Measurement of electroweak boson production in pp, p+Pb and Pb+Pb collisions with the ATLAS detector

Piotr Janus

doi:10.1088/1742-6596/1390/1/012023

Abstract

Measurement of electroweak boson production in different collision systems are of great interest to understanding the partonic structure of heavy nuclei, and serve as a constraint on the initial state in larger collision systems. Their production yields in Pb+Pb with respect to pp collisions provide direct tests of both binary collision scaling and possible modification of parton distribution functions (nPDF) due to nuclear effects. Further, the p+Pb collisions provide a relatively clean environment to study nPDFs in detail. The ATLAS detector has a broad acceptance with excellent performance even in the high occupancy environment of central heavy-ion collisions. In this proceedings the latest ATLAS results on W and Z boson production at the centre-of-mass energy of 5.02 TeV are presented, including updated precise result production in pp collisions. Also photon yields are reported in 8.16 TeV in different collision systems are presented.

Highlights

The Relativistic Heavy Ion Colider (RHIC) showed that strongly interacting matter produced in collision of two heavy nuclei takes the form of quark gluon plasma (QGP) [1]
A measurement of direct photon production [5] by the PHENIX experiment at RHIC showed that photon rates scale with the nuclear thickness function
Measurements of W ± and Z boson production in pp collisions provide a benchmark for the understanding of quantum chromodynamics (QCD) and EW processes

Summary

Introduction

The Relativistic Heavy Ion Colider (RHIC) showed that strongly interacting matter produced in collision of two heavy nuclei takes the form of quark gluon plasma (QGP) [1] In such medium produced colour particles are expected to lose energy which leads to a phenomenon known as jet quenching. EW bosons production can be affected by effects arising from partons being bound in the nucleus where the PDF of the free nucleon might be modified leading to parton depletion or enhancement [11] This proceedings cov√ers the most recent measurements on W ± and Z production in the pp and√Pb+Pb system at sNN = 5.02 TeV and prompt photon production in the p+Pb system at sNN = 8.16 TeV. They are based on data collected in 2015 and 2016 by the ATLAS experiment [12] at the LHC

W and Z production in pp collisions

Conclusions