Using data collected by the HERA-B experiment, we have measured the fraction of J\psi's produced via radiative chi_c decays in interactions of 920 GeV protons with carbon and titanium targets. We obtained R_{\chi_c} = 0.32 \pm 0.06_{stat} \pm 0.04_{sys} for the fraction of J\psi from chi_c decays averaged over proton-carbon and proton-titanium collisions. This result is in agreement with previous measurements and is compared with theoretical predictions.
Ratio of CHIC to J/PSI production cross section in P C interactions for the E+ E- and MU+ MU- channels separately.
Ratio of CHI/C to J/PSI production cross section in P TI interactions for the E+ E- and MU+ MU- channels separately.
Averaged ratio of CHIC to J/PSI production cross section in P C and P Ti interactions.
Using the HERA-B detector, the b-bbar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b-bbar production was tagged via inclusive bottom quark decays into J/psi, by exploiting the longitudinal separation of J/psi->ll decay vertices from the primary proton-nucleus interaction. Both $e^+e^-$ and $\mu^+\mu^-$ channels have been reconstructed and the combined analysis yields the cross section $\sigma(b \bar b) = 32 ^{+14}_{-12} (stat) ^{+6}_{-7} (sys) nb/nucleon$.
The measured cross section for the E+ E- and MU+ MU- channels separately.
The measured and extrapolated combined B-BBAR production cross section.
We have measured the analyzing power ANO and the spin transfer KNN for np-elastic scattering from about 60° to 170° c.m. at 485, 635, and 788 MeV. The new data clarify previous discrepancies and complete the first-order determination of nucleon-nucleon elastic scattering at these energies.
For definition of the POL(NAME=SPIN-TRANSFER) see text.
For definition of the POL(NAME=SPIN-TRANSFER) see text.
For definition of the POL(NAME=SPIN-TRANSFER) see text.