Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at root s=13 TeV

Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at root s = 13TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb(-1). Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12 +/- 0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.Peer reviewe

Measurement of the top quark mass using events with a single reconstructed top quark in pp collisions at root s=13 TeV

Abstract:A measurement of the top quark mass is performed using a data sample en-riched with single top quark events produced in thetchannel. The study is based on proton-proton collision data, corresponding to an integrated luminosity of 35.9 fb−1, recorded at√s= 13TeV by the CMS experiment at the LHC in 2016. Candidate events are selectedby requiring an isolated high-momentum lepton (muon or electron) and exactly two jets,of which one is identified as originating from a bottom quark. Multivariate discriminantsare designed to separate the signal from the background. Optimized thresholds are placedon the discriminant outputs to obtain an event sample with high signal purity. The topquark mass is found to be172.13+0.76−0.77GeV, where the uncertainty includes both the sta-tistical and systematic components, reaching sub-GeV precision for the first time in thisevent topology. The masses of the top quark and antiquark are also determined separatelyusing the lepton charge in the final state, from which the mass ratio and difference aredetermined to be0.9952+0.0079−0.0104and0.83+1.79−1.35GeV, respectively. The results are consistentwithCPTinvariance

Search for a heavy resonance decaying to a top quark and a w boson at √s = 13 tev in the fully hadronic final state

A search for a heavy resonance decaying to a top quark and a W boson in the fully hadronic final state is presented. The analysis is performed using data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb−1 recorded by the CMS experiment at the LHC. The search is focused on heavy resonances, where the decay products of each top quark or W boson are expected to be reconstructed as a single, large-radius jet with a distinct substructure. The production of an excited bottom quark, b*, is used as a benchmark when setting limits on the cross section for a heavy resonance decaying to a top quark and a W boson. The hypotheses of b* quarks with left-handed, right-handed, and vector-like chiralities are excluded at 95% confidence level for masses below 2.6, 2.8, and 3.1 TeV, respectively. These are the most stringent limits on the b* quark mass to date, extending the previous best limits by almost a factor of two

Estudo qualitativo dos principais atributos que determinam a percepção de qualidade e de preço dos consumidores de restaurantes a la carte Qualitative study of main attributes that determine the consumer quality and price perceptions of a la carte restaurants

Este trabalho apresenta um estudo qualitativo dos principais determinantes da qualidade e do preço percebidos por clientes de restaurantes a la carte. Para isto, foram realizadas entrevistas em grupos focados, contemplando quatro tipos de consumidores avaliados (casais sem filhos, grupos de amigos, família e executivos). Os principais determinantes da qualidade percebida identificados foram: atributos da comida, atendimento, ambiente, tempo de espera, limpeza, segurança, instalações de apoio, cardápio, atributos da bebida, privacidade, exatidão, decoração e confirmação de expectativas. Realizou-se uma comparação com o modelo das dimensões da qualidade de Parasuraman et al. (1985) e propuseram-se algumas modificações baseadas nos resultados obtidos para o serviço de restaurantes a la carte e em outras pesquisas da literatura. Por outro lado, os determinantes mais importantes do preço percebido obtidos foram: qualidade da comida, decoração, ambiente, atendimento, instalações de apoio, cardápio, limpeza, atributos da bebida, quantidade das porções, expectativas prévias e privacidade. Os resultados obtidos sugerem a existência de relação entre os determinantes da qualidade percebida e preço percebido. Os resultados são comparados com outras pesquisas da literatura.<br>This paper presents a qualitative study of the determinants of perceived quality and price for la carte restaurant customers. For this, four focus group interviews were conducted joining customers categorized as: couples without children, friends' group, families, and executives. The most important identified determinants of perceived quality were: food attributes, service, ambient, wait time, cleaning, safety, support facilities, menu, drink attributes, privacy, accuracy, decoration, and confirmation of expectations. These determinants were compared with the perceived quality model suggested by Parasuraman et al. (1985) and some modifications were proposed based on the results gathered on the la carte restaurants study and on other evidences presented in literature. On the other hand, the most important determinants of perceived price were: food quality, decoration, ambient, service, support facilities, menu, cleaning, drink attributes, portion amount, previous expectations, and privacy. The results suggest the existence of a relationship between the determinants of perceived quality and perceived price for la carte restaurants customers. These results are compared with other literature studies

Precision luminosity measurement in proton-proton collisions at root S=13 TeV in 2015 and 2016 at CMS

The measurement of the luminosity recorded by the CMS detector installed at LHC interaction point 5, using proton-proton collisions at root S = 13 TeV in 2015 and 2016, is reported. The absolute luminosity scale is measured for individual bunch crossings using beam-separation scans (the van der Meer method), with a relative precision of 1.3 and 1.0% in 2015 and 2016, respectively. The dominant sources of uncertainty are related to residual differences between the measured beam positions and the ones provided by the operational settings of the LHC magnets, the factorizability of the proton bunch spatial density functions in the coordinates transverse to the beam direction, and the modeling of the effect of electromagnetic interactions among protons in the colliding bunches. When applying the van der Meer calibration to the entire run periods, the integrated luminosities when CMS was fully operational are 2.27 and 36.3 fb(-1) in 2015 and 2016, with a relative precision of 1.6 and 1.2%, respectively. These are among the most precise luminosity measurements at bunched-beam hadron colliders.Peer reviewe

Measurements of angular distance and momentum ratio distributions in three-jet and Z plus two-jet final states in pp collisions

Collinear (small-angle) and large-angle, as well as soft and hard radiations are investigated in three-jet and Z + two-jet events collected in proton-proton collisions at the LHC. The normalized production cross sections are measured as a function of the ratio of transverse momenta of two jets and their angular separation. The measurements in the three-jet and Z + two-jet events are based on data collected at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb(-1). The Z + two-jet events are reconstructed in the dimuon decay channel of the Z boson. The three-jet measurement is extended to include root s = 13 TeV data corresponding to an integrated luminosity of 2.3 fb(-1). The results are compared to predictions from event generators that include parton showers, multiple parton interactions, and hadronization. The collinear and soft regions are in general well described by parton showers, whereas the regions of large angular separation are often best described by calculations using higher-order matrix elements.Peer reviewe