Resummed Mass Distribution for Jets Initiated by Massive Quarks

Aglietti, Ugo; Di Giustino, Leonardo; Ferrera, Giancarlo; Trentadue, Luca

Resummed Mass Distribution for Jets Initiated by Massive Quarks

Authors

Aglietti, Ugo

Di Giustino, Leonardo

Ferrera, Giancarlo

Trentadue, Luca

Description

We resum the invariant mass distribution of jets initiated by massive quarks in next-to-leading logarithmic approximation and beyond in heuristic way. We find that the inclusion of mass terms, in the N-moment space, results in the universal factor delta_N(Q^2;m^2), taking into account dead-cone effects and soft radiation characteristic of massive charges. This factor multiplies the massless jet distribution function J_N(Q^2). The variable N is rescaled by the mass correction parameter r = m^2/Q^2 << 1 with respect to the standard massless case, being m the quark mass and Q the hard scale. The functions A(alpha_S) and B(alpha_S), appear with a minus sign suppressing collinear effects at large N, as expected. In the same region, soft radiation not collinearly enhanced, characteristic of massive charges, makes its appearance with the function D(alpha_S). Phenomenological applications, such as the resummation of b --> c l nu decay spectra or the inclusion of beauty mass effects in t --> b W decays, are briefly sketched.
28 pages, stylistic changes, version accepted by journal