Resummation of the jet broadening in DIS
M. Dasgupta, G. P. Salam
TL;DR
The paper tackles the resummation of jet broadening in deep inelastic scattering by computing the leading and next-to-leading logarithmic distribution for $B_{zE}$, as well as the accompanying power corrections to both the distribution and its mean. It identifies unphysical divergences arising from standard NLL truncation and develops a DIS-specific remedy that redefines the accuracy criterion and employs a saddle-point–based expansion, enabling stable predictions. The authors implement DIS-specific matching to fixed-order calculations (including new $M$ and $M_2$ schemes) and incorporate non-perturbative corrections, comparing results with HERA data using an in-house PDF evolution code. The study also investigates the compatibility of their results with MRST and CTEQ PDFs, finding limited discrepancies, and sets a framework for precise event-shape analyses in DIS with potential implications for αs determinations and hadronisation studies.
Abstract
We calculate the leading and next-to-leading logarithmic resummed distribution for the jet broadening in deep inelastic scattering, as well as the power correction for both the distribution and mean value. A truncation of the answer at NLL accuracy, as is standard, leads to unphysical divergences. We discuss their origin and show how the problem can be resolved. We then examine DIS-specific procedures for matching to fixed-order calculations and compare our results to data. One of the tools developed for the comparison is an NLO parton distribution evolution code. When compared to PDF sets from MRST and CTEQ it reveals limited discrepancies in both.