A search is described for the production of a pair of bottom-type vector-like quarks (VLQs), each decaying into a b or $\mathrm{\bar{b}}$ quark and either a Higgs or a Z boson, with a mass greater than 1000 GeV. The analysis is based on data from proton-proton collisions at a 13 TeV center-of-mass energy recorded at the CERN LHC, corresponding to a total integrated luminosity of 137 fb$^{-1}$. As the predominant decay modes of the Higgs and Z bosons are to a pair of quarks, the analysis focuses on final states consisting of jets resulting from the six quarks produced in the events. Since the two jets produced in the decay of a highly Lorentz-boosted Higgs or Z boson can merge to form a single jet, nine independent analyses are performed, categorized by the number of observed jets and the reconstructed event mode. No signal in excess of the expected background is observed. Lower limits are set on the VLQ mass at 95% confidence level equal to 1570 GeV in the case where the VLQ decays exclusively to a b quark and a Higgs boson, 1390 GeV for when it decays exclusively to a b quark and a Z boson, and 1450 GeV for when it decays equally in these two modes. These limits represent significant improvements over the previously published VLQ limits.
Measured values of the trigger efficiencies for events with $\HT > 1350\GeV$. The uncertainties are statistical only.
Reconstructed VLQ mass distributions for simulated signal events with a generated VLQ mass $m_{B} = 1200\GeV$. A moderate requirement of $\chi^{2}$/ndf < 2$ is applied to the events. Mass distributions for 4-jet (left), 5-jet (center), and 6-jet (right) events are shown for the three decay modes: bHbH (upper row), bHbZ (middle row), and bZbZ (lower row).
Reconstructed VLQ mass distributions for simulated signal events with a generated VLQ mass $m_{B} = 1200\GeV$. A moderate requirement of $\chi^{2}$/ndf < 2$ is applied to the events. Mass distributions for 4-jet (left), 5-jet (center), and 6-jet (right) events are shown for the three decay modes: bHbH (upper row), bHbZ (middle row), and bZbZ (lower row).
The first direct, model-independent measurement is presented of the modulus of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements $|V_\mathrm{tb}|$, $|V_\mathrm{td}|$, and $|V_\mathrm{ts}|$, in final states enriched in single top quark $t$-channel events. The analysis uses proton-proton collision data from the LHC, collected during 2016 by the CMS experiment, at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. Processes directly sensitive to these matrix elements are considered at both the production and decay vertices of the top quark. In the standard model hypothesis of CKM unitarity, a lower limit of $|V_\mathrm{tb}|$ $>$ 0.970 is measured at the 95% confidence level. Several theories beyond the standard model are considered, and by releasing all constraints among the involved parameters, the values $|V_\mathrm{tb}| =$ 0.988 $\pm$ 0.024, and $|V_\mathrm{td}|^2 + |V_\mathrm{ts}|^2 =$ 0.06 $\pm$ 0.06, where the uncertainties include both statistical and systematic components, are measured.
The $m_{W}^{T}$ distribution from data (points) and simulation (shaded histograms) in the 2j1t (left) and 3j1t (right) categories for the muon (upper) and electron (lower) channels. The vertical lines on the points and the hatched bands show the experimental and MC statistical uncertainties, respectively. The expected distribution from the STq,b+STb,q processes (multiplied by a factor of 1000) is shown by the solid blue line. The lower panels show the ratio of the data to the MC prediction.
The $m_{W}^{T}$ distribution from data (points) and simulation (shaded histograms) in the 2j1t (left) and 3j1t (right) categories for the muon (upper) and electron (lower) channels. The vertical lines on the points and the hatched bands show the experimental and MC statistical uncertainties, respectively. The expected distribution from the STq,b+STb,q processes (multiplied by a factor of 1000) is shown by the solid blue line. The lower panels show the ratio of the data to the MC prediction.
The $m_{W}^{T}$ distribution from data (points) and simulation (shaded histograms) in the 2j1t (left) and 3j1t (right) categories for the muon (upper) and electron (lower) channels. The vertical lines on the points and the hatched bands show the experimental and MC statistical uncertainties, respectively. The expected distribution from the STq,b+STb,q processes (multiplied by a factor of 1000) is shown by the solid blue line. The lower panels show the ratio of the data to the MC prediction.
