The amount of data collected by the CMS experiment at the CERN LHC in the second data taking period provides the possibility to study absolute and differential cross sections of top quark interaction processes with high precision. Utilizing these results, fundamental standard model parameters such as the top quark mass are extracted. Moreover, given standard model measurements are interpreted in the context of Beyond the standard model theories. Recent results on top quark properties and rare or anomalous top quark interactions by CMS are presented in these proceedings. Furthermore, the implications of experimental results to effective field theory are discussed.
Measurements of single top and rare top quark production may be sensitive to theories of physics beyond the standard model (SM), including those in which the energy scale of new physics is beyond the energies directly accessible at the Large Hadron Collider. Such models may be observable through signatures like forbidden SM interactions or deviations of the top quark's couplings from the SM predictions. An overview of recent searches from the ATLAS and CMS Collaborations is presented, with a focus on flavor-changing neutral currents.
The Flavor Changing Neutral Current mediated decays $B \rightarrow μ^{+}μ^{-}$ and $B^{0} \rightarrow K^{*0}μ^{+}μ^{-}$ provide high sensitivity to new physics contributions. Sensitive observables include the branching fraction, the muon forward-backward asymmetry, the fraction of $K^{*0}$ longitudinal polarisation and the differential branching fraction. We report herein the recent results from CMS on these decay modes.
The production of top quarks through single or rare production modes has become important due to the large amount of data collected by both ATLAS and CMS at the LHC. Many searches are now studying these processes either as a targeted signal or as an important source of background. This document reviews the Monte Carlo simulations used to model these processes in ATLAS and CMS, and how the modeling systematic uncertainties are estimated. Many analyses have also recently released a large variety of unfolded distributions. These distributions are shown and the modeling from various Monte Carlo ge…
Recent results of searches for Higgs bosons by the CMS collaboration are presented. These consist of searches for rare Higgs boson decays, searches for additional neutral Higgs bosons, and searches for charged Higgs bosons.
The discovered Higgs boson with a mass of 125 GeV exhibits properties which are all in agreement with Standard Model predictions. However, the corresponding measurements still allow for a considerable non-Standard Model behavior of the h(125). Beyond Standard Model properties can show up in non-Standard Model decays of the h(125) or in anomalous couplings of the Higgs boson. This article presents four different analyses done at the CMS experiment with 2012 and 2016 data that search for properties of the discovered Higgs boson beyond the Standard Model. These include a search for lepton flavor …
The measurement of the ZZ production cross section in proton-proton collisions at center-of-mass energies of 7 and 8 TeV from data acquired by the CMS experiment at the LHC is presented. The decay channel ZZ to 2l2nu is selected from data corresponding to an integrated luminosity of 5.1 fb-1 at 7 TeV and 19.6 fb-1 at 8 TeV. The measured cross sections are in good agreement with the standard model NLO predictions. The selected data are analyzed to search for anomalous triple gauge couplings involving the $ZZ$ final state.
Model (BSM). ATLAS and CMS concentrate on B decays that can be registered by a di-muon signature. B-hadrons decaying to J/psi(mumu) will statistically dominate B-physics analyses allowing high precision measurements, in particular a test of BSM effects in the CP violation of Bs-Jpsiphi. In the so-called rare B-decay sector, ATLAS and CMS will concentrate on a family of semi-muonic exclusive channels, b - s mumu and on the purely muonic decay Bs - mumu. After three years of LHC running at a luminosity of a few times 1033 cm-2 s-1 (corresponding to 30 fb-1), each of these two experiments can mea…
Latest results from the CMS experiment at the LHC on top quark production in association with a Z boson or a photon, and the production of four top quarks, are summarized. Proton-proton collision data corresponding to an integrated luminosity of up to 138 fb$^{-1}$, collected at 13 TeV center-of-mass energy are used. Among the measured results, most precise inclusive cross sections, most stringent limits on models beyond the standard model and first differential measurements are presented. Overall, good agreement with standard model predictions is observed.
