\bar{t}$), a production mechanism that was discovered more than twenty years ago at the Tevatron in Fermilab. Although the \ttbar process has already entered the domain of "precision" physics, especially with the advent of the multi-TeV energies at the CERN LHC, there still remains room for dedicated experimental measurements of the top quark in the "gap" of energies between Tevatron and LHC. Hence, in the study presented here the total inclusive cross section for pair production at a center-of-mass energy of 5.02 TeV is measu…
Pseudorapidity (eta) distributions of charged particles produced in proton-proton collisions at a centre-of-mass energy of 8 TeV are measured in the ranges abs(eta) < 2.2 and 5.3 < abs(eta) < 6.4 covered by the CMS and TOTEM detectors, respectively. The data correspond to an integrated luminosity of 45 inverse microbarns. Measurements are presented for three event categories. The most inclusive category is sensitive to 91-96% of the total inelastic proton-proton cross section. The other two categories are disjoint subsets of the inclusive sample that are either enhanced or depleted in single d…
We report on recent measurements of W and Z boson production at CMS. These include measurements of inclusive and differential W and Z boson production cross sections at $\sqrt{s}$ = 8 and 13 TeV, measurements of the angular coefficients of Z boson production, forward-backward asymmetry of Z/$γ^{*}$ events, and W charge asymmetry at $\sqrt{s}$ = 8 TeV. These measurements can be used to improve PDFs and refine QCD calculations of weak boson production processes. In addition, a W-like mass measurement using Z boson events has been performed to probe the experimental uncertainties expected for a W…
Measurements of normalized differential top-quark-pair ($t\bar{t}$) production cross sections are performed using final states with two leptons ($e^+e^-$, $μ^+μ^-$, and $e^\pmμ^\mp$) in proton-proton ($pp$) collisions at $\sqrt{s}$ = 13 TeV at the CERN LHC. The data were recorded in 2015 with the CMS detector and correspond to an integrated luminosity of 2.2 fb$^{-1}$. The $t\bar{t}$ production cross section is measured as a function of kinematic properties of the top quarks and the $t\bar{t}$ system in the full phase space, as well as of the jet multiplicity in the event in the fiducial phase…
The exclusive photoproduction of $Υ$(1S), $Υ$(2S) and $Υ$(3S) mesons is studied in their leptonic ($μ^{+}μ^{-}$) decay modes, in ultraperipheral pPb collisions at $\sqrt{s_{NN}} = 5.02$ TeV. The data was recorded by the CMS experiment corresponding to an integrated luminosity of $32.6$ nb$^{-1}$. The differential cross-section for $Υ$(n) states (n=1,2,3), has been measured as a function of transverse momentum squared $p_{T}^{2}$, and rapidity $y$. The $Υ$(1S) photoproduction cross-section is extracted in the region $|y|<2.2$ as a function of the photon-proton centre-of-mass energies $W_{γp}$, …
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…
The top quark mass is measured using $35.9~\mathrm{fb}^{-1}$ of LHC proton-proton collision data collected with the CMS detector at $\sqrt{s}=13~\mathrm{TeV}$ in 2016. The measurement uses the $\mathrm{t}\overline{\mathrm{t}}$ all-jets final state, which comprises a total of six jets. A kinematic fit is performed to reconstruct the decay of the $\mathrm{t}\overline{\mathrm{t}}$ system and suppress QCD multijet background. By means of the ideogram method, the top quark mass is determined, simultaneously constraining an additional jet energy scale factor ($\text{JSF}$). The result of $172.34\pm0…
Studies of forward processes are important tests of the standard model and inputs for Monte Carlo tuning. A measurement of the energy flow in the forward pseudorapidity region of CMS, $3.15 < \vert η\vert < 4.9$, is presented for 3 values of the centre-of-mass energy $\sqrt{s}$ = 0.9 TeV, 2.36 TeV and 7 TeV. The forward energy flow is measured for minimum bias events and for events with a central dijet system the transverse energy of which provides a hard scale. The energy flow is compared to various Monte Carlo models with different multiparton interaction schemes. A study of forward jets in …
A search for direct top squark pair production is presented. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV recorded by the CMS experiment at the LHC during 2016, 2017, and 2018, corresponding to an integrated luminosity of 137 fb$^{-1}$. The search is carried out using events with a single isolated electron or muon, multiple jets, and large transverse momentum imbalance. The observed data are consistent with the expectations from standard model processes. Exclusions are set in the context of simplified top squark pair production models. Depending on t…
We present the first results on searches for new massive resonances decaying to a top-antitop quark ($t\bar{t}$) pair with the CMS detector at the LHC in proton-proton collisions with a center of mass energy of $\sqrt{s}=13~\mathrm{TeV}$. The data set considered corresponds to an integrated luminosity of $2.6~\mathrm{fb}^{-1}$ recorded during the the first year of the LHC Run-2. Searches are performed by measuring the invariant mass distribution of the $t\bar{t}$ system in semileptonic and fully-hadronic final states. Dedicated techniques are used to identify the decay of highly-boosted top qu…
