Header

UZH-Logo

Maintenance Infos

Event activity dependence of Y (nS) production in $\sqrt{{{s_{NN }}}}$ = 5.02 TeV pPb and $\sqrt{s}$ = 2.76 TeV pp collisions


CMS Collaboration; Chatrchyan, S; Khachatryan, V; Sirunyan, A M; et al; Chiochia, V; Kilminster, B; Robmann, P (2014). Event activity dependence of Y (nS) production in $\sqrt{{{s_{NN }}}}$ = 5.02 TeV pPb and $\sqrt{s}$ = 2.76 TeV pp collisions. Journal of High Energy Physics, 2014(103):online.

Abstract

The production of Y(1S), Y(2S), and Y(3S) is investigated in pPb and pp collisions at centre-of-mass energies per nucleon pair of 5.02 TeV and 2.76 TeV, respectively. The datasets correspond to integrated luminosities of about 31 inverse nanobarns (pPb) and 5.4 inverse picobarns (pp), collected in 2013 by the CMS experiment at the LHC. Upsilons that decay into muons are reconstructed within the rapidity interval abs(y[CM])<1.93 in the nucleon-nucleon centre-of-mass frame. Their production is studied as a function of two measures of event activity, namely the charged-particle multiplicity measured in the pseudorapidity interval abs(eta)<2.4, and the sum of transverse energy deposited at forward pseudorapidity, 4.0<abs(eta)<5.2. The Y cross sections normalized by their event activity integrated values, Y(nS)/<Y((nS)>, are found to rise with both measures of the event activity in pp and pPb. In both collision systems, the ratios of the excited to the ground state cross sections, Y(nS)/Y(1S), are found to decrease with the charged-particle multiplicity, while as a function of the transverse energy the variation is less pronounced. The event activity integrated double ratios, [Y(nS)/Y(1S)][pPb] / [Y(nS)/Y(1S)][pp], are also measured and found to be 0.83 +/- 0.05 (stat.) +/- 0.05 (syst.) and 0.71 +/- 0.08 (stat.) +/- 0.09 (syst.) for Y(2S) and Y(3S), respectively.

Abstract

The production of Y(1S), Y(2S), and Y(3S) is investigated in pPb and pp collisions at centre-of-mass energies per nucleon pair of 5.02 TeV and 2.76 TeV, respectively. The datasets correspond to integrated luminosities of about 31 inverse nanobarns (pPb) and 5.4 inverse picobarns (pp), collected in