The dependence of the ratio between the B$_\mathrm{s}^0$ and B$^+$ hadron production fractions, $f_\mathrm{s} / f_\mathrm{u}$, on the transverse momentum ($p_\mathrm{T}$) and rapidity of the B mesons is studied using the decay channels B$_\mathrm{s}^0$$\to$ J$/\psi\,\phi$ and B$^+$$\to$ J$/\psi$ K$^+$. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6 fb$^{-1}$. The $f_\mathrm{s} / f_\mathrm{u}$ ratio is observed to depend on the B $p_\mathrm{T}$ and to be consistent with becoming asymptotically constant at large $p_\mathrm{T}$. No rapidity dependence is observed. The ratio of the B$^0$ to B$^+$ hadron production fractions, $f_\mathrm{d} / f_\mathrm{u}$, measured using the B$^0$$\to$ J$/\psi$ K$^{*0}$ decay channel, is found to be consistent with unity and independent of $p_\mathrm{T}$ and rapidity, as expected from isospin invariance.
The $\mathrm{J/\psi \phi}$, $\mathrm{J/\psi K}$, and $\mathrm{J/\psi} \mathrm{K}^{*0}$ invariant mass distributions, for $\mathrm{B}$ meson candidates with $20 < p_T < 23$ GeV, and asociated fits as described in the text.
The $\mathrm{J/\psi \phi}$, $\mathrm{J/\psi K}$, and $\mathrm{J/\psi} \mathrm{K}^{*0}$ invariant mass distributions, for $\mathrm{B}$ meson candidates with $20 < p_T < 23$ GeV, and asociated fits as described in the text.
The $\mathrm{J/\psi \phi}$, $\mathrm{J/\psi K}$, and $\mathrm{J/\psi} \mathrm{K}^{*0}$ invariant mass distributions, for $\mathrm{B}$ meson candidates with $20 < p_T < 23$ GeV, and asociated fits as described in the text.
Spectra of identified charged hadrons are measured in pp collisions at the LHC for sqrt(s) = 0.9, 2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and for rapidities abs(y) < 1 are identified via their energy loss in the CMS silicon tracker. The average pt increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully corrected pt spectra and integrated yields are compared to various tunes of the PYTHIA6 and PYTHIA8 event generators.
Measured transverse momentum distributions of identified charged hadrons (PI+, K+ and P) and at a centre-of-mass energy of 900 GeV.
Measured transverse momentum distributions of identified charged hadrons (PI-, K- and PBAR) and at a centre-of-mass energy of 900 GeV.
Measured transverse momentum distributions of identified charged hadrons (PI+, K+ and P) and at a centre-of-mass energy of 2760 GeV.
The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.
The measured Lambda/B integrated cross section and the ratio of anti-Lambda/B to Lambda/B cross sections.
The measured Lambda/B differential cross section and the ratio of anti-Lambda/B to Lambda/B cross sections as a function of the Lambda/B transverse momentum The second and third systematic errors on the cross sections are the common luminosity and branching fraction uncertainties respectively.
The measured Lambda/B differential cross section and the ratio of anti-Lambda/B to Lambda/B cross sections as a function of the Lambda/B absolute rapidity. The second and third systematic errors on the cross sections are the common luminosity and branching fraction uncertainties respectively.
The production of Z bosons associated with jets is measured in pp collisions at $\sqrt{s}$ = 13 TeV with data recorded with the CMS experiment at the LHC corresponding to an integrated luminosity of 36.3 fb$^{-1}$. The multiplicity of jets with transverse momentum $p_\mathrm{T}$$\gt$ 30 GeV is measured for different regions of the Z boson's $p_\mathrm{T}$(Z), from lower than 10 GeV to higher than 100 GeV. The azimuthal correlation $\Delta \phi$ between the Z boson and the leading jet, as well as the correlations between the two leading jets are measured in three regions of $p_\mathrm{T}$(Z). The measurements are compared with several predictions at leading and next-to-leading orders, interfaced with parton showers. Predictions based on transverse-momentum dependent parton distributions and corresponding parton showers give a good description of the measurement in the regions where multiple parton interactions and higher jet multiplicities are not important. The effects of multiple parton interactions are shown to be important to correctly describe the measured spectra in the low $p_\mathrm{T}$(Z) regions.