Measurement of the fiducial inclusive and differential production cross sections of the Higgs boson in proton-proton collisions at $\sqrt{s} =$ 13 TeV are performed using events where the Higgs boson decays into a pair of W bosons that subsequently decay into a final state with an electron, a muon, and a pair of neutrinos. The analysis is based on data collected with the CMS detector at the LHC during 2016-2018, corresponding to an integrated luminosity of 137 fb$^{-1}$. Production cross sections are measured as a function of the transverse momentum of the Higgs boson and the associated jet multiplicity. The Higgs boson signal is extracted and simultaneously unfolded to correct for selection efficiency and resolution effects using maximum-likelihood fits to the observed distributions in data. The integrated fiducial cross section is measured to be 86.5 $\pm$ 9.5 fb, consistent with the Standard Model expectation of 82.5 $\pm$ 4.2 fb. No significant deviation from the Standard Model expectations is observed in the differential measurements.
The fiducial differential signal strength and cross section in each Higgs pT bin. Both the unregularized and regularized signal strengthes are given. For the regularized case the uncertainty breakdown is given in terms of statistical (stat), experimental (exp), theoretical uncertainties on the background (bkg) and on the signal (sig), and the luminosity uncertainty (lumi). The regularization estimated bias (bias) is also given. The fiducial cross section and its full uncertainty in each bin are also given. The last bin is inclusive.
The correlation matrix for the ptH measurements, both for the unregularized and regularized fits. The last bin is inclusive.
The fiducial differential signal strength and cross section in each njet bin. The uncertainty breakdown is given in terms of statistical (stat), experimental (exp), theoretical uncertainties on the background (bkg) and on the signal (sig), and the luminosity uncertainty (lumi). The fiducial cross section and its full uncertainty in each bin are also given. The last bin is inclusive.
Anisotropies in the initial energy density distribution of the quark-gluon plasma created in high energy heavy ion collisions lead to anisotropies in the azimuthal distributions of the final-state particles known as collective flow. Fourier harmonic decomposition is used to quantify these anisotropies. The higher-order harmonics can be induced by the same order anisotropies (linear response) or by the combined influence of several lower order anisotropies (nonlinear response) in the initial state. The mixed higher-order anisotropic flow and nonlinear response coefficients of charged particles are measured as functions of transverse momentum and centrality in PbPb collisions at nucleon-nucleon center-of-mass energies $\sqrt{s_\mathrm{NN}} =$ 2.76 and 5.02 TeV with the CMS detector. The results are compared with viscous hydrodynamic calculations using several different initial conditions, as well as microscopic transport model calculations. None of the models provides a simultaneous description of the mixed higher-order flow harmonics and nonlinear response coefficients.
Mixed higher-order flow harmonic $v_4\{\Psi_{22}\}$ from the scalar-product method at 5.02 TeV as a function of PT in the 0-20% centrality range.
Mixed higher-order flow harmonic $v_5\{\Psi_{23}\}$ from the scalar-product method at 5.02 TeV as a function of PT in the 0-20% centrality range.
Mixed higher-order flow harmonic $v_6\{\Psi_{222}\}$ from the scalar-product method at 5.02 TeV as a function of PT in the 0-20% centrality range.
Evidence for Higgs boson decay to a pair of muons is presented. This result combines searches in four exclusive categories targeting the production of the Higgs boson via gluon fusion, via vector boson fusion, in association with a vector boson, and in association with a top quark-antiquark pair. The analysis is performed using proton-proton collision data at $\sqrt{s} =$ 13 TeV, corresponding to an integrated luminosity of 137 fb$^{-1}$, recorded by the CMS experiment at the CERN LHC. An excess of events over the background expectation is observed in data with a significance of 3.0 standard deviations, where the expectation for the standard model (SM) Higgs boson with mass of 125.38 GeV is 2.5. The combination of this result with that from data recorded at $\sqrt{s} =$ 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb$^{-1}$, respectively, increases both the expected and observed significances by 1%. The measured signal strength, relative to the SM prediction, is 1.19 $^{+0.40}_{-0.39}$ (stat) $^{+0.15}_{-0.14}$ (syst). This result constitutes the first evidence for the decay of the Higgs boson to second generation fermions and is the most precise measurement of the Higgs boson coupling to muons reported to date.
The observed DNN output distribution in the VBF-SR region for data collected in 2016 compared to the post-fit background estimate for the contributing SM processes. The post-fit distributions for the Higgs boson signal produced via ggH and VBF modes with mass of 125.38 GeV are also reported. The predicted backgrounds are obtained from a S+B fit performed across analysis regions and years. The total post-fit and pre-fit uncertainties on the background prediction are also reported.