Recent measurements of multiboson production from the CMS experiment will be presented, as well as limits on anomalous triple and quartic gauge couplings. Precision measurements of multiboson production allow a basic test of the Standard Model, where higher order QCD and electroweak corrections can be probed. In addition searches of physics beyond the Standard Model in multiboson final states rely on precise determination of the Standard Model multiboson processes. The presence of triple and quartic gauge couplings in multiboson production also allows for tests of modification of these vertice…
The flavour changing neutral current decays can be interesting probes for searching for New Physics. Angular distributions of the decay $\mathrm{B}^0 \to \mathrm{K}^{*0} μ^ +μ^-$ are studied using a sample of proton-proton collisions at $\sqrt{s} = 8~\mathrm{TeV}$ collected with the CMS detector at the LHC, corresponding to an integrated luminosity of $20.5~\mathrm{fb}^{-1}$. An angular analysis is performed to determine $P_1$ and $P_5'$, where $P_5'$ is of particular interest due to recent measurements that indicate a potential discrepancy with the standard model. Based on a sample of 1397 si…
The most recent studies in the top quark sector are reviewed with the focus on the rare production mechanisms and suppressed decays. The experimental results obtained with the ATLAS and CMS detectors in proton-proton collisions at the center-of-mass energy of 13 TeV include the measurements of the associated production of top quark pairs with vector bosons (${\rm t\bar{t}W}$, ${\rm t\bar{t}Z}$, ${\rm t\bar{t}γ}$), the first evidence for the ${\rm t(\bar{t})γq}$ process, the first observation of the ${\rm t(\bar{t})Zq}$ production, the study of the ${\rm t\bar{t}+b\bar{b}}$ and ${\rm t\bar{t}+t…
We describe the most recent results from the Proton Precision Spectrometer from the CMS and TOTEM collaborations, namely the first observation of exclusive di-lepton production at high mass at the LHC, and the prospects concerning the sensitivity to quartic anomalous couplings..
Precision studies of top quark properties provide a unique playground to test the predictions of the standard model and to search for new physics. Reviewed results from the CMS experiment done with the data collected at 8 TeV include studies of top quark Wtb anomalous and FCNC couplings, polarization, CP-violation, and spin correlation effects. No significant deviations from the SM predictions are observed.
The CMS Collaboration has recently reported some excess events in final states with electrons and jets, in searches for leptoquarks and $W'$ bosons. Although these excesses may be due to some yet-to-be-understood background mismodeling, it is useful to seek realistic interpretations involving new particles that could generate such events. We show that resonant pair production of vector-like leptons that decay to an electron and two jets leads to kinematic distributions consistent with the CMS data.
A two Higgs doublet model (2HDM) is one of the minimal extensions of the Standard Model (SM), and it is well-known that the general setup predicts the flavor-violating phenomena, mediated by neutral Higgs interactions. Recently the CMS collaboration has reported an excess of the lepton-flavor-violating Higgs decay in $h \rightarrow μτ$ channel with a significance of 2.5 $ σ$. We investigate the CMS excess in a general 2HDM with tree-level Flavor Changing Neutral Currents (FCNCs), and discuss its impact on the other physical observations. Especially, we see that the FCNCs relevant to the excess…
We present some of the most recent results from the CMS Collaboration on searches for Higgs-like particles in models beyond the Standard Model. Several rare and exotic decay modes of the Higgs boson are explored. The results of the searches are relevant for establishing whether the 125 GeV particle observed in Higgs boson searches at the LHC has the properties expected for a Standard Model Higgs boson.