The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $p_T<10$ GeV
The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $10<p_T<30$ GeV
The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $30<p_T<50$ GeV
Spectra of identified charged hadrons are measured in pPb collisions with the CMS detector at the LHC at sqrt(sNN) = 5.02 TeV. Charged pions, kaons, and protons in the transverse-momentum range pt approximately 0.1-1.7 GeV and laboratory rapidity abs(y) < 1 are identified via their energy loss in the silicon tracker. The average pt increases with particle mass and the charged multiplicity of the event. The increase of the average pt with charged multiplicity is greater for heavier hadrons. Comparisons to Monte Carlo event generators reveal that EPOS LHC, which incorporates additional hydrodynamic evolution of the created system, is able to reproduce most of the data features, unlike HIJING and AMPT. The pt spectra and integrated yields are also compared to those measured in pp and PbPb collisions at various energies. The average transverse momentum and particle ratio measurements indicate that particle production at LHC energies is strongly correlated with event particle multiplicity.
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The $B_\mathrm{c}^+$ meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the $B_\mathrm{c}^+$ meson in lead-lead (PbPb) and proton-proton (pp) collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}} =$ 5.02 TeV, via the $B_\mathrm{c}^+ \to (J/\psi\to\mu^+\mu^-)\mu^+\nu_\mu$ decay. The $B_\mathrm{c}^+$ nuclear modification factor, derived from the PbPb-to-pp ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the PbPb collision centrality. The B$_\mathrm{c}^+$ meson is shown to be less suppressed than quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This measurement sets forth a promising new probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma.
The $B_c$ meson production (pp-equivalent) cross-section times branching fraction of the $B_c\rightarrow (J/\psi \rightarrow \mu\mu) \mu \nu_{\mu}$ decay in pp and PbPb collisions. The used kinematic variables correspond to those of the trimuon final state. The two $p_T$ bins correspond to different rapidity ranges. The total uncertainty is decomposed in an uncertainty from the fit and one representing all other sources. The markers of the $p_T^{\mu\mu\mu}$ bins are placed according to the Lafferty-Wyatt prescription.
The $B_c$ meson nuclear modification factor in PbPb collisions, in $p_T^{\mu\mu\mu}$ bins corresponding to different trimuon rapidity ranges. The total uncertainty is decomposed in a bin-to-bin-uncorrelated uncertainty and one fully correlated along the two bins. The markers of the $p_T^{\mu\mu\mu}$ bins are placed at the average of the Lafferty-Wyatt prescriptions applied to the pp and PbPb spectra.
The $B_c$ meson nuclear modification factor in PbPb collisions, in centrality bins, integrated over the studied kinematic range. The cut on the trimuon rapidity depends on the trimuon $p_T$. The total uncertainty is decomposed in a bin-to-bin-uncorrelated uncertainty and one fully correlated along the two bins. The centrality bin markers are placed at the minimum bias average number of participants $N_{part}$.
Characteristics of multi-particle production in proton-proton collisions at $\sqrt{s}$=7 TeV are studied as a function of the charged-particle multiplicity, $N_{ch}$. The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |η|<2.4 and transverse momentum $p_T$ > 0.25 GeV/c. Jets are reconstructed from charged-particles only and required to have $p_T$ > 5 GeV/c. The distributions of jet $p_T$, average $p_T$ of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of $N_{ch}$ and compared to the predictions of the PYTHIA and HERWIG event generators. Predictions without multi-parton interactions fail completely to describe the $N_{ch}$-dependence observed in the data. For increasing $N_{ch}$, PYTHIA systematically predicts higher jet rates and harder $p_T$ spectra than seen in the data, whereas HERWIG shows the opposite trends. At the highest multiplicity, the data–model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients.
Mean $p_T$, all charged particles.
Mean $p_T$, UE charged particles.
Mean $p_T$, in-jet charged particles.
