Production cross-sections of prompt charm mesons are measured using data from $pp$ collisions at the LHC at a centre-of-mass energy of $5\,$TeV. The data sample corresponds to an integrated luminosity of $8.60\pm0.33\,$pb$^{-1}$ collected by the LHCb experiment. The production cross-sections of $D^0$, $D^+$, $D_s^+$, and $D^{*+}$ mesons are measured in bins of charm meson transverse momentum, $p_{\text{T}}$, and rapidity, $y$. They cover the rapidity range $2.0<y<4.5$ and transverse momentum ranges $0 < p_{\text{T}} < 10\, \text{GeV}/c$ for $D^0$ and $D^+$ and $1 < p_{\text{T}} < 10\, \text{GeV}/c$ for $D_s^+$ and $D^{*+}$ mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of $1 < p_{\text{T}} < 8\, \text{GeV}/c$ are determined to be \sigma(pp\rightarrow D^0 X) = 1004 \pm 3 \pm 54\,\mu\text{b} \sigma(pp\rightarrow D^+ X) = 402 \pm 2 \pm 30\,\mu\text{b} \sigma(pp\rightarrow D_s^+ X) = 170 \pm 4 \pm 16\,\mu\text{b} \sigma(pp\rightarrow D^{*+} X)= 421 \pm 5 \pm 36\,\mu\text{b} where the uncertainties are statistical and systematic, respectively.
Differential production cross-sections for prompt $D^{0} + \bar{D}^{0}$ mesons in bins of $(p_{\mathrm{T}}, y)$. The first uncertainty is statistical, and the second is the total systematic.
Differential production cross-sections for prompt $D^{+} + D^{-}$ mesons in bins of $(p_{\mathrm{T}}, y)$. The first uncertainty is statistical, and the second is the total systematic.
Differential production cross-sections for prompt $D_{s}^{+} + D_{s}^{-}$ mesons in bins of $(p_{\mathrm{T}}, y)$. The first uncertainty is statistical, and the second is the total systematic.
The nuclear modification factor RAA and the azimuthal anisotropy coefficient v[2] of prompt and nonprompt (i.e. those from decays of b hadrons) J/psi mesons, measured from PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta pt > 6.5 GeV/c and rapidity abs(y) < 2.4, extending down to pt = 3 GeV/c in the 1.6 < abs(y) < 2.4 range. The v[2] of prompt J/psi is found to be nonzero, but with no strong dependence on centrality, rapidity, or pt over the full kinematic range studied. The measured v[2] of nonprompt J/psi is consistent with zero. The RAA of prompt J/psi exhibits a suppression that increases from peripheral to central collisions but does not vary as a function of either y or pt in the fiducial range. The nonprompt J/psi RAA shows a suppression which becomes stronger as rapidity or pt increase. The v[2] and nuclear suppression of open and hidden charm, and of open charm and beauty, are compared.
Prompt J/$\psi$ $v_{2}$ as a function of centrality. The average ${N}_{\rm part}$ values correspond to events flatly distributed across centrality.
Prompt J/$\psi$ $v_{2}$ as a function of centrality. The average ${N}_{\rm part}$ values correspond to events flatly distributed across centrality.
Prompt J/$\psi$ $v_{2}$ as a function of rapidity.
Charge-dependent azimuthal particle correlations with respect to the second-order event plane in pPb and PbPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV have been studied with the CMS experiment at the LHC. The measurement is performed with a three-particle correlation technique, using two particles with the same or opposite charge within the pseudorapidity range abs(eta) < 2.4, and a third particle measured in the hadron forward calorimeters (4.4 < abs(eta) < 5). The observed differences between the same and opposite sign correlations, as functions of multiplicity and eta gap between the two charged particles, are of similar magnitude in pPb and PbPb collisions at the same multiplicities. These results pose a challenge for the interpretation of charge-dependent azimuthal correlations in heavy ion collisions in terms of the chiral magnetic effect.
