Factorization at Subleading Power, Sudakov Resummation and Endpoint Divergences in Soft-Collinear Effective Theory

TL;DR

This paper develops a systematic approach to factorization and resummation at subleading power in soft-collinear effective theory, addressing endpoint divergences and applying it to Higgs decay processes.

Contribution

It introduces the first renormalized factorization theorem at subleading power and demonstrates how to regularize endpoint divergences in convolution integrals.

Findings

Resummed large logarithms in Higgs decay at next-to-leading order.

Regularized endpoint divergences in subleading power factorization.

Applied the framework to $b$-quark induced Higgs decay and related processes.

Abstract

Starting from the first renormalized factorization theorem for a process described at subleading power in soft-collinear effective theory, we discuss the resummation of Sudakov logarithms for such processes in renormalization-group improved perturbation theory. Endpoint divergences in convolution integrals, which arise generically beyond leading power, are regularized and removed by systematically rearranging the factorization formula. We study in detail the example of the $b$-quark induced $h\to\gamma\gamma$ decay of the Higgs boson, for which we resum large logarithms of the ratio $M_h/m_b$ at next-to-leading logarithmic order. We also briefly discuss the related $gg\to h$ amplitude.