Non-perturbative corrections to the Drell-Yan transverse momentum distribution

by Sofiane TAFAT (LPTHE Orsay)

Friday 6 Apr 2001, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

We study non-perturbative corrections to the transverse momentum distribution of vector bosons in the Drell-Yan process. Factorizing out the Sudakov effects due to soft gluons, we express their contribution to the distribution in the form of the vacuum-averaged Wilson loop operator. We calculate the non-perturbative contribution to the Sudakov form factor using the expansion of the Wilson loop over vacuum fields supplemented with the expression for the non-local gauge invariant field strength correlator. Although the Wilson loop is defined in an essentially Minkowski kinematics, the part of the non-perturbative contribution depending on the invariant mass of the produced vector bosons is governed by asymptotics of the correlator at large space-like (Euclidean) separations, and therefore can be calculated using conventional non-perturbative methods. Applying the results of lattice calculations we found that the obtained expression for the non-perturbative power corrections is in qualitative agreement with known phenomenological expressions at large transverse momenta and deviates from them at small transverse momenta.