The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The K^0_s, Lambda, and Xi^- particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapidity and transverse momentum. The results are compared to other experiments and to predictions of the PYTHIA Monte Carlo program. The transverse momentum distributions are found to differ substantially from the PYTHIA results and the production rates exceed the predictions by up to a factor of three.
The rapidity production spectra per NSD event spectra for KS mesons at 0.9 and 7 TeV.
The transverse momentum production spectra per NSD event spectra for KS mesons at 0.9 and 7 TeV.
The rapidity production spectra per NSD event spectra for LAMBDA mesons at 0.9 and 7 TeV.
Measurements of the kinematic distributions of $J/\psi$ mesons produced in $p-$C, $p-$Ti and $p-$W collisions at $\sqrt{s}=41.6 \mathrm{GeV}$ in the Feynman-$x$ region $-0.34 < x_{F} < 0.14$ and for transverse momentum up to $p_T = 5.4 \mathrm{GeV}/c$ are presented. The $x_F$ and $p_T$ dependencies of the nuclear suppression parameter, $\alpha$, are also given. The results are based on $2.4 \cdot 10^{5}$ $J/\psi$ mesons in both the $e^+ e^-$ and $\mu^{+}\mu^{-}$ decay channels. The data have been collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The measurement explores the negative region of $x_{F}$ for the first time. The average value of $\alpha$ in the measured $x_{F}$ region is $0.981 \pm 0.015$. The data suggest that the strong nuclear suppression of $J/\psi$ production previously observed at high $x_F$ turns into an enhancement at negative $x_F$.
J/PSI distributions (dN/dp_T, normalized to their integrals over the measured range) for three targets materials with statistical and systematics uncertainties.
J/PSI distributions (dN/dx_F, normalized to their integrals over the measured range) for three targets materials with statistical and systematics uncertainties.
The parameter Alpha as a function of p_T. Statistical and systematic uncertainties are indicated separately.
The shape of the transverse momentum distribution of W bosons (p_T(W)) produced in pbarp collisions at sqrt(s)= 1.8 TeV is measured with the DO detector at Fermilab. The result is compared to QCD perturbative and resummation calculations over the p_T(W) range from 0-200 GeV/c. The shape of the distribution is consistent with the theoretical prediction.
The first error is statistical, the first systematic (DSYS) error is the uncertainty in the background and efficiencies, the second is the systematic errorin the detector modelling.
Forum