Prospects for strong coupling measurement at hadron colliders using soft-drop jet mass

TL;DR

This paper calculates the soft-drop jet-mass distribution at NNLL accuracy, including nonperturbative effects, to evaluate the potential for precise strong coupling constant measurements at hadron colliders.

Contribution

It provides a NNLL calculation of the soft-drop jet-mass distribution with nonperturbative corrections and assesses its use for high-precision alpha_s measurements.

Findings

Alpha_s can be measured to 10% with current methods.

Higher-logarithmic resummation significantly affects the distribution shape.

Quark and gluon jets have similar sensitivity to alpha_s.

Abstract

We compute the soft-drop jet-mass distribution from $pp$ collisions to NNLL accuracy while including nonperturbative corrections through a field-theory based formalism. Using these calculations, we assess the theoretical uncertainties on an $\alpha_s$ precision measurement due to higher order perturbative effects, nonperturbative corrections, and PDF uncertainty. We identify which soft-drop parameters are well-suited for measuring $\alpha_s$, and find that higher-logarithmic resummation has a qualitatively important effect on the shape of the jet-mass distribution. We find that quark jets and gluon jets have similar sensitivity to $\alpha_s$, and emphasize that experimentally distinguishing quark and gluon jets is not required for an $\alpha_s$ measurement. We conclude that measuring $\alpha_s$ to the 10% level is feasible now, and with improvements in theory a 5% level measurement is possible. Getting down to the 1% level to be competitive with other state-of-the-art measurements will be challenging.