Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10407583" target="_blank" >RIV/00216208:11320/19:10407583 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=UB-3.xKP1O" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=UB-3.xKP1O</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2019.134826" target="_blank" >10.1016/j.physletb.2019.134826</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV

Popis výsledku v původním jazyce

Evidence for the light-by-light scattering process, gamma gamma -&gt; gamma gamma, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390 mu b(-1) recorded by the CMS experiment at the LHC. Light-by-light scattering processes are selected in events with two photons exclusively produced, each with transverse energy E-T(gamma) &gt; 2 GeV, pseudorapidity vertical bar eta(gamma)vertical bar &lt; 2.4, diphoton invariant mass m(gamma gamma) &gt; 5 GeV, diphoton transverse momentum p(T)(gamma gamma) &lt; 1 GeV, and diphoton acoplanarity below 0.01. After all selection criteria are applied, 14 events are observed, compared to expectations of 9.0 +/- 0.9 (theo) events for the signal and 4.0 +/- 1.2 (stat) for the background processes. The excess observed in data relative to the background-only expectation corresponds to a significance of 3.7 standard deviations, and has properties consistent with those expected for the light-by-light scattering signal. The measured fiducial light-by-light scattering cross section, sigma(fid)(gamma gamma -&gt; gamma gamma) = 120 +/- 46(stat) +/- 28(syst) +/- 12(theo) nb, is consistent with the standard model prediction. The m(gamma gamma) distribution is used to set new exclusion limits on the production of pseudoscalar axion-like particles, via the gamma gamma -&gt; a -&gt; gamma gamma process, in the mass range m(a) = 5-90 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.

Název v anglickém jazyce

Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV

Popis výsledku anglicky

Evidence for the light-by-light scattering process, gamma gamma -&gt; gamma gamma, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390 mu b(-1) recorded by the CMS experiment at the LHC. Light-by-light scattering processes are selected in events with two photons exclusively produced, each with transverse energy E-T(gamma) &gt; 2 GeV, pseudorapidity vertical bar eta(gamma)vertical bar &lt; 2.4, diphoton invariant mass m(gamma gamma) &gt; 5 GeV, diphoton transverse momentum p(T)(gamma gamma) &lt; 1 GeV, and diphoton acoplanarity below 0.01. After all selection criteria are applied, 14 events are observed, compared to expectations of 9.0 +/- 0.9 (theo) events for the signal and 4.0 +/- 1.2 (stat) for the background processes. The excess observed in data relative to the background-only expectation corresponds to a significance of 3.7 standard deviations, and has properties consistent with those expected for the light-by-light scattering signal. The measured fiducial light-by-light scattering cross section, sigma(fid)(gamma gamma -&gt; gamma gamma) = 120 +/- 46(stat) +/- 28(syst) +/- 12(theo) nb, is consistent with the standard model prediction. The m(gamma gamma) distribution is used to set new exclusion limits on the production of pseudoscalar axion-like particles, via the gamma gamma -&gt; a -&gt; gamma gamma process, in the mass range m(a) = 5-90 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

<a href="/cs/project/LM2015058" target="_blank" >LM2015058: Výzkumná infrastruktura pro experimenty v CERN</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

ISSN

0370-2693

e-ISSN

—

Svazek periodika

797

Číslo periodika v rámci svazku

2019

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

27

Strana od-do

15

Kód UT WoS článku

000488071200025

EID výsledku v databázi Scopus

2-s2.0-85070721104