Three-particle correlation with respect to the 2nd order event plane from Pb-going side in pPb collisions at multiplicity [185,220), with individual track pT between 0.3 to 3.0 GeV/c. Data points are plotted at the bin center.
Three-particle correlation with respect to the 2nd order event plane from p-going side in pPb collisions at multiplicity [185,220), with individual track pT between 0.3 to 3.0 GeV/c. Data points are plotted at the bin center.
Three-particle correlation with respect to the 2nd order event plane in PbPb collisions at multiplicity [185,220), with individual track pT between 0.3 to 3.0 GeV/c. Data points are plotted at the bin center.
The $W$ boson angular distribution in events with high transverse momentum jets is measured using data collected by the ATLAS experiment from proton-proton collisions at a centre-of-mass energy $\sqrt{s}=$ 8 TeV at the Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. The focus is on the contributions to $W$ + jets processes from real $W$ emission, which is achieved by studying events where a muon is observed close to a high transverse momentum jet. At small angular separations, these contributions are expected to be large. Various theoretical models of this process are compared to the data in terms of the absolute cross-section and the angular distributions of the muon from the leptonic $W$ decay.
Measured integrated cross-sections as a function of leading jet transverse momentum for the collinear region ($0.2 < \Delta R < 2.4$), the back-to-back region ($\Delta R > 2.4$) and inclusively.
Measured cross-section as a function of angular separation between the muon and the closest jet. Multiplicative correction factors for using prompt muons and prompt dressing photons in the particle-level selection, derived from ALPGEN 2.14 interfaced with PYTHIA 6.426, are also shown.
Breakdown of uncertainties in percent.
The WZ production cross section is measured by the CMS experiment at the CERN LHC in proton-proton collision data samples corresponding to integrated luminosities of 4.9 inverse femtobarns collected at sqrt(s)= 7 TeV, and 19.6 inverse femtobarns at sqrt(s)= 8 TeV. The measurements are performed using the fully-leptonic WZ decay modes with electrons and muons in the final state. The measured cross sections for 71 < m[Z] < 111 GeV are sigma(pp to WZ; sqrt(s)= 7 TeV) = 20.14 +/- 1.32 (stat) +/- 1.13 (syst) +/- 0.44 (lumi) pb and sigma(pp to WZ; sqrt(s)= 8 TeV) = 24.09 +/- 0.87 (stat) +/- 1.62 (syst) +/- 0.63 (lumi) pb. Differential cross sections with respect to the Z boson pt, the leading jet pt, and the number of jets are obtained using the sqrt(s)= 8 TeV data. The results are consistent with standard model predictions and constraints on anomalous triple gauge couplings are obtained.
The measured WZ cross section for 71 < mZ < 111 GeV using 7 TeV data. The theory uncertainty only includes QCD scales variations.
The measured WZ cross section for 71 < mZ < 111 GeV using 8 TeV data. The theory uncertainty only includes QCD scales variations.
Differential cross section as function of the Z boson transverse momentum.
A measurement of the double-differential inclusive jet cross section as a function of the jet transverse momentum pT and the absolute jet rapidity abs(y) is presented. Data from LHC proton-proton collisions at sqrt(s) = 8 TeV, corresponding to an integrated luminosity of 19.7 inverse femtobarns, have been collected with the CMS detector. Jets are reconstructed using the anti-kT clustering algorithm with a size parameter of 0.7 in a phase space region covering jet pT from 74 GeV up to 2.5 TeV and jet absolute rapidity up to abs(y) = 3.0. The low-pT jet range between 21 and 74 GeV is also studied up to abs(y) = 4.7, using a dedicated data sample corresponding to an integrated luminosity of 5.6 inverse picobarns. The measured jet cross section is corrected for detector effects and compared with the predictions from perturbative QCD at next-to-leading order (NLO) using various sets of parton distribution functions (PDF). Cross section ratios to the corresponding measurements performed at 2.76 and 7 TeV are presented. From the measured double-differential jet cross section, the value of the strong coupling constant evaluated at the Z mass is alpha[S(M[Z]) = 0.1164 +0.0060 -0.0043, where the errors include the PDF, scale, nonperturbative effects and experimental uncertainties, using the CT10 NLO PDFs. Improved constraints on PDFs based on the inclusive jet cross section measurement are presented.
