T-2, Nuclear and Particle Physics, Astrophysics and Cosmology

A fast and accurate method for perturbative resummation of transverse momentum-dependent observables

Varun Vaidya

We propose a novel strategy for the perturbative resummation of transverse momentum-dependent (TMD) observables, using the qT spectra of gauge bosons (γ∗, Higgs) in pp collisions in the regime of low (but perturbative) transverse momentum qT as a specific example. First we introduce a scheme to choose the factorization scale for virtuality in momentum space instead of in impact parameter space, allowing us to avoid integrating over (or cutting off) a Landau pole in the inverse Fourier transform of the latter to the former. The factorization scale for rapidity is still chosen as a function of impact parameter b, but in such a way designed to obtain a Gaussian form (in ln⁡ b) for the exponentiated rapidity evolution kernel, guaranteeing convergence of the b integral. We then apply this scheme to obtain the qT spectra for Drell-Yan and Higgs production at NNLL accuracy. In addition, using this scheme we are able to obtain a fast semi-analytic formula for the perturbative resummed cross sections in momentum space: analytic in its dependence on all physical variables at each order of logarithmic accuracy, up to a numerical expansion for the pure mathematical Bessel function in the inverse Fourier transform that needs to be performed just once for all observables and kinematics, to any desired accuracy.


Contact Us | Careers | Bradbury Science Museum | Emergencies | Inside LANL | Maps | Site Feedback | SSL Portal | Training

Operated by Los Alamos National Security, LLC for the U.S. Department of Energy's NNSA© Copyright 2010-11 LANS, LLC All rights reserved | Terms of Use | Privacy Policy