Multiplicity distributions in QCD jets and jet topics

7 May 2026, 10:00
20m
Sala GIOVE A, Ground Floor (Hotel Carlton)

Sala GIOVE A, Ground Floor

Hotel Carlton

Talk WG4 QCD with Heavy Flavors and Hadronic Final States WG4 QCD with Heavy flavours and Hadronic Final States

Speaker

Bin Wu (IGFAE, Universidade de Santiago de Compostela)

Description

In this talk, we will present our recent studies of the Koba–Nielsen–Olesen (KNO) scaling in multiplicity distributions within QCD jets. Specificially, We evaluate the KNO scaling functions for quark- and gluon-initiated jets by incorporating energy conservation into the Double Logarithmic Approximation (DLA). The resulting modified DLA (MDLA) expressions differ substantially from the DLA predictions and qualitatively align with the recently proposed QCD-inspired expressions, albeit with some quantitative differences. By fixing the two parameters in the MDLA expressions, we show that the inclusive charged-particle multiplicity distributions of the two leading jets in $pp$ collisions at $\sqrt{s} = 13$ TeV, measured by ATLAS over a wide jet $p_T$ range of $0.1$–$2.5$ TeV, are well described within experimental uncertainties and consistent with PYTHIA simulations. This conclusion is further supported by direct comparisons with quark- and gluon-initiated jet distributions extracted via jet topics, though the propagated uncertainties from experimental data remain sizable.

Speaker confirmation Yes

Authors

Ms Xiang-Pan Duan Dr Lin Chen Prof. Guo-Liang Ma Carlos A. Salgado (IGFAE - U Santiago de Compostela) Bin Wu (IGFAE, Universidade de Santiago de Compostela)

Presentation materials