The top quark jet-function at two loops

TL;DR

This paper computes the two-loop heavy quark jet-function crucial for precise top-quark mass measurements in e^+e^- collisions, enabling advanced resummation techniques at NNLL order.

Contribution

It presents the first calculation of the two-loop heavy quark jet-function, facilitating NNLL resummation in top-quark invariant mass distributions.

Findings

Computed the two-loop heavy quark jet-function.

Defined a jet-based top-mass scheme with known anomalous dimension.

Enabled resummation of large logs at NNLL order.

Abstract

Far above threshold the production process e^+e^-to t t-bar can be analyzed using effective field theories. In this talk we consider the invariant mass distribution of top-jets and report about our computation of the two-loop heavy quark jet-function. This is a key part of a next-to-next-to-leading order analysis, and already allows for a resummation of all large logs which effect the shape of the top-invariant mass distribution at next-to-next-to-leading log order. A top-mass scheme is defined which is suitable for measurements involving jets, and whose anomalous dimension is determined by the cusp-anomalous dimension to all orders in perturbation theory.