Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, ...including the transverse momenta ( ) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta ( ), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb super(-1). The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the distributions of the leading jets at high values, the distributions of the at high- and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Dijet production has been measured in ... collisions at a nucleon-nucleon centre-of-mass energy of 5.02... A data sample ...corresponding to an integrated luminosity of 35 ... was collected using the Compact Muon Solenoid detector at the Large Hadron Collider. The dijet transverse momentum balance, azimuthal angle correlations, and pseudorapidity distributions are studied as a function of the transverse energy in the forward calorimeters (...). For ... collisions, the dijet transverse momentum ratio and the width of the distribution of dijet azimuthal angle difference are comparable to the same quantities obtained from a simulated ... reference and insensitive to ... In contrast, the mean value of the dijet pseudorapidity is found to change monotonically with increasing ..., indicating a correlation between the energy emitted at large pseudorapidity and the longitudinal motion of the dijet frame. The pseudorapidity distribution of the dijet system in minimum bias ... collisions is compared with next-to-leading-order perturbative QCD predictions obtained from both nucleon and nuclear parton distribution functions, and the data more closely match the latter.
An updated search for heavy narrow resonances decaying to muon or electron pairs using the CMS detector is presented. Data samples from pp collisions at s = 7 TeV and 8 TeV at the LHC, with ...integrated luminosities of up to 5.3 and 4.1 fb - 1 , respectively, are combined. No evidence for a heavy narrow resonance is observed. The analysis of the combined data sets excludes, at 95% confidence level, a Sequential Standard Model Z SSM a2 resonance lighter than 2590 GeV, a superstring-inspired Z I a2 lighter than 2260 GeV, and KaluzaaKlein gravitons lighter than 2390 (2030) GeV, assuming that the coupling parameter k / M A= Pl is 0.10 (0.05). These are the most stringent limits to date.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A measurement of W super(+)W super(-) production in pp collisions at ... is presented. The data were collected with the CMS ...detector at the LHC, and correspond to an integrated luminosity of 4.92 plus or minus 0.11 fb super(-1). The W super(+)W super(-) candidates consist of two oppositely charged leptons, electrons or muons, accompanied by large missing transverse energy. The W super(+)W super(-) production cross section is measured to be 52.4 plus or minus 2.0 (stat.) plus or minus 4.5 (syst.) plus or minus 1.2 (lum.) pb. This measurement is consistent with the standard model prediction of 47.0 plus or minus 2.0 pb at next-to-leading order. Stringent limits on the WW gamma and WWZ anomalous triple gauge-boson couplings are set.
An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample ...corresponds to an integrated luminosity of 11.7 fb super(-1) collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, alpha sub(T), is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Cross sections for the production of a Z boson in association with jets in proton-proton collisions at a centre-of-mass ...energy of ... TeV are measured using a data sample collected by the CMS experiment at the LHC corresponding to 19.6 fb super(-1). Differential cross sections are presented as functions of up to three observables that describe the jet kinematics and the jet activity. Correlations between the azimuthal directions and the rapidities of the jets and the Z boson are studied in detail. The predictions of a number of multileg generators with leading or next-to-leading order accuracy are compared with the measurements. The comparison shows the importance of including multi-parton contributions in the matrix elements and the improvement in the predictions when next-to-leading order terms are included. Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The spectra of charged particles produced within the pseudorapidity window | eta | < 1 at ... TeV are measured using 404 mu ...b super(-1) of PbPb and 27.4 pb super(-1) of pp data collected by the CMS detector at the LHC in 2015. The spectra are presented over the transverse momentum ranges spanning 0.5 < p sub(T) < 400 GeV in pp and 0.7 < p sub(T) < 400 GeV in PbPb collisions. The corresponding nuclear modification factor, R sub(AA), is measured in bins of collision centrality. The R sub(AA) in the 5% most central collisions shows a maximal suppression by a factor of 7-8 in the p sub(T) region of 6-9 GeV. This dip is followed by an increase, which continues up to the highest p sub(T) measured, and approaches unity in the vicinity of p sub(T) = 200 GeV. The R sub(AA) is compared to theoretical predictions and earlier experimental results at lower collision energies. The newly measured pp spectrum is combined with the pPb spectrum previously published by the CMS collaboration to construct the pPb nuclear modification factor, R sub(pA), up to 120 GeV. For p sub(T) > 20 GeV, R sub(pA) exhibits weak momentum dependence and shows a moderate enhancement above unity. Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Results are presented from a search for the electroweak production of supersymmetric particles in pp collisions in final ...states with two tau leptons. The data sample corresponds to an integrated luminosity between 18.1 fb super(-1) and 19.6 fb super(-1) depending on the final state of tau lepton decays, at ... TeV, collected by the CMS experiment at the LHC. The observed event yields in the signal regions are consistent with the expected standard model backgrounds. The results are interpreted using simplified models describing the pair production and decays of charginos or tau sleptons. For models describing the pair production of the lightest chargino, exclusion regions are obtained in the plane of chargino mass vs. neutralino mass under the following assumptions: the chargino decays into third-generation sleptons, which are taken to be the lightest sleptons, and the sleptons masses lie midway between those of the chargino and the neutralino. Chargino masses below 420 GeV are excluded at a 95% confidence level in the limit of a massless neutralino, and for neutralino masses up to 100 GeV, chargino masses up to 325 GeV are excluded at 95% confidence level. Constraints are also placed on the cross section for pair production of tau sleptons as a function of mass, assuming a massless neutralino. Figure not available: see fulltext.
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