Inclusive Jet Cross Section for 0.0 < |y| < 0.5 as a function of the jet transverse momentum. The (sys) error is the total systematic error, including the luminosity uncertainty of 2.6%.
Inclusive Jet Cross Section for 0.5 < |y| < 1.0 as a function of the jet transverse momentum. The (sys) error is the total systematic error, including the luminosity uncertainty of 4.4%.
Inclusive Jet Cross Section for 1.0 < |y| < 1.5 as a function of the jet transverse momentum. The (sys) error is the total systematic error, including the luminosity uncertainty of 4.4%.
Inclusive jet spectra from pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV, collected with the CMS detector at the LHC, are presented. Jets are reconstructed with three different distance parameters (R = 0.2, 0.3, and 0.4) for transverse momentum (pT) greater than 70 GeV and pseudorapidity abs(eta) < 2. Next-to-leading-order quantum chromodynamic calculations with non-perturbative corrections are found to over-predict jet production cross sections in pp for small distance parameters. The jet nuclear modification factors for PbPb compared to pp collisions, show a steady decrease from peripheral to central events, along with a weak dependence on the jet pT. They are found to be independent of the distance parameter in the measured kinematic range.
Raw subtracted $p_T$ for jets reconstructed in PbPb collisions (in different centrality bins) with the anti-k$_T$ algorythm with distance parameter $R=0.3$, in the range $70< p_{T} < 80$GeV/c and $|\eta|<2$. Quantity found by taking the difference of the sum of PF candidates within the jet cone and raw jet $p_T$.
Raw subtracted $p_T$ for jets reconstructed in PbPb collisions (in different centrality bins) with the anti-k$_T$ algorythm with a distance parameter $R=0.3$, in the range $110< p_{T} < 130$GeV/c and $|\eta|<2$. Quantity found by taking the difference of the sum of PF candidates within the jet cone and raw jet $p_T$.
Average raw subtracted $p_T$ for PF jets reconstructed in PbPb collisions (in different centrality bins) with the anti-k$_T$ algorythm with a distance parameter $R=0.3$, in $|\eta|<0.2$.
Differences in the behaviour of matter and antimatter have been observed in $K$ and $B$ meson decays, but not yet in any baryon decay. Such differences are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as $C\!P$ violation. Using data from the LHCb experiment at the Large Hadron Collider, a search is made for $C\!P$-violating asymmetries in the decay angle distributions of $\Lambda^0_b$ baryons decaying to $p\pi^-\pi^+\pi^-$ and $p\pi^-K^+K^-$ final states. These four-body hadronic decays are a promising place to search for sources of $C\!P$ violation both within and beyond the Standard Model of particle physics. We find evidence for $C\!P$ violation in $\Lambda^0_b$ to $p\pi^-\pi^+\pi^-$ decays with a statistical significance corresponding to 3.3 standard deviations including systematic uncertainties. This represents the first evidence for $C\!P$ violation in the baryon sector.
Binning scheme A is defined to exploit interference patterns arising from the resonant structure of the decay. Bins 1-4 focus on the region dominated by the $\Delta(1232)^{++}\to p\pi^{+}$. The other eight bins are defined to study regions where $p\pi^{-}$ resonances are present (5-8) on either side of the $\rho(770)^{0}\to\pi^{+}\pi^{-}$ resonances (5-12). Further splitting for $|\Phi|$ lower or greater than $\pi/2$ is done to reduce potential dilution of asymmetries.
Definition of binning scheme B for the decay mode $\Lambda_b^0\to p\pi^-\pi^+\pi^-$.
For $\Lambda_b^0\to p\pi^-\pi^+\pi^-$ decays, the CP- and P-violating observables, $a^{\hat{T}-odd}_{CP}$ and $a^{\hat{T}-odd}_{P}$, resulting from the fit to the data are listed with their statistical and systematic uncertainties. Each value is obtained through an independent fit to a region of the phase space defined in Scheme A.