The observed DNN output distribution in the VBF-SR region for data collected in 2017 compared to the post-fit background estimate for the contributing SM processes. The post-fit distributions for the Higgs boson signal produced via ggH and VBF modes with mass of 125.38 GeV are also reported. The predicted backgrounds are obtained from a S+B fit performed across analysis regions and years. The total post-fit and pre-fit uncertainties on the background prediction are also reported.
The observed DNN output distribution in the VBF-SR region for data collected in 2018 compared to the post-fit background estimate for the contributing SM processes. The post-fit distributions for the Higgs boson signal produced via ggH and VBF modes with mass of 125.38 GeV are also reported. The predicted backgrounds are obtained from a S+B fit performed across analysis regions and years. The total post-fit and pre-fit uncertainties on the background prediction are also reported.
We present the first measurement of the proton-$\Omega$ correlation function in heavy-ion collisions for central (0-40$\%$) and peripheral (40-80$\%$) Au+Au collisions at \sqrtsNN\,\,=200 GeV by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Predictions for the ratio of peripheral collisions to central collisions for the proton-$\Omega$ correlation function are sensitive to the presence of a nucleon-$\Omega$ bound state. These predictions are based on the proton-$\Omega$ interaction extracted from (2+1)-flavor lattice QCD calculations at the physical point. The measured ratio of proton-$\Omega$ correlation function from peripheral (small system) to central (large system) collisions is less than unity for relative momentum smaller than 40 MeV/c. Comparison of our measured correlation ratio with the theoretical calculation slightly favors a proton-$\Omega$ bound system with a binding energy of $\sim$ 27~MeV.
Measured correlation function (C($k^{*}$)) for proton-$\Omega$ and antiproton-$\bar{\Omega}$ (P$\Omega$ + $\bar{P}$$\bar{\Omega}$) for (0-40)$\%$ and (40-80$\%$) Au+Au collisons at $\sqrt{s}_{NN}$ = 200 GeV. The errors are statistical and systematic.
Ratio of small system (40-80$\%$) to large system (0-40$\%$) for proton-$\Omega$ and antiproton-$\bar{\Omega}$ (P$\Omega$ + $\bar{P}$$\Omega$). The errors are statistical and symmetric.
We present a measurement of inclusive $J/\psi$ production at mid-rapidity ($|y|<1$) in $p+p$ collisions at a center-of-mass energy of $\sqrt{s}$ = 200 GeV with the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The differential production cross section for $J/\psi$ as a function of transverse momentum ($p_T$) for $0
Top$:$ J/$\psi$ cross section times branching ratio as a function of pT in p+p collisions at $\sqrt{s_{NN}}$ = 200 GeV. Solid circles are from this analysis for |y| < 1; open circles and blue squares are the published results for |y| < 1 from STAR; triangles are the published results for |y| < 0.35 from PHENIX. Bars and boxes are statistical and systematic uncertainties, respectively. The curves are CEM (green), NLO NRQCD A (orange) [4], CGC + NRQCD (blue) , and NLO NRQCD B (magenta) theoretical calculations, respectively. Bottom$:$ ratios of these results with respect to the central value from this analysis.
The corrected $n_{ch}$ distributions at mid-rapidity (|$\eta$| < 1) for MB events (open circles) and J/$\psi$ events with J/$\psi$ $p_{T}$ greater than 0 (purple circles), 1.5 (blue squares), and 4 GeV/c (red triangles) in p+p collisions at $\sqrt{s}$ = 200 GeV. The fit function is a negative binomial function. Bars and boxes are statistical and systematic uncertainties, respectively.
The multiplicity dependence of J/$\psi$ production in p+p collisions at $\sqrt{s}$ = 200 GeV. Purple circles, blue squares, and red triangles represent the results for J/$\psi$ with $p_{T}$ greater than 0, 1.5, and 4 GeV/c, respectively. Bars and open boxes are statistical and systematic uncertainties, respectively. The ALICE result is shown in the left panel. The purple, blue and red bands in the middle panel are generated from PYTHIA8 for J/$\psi$ with $p_{T}$ greater than 0, 1.5, and 4 GeV/c, respectively. The blue and red bands in the right panel are from EPOS3 model calculations for D$^{0}$ with 2 < $p_{T}$ < 4 and 4 < $p_{T}$ < 8 GeV/c, respectively, while the green curve is from the Percolation model for J/$\psi$ with $p_{T}$ > 0 GeV/c.
