The observation of single top quark production in association with a Z boson and a quark (tZq) is reported. Events from proton-proton collisions at a center-of-mass energy of 13 TeV containing three charged leptons (either electrons or muons) and at least two jets are analyzed. The data were collected with the CMS detector in 2016 and 2017 and correspond to an integrated luminosity of 77.4fb-1. The increased integrated luminosity, a multivariate lepton identification, and a redesigned analysis strategy improve significantly the sensitivity of the analysis compared to previous searches for tZq production. The tZq signal is observed with a significance well over 5 standard deviations. The measured tZq production cross section is σ(pp→tZq→t?+?-q)=111±13(stat)-9+11(syst) fb, for dilepton invariant masses above 30 GeV, in agreement with the standard model expectation. © 2019 CERN.

Prafulla Kumar Behera

Department Of Physics

A. S. Muhammad

Luminance

Tellurium compounds

ANALYSIS STRATEGIES

Charged leptons

Integrated luminosity

Invariant mass

Production cross section

Proton proton collisions

Standard deviation

The standard model

Bosons

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

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IIT Madras

Physical Review Letters

The CMS muon detector system, muon reconstruction software, and high-level trigger underwent significant changes in 2013-2014 in preparation for running at higher LHC collision energy and instantaneous luminosity. The performance of the modified system is studied using proton-proton collision data at center-of-mass energy s=13 TeV, collected at the LHC in 2015 and 2016. The measured performance parameters, including spatial resolution, efficiency, and timing, are found to meet all design specifications and are well reproduced by simulation. Despite the more challenging running conditions, the modified muon system is found to perform as well as, and in many aspects better than, previously. We dedicate this paper to the memory of Prof. Alberto Benvenuti, whose work was fundamental for the CMS muon detector. © 2018 CERN for the benefit of the CMS collaboration..

Journal of Instrumentation

Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at s=13 TeV

A measurement of the inelastic proton-proton cross section with the CMS detector at a center-of-mass energy of s=13 TeV is presented. The analysis is based on events with energy deposits in the forward calorimeters, which cover pseudorapidities of −6.6 &lt; η &lt; −3.0 and +3.0 &lt; η &lt; +5.2. An inelastic cross section of 68.6 ± 0.5(syst) ± 1.6(lumi) mb is obtained for events with MX&gt; 4.1 GeV and/or MY&gt; 13 GeV, where MX and MY are the masses of the diffractive dissociation systems at negative and positive pseudorapidities, respectively. The results are compared with those from other experiments as well as to predictions from high-energy hadron-hadron interaction models. © 2018, The Author(s).

Journal of High Energy Physics

Measurement of the inelastic proton-proton cross section at √s=13 TeV

The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic τ decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8\TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions. © 2017 CERN.

Particle-flow reconstruction and global event description with the CMS detector

A search for new physics is performed using events with two isolated same-sign leptons, two or more jets, and missing transverse momentum. The results are based on a sample of proton–proton collisions at a center-of-mass energy of 13TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 2.3 fb1. Multiple search regions are defined by classifying events in terms of missing transverse momentum, the scalar sum of jet transverse momenta, the transverse mass associated with a W boson candidate, the number of jets, the number of b quark jets, and the transverse momenta of the leptons in the event. The analysis is sensitive to a wide variety of possible signals beyond the standard model. No excess above the standard model background expectation is observed. Constraints are set on various supersymmetric models, with gluinos and bottom squarks excluded for masses up to 1300 and 680GeV, respectively, at the 95 % confidence level. Upper limits on the cross sections for the production of two top quark-antiquark pairs (119fb) and two same-sign top quarks (1.7pb) are also obtained. Selection efficiencies and model independent limits are provided to allow further interpretations of the results. © 2016, CERN for the benefit of the CMS collaboration.

European Physical Journal C

Search for new physics in same-sign dilepton events in proton–proton collisions at √s = 13 TeV

Trace Elements in Medicine (Moscow)

THE INFLUENCE OF RHYTHMS OF THE HYDROMETEOROLOGICAL INDICES ON THE WATER-MINERAL HOMEOSTASIS IN HYPERTENSIVE DISEASE (HD)

Observation of Single Top Quark Production in Association with a Z Boson in Proton-Proton Collisions at s =13 TeV

Journal	Data powered by TypesetPhysical Review Letters
Publisher	Data powered by TypesetAmerican Physical Society
ISSN	00319007
Open Access	No