2024/09/12 by Melissa van Beekveld, van Beekveld, Melissa, Mrinal Dasgupta +9
Decision Sciences · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Scientific Computing and Data Management
paper · doi:10.48550/arxiv.2409.08316
openalex publication_date 2024/09/12 · openalex created_date 2024/10/23 · openalex updated_date 2026/07/30
We formulate a collinear partonic shower algorithm that achieves next-to-single-logarithmic (NSL, αsn Ln-1) accuracy for collinear-sensitive non-singlet fragmentation observables. This entails the development of an algorithm for nesting triple-collinear splitting functions. It also involves the inclusion of the one-loop double-collinear corrections, through a z-dependent NLO-accurate effective 1→ 2 branching probability, using a formula that can be applied more generally also to future full showers with 1→3 splitting kernels. The specific NLO branching probability is calculated in two ways, one based on slicing, the other using a subtraction approach based on recent analytical calculations. We close with demonstrations of the shower's accuracy for non-singlet partonic fragmentation functions and the energy spectrum of small-R quark jets. This work represents an important conceptual step towards general NNLL accuracy in parton showers.