Semi-inclusive processes at low and high transverse momentum

TL;DR

This paper investigates the relationship between high and low transverse momentum descriptions of semi-inclusive deep inelastic scattering, revealing conditions for their matching and highlighting potential limitations of current factorization approaches.

Contribution

It provides a detailed analysis of the connection between collinear and transverse-momentum-dependent factorization, identifying when they align or diverge at intermediate transverse momentum.

Findings

Different power behaviors imply distinct mechanisms and no matching.

Matching occurs when power behaviors are the same.

Some observables do not match, indicating possible incompleteness of TMD factorization beyond leading twist.

Abstract

This talk reports on recent work where we studied the connection between the description of semi-inclusive DIS at high transverse momentum (based on collinear factorization) and low transverse momentum (based on transverse-momentum-dependent factorization). We used power counting to determine the leading behavior of the structure functions at intermediate transverse momentum in the two descriptions. When the power behaviors are different, two distinct mechanisms are present and there can be no matching between them. When the power behavior is the same, the two descriptions must match. An explicit calculation however shows that for some observables this is not the case, suggesting that the transverse-momentum-dependent-factorization description beyond leading twist is incomplete.