Measurements of the differential branching fraction and angular moments of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the $K^+\pi^-$ invariant mass range $1330<m(K^+ \pi^-)<1530~MeV/c^2$ are presented. Proton-proton collision data are used, corresponding to an integrated luminosity of 3 $fb^{-1}$ collected by the LHCb experiment. Differential branching fraction measurements are reported in five bins of the invariant mass squared of the dimuon system, $q^2$, between 0.1 and 8.0 $GeV^2/c^4$. For the first time, an angular analysis sensitive to the S-, P- and D-wave contributions of this rare decay is performed. The set of 40 normalised angular moments describing the decay is presented for the $q^2$ range 1.1--6.0 $GeV^2/c^4$.
: Differential branching fraction of $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in bins of $q^2$ for the range $1330<m(K^+ \pi^-)<1530~MeV/c^2$. The first uncertainty is statistical, the second systematic and the third due to the uncertainty on the $B^0 \to J/\psi K^*(892)^0$ and $J/\psi \to \mu\mu$ branching fractions.
Measurement of the normalised moments, $\overline{\Gamma}_{i}$, of the decay $B^0 \to K^+ \pi^- \mu^+ \mu^-$ in the range $1.1< q^2<6.0 GeV^2/c^4$ and $1330<m(K^+ \pi^-)<1530~MeV/c^2$. The first uncertainty is statistical and the second systematic.
Full covariance matrix of the normalised moments. The statistical and systematic uncertainties are combined.
A measurement of the $t$-channel single-top-quark and single-top-antiquark production cross-sections in the lepton+je ts channel is presented, using 3.2 fb$^{-1}$ of proton--proton collision data at a centre-of-mass energy of 13 TeV, recorded with the ATLAS detector at the LHC in 2015. Events are selected by requiring one charged lepton (electron or muon), missing transverse momentum, and two jets with high transverse momentum, exactly one of which is required to be $b$-tagged. Using a binned maximum-likelihood fit to the discriminant distribution of a neural network, the cross-sections are determined to be $\sigma(tq) = 156 \pm 5 \, (\mathrm{stat.}) \pm 27 \, (\mathrm{syst.}) \pm 3\,(\mathrm{lumi.})$ pb for single top-quark production and $\sigma(\bar{t}q) = 91 \pm 4 \, (\mathrm{stat.}) \pm 18 \, (\mathrm{syst.}) \pm 2\,(\mathrm{lumi.})$ pb for single top-antiquark production, assuming a top-quark mass of 172.5 GeV. The cross-section ratio is measured to be $R_t = \sigma(tq)/\sigma(\bar{t}q) = 1.72 \pm 0.09 \, (\mathrm{stat.}) \pm 0.18 \, (\mathrm{syst.})$.
Predicted and observed event yields for the signal region. The quoted uncertainties include uncertainties in the theoretical cross-sections, in the number of multijet events, and the statistical uncertainties. The event yield of the $W^+ + $jets process in the $\ell^-$ channel is reported to be $<1$ in the paper. To provide a numerical value for this table in HEPdata, the yield is approximated with $1\pm 1$. The same is done for the event yield of the $W^- + $jets process in the $\ell^+$ channel.
Estimated scale factors, $\hat{\beta}$, and number of events, $\hat{\nu}=\hat{\beta}\cdot\nu$, for the $\ell^+$ and $\ell^-$ channel from the minimisation of the likelihood function. The quoted uncertainties in $\hat{\beta}$ and $\hat{\nu}$ include the statistical uncertainty and the uncertainties from the constraints on the background normalisation as used in the likelihood function.
Measured total cross sections of single top-quark and single top-antiquark production and their ratio $R_t$. In addition, the sum of top-quark and top-antiquark production is provided as well. Based on the total cross section the value of $f_\mathrm{LV}\cdot |V_{tb}|$ is determined.
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