Speaker
Description
Understanding the infrared sensitivity of perturbative predictions in QCD is important for assessing the magnitude of possible non-perturbative power corrections to processes with large momentum transfer. In renormalon models, this sensitivity can be related to computable dependences of perturbative quantities on a small gluon mass. However, this procedure cannot be applied to collider processes with gluons at the Born level.
To address this problem, we promote the gluon mass to a parameter of a consistent non-Abelian quantum field theory where the gauge symmetry is spontaneously broken through the Higgs mechanism. Working in the limit in which the gluon mass $m_g$ is the smallest dimensionful parameter, we compute through two loops the $\mathcal{O}(m_g)$ contributions to the relation between the pole and $\overline{\rm MS}$ masses of a heavy quark and to the relation between corresponding field counterterms. We also report on first steps towards applying this framework to computing $\mathcal{O}(m_g)$ contributions to top-pair production through two loops. We expect that the proposed framework will provide a useful laboratory for probing linear infrared sensitivity of this and other collider observables in QCD.