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Measurement of the Upsilon production cross-section in 920-GeV fixed-target proton-nucleus collisions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Phys.Lett.B 638 (2006) 13-21, 2006.
Inspire Record 711926 DOI 10.17182/hepdata.57495

The proton-nucleon cross section ratio $R=Br(\Upsilon\to l^+l^-) d\sigma(\Upsilon)/dy|_{y=0} / {\sigma(J/\psi)}$ has been measured with the HERA-B spectrometer in fixed-target proton-nucleus collisions at 920 GeV proton beam energy corresponding to a proton-nucleon cms energy of sqrt{s}=41.6 GeV. The combined results for the Upsilon decay channels Upsilon $\to e^+e^-$ and Upsilon $\to\mu^+\mu^-$ yield a ratio $R=(9.0 \pm 2.1) 10^{-6}$. The corresponding Upsilon production cross section per nucleon at mid-rapidity (y=0) has been determined to be $Br(\Upsilon\to{}l^+l^-) {d\sigma(\Upsilon)/dy}|_{y=0}= 4.5 \pm 1.1 $ pb/nucleon.

2 data tables
Table 1

Ratio of the UPSILON production cross section to the total J/PSI production cross section in P NUCLEON interactions for the E+ E- and MU+ MU- channels separately and combined. The total uncertainty is indicated for the combined results.

Table 2

UPSILON production cross section at midrapidity in P NUCLEON interactions for the E+ E- and MU+ MU- channels separately and combined. The total uncertainty is indicated for the combined results.