Measurements are presented of differential cross-sections for top quark pair production in pp collisions at sqrt(s) = 7 TeV relative to the total inclusive top quark pair production cross-section. A data sample of 2.05/fb recorded by the ATLAS detector at the Large Hadron Collider is used. Relative differential cross-sections are derived as a function of the invariant mass, the transverse momentum and the rapidity of the top quark pair system. Events are selected in the lepton (electron or muon) + jets channel. The background-subtracted differential distributions are corrected for detector effects, normalized to the total inclusive top quark pair production cross-section and compared to theoretical predictions. The measurement uncertainties range typically between 10% and 20% and are generally dominated by systematic effects. No significant deviations from the Standard Model expectations are observed.
Relative differential cross-section (1/SIG)*D(SIG)/DM(ttbar) measured in the e+jets, mu+jets and the combined lepton+jets channel.
Relative differential cross-section (1/SIG)*D(SIG)/DPT(ttbar) measured in the e+jets, mu+jets and the combined lepton+jets channel.
Relative differential cross-section (1/SIG)*D(SIG)/DYRAP(ttbar) measured in the e+jets, mu+jets and the combined lepton+jets channel.
The $p_{\rm T}$-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D$^0$, D$^+$, and D$^{*+}$ in the rapidity range $|y|<0.5$, and for transverse momentum $1< p_{\rm T} <12$ GeV/$c$, were measured in proton-proton collisions at $\sqrt{s} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D$^0 \rightarrow $K$\pi$, D$^+ \rightarrow $K$\pi\pi$, D$^{*+} \rightarrow $D$^0\pi$, and their charge conjugates, and was performed on a $L_{\rm int} = 1.1$ nb$^{-1}$ event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at $\sqrt{s} = 2.76$ TeV and at 7 TeV was evaluated by extrapolating to the full phase space the $p_{\rm T}$-differential production cross sections at $\sqrt{s} = 2.76$ TeV and our previous measurements at $\sqrt{s} = 7$ TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.
Production cross section in |y| < 0.5 for prompt D0, D+, and D*+ mesons in pp collisions at sqrt(s) = 2.76 TeV, in transverse momentum intervals. The second (sys) error is the uncertainty on the respective branching ratios.
Visible production cross sections of prompt D mesons for |y|<0.5 in pp collisions at sqrts=2.76 and 7 TeV. The normalization systematic uncertainty of 1.9% (3.5%) at sqrts=2.76 (7) TeV and the decay BR uncertainties are not quoted here.
Production cross sections dsig/dy of D mesons, integrated over all pt for |y|<0.5. The second (sys) error is the from the luminosity uncertainty, the third from the branching-ratio uncertainties and the fourth is from the extrapolation uncertainty.
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.
A study of dijet production in proton-proton collisions was performed at sqrt(s) = 7 TeV for jets with pt > 35 GeV and abs(y) < 4.7 using data collected with the CMS detector at the LHC in 2010. Events with at least one pair of jets are denoted as 'inclusive'. Events with exactly one pair of jets are called 'exclusive'. The ratio of the cross section of all pairwise combinations of jets to the exclusive dijet cross section as a function of the rapidity difference between jets abs(Delta(y)) is measured for the first time up to abs(Delta(y)) = 9.2. The ratio of the cross section for the pair consisting of the most forward and the most backward jet from the inclusive sample to the exclusive dijet cross section is also presented. The predictions of the Monte Carlo event generators PYTHIA6 and PYTHIA8 agree with the measurements. In both ratios the HERWIG++ generator exhibits a more pronounced rise versus abs(Delta(y)) than observed in the data. The BFKL-motivated generators CASCADE and HEJ+ARIADNE predict for these ratios a significantly stronger rise than observed.
Inclusive to exclusive dijet production ratio.
Mueller-Navelet to exclusive dijet production ratio.
The inclusive b-jet production cross section in pp collisions at a center-of-mass energy of 7 TeV is measured using data collected by the CMS experiment at the LHC. The cross section is presented as a function of the jet transverse momentum in the range 18 < pT < 200 GeV for several rapidity intervals. The results are also given as the ratio of the b-jet production cross section to the inclusive jet production cross section. The measurement is performed with two different analyses, which differ in their trigger selection and b-jet identification: a jet analysis that selects events with a b jet using a sample corresponding to an integrated luminosity of 34 inverse picobarns, and a muon analysis requiring a b jet with a muon based on an integrated luminosity of 3 inverse picobarns. In both approaches the b jets are identified by requiring a secondary vertex. The results from the two methods are in agreement with each other and with next-to-leading order calculations, as well as with predictions based on the PYTHIA event generator.
