Theory

Theory seminar: Vicent Mateu

Europe/Amsterdam
Nikhef

Nikhef

Description
Massless and massive Jets in the in the large-$\beta_0$ limit In this talk I will discuss an alternative way of organising perturbative computations in QCD, using $1/\beta_0$ as the small expansion parameter. The leading correction in this expansion can be computed in an exact form and is very useful to study the convergence properties of series, in particular so-called renormalons. I will present a formalism to compute renormalised matrix elements to all orders in alphaS in this particular limit, adapting the existing formalism to account for quantities with cusp anomalous dimensions. We will apply this result to various short-distance masses, as well as the hard and jet functions in SCET (massless quarks) and bHQET (massive quarks), finding closed expressions for them as well as for their cusp and non-cusp anomalous dimensions, reproducing known results up to O[alphaS * (nf * alphaS)^3]. Some phenomenological applications will be presented.
Video