Scaled momentum distributions for the strange hadrons K0s and Lambda/bar Lambda were measured in deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 330 pb-1. The evolution of these distributions with the photon virtuality, Q2, was studied in the kinematic region 10<Q2<40000 GeV2 and 0.001<x<0.75, where x is the Bjorken scaling variable. Clear scaling violations are observed. Predictions based on different approaches to fragmentation were compared to the measurements. Leading-logarithm parton-shower Monte Carlo calculations interfaced to the Lund string fragmentation model describe the data reasonably well in the whole range measured. Next-to-leading-order QCD calculations based on fragmentation functions, FFs, extracted from e+e- data alone, fail to describe the measurements. The calculations based on FFs extracted from a global analysis including e+e-, ep and pp data give an improved description. The measurements presented in this paper have the potential to further constrain the FFs of quarks, anti-quarks and gluons yielding K0s and Lambda/bar Lambda strange hadrons.
The measured scaled momentum distributions for K0S production as a function of Q^2 in three XP regions.
The measured scaled momentum distributions for K0S production as a function of Q^2 in six XP regions.
The measured scaled momentum distributions for K0S production as a function of Q^2 in three XP regions.
The STAR collaboration at RHIC reports measurements of the inclusive yield of non-photonic electrons, which arise dominantly from semi-leptonic decays of heavy flavor mesons, over a broad range of transverse momenta ($1.2 < \pt < 10$ \gevc) in \pp, \dAu, and \AuAu collisions at \sqrtsNN = 200 GeV. The non-photonic electron yield exhibits unexpectedly large suppression in central \AuAu collisions at high \pt, suggesting substantial heavy quark energy loss at RHIC. The centrality and \pt dependences of the suppression provide constraints on theoretical models of suppression.
Non photonic electron yield in P+P collisions versus PT To obtain a differential cross-section in mb/(GeV2), multiply listed data by 30 Note that, in addition to the statistical and systematical errors, there is a normalization error on the value, given in the second column.
Non photonic electron yield in P+P collisions versus $p_{T}$. To obtain a differential cross-section in mb/(GeV$^2$), multiply listed data by 30.
Non photonic electron yield in minimum bias D+AU collisions versus PT To obtain a differential cross-section in mb/(GeV2), multiply listed data by 30 Note that, in addition to the statistical and systematical errors, there is a normalization error on the value, given in the second column.
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N IS FAST IN LABORATORY SYSTEM. CUT FOR 'FAST' SELECTION WAS:. PLAB(P=3) > PMIN(P=3), WHERE PMIN IS DETERMINED FROM ALL EVENTS.
N IS FAST IN LABORATORY SYSTEM. CUT FOR 'FAST' SELECTION WAS:. PLAB(P=3) > PMIN(P=4,5,6), WHERE PMIN IS DETERMINED FROM ALL EVENTS.
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Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
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The high mass μ + μ − pairs produced by 280 GeV μ + on a carbon target are studied in a search for the Y production. The high mass continuum in the region 2–18 GeV is interpreted in terms of QED pair production and of μ pairs originating from the decay of hidden and open charm particles as well as of hadrons ( π , K) from deep inelastic interactions. The upper limit for the upsilon production by muons is found to be, at the 90% confidence level, σ γ ·(γ→μ + μ − )<13·10 −39 cm 2 /nucleon.
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First measurements of azimuthal asymmetries in hadron-pair production in deep-inelastic scattering of muons on transversely polarised ^6LiD (deuteron) and NH_3 (proton) targets are presented. The data were taken in the years 2002-2004 and 2007 with the COMPASS spectrometer using a muon beam of 160 GeV/c at the CERN SPS. The asymmetries provide access to the transversity distribution functions, without involving the Collins effect as in single hadron production. The sizeable asymmetries measured on the NH_ target indicate non-vanishing u-quark transversity and two-hadron interference fragmentation functions. The small asymmetries measured on the ^6LiD target can be interpreted as indication for a cancellation of u- and d-quark transversities.
The measured transverse asymmetry from the proton target as a function of the variable X. Mean values are also given for the variables Q**2[GeV^2], Y, Z, M[GeV], M**2[GeV^2], SIN(THETA), COS(THETA), COS(THETA)**2 and the transverse spin transfer coefficient DNN.
The measured transverse asymmetry from the proton target as a function of the variable Z. Mean values are also given for the variables Q**2[GeV^2], Y, X, M[GeV], M**2[GeV^2], SIN(THETA), COS(THETA), COS(THETA)**2 and the transverse spin transfer coefficient DNN.
The measured transverse asymmetry from the proton target as a function of the variable M. Mean values are also given for the variables Q**2[GeV^2], Y, Z, X, M**2[GeV^2], SIN(THETA), COS(THETA), COS(THETA)**2 and the transverse spin transfer coefficient DNN Note that the data in the last bin (>1.5) does not contribute to the X and Z distributions.
Dijet angular distributions from the first LHC pp collisions at center-of-mass energy sqrt(s) = 7 TeV have been measured with the ATLAS detector. The dataset used for this analysis represents an integrated luminosity of 3.1 pb-1. Dijet $\chi$ distributions and centrality ratios have been measured up to dijet masses of 2.8 TeV, and found to be in good agreement with Standard Model predictions. Analysis of the $\chi$ distributions excludes quark contact interactions with a compositeness scale $\Lambda$ below 3.4 TeV, at 95% confidence level, significantly exceeding previous limits.
CHI distribution for mass bin 340 to 520 GeV.
CHI distribution for mass bin 520 to 800 GeV.
CHI distribution for mass bin 800 to 1200 GeV.
The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb-1. The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, Lambda_eff, and the LPHD parameter, kappa^ch, are extracted.
Distribution of multiplicity of charged particles in a jet as a function of LN(1/X) for mean jet energy 19 GeV and jet cone opening angle 0.23.
Distribution of multiplicity of charged particles in a jet as a function of LN(1/X) for mean jet energy 23 GeV and jet cone opening angle 0.23.
Distribution of multiplicity of charged particles in a jet as a function of LN(1/X) for mean jet energy 28 GeV and jet cone opening angle 0.23.
The charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic $ep$ scattering with the ZEUS detector at HERA, using an integrated luminosity of 38.6 pb$^{-1}$. The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame. The KNO-scaling properties of the data were investigated and the energy dependence was studied using different energy scales. The data are compared to results obtained in $\epem$ collisions and to previous DIS measurements as well as to leading-logarithm parton-shower Monte Carlo predictions.
Multiplicity distributions measured in the current region of the Breit frame for the bin of 2*E(Breit,current region) = 1.5 to 4.
Multiplicity distributions measured in the current region of the Breit frame for the bin of 2*E(Breit,current region) = 4 to 8.
Multiplicity distributions measured in the current region of the Breit frame for the bin of 2*E(Breit,current region) = 8 to 12.
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