The properties of a Higgs boson candidate are measured in the H→ZZ→4l decay channel, with l=e,μ, using data from pp collisions corresponding to an integrated luminosity of 5.1 inverse femtobarns at center-of-mass energy of s√=7 TeV and 19.7 inverse femtobarns at s√=8 TeV, recorded with the CMS detector at the LHC. The new boson is observed as a narrow resonance with a local significance of 6.8 standard deviations, a measured mass of 125.6±0.4 (stat.) ±0.2 (syst.) GeV, and a total width less than 3.4 GeV at a 95% confidence level. The production cross section of the new boson times the branching fraction to four leptons is measured to be 0.93+0.26−0.23(stat.)+0.13−0.09 (syst.) times that predicted by the standard model. Its spin-parity properties are found to be consistent with the expectations for the standard model Higgs boson. The hypotheses of a pseudoscalar and all tested spin-one boson hypotheses are excluded at a 99% confidence level or higher. All tested spin-two boson hypotheses are excluded at a 95% confidence level or higher

Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31 inverse nanobarns, were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (abs(Delta(phi)~0) associated pair yields and the azimuthal anisotropy Fourier harmonics (v[n]). The second-order (v[2]) and third-order (v[3]) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of v[2] and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle v[2], and the v[3] become apparent at about the same multiplicity. A remarkable similarity in the v[3] signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental results

Measurements of two- and multi-particle angular correlations in pp collisions at root s = 5, 7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 pb(-1) (5 TeV), 6.2 pb(-1) (7 TeV), and 0.7 pb(-1) (13 TeV), were collected using the CMS detector at the LHC. The second-order (v(2)) and third-order (v(3)) azimuthal anisotropy harmonics of unidentified charged particles, as well as v(2) of K-S(0) and Lambda/(Lambda) over bar particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v(2) values of charged hadrons (mostly pions), K-S(0), and Lambda/(Lambda) over bar, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT approximate to GeV/c. For 13 TeV data, the v(2) signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions. (C) 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license

The observation of the standard model (SM) Higgs boson decay to a pair of bottom quarks is presented. The main contribution to this result is from processes in which Higgs bosons are produced in association with a W or Z boson (VH), and are searched for in final states including 0, 1, or 2 charged leptons and two identified bottom quark jets. The results from the measurement of these processes in a data sample recorded by the CMS experiment in 2017, comprising 41.3 fb −1 of proton-proton collisions at √ s = 13 TeV, are described. When combined with previous VH measurements using data collected at √ s = 7, 8, and 13 TeV, an excess of events is observed at m H = 125 GeV with a significance of 4.8 standard deviations, where the expectation for the SM Higgs boson is 4.9. The corresponding measured signal strength is 1.01 ± 0.22. The combination of this result with searches by the CMS experiment for H → bb in other production processes yields an observed (expected) significance of 5.6 (5.5) standard deviations and a signal strength of 1.04 ± 0.20.

This paper presents a search for the pair production of top squarks in events with a single isolated electron or muon, jets, large missing transverse momentum, and large transverse mass. The data sample corresponds to an integrated luminosity of 19.5 fb −1 of pp collisions collected in 2012 by the CMS experiment at the LHC at a center-of-mass energy of √ s = 8 TeV. No significant excess in data is observed above the expectation from standard model processes. The results are interpreted in the context of supersymmetric models with pair production of top squarks that decay either to a top quark and a neutralino or to a bottom quark and a chargino. For small mass values of the lightest supersymmetric particle, top-squark mass values up to around 650 GeV are excluded.Published in the European Physical Journal C as doi:10.1140/epjc/s10052-013-2677-2. IntroductionThe standard model (SM) has been extremely successful at describing particle physics phenomena. However, it suffers from such shortcomings as the hierarchy problem, where fine-tuned cancellations of large quantum corrections are required in order for the Higgs boson to have a mass at the electroweak symmetry breaking scale of order 100 GeV [1][2][3][4][5][6]. Supersymmetry (SUSY) is a popular extension of the SM that postulates the existence of a superpartner for every SM particle, with the same quantum numbers but differing by one half-unit of spin. SUSY potentially provides a "natural", i.e., not fine-tuned, solution to the hierarchy problem through the cancellations of the quadratic divergences of the top-quark and top-squark loops. In addition, it provides a connection to cosmology, with the lightest supersymmetric particle (LSP), if neutral and stable, serving as a dark matter candidate in R-parity conserving SUSY models. This paper describes a search for the pair production of top squarks using the full dataset collected at √ s = 8 TeV by the Compact Muon Solenoid (CMS) experiment [7] at the Large Hadron Collider (LHC) during 2012, corresponding to an integrated luminosity of 19.5 fb −1 . This search is motivated by the consideration that relatively light top squarks, with masses below around 1 TeV, are necessary if SUSY is to be the natural solution to the hierarchy problem [8][9][10][11][12]. These constraints are especially relevant given the recent discovery of a particle that closely resembles a Higgs boson, with a mass of ∼125 GeV [13][14][15]. Searches for top-squark pair production have also been performed by the ATLAS Collaboration at the LHC in several final states [16][17][18][19][20], and by the CDF [21] and D0 [22] Collaborations at the Tevatron.The search presented here focuses on two decay modes of the top squark ( t): t → t χ 0 1 and t → b χ + . These modes are expected to have large branching fractions if kinematically allowed. Here t and b are the top and bottom quarks, and the neutralinos ( χ 0 ) and charginos ( χ ± ) are the mass eigenstates formed by the linear combination of the gauginos and higgsinos, which are the fermi...