A measurement of the triple-differential cross section (sigma as a function of the photon pt and eta and the jet eta) in photon + jets final states using a data sample from proton-proton collisions at sqrt(s) = 7 TeV is presented. This sample corresponds to an integrated luminosity of 2.14 inverse femtobarns collected by the CMS detector at the LHC. Photons and jets are reconstructed within a pseudorapidity range of abs(eta) < 2.5, and are required to have transverse momenta in the range 40 < pt(gamma) < 300 GeV and pt(jet) > 30 GeV, respectively. The measurements are compared to theoretical predictions from the SHERPA leading-order QCD Monte Carlo event generator and the next-to-leading-order perturbative QCD calculation from JETPHOX. The predictions are found to be consistent with the data over most of the examined kinematic region.
The triple-differential cross sections d3sig/(dp^gamma_T deta^gamma deta^jet) for photons located in the central region ,|eta(gamma)|<0.9. A 2.2 PCT luminosity uncertainty is included in the systematic uncertainty.
The triple-differential cross sections d3sig/(dp^gamma_T deta^gamma deta^jet) for photons located in the central region,|eta(gamma)|=0.9-1.44. A 2.2 PCT luminosity uncertainty is included in the systematic uncertainty.
The triple-differential cross sections d3sig/(dp_T^gamma deta^gamma deta^jet) for photons located in forward region,|eta(gamma)|=1.57-2.1. A 2.2% luminosity uncertainty is included in the systematic uncertainty.
A search is performed for pair-produced spin-3/2 excited top quarks ($t^*\bar{t}^*$), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp collisions at a center-of-mass energy of $\sqrt{s}$=8 TeV, selecting events that have a single isolated muon or electron, an imbalance in transverse momentum, and at least six jets, of which one must be compatible with originating from the fragmentation of a b quark. The data, corresponding to an integrated luminosity of 19.5 inverse femtobarns, show no significant excess over standard model predictions, and provide a lower limit of 803 GeV at 95% confidence on the mass of the spin-3/2 t* quark in an extension of the Randall-Sundrum model, assuming a 100% branching fraction of its decay into a top quark and a gluon. This is the first search for a spin-3/2 excited top quark performed at the LHC.
Kinematic distributions of single l + > 5-jet events in data (points), compared to MC simulation normalized to the number of events observed in data. Shown are pT spectra for muons (a) and electrons (b), and jet spectra for the channels $\mu$+jets (c) and e+jets (d). The reconstructed mtg distribution is shown for the $\mu$+jets channel in (e) and for e+jets in (f).
Kinematic distributions of single l + > 5-jet events in data (points), compared to MC simulation normalized to the number of events observed in data. Shown are pT spectra for muons (a) and electrons (b), and jet spectra for the channels $\mu$+jets (c) and e+jets (d). The reconstructed mtg distribution is shown for the $\mu$+jets channel in (e) and for e+jets in (f).
Kinematic distributions of single l + > 5-jet events in data (points), compared to MC simulation normalized to the number of events observed in data. Shown are pT spectra for muons (a) and electrons (b), and jet spectra for the channels $\mu$+jets (c) and e+jets (d). The reconstructed mtg distribution is shown for the $\mu$+jets channel in (e) and for e+jets in (f).
Measurements of inclusive jet and dijet production cross sections are presented. Data from LHC proton-proton collisions at $\sqrt{s}$ = 7 TeV, corresponding to 5.0 inverse femtobarns of integrated luminosity, have been collected with the CMS detector. Jets are reconstructed up to rapidity 2.5, transverse momentum 2 TeV, and dijet invariant mass 5 TeV, using the anti-k$_t$ clustering algorithm with distance parameter R = 0.7. The measured cross sections are corrected for detector effects and compared to perturbative QCD predictions at next-to-leading order, using five sets of parton distribution functions.
Inclusive Jet Cross Section for |rapidity| < 0.5 as a function of the jet transverse momentum. The (sys) error is the total systematic error, including the luminosity uncertainty of 2.2%.
Inclusive Jet Cross Section for |rapidity| 0.5 TO 1.0 as a function of the jet transverse momentum. The (sys) error is the total systematic error, including the luminosity uncertainty of 2.2%.
Inclusive Jet Cross Section for |rapidity| 1.0 TO 1.5 as a function of the jet transverse momentum. The (sys) error is the total systematic error, including the luminosity uncertainty of 2.2%.
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