The ALICE collaboration at the CERN Large Hadron Collider reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at $\sqrt{s} = 2.76$ TeV, with integrated luminosity of 13.6 nb$^{-1}$. Jets are measured over the transverse momentum range 20 to 125 GeV/c and are corrected to the particle level. Calculations based on Next-to-Leading Order perturbative QCD are in good agreement with the measurements. The ratio of inclusive jet cross sections for jet radii $R = 0.2$ and $R = 0.4$ is reported, and is also well reproduced by a Next-to-Leading Order perturbative QCD calculation when hadronization effects are included.
Inclusive differential jet cross section for R=0.2 and R=0.4.
Ratio of the inclusive differential jet cross section for R=0.2 and R=0.4.
The ALICE Collaboration has measured inclusive J/psi production in pp collisions at a center of mass energy sqrt(s)=2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges |y|<0.9 and 2.5<y<4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are L^e_int=1.1 nb^-1 and L^mu_int=19.9 nb^-1, and the corresponding signal statistics are N_J/psi^e+e-=59 +/- 14 and N_J/psi^mu+mu-=1364 +/- 53. We present dsigma_J/psi/dy for the two rapidity regions under study and, for the forward-y range, d^2sigma_J/psi/dydp_t in the transverse momentum domain 0<p_t<8 GeV/c. The results are compared with previously published results at sqrt(s)=7 TeV and with theoretical calculations.
Double differential J/$\psi$ production cross section at $\sqrt{s}=2.76$ TeV. The first uncertainty is statistical, the second one is $p_{\rm T}$-coorelated, the third one is uncorrelated. Polarization-related uncertainties are not included.
The $\sqrt{s}$-dependence of $\langle p_{\rm T}\rangle$ for inclusive J/$\psi$ production (forward rapidity).
the $\sqrt{s}$-dependence of $\langle p_{\rm T}\rangle$ for inclusive J/$\psi$ production (forward rapidity).
The ALICE experiment has measured low-mass dimuon production in pp collisions at $\sqrt{s} = 7$ TeV in the dimuon rapidity region 2.5<y<4. The observed dimuon mass spectrum is described as a superposition of resonance decays ($\eta$, $\rho$, $\omega$, $\eta^{'}$, $\phi$) into muons and semi-leptonic decays of charmed mesons. The measured production cross sections for $\omega$ and $\phi$ are $\sigma_\omega$ (1<$p_{\rm T}$<5 GeV/$c$,2.5<y<4) = 5.28 $\pm$ 0.54 (stat) $\pm$ 0.50 (syst) mb and $\sigma_\phi$(1<$p_{\rm T}$<5 GeV/$c$,2.5<y<4)=0.940 $\pm$ 0.084 (stat) $\pm$ 0.078 (syst) mb. The differential cross sections $d^2\sigma/dy dp_{\rm T}$ are extracted as a function of $p_{\rm T}$ for $\omega$ and $\phi$. The ratio between the $\rho$ and $\omega$ cross section is obtained. Results for the $\phi$ are compared with other measurements at the same energy and with predictions by models.
Differential phi cross section from the di-muon channel as a function of transverse momentum, the first error is statistical, the first systematic error is the correlated one, the second is the non-correlated one.
Differential omega cross section from the di-muon channel as a function of transverse momentum, the first error is statistical, the first systematic error is the correlated one, the second is the non-correlated one.
Total phi cross section from the di-muon data. The first error is statistical, the second is a systematic error.
The central inclusive jet cross section has been measured using a successive-combination algorithm for reconstruction of jets. The measurement uses 87.3 pb^{-1} of data collected with the D0 detector at the Fermilab Tevatron ppbar Collider during 1994-1995. The cross section, reported as a function of transverse momentum (pT>60 GeV) in the central region of pseudorapidity (|\eta|<0.5), exhibits reasonable agreement with next-to-leading order QCD predictions, except at low pT where the agreement is marginal.
The inclusive jet cross section as a function of PT.
The inclusive cross section for production of isolated photons has been measured in \pbarp collisions at $\sqrt{s} = 630$ GeV with the \D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy ($E_T$) range from 7-49 GeV and have pseudorapidity $|\eta| < 2.5$. This measurement is combined with to previous \D0 result at $\sqrt{s} = 1800$ GeV to form a ratio of the cross sections. Comparison of next-to-leading order QCD with the measured cross section at 630 GeV and ratio of cross sections show satisfactory agreement in most of the $E_T$ range.
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We report a new measurement of the pseudorapidity (eta) and transverse-energy (Et) dependence of the inclusive jet production cross section in pbar b collisions at sqrt(s) = 1.8 TeV using 95 pb**-1 of data collected with the DZero detector at the Fermilab Tevatron. The differential cross section d^2sigma/dEt deta is presented up to |eta| = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.
Single Inclusive Jet Production Cross Section.
Single Inclusive Jet Production Cross Section.
Single Inclusive Jet Production Cross Section.
We report a new measurement of the cross section for the production of isolated photons, with transverse energies (ET) above 10 GeV and pseudorapidities |eta| < 2.5, in p pbar collisions at sqrt{s} = 1.8 TeV. The results are based on a data sample of 107.6 pb-1 recorded during 1992--1995 with the D0 detector at the Fermilab Tevatron collider. The background, predominantly from jets which fragment to neutral mesons, was estimated using the longitudinal shower shape of photon candidates in the calorimeter. The measured cross section is in good agreement with the next-to-leading order (NLO) QCD calculation for ET > 36 GeV.
The measured isolated photon cross sections. The first error contains the statistics and uncorrelated systematic uncertainties, the DSYS error is the correlated systematic uncertainty.
The measured isolated photon cross sections. The first error contains the statistics and uncorrelated systematic uncertainties, the DSYS error is the correlated systematic uncertainty.
We have studied hadronic events from e+e- annihilation data at centre-of-mass energies of sqrt{s}=172, 183 and 189 GeV. The total integrated luminosity of the three samples, measured with the OPAL detector, corresponds to 250 pb^-1. We present distributions of event shape variables, charged particle multiplicity and momentum, measured separately in the three data samples. From these we extract measurements of the strong coupling alpha_s, the mean charged particle multiplicity <nch> and the peak position xi_0 in the xi_p=ln(1/x_p) distribution. In general the data are described well by analytic QCD calculations and Monte Carlo models. Our measured values of alpha_s, <nch> and xi_0 are consistent with previous determinations at sqrt{s}=MZ.
Distribution of Thrust.
Distribution of Thrust Major.
Distribution of Thrust Minor.
This Letter describes a measurement of the muon cross section originating from b quark decay in the forward rapidity range 2.4 < y(mu) < 3.2 in pbarp collisions at sqrt(s) = 1.8 TeV. The data used in this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that NLO QCD calculations underestimate b quark production by a factor of four in the forward rapidity region. A cross section measurement using muon+jet data has been included in this version of the paper.
The forward muon cross section (per unit rapidity).
The cross section for muons originating from b-quark decay.
Integrated cross sections for muons originating from b-quark decay. The statistical and systematic errors are added in quadrature.
This paper presents the first measurement of the inclusive J/Psi production cross section in the forward pseudorapidity region 2.5<|eta|<3.7 in ppbar collisions at sqrt(s)=1.8TeV. The results are based on 9.8 pb-1 of data collected using the D0 detector at the Fermilab Tevatron Collider. The inclusive J/Psi cross section for transverse momenta between 1 and 16 GeV/c is compared with theoretical models of charmonium production.
Only statistical errors are shown. Cross section tines branching ratio.
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