engleski

Measurements of B → J/ψ at forward rapidity in p + p collisions at √s=510 GeV

We report the first measurement of the fraction of J/ψ mesons coming from B-meson decay (FB→J/ψ) in p+p collisions at √s=510 GeV. The measurement is performed using the forward silicon vertex detector and central vertex detector at PHENIX, which provide precise tracking and distance-of- closest-approach determinations, enabling the statistical separation of J/ψ due to B-meson decays from prompt J/ψ. The measured value of FB→J/ψ is 8.1%±2.3% (stat)±1.9%(syst) for J/ψ with transverse momenta 0<pT<5 GeV/c and rapidity 1.2<|y|<2.2. The measured fraction FB→J/ψ at PHENIX is compared to values measured by other experiments at higher center of mass energies and to fixed-order-next-to-leading-logarithm and color- evaporation-model predictions. The b¯b cross section per unit rapidity [dσ/dy(pp→b¯b)] extracted from the obtained FB→J/ψ and the PHENIX inclusive J/ψ cross section measured at 200 GeV scaled with color-evaporation-model calculations, at the mean B hadron rapidity y=±1.7 in 510 GeV p+p collisions, is 3.63+1.92−1.70 μb. It is consistent with the fixed-order-next-to-leading- logarithm calculations.

p(p)over-bar collisions ; TeV ; PHENIX ; collider ; detector ; prompt

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