The Upsilon production cross section in proton-proton collisions at sqrt(s) = 7 TeV is measured using a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 3.1 +/- 0.3 inverse picobarns. Integrated over the rapidity range |y|<2, we find the product of the Upsilon(1S) production cross section and branching fraction to dimuons to be sigma(pp to Upsilon(1S) X) B(Upsilon(1S) to mu+ mu-) = 7.37 +/- 0.13^{+0.61}_{-0.42}\pm 0.81 nb, where the first uncertainty is statistical, the second is systematic, and the third is associated with the estimation of the integrated luminosity of the data sample. This cross section is obtained assuming unpolarized Upsilon(1S) production. If the Upsilon(1S) production polarization is fully transverse or fully longitudinal the cross section changes by about 20%. We also report the measurement of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections as a function of transverse momentum and rapidity.
Production cross sections integrated over the range |eta| < 2 and PT < 30 GeV. The second systematic error is the uncertainty on the luminosity.
UPSI(1S) differential cross sections for |y| < 2.
UPSI(2S) differential cross sections for |y| < 2.
We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, $\sigma (p + d \to \Upsilon) / 2\sigma (p + p\to \Upsilon)$, is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0 < x_F < 0.6, this ratio is found to be consistent with unity, in striking contrast to the behavior of the Drell-Yan cross section ratio $\sigma(p+d)_{DY}/2\sigma(p+p)_{DY}$. This result shows that the gluon distributions in the proton and neutron are very similar. The Upsilon production cross sections are also compared with the p+d and p+Cu cross sections from earlier measurements.
Differential cross section per nucleon as a function of Feynman X for UPSILON production on the DEUT target.
Differential cross section per nucleon as a function of Feynman X for UPSILON production on the P target.
Differential cross section per nucleon as a function of transverse momentum for UPSILON production on the DEUT target.
We present measurements of the total production rates and momentum distributions of the charmed baryon $\Lambda_c^+$ in $e^+e^- \to$ hadrons at a center-of-mass energy of 10.54 GeV and in $\Upsilon(4S)$ decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in $e^+e^- \to c\bar{c}$ events, allowing direct studies of $c$-quark fragmentation. We measure a momentum distribution for $\Lambda_c^+$ baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of $\left< x_p \right> = 0.574\pm$0.009 and a total rate of $N_{\Lambda c}^{q\bar{q}} = 0.057\pm$0.002(exp.)$\pm$0.015(BF) $\Lambda_c^+$ per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, $pK^-\pi^+$. In $\Upsilon (4S)$ decays we measure a total rate of $N_{\Lambda c}^{\Upsilon} = 0.091\pm$0.006(exp.)$\pm$0.024(BF) per $\Upsilon(4S)$ decay, and find a much softer momentum distribution than expected from B decays into a $\Lambda_c^+$ plus an antinucleon and one to three pions.
LAMBDA/C+ differential production rate per hadronic event for the continuum at cm energy 10.54 GeV.
The integrated number of LAMBDA/C+'s per hadronic event for the continuum at cm energy 10.54 GeV.
LAMBDA/C+ differential production rate per UPSILON(4S) decay at cm energy 10.58 GeV.
We present measurements of the inclusive production cross sections of the Upsilon(1S) bottomonium state in ppbar collisions at sqrt(s) = 1.96 TeV. Using the Upsilon(1S) to mu+mu- decay mode for a data sample of 159 +- 10 pb^-1 collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Upsilon(1S) transverse momentum for three ranges of the Upsilon(1S) rapidity: 0 < |y| < 0.6, 0.6 < |y| < 1.2, and 1.2 < |y| < 1.8.
Cross section per unit of rapidity times branching ratio to MU+ MU-. Systematic (DSYS) error does not include the 6.1 PCT uncertainty on the luminosity.
Normalized differential cross section for UPSI(1S) production.. Errors contain statistical and systematics (excluding luminosity error).
The photoproduction reaction gamma p -> mu+ mu- p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb^{-1}. The Upsilon meson has been observed in photoproduction for the first time. The sum of the products of the elastic Upsilon(1S), Upsilon(2S), Upsilon(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 +- 6.0(stat.)^{+2.7}_{-2.3}(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model.
Unresolved UPSILON cross sections (times branching ratio to two muons).
Mean photoproduction cross section for UPSI(1S) production.
None
Cross section times the branching ratio for decay into dimuons.
Using the CLEO II detector at the Cornell Electron Storage Ring, we have determined the inclusive B* cross section above the Υ(4S) resonance in the energy range from 10.61 to 10.70 GeV. We also report a new measurement of the energy of the B*→Bγ transition photon of 46.2±0.3±0.8 MeV.
Hadronic cross section above the continuum. The final state is an unknown mixture of B BBAR + B* BBAR + B B*BAR (+ B* B*BAR only at the highest energy).
Inclusive B* cross section.
Forum