Results from bottomonia production at the Tevatron and prospects for the LHC

Abstract

We extend our previous analysis on inclusive heavy quarkonia hadroproduction to the whole Υ(nS) (n=1,2,3) resonance family. We use a Monte Carlo framework with the colour-octet mechanism implemented in the PYTHIA event generator. We include in our study higher order QCD effects such as initial-state emission of gluons and Altarelli-Parisi evolution of final-state gluons. We extract some NRQCD colour-octet matrix elements relevant for Υ(nS) (n=1,2,3) hadroproduction from CDF data at the Fermilab Tevatron. Then we extrapolate to LHC energies to predict prompt bottomonia production rates. Finally, we examine the prospect to probe the gluon density in protons from heavy quarkonia inclusive hadroproduction at high transverse momentum and its feasibility in LHC general-purpose experiments.

Prospects for probing the gluon density in protons using heavy quarkonium hadroproduction

“…On the other hand, the Feynman x can be known with a precision limited by the rapidity uncertainty of the resonance; indeed, for a fixed p T value, the typical uncertainty ∆x is given by [6] |∆x| x < y cut…”

“…Actually the ratio given by Eq. (12) involves the so-called effective gluon distributions [14], since quark distributions can contribute to some extent via the partonic scattering channel gq→g * q, and to a much lower extent via the channel qq→g * g [6]. It is important to note that the number of independent x values is basically limited by ∆x (i.e.…”

“…[6]). For the purpose of illustration we plot in Fig.2 the combined production rate at p T > 10 GeV and |y Υ | < 0.2 for the upper and lower values of the colour-octet matrix element obtained in [6] from previous fits to CDF experimental data of Run IB at the Tevatron.…”

“…3.b we show the xshape for different choices (CTEQ, MRST, GRV) [19]. All distributions were normalized 6 We are considering the possibility of extending our proposal to the high luminosity regime at the LHC coping with pile-up effects, as well as using the electronic decay channel of the Υ resonances, too. This would mean to increase considerably the foreseen statistics allowing to raise the x range available in our study.…”

“…[5,6]. In particular we are focusing on bottomonia production in proton-proton collisions at the LHC.…”