The LHC experiments will perform sensitive tests of physics beyond the Standard Model (BSM). The investigation of decays of beauty hadrons represents an alternative approach in addition to direct BSM searches. The ATLAS and CMS efforts concentrate on those B-decays that can be efficiently selected already at the first and second level trigger. The most favorable trigger signature will be for $B$-hadron decays with muons in the final state. Using this trigger, ATLAS and CMS will be able to accommodate unprecedentedly high statistics in the rare decay sector. These are purely dimuon decays, and …
We describe recent results from CMS and TOTEM on hard diffraction, diffractive jets and jet gap jet events. We also give the first sensitivities and limits on quartic anomalous couplings and axion-like particles at high mass using the LHC as a $γγ$ collider. The predicted sensitivities with 300 fb$^{-1}$ are better by two or three orders of magnitude compared to the more standard methods at the LHC without measuring intact protons after collision
The latest results in the search for rare and exotic Higgs boson decays in proton-proton collision events collected with the CMS detector at the LHC are presented. The searches are performed for several decay modes of Higgs boson including $\mathrm{H}\rightarrow{\rm X (X \rightarrow2\ell)γ}$ ($X= {\rm Z}, γ^* $ and $\ell={\rm e},μ$), $\mathrm{H}\rightarrow{ μμ/ {\rm e}{\rm e}}$, invisible decays, lepton flavour violating decays and Higgs decay to light scalars or pseudo-scalars. No hint for new physics has been found from the analyzed results with the full LHC run-1 data collected during 2011 …
In absence of any distinct evidence of new physics phenomena at the LHC, an increasing number of experimental studies aim at probing anomalous effects with an effective field theory (EFT) that represents a comprehensive approach for interpretation of various experimental results. The processes with the production of top quarks are sensitive to several classes of EFT operators including the flavour-changing neutral currents (FCNC). The summary of the latest CMS results based on the recent studies of the standard model processes and searches for new physics effects involving top quarks are prese…
We present a Monte Carlo simulation study of measuring the rare leptonic decay Bs->mu+mu- with the CMS experiment at the LHC. The study is based on a full detector simulation for signal and background events. We discuss the high-level trigger algorithm and the offline event selection.
As a top-factory, the LHC is performing a direct study of top-quark anomalous FCNC couplings, which are, however, correlated closely with the rare B- and K-meson decays. In this paper, we study the effects of anomalous $tqZ$ (with $q=u,c$) couplings in the rare decays $B_{s,d}\to μ^+μ^-$, $B\to X_s ν\barν$, $B\to K^{(*)}ν\barν$, $K^+\to π^+ ν\barν$, and $K_L\to π^0 ν\barν$. With the up-to-date experimental bounds on the branching ratios of these channels, constraints on the left-handed anomalous couplings $X_{ct}^L$ and $X_{ut}^L$ are derived, respectively. With these low-energy constraints ta…
CMS measurements of properties related to top quark decays are discussed. The results presented regard the measurement of the W boson helicity, the investigation of anomalous couplings in the Wtb vertex, and the search for very rare decays, such as t -> Zq and t -> Hq, which are associated to flavor-changing neutral currents.
Rare decay of the Higgs boson is a powerful tool to probe new physics beyond the standard model. The rare decays occur through quantum loops in which the standard model and new physics contributions might cancel each other out. We consider a faked-no-new-physics scenario that the new physics contributions are about minus two times the standard model contribution such that partial widths of Higgs boson rare decays are the same as the standard model predictions. We propose to measure the $HZγ$ and $Hγγ$ anomalous couplings in the process of $e^+ e^- \to Hγ$ that is strongly correlated to Higgs b…
Recent results from the CMS experiment on the production of multiple vector bosons in proton-proton collisions at the CERN LHC are presented. Measurements of WZ and ZZ production with fully leptonic decays, Z$(νν)γ$, and WV (V $=$ W,Z $\rightarrow q\bar{q}$) production at 8 and 13 TeV are discussed. Selected cross section measurements, unfolded differential measurements, and limits on anomalous triple gauge couplings are presented and compared with theoretical predictions.
Thanks to the excellent performances of ATLAS and CMS in triggering on muon signals and reconstructing these particles down to low transverse momentum, large samples of heavy-flavored hadrons have been collected in the 2011 LHC run at sqrt(s) = 7 TeV. The analysis of these samples has enabled both experiments to perform competitive measurements of heavy-flavor properties, such as quarkonium polarization, lifetime and CP-violation measurements, hadron spectroscopy and branching ratios of rare B decays.