B-jet cross section from the 'jet' analysis.
B-jet cross section from the 'muon' analysis.
B-jet cross section extrapolated from the 'muon' analysis.
The production of muons from heavy flavour decays is measured at forward rapidity in proton-proton collisions at $\sqrt{s} = 7$ TeV collected with the ALICE experiment at the LHC. The analysis is carried out on a data sample corresponding to an integrated luminosity $L_{\rm int} = 16.5$ nb$^{-1}$. The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5 < y < 4, over the transverse momentum range 2 < $p_{\rm T}$ < 12 GeV/$c$. The results are compared to predictions based on perturbative QCD calculations.
pT-differential production cross section of muons from heavy flavour decays, in the rapidity range 2.5<y<4.
y-differential production cross section of muons from heavy flavour decays, in the range 2<pT<12 GeV/C.
pT-differential production cross section of muons from heavy flavour decays, in the rapidity range 2.5<y<2.8.
Results are presented on the production of jets of particles in association with a Z/gamma* boson, in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector. The analysis includes the full 2010 data set, collected with a low rate of multiple proton-proton collisions in the accelerator, corresponding to an integrated luminosity of 36 pb^-1. Inclusive jet cross sections in Z/gamma* events, with Z/gamma* decaying into electron or muon pairs, are measured for jets with transverse momentum pT > 30 GeV and jet rapidity |y| < 4.4. The measurements are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carlo generators implementing leading-order matrix elements supplemented by parton showers.
Cross section for Inclusive Jet Multiplicity corrected to the lepton common fiducial region and for QED radiation effects.
Ratio of cross sections for N/N-1 inclusive jet multiplicities corrected to the lepton common fiducial region and for QED radiation effects.
Inclusive jet differential cross section dsigma/dpt corrected to the lepton common fiducial region and for QED radiation effects.
Measurements of the normalized rapidity (y) and transverse momentum (qT) distributions of Drell-Yan muon and electron pairs in the Z-boson mass region (60
Normalized differential cross section for Drell-Yan lepton pairs in the Z0 mass region as a function of the absolute value of rapidity of the Z0, for separate muon and lepton channels and the combined measurement. The error shown is the combined statistical and systematic.
Normalized differential cross section for Drell-Yan lepton pairs in the Z0 mass region as a function of the transverse momentum of the Z0, for separate muon and lepton channels and the combined measurement. The error shown is the combined statistical and systematic.
Covariance matrix values between the rapidity bins for the muons data sample.
The production cross sections of the inclusive Drell-Yan processes W to l nu and Z/gamma to ll (l=e,mu) are measured in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector. The cross sections are reported integrated over a fiducial kinematic range, extrapolated to the full range and also evaluated differentially as a function of the W decay lepton pseudorapidity and the Z boson rapidity, respectively. Based on an integrated luminosity of about 35 pb^-1 collected in 2010, the precision of these measurements reaches a few per cent. The integrated and the differential W+- and Z/gamma cross sections in the e and mu channels are combined, and compared with perturbative QCD calculations, based on a number of different parton distribution sets available at NNLO.
Cross sections for Z0 production from the combined electron and muon data sets in the defined fiducial regions. The first (sys) error is the uncorrelated systematic error and the second is the correlated systematic error.
Correlated Systematic Uncertainties for Z0 production.
Cross sections for W- production from the combined electron and muon data sets in the defined fiducial regions. The first (sys) error is the uncorrelated systematic error and the second is the correlated systematic error.
The B^0_s differential production cross section is measured as functions of the transverse momentum and rapidity in pp collisions at sqrt(s) = 7 TeV, using the J/Psi phi decay, and compared with predictions based on perturbative QCD calculations at next-to-leading order. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 40 inverse picobarns. The B^0_s is reconstructed from the decays J/Psi to an oppositely charged muon pair and phi to K+ K-. The integrated B^0_s cross section times B^0_s to J/Psi phi branching fraction in the range 8 < pt(B) < 50 GeV/c and |y(b)| < 2.4 is measured to be 6.9 +/- 0.6 +/- 0.6 nb, where the first uncertainty is statistical and the second is systematic.
Total integrated B/S cross section times the branching fraction to J/PSI PHI in the given kinematic range.
The measured differential cross section as a function of the transverse momentum of the B/S in the |rapidity| range < 24.
The measured differential cross section as a function of the rapidity of the B/S in the transverse momentum range 8 to 50 GeV.
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