In this letter, measurements of the shared momentum fraction ($z_{\rm{g}}$) and the groomed jet radius ($R_{\rm{g}}$), as defined in the SoftDrop algorihm, are reported in \pp collisions at $\sqrt{s} = 200$ GeV collected by the STAR experiment. These substructure observables are differentially measured for jets of varying resolution parameters from $R = 0.2 - 0.6$ in the transverse momentum range $15 < p_{\rm{T, jet}} < 60$ GeV$/c$. These studies show that, in the $p_{\rm{T, jet}}$ range accessible at $\sqrt{s} = 200$ GeV and with increasing jet resolution parameter and jet transverse momentum, the $z_{\rm{g}}$ distribution asymptotically converges to the DGLAP splitting kernel for a quark radiating a gluon. The groomed jet radius measurements reflect a momentum-dependent narrowing of the jet structure for jets of a given resolution parameter, i.e., the larger the $p_{\rm{T, jet}}$, the narrower the first splitting. For the first time, these fully corrected measurements are compared to Monte Carlo generators with leading order QCD matrix elements and leading log in the parton shower, and to state-of-the-art theoretical calculations at next-to-leading-log accuracy. We observe that PYTHIA 6 with parameters tuned to reproduce RHIC measurements is able to quantitatively describe data, whereas PYTHIA 8 and HERWIG 7, tuned to reproduce LHC data, are unable to provide a simultaneous description of both $z_{\rm{g}}$ and $R_{\rm{g}}$, resulting in opportunities for fine parameter tuning of these models for \pp collisions at RHIC energies. We also find that the theoretical calculations without non-perturbative corrections are able to qualitatively describe the trend in data for jets of large resolution parameters at high $p_{\rm{T, jet}}$, but fail at small jet resolution parameters and low jet transverse momenta.
The data points and the error bars represent the mean $p_{\rm{T, jet}}^{\rm{det}}$ and the width (RMS) for a given $p_{\rm{T, jet}}^{\rm{part}}$ selection $R = 0.4$.
Uncorrected $z_{g}$ for $20 < p_{\rm{T, jet}} < 25$ GeV/c, R=0.4 anti-kT jets
Uncorrected $R_{g}$ for $20 < p_{\rm{T, jet}} < 25$ GeV/c, R=0.4 anti-kT jets
The transverse momentum spectra of weak vector bosons are measured in the CMS experiment at the LHC. The measurement uses a sample of proton-proton collisions at sqrt(s) = 8 TeV, collected during a special low-luminosity running that corresponds to an integrated luminosity of 18.4 +/- 0.5 inverse picobarns. The production of W bosons is studied in both electron and muon decay modes, while the production of Z bosons is studied using only the dimuon decay channel. The ratios of W- to W+ and Z to W differential cross sections are also measured. The measured differential cross sections and ratios are compared with theoretical predictions up to next-to-next leading order in QCD.
Normalized fiducial differential cross sections of W+ boson and W- boson decaying to electron plus neutrino and positron plus neutrino respectively at the pre-FSR level.
Normalized fiducial differential cross sections of W+ boson and W- boson decaying to electron plus neutrino and positron plus neutrino respectively at the pre-FSR level.
Normalized fiducial differential cross sections of W+ boson and W- boson decaying to muon and neutrino at pre-FSR level.
We report on new measurements of inclusive J/$\psi$ polarization at mid-rapidity in p+p collisions at $\sqrt{s}$ = 200 GeV by the STAR experiment at RHIC. The polarization parameters, $\lambda_\theta$, $\lambda_\phi$, and $\lambda_{\theta\phi}$, are measured as a function of transverse momentum ($p_T$) in both the Helicity and Collins-Soper (CS) reference frames within $p_T< 10$ GeV/$C$. Except for $\lambda_\theta$ in the CS frame at the highest measured $p_T$, all three polarization parameters are consistent with 0 in both reference frames without any strong $p_T$ dependence. Several model calculations are compared with data, and the one using the Color Glass Condensate effective field theory coupled with non-relativistic QCD gives the best overall description of the experimental results, even though other models cannot be ruled out due to experimental uncertainties.
The J/PSI(1S) polarization parameter $\lambda_\theta$ as a function of pT measured through dielectron channel in the HX frame.
The J/PSI(1S) polarization parameter $\lambda_\phi$ as a function of pT measured through dielectron channel in the HX frame.
The J/PSI(1S) polarization parameter $\lambda_\thetaphi$ as a function of pT measured through dielectron channel in the HX frame.
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