We present heavy flavor measurements performed by the ATLAS and CMS Collaborations with data collected at the Large Hadron Collider. The production mechanism of heavy flavor hadrons is discussed as well as lifetime measurements and searches for the rare decay Bs->mumu. The large available statistics of about 5 fb-1 per experiment collected during the year 2011 together with the excellent detector performance allows to perform competitive heavy flavor measurements.
Selected results from the following topics are presented: Measurements of several top quark properties are obtained from the CMS data collected in 2011 at a center-of-mass energy of 7 TeV. The results include measurements of the top quark mass, the W helicity in top decays, the top quark charge, and of the $t\bar{t}$ spin correlation and the search for anomalous couplings.
It is here presented the diboson production cross section measured by the CMS collaboration in $pp$ collisions data at $\sqrt{s}$=7 TeV. $W γ$ and $Z γ$ results from 2010 analyses (36 pb$^{-1}$) are presented together with 2011 first measurements of $WW$, $WZ$ and $ZZ$ final states obtained using 1.1 fb$^{-1}$. Results obtained with 2010 data are also interpreted in term of anomalous triple gauge couplings.
Precision studies of top quark properties are currently underway at the LHC and Tevatron colliders with the prospect of probing anomalous t-W -b interactions. In the mean time, recent experimental results for the B_{d,s} - \bar{B}_{d,s} oscillation observables, the branching ratio B_s->μ^+μ^-, as well as the forward - backward asymmetry in B->K\starl^+l^-, accompanied by the accurate theoretical predictions for the relevant observables obtained within the SM motivate a combined study of these observables in the presence of anomalous t - W - b vertices. We investigate contributions of such anom…
A summary of studies of electroweak top-quark production performed by the CMS collaboration is presented. The results include measurements of production cross sections, extraction of the value of $|V_{tb}|$, determination of W-boson helicity in top-quark decays and top-quark spin asymmetry, and a search for anomalous couplings in the Wtb vertex. No deviations from predictions of the standard model are found.
In this article we describe the methods of observing WZ signal at CMS experiment at Large Hadron Collider. To reduce the dependence on Monte Carlo simulation we use data-driven techniques and estimate that 5sigma significance of WZ signal can be reached with less than 350 pb^{-1} at 95% C.L. for sqrt{s} = 14 TeV. We also overview several models that would yield anomalous production of the WZ final state, sensitivity to which can be achieved with less data.
The rare decays $B_{s,d}^0 \to μ^+μ^-$ are important probes for new physics beyond the Standard Model. These decays are subjects of studies at the LHC. The ATLAS and CMS collaborations have analyzed the proton-proton collisions data at 7 TeV centre-of-mass energy collected in the year 2011. They have established upper limits on the branching fractions of the two decays. This paper presents a report.
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 are presented from a search for the rare decays B(s) to mu+ mu- and B0 to mu+ mu- in pp collisions at sqrt(s) = 7 and 8 TeV, with data samples corresponding to integrated luminosities of 5 and 20 inverse femtobarns, respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction B(B(s) to mu+ mu-) = (3 +1.0/-0.9)E-9, where the uncertainty includes both statistical and systematic contributions. An excess of B(s) to mu+ mu- events with respect to background is observed with a significance of…
In our latest paper "Search for anomalous top-gluon couplings at LHC revisited" in Eur. Phys. J. C65 (2010), 127-135 (arXiv:0910.3049 [hep-ph]), we studied possible effects of nonstandard top-gluon couplings through the chromoelectric and chromomagnetic moments of the top quark using the total cross section of ppbar/pp --> ttbar X at Tevatron/LHC. There we pointed out that LHC data could give a stronger constraint on those two parameters, which would be hard to obtain from Tevatron data alone. We show here the first CMS measurement of this cross section actually makes it possible.
This review summarizes the current experimental results on rare B0_(s) -> mu+mu- decays of the Tevatron experiments CDF and D0, and the LHC experiments ATLAS, CMS and LHCb. The experimental branching fraction upper limits for the B0_s -> mu+mu- are already quite close to the branching fraction predicted by the Standard Model, and the first observation of the B0_s -> mu+mu- decay is expected soon. The rare decays B0_(s) -> mu+mu- are highly suppressed in the Standard Model, and therefore accurate measurements of these branching fractions provide complementary constraints to the free parameters …
Measurements of $\mathrm{t\bar{t}}$ spin correlations are presented in events with top quarks produced in $\mathrm{pp}$ collisions at the LHC. The data correspond to an integrated luminosity of $36\:\mathrm{fb^{-1}}$ at $\sqrt{s}=13\:\mathrm{TeV}$ collected at both the ATLAS and CMS detectors. The spin correlations are measured using the angular distributions of the leptons in dilepton channel $\mathrm{t\bar{t}}$ events. The spin correlations are probed both directly, using distributions measured in the top quark rest frames that depend only on the top quark spin, and indirectly, using distrib…
We present a summary of the latest measurements of the VV crosssections, where V=W or Z and one of the bosons decays into a pair of jets while the other decays leptonically. The data sample(s) correspond to proton-proton collision events collected with the CMS detector at sqrt{s} = 7 TeV. Subsequent searches for Anomalous Triple Gauge couplings, which allow us to probe the non-Abelian structure in the Electroweak Sector, are described. We present the exclusion limits on the corresponding couplings.
The recent data from E821 Brookhaven experiment in conjunction with a new determination of the hadronic vacuum polarization contribution to the anomalous magnetic moment of muon, put new bounds on the parameters of the Constrained Minimal Supersymmetric Standard Model. We study the impact this experimental information, along with the $b \goes s γ$ branching ratio and light Higgs boson mass bound from LEP, to constrain regions of the model which are consistent with the cosmological data. The effect of these to Dark Matter direct searches is also discussed.
Experimental results on top-quark physics obtained at the CMS experiment are reported based on the data recorded at centre-of-mass energy up to 13 TeV. Inclusive and differential cross sections for both top-quark pair and single top-quark production are presented, as well as measurements of top-quark properties in production and decay, and searches for anomalous couplings. The presented measurements test theoretical predictions, including recent perturbative QCD calculations, provide constraints of fundamental standard model parameters, and set limits on physics beyond the standard model.
We analyze the possibility of probing anomalous Higgs couplings in the rare decays $H \to Z V$, $V$ being a vector quarkonium state. These rare decays involve both gauge as well as the Yukawa sectors and either of them can potentially be anomalous. We show that the branching fractions for $H \to Z V$ decays in Standard Model are small, making it a sensitive probe for anomalous Higgs couplings originating from physics beyond Standard Model. Moreover, as both $V$ and $Z$ can decay into pair of charged leptons, they provide experimentally clean channels and future LHC runs should observe such dec…
The CMS experiment at the LHC accelerator at CERN relies on its computing infrastructure to stay at the frontier of High Energy Physics, searching for new phenomena and making discoveries. Even though computing plays a significant role in physics analysis we rarely use its data to predict the system behavior itself. A basic information about computing resources, user activities and site utilization can be really useful for improving the throughput of the system and its management. In this paper, we discuss a first CMS analysis of dataset popularity based on CMS meta-data which can be used as a…
The CMS experiment uses missing E_T to both measure processes in the Standard Model and test models of physics beyond the Standard Model. These proceedings show the performance of the missing E_T reconstruction evaluated by using 4.6 fb-1 of proton-proton collision data at the center-of-mass energy 7 TeV collected in 2011 with the CMS detector at the Large Hadron Collider. Missing E_T was reconstructed based on a particle-flow technique. Jet energy corrections were propagated to missing E_T. After anomalous signals and events were addressed, the missing E_T spectrum was well reproduced by MC s…
Heavy-flavor physics offers the opportunity to make indirect tests of physics beyond the Standard Model through precision measurements, and of quantum chromodynamics (QCD) through particle production studies. The rare decays B0s, B0 and D0 to dimuon final states are excellent tests of the flavor sector of the Standard Model and are sensitive to new physics. We report on studies of these decays and present the first observation of the excited b baryon Xib*0 in strong decays to Xib and a charged pion, the observation of two Bc meson decay modes and production properties of the Lambda_b baryon, a…
We report the results on the search for exclusive production of $W$ pairs in the LHC with data collected by the Compact Muon Solenoid detector in proton-proton collisions at $\sqrt{s}$ = 7 TeV. The analysis comprises the two-photon production of a $W$ pairs, ${pp\to p\,W^{+}W^{-}\,p\to p\,νe^{\pm}νμ^{\mp}\,p}$. Two events are observed in data for $p_{\textrm{\footnotesize T}}(\ell)>$ 4 GeV, $|η(\ell)|<$ 2.4 and $m(μ^{\pm}e^{\mp})>$ 20 GeV, in agreement with the standard model prediction of 2.2 $\pm$ 0.4 signal events with 0.84 $\pm$ 0.15 background events. Moreover, a study of the tail of the …
A search for the rare decays (Bs -> μμ) and (B0 -> μμ) performed in pp collisions at sqrt{s} = 7 TeV is presented. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 1.14 /fb. In both cases the number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions. The resulting upper limits on the branching fractions are BF(Bs -> μμ) < 1.9 * 10^{-8} and BF(B0 -> μμ) < 4.6 * 10^{-9} at 95% confidence level (CL). Furthermore, the combination of the results of the search…
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…
We show that the No-Scale Flipped SU(5) construction is transparently consistent with recent LHCb results for B_s^0 to μ^+ μ^- decays, due primarily to suppression from the rather small value of tanβ~ 20 that is globally enforced across the model space. This fact should be interpreted in conjunction with the demonstrated evasion of mass limits from the ATLAS and CMS SUSY searches and the more important potential explanation of small observed excesses in the multijet data. The No-Scale Flipped SU(5) benchmark model that best fits these excesses has a gaugino mass scale of M_{1/2} = 708 GeV, whi…
Recent measurements of top-quark properties (excluding the top quark mass) at ATLAS and CMS are discussed. This includes latest updates of measurements of $t\bar{t}$ production asymmetries, spin correlations and $W$ helicity, as well as the polarization and anomalous couplings of the top quark. Furthermore results on the associate production of $W$, $Z$ and $γ$ with a $t\bar{t}$ pair are presented. All of these measurements employ the full data set at $\sqrt{s} = 7$ or 8 TeV corresponding to an integrated luminosity of $4.7/$fb or $19.7/$fb. The results of all these measurements agree well wit…
Measurements of several top-quark properties, obtained from the CMS data collected in 2011 and 2012 at centre-of-mass energies of 7 and 8 TeV are presented. The results include measurements of the top pair charge asymmetry, the W helicity in top quark decays and the search for anomalous couplings, the top quark charge, and of the ttbar spin correlation. The fraction of top quarks decaying into a W-boson and a b-quark relative to all top quark decays, R=Br(t->Wb)/Br(t->Wq), as well as, the cross sections of ttbar events produced in association with a photon or a W or a Z boson are also presente…
We consider the Higgs boson anomalous FCNC interactions with $u$, $c$, $d$, $s$ and $b$ quarks using the effective field theory framework. Constraints on anomalous couplings are derived from experimental results on Higgs boson production with subsequent decay into $b \bar{b}$ pair at LHC with $\sqrt{s} = 13 $~TeV. Upper limits on the branching fractions of $H \to b\bar{s}$ and $H \to b\bar{d}$ are set by performing a realistic detector simulation and accurately reproducing analysis selections of the CMS Higgs boson measurement in the four-lepton final state at $\sqrt{s} = 13$ TeV. The searches…
