Measurement of the exclusive B+→ J/ψ K+ cross section in ppbar collisions at sqrt(s)=1960 GeV

We report a new measurement of the B+ meson differential cross section d σ/d pT at \sqrt{s}=1960 GeV. The data corresponds to an integrated luminosity of 739 pb-1, collected with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider. B+ candidates are reconstructed through the decay B+ --> J/ψ K+, with J/ψ --> &mu+ &mu-.

We measure the total cross section, in the central rapidity region |y| < 1 and for pT(B+) > 6 GeV/c to be:

σ(pT> 6GeV/c, |y|< 1) = 2.65 ± 0.12 (stat) ± 0.21 (syst) μb.

The differential cross section (nb/GeV/c) is reported in the table below. The 7.5% systematic error of the differential cross section is the same for all pT bins.

The values in the fourth and fifth columns are the cross sections before and after the correction for the Cabibbo suppressed mode  B+ --> J/ψ π+, respectively.

A more detailed summary of the results can be found here: ps pdf.

eps and gif versions of all figures: