31st International Workshop on Deep Inelastic Scattering

The azimuthal correlation between the leading jet and the scattered lepton in deep inelastic scattering at HERA

11 avr. 2024, 09:10

20m

Maison MINATEC, Grenoble, FRANCE

Regular parallel talk WG4: QCD with Heavy Flavors and Hadronic Final States WG4

Orateur

Jae Nam (Temple University)

Description

The azimuthal correlation angle, $\mathrm{\Delta }\varphi$, between the scattered lepton and the leading jet in deep inelastic $ep$ scattering at HERA has been studied using HERA II data collected with the ZEUS detector. The data set features $e^{\pm }p$ collisions at a centre-of-mass energy of $\sqrt{s}=318$ GeV, corresponding to an integrated luminosity of 326 pb${}^{-1}$. A measurement of jet cross sections was performed within the fiducial region, specified in the laboratory frame, of the photon virtuality 10 GeV${}^2<Q^2<350$ GeV${}^2$, inelasticity $0.04<y<0.7$, outgoing lepton energy $E_e>10$ GeV, lepton polar angle ${140}^o<{\theta }_e<{180}^o$, jet transverse momentum 2.5 GeV < $p_{\mathrm{T},\mathrm{jet}}<30$ GeV, and jet pseudorapidity $-1.5<{\eta }_{\mathrm{jet}}<1.8$. Jets were reconstructed using the $k_{\mathrm{T}}$ algorithm with the radius parameter $R=1$. Leading jets are defined as jets that carry the highest $p_{\mathrm{T},\mathrm{jet}}$. Differential cross sections, $d\sigma /d\mathrm{\Delta }\varphi$, will are presented as a function of the azimuthal correlation angle in various $p_{\mathrm{T},\mathrm{jet}}$, $Q^2$ and jet-multiplicity ranges. Perturbative calculations at $\mathcal{O}({\alpha }_s^2)$ accuracy successfully describe the data within the fiducial region, while a lower level of agreement is observed near $\mathrm{\Delta }\varphi \to \pi$ for events with high jet-multiplicity due to limitations of the perturbative approach in describing soft QCD phenomena. Monte Carlo predictions that supplement leading-order matrix elements with parton showering describe the data as well as the $\mathcal{O}({\alpha }_s^2)$ calculations do.

Documents de présentation

Nam_20240411_v2.pdf