Transverse Momentum Distributions from Effective Field Theory

Abstract: We review a new approach to calculating transverse momentum distributions of the Higgs and electroweak gauge bosons using the Soft-Collinear Effective Theory. We derive a factorization theorem for transverse momentum distributions in terms of newly-defined impact-parameter beam functions (iBFs) and an inverse soft function (iSF). The iBFs correspond to completely unintegrated parton distribution functions and provide interesting probes of momentum distributions within nucleons. The numerical matching between the low and high transverse momentum regions is improved in this approach with respect to standard techniques. We present results for next-to-leading logarithmic resummation for the Higgs and Z-boson distributions and give a comparison with Tevatron data.