# Nonperturbative Corrections to Soft Drop Jet Mass

## TL;DR

This paper develops a quantum field theory framework to analyze nonperturbative hadronization effects on soft drop jet mass distributions, identifying universal parameters and their dependence on jet and grooming variables.

## Contribution

It introduces a novel effective theory approach to describe nonperturbative corrections in soft drop jet mass, including universal parameters and their kinematic dependencies.

## Key findings

- Universal nonperturbative parameters are identified for intermediate jet mass regions.
- Power corrections depend on subjet kinematics via short-distance coefficients.
- A non-standard shape function describes low jet mass nonperturbative effects.

## Abstract

We provide a quantum field theory based description of the nonperturbative effects from hadronization for soft drop groomed jet mass distributions using the soft-collinear effective theory and the coherent branching formalism. There are two distinct regions of jet mass $m_J$ where grooming modifies hadronization effects. In a region with intermediate $m_J$ an operator expansion can be used, and the leading power corrections are given by three universal nonperturbative parameters that are independent of all kinematic variables and grooming parameters, and only depend on whether the parton initiating the jet is a quark or gluon. The leading power corrections in this region cannot be described by a standard normalized shape function. These power corrections depend on the kinematics of the subjet that stops soft drop through short distance coefficients, which encode a perturbatively calculable dependence on the jet transverse momentum, jet rapidity, and on the soft drop grooming parameters $z_{\rm cut}$ and $\beta$. Determining this dependence requires a resummation of large logarithms, which we carry out at LL order. For smaller $m_J$ there is a nonperturbative region described by a one-dimensional shape function that is unusual because it is not normalized to unity, and has a non-trivial dependence on $\beta$.