Analytic and Monte Carlo studies of jets with heavy mesons and quarkonia

作者：Bain Reggie^*; Dai Lin; Hornig Andrew; Leibovich Adam K; Markris Yiannis; Mehen Thomas

来源：The Journal of High Energy Physics, 2016, 2016(6): 121.

DOI：10.1007/JHEP06(2016)121

• Jets

We study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified hadron in a jet with angularity, tau(a). The FJFs are convolutions of fragmentation functions (FFs), evolved to the jet energy scale, with perturbatively calculable matching coefficients. Renormalization group equations are used to provide resummed calculations with next-to-leading logarithm prime (NLL') accuracy. We apply this formalism to two-jet events in e(+)e(-) collisions with B mesons in the jets, and three-jet events in which a J/psi is produced in the gluon jet. In the case of B mesons, we use a phenomenological FF extracted from e(+)e(-) collisions at the Z(0) pole evaluated at the scale mu = m(b). For events with J/psi, the FF can be evaluated in terms of Non-Relativistic QCD (NRQCD) matrix elements at the scale mu = 2m(c). The z and tau(a) distributions from our NLL' calculations are compared with predictions from monte carlo event generators. While we find consistency between the predictions for B mesons and the J/psi distributions in tau(a), we find the z distributions for J/psi differ significantly. We describe an attempt to merge PYTHIA showers with NRQCD FFs that gives good agreement with NLL' calculations of the z distributions.

• 出版日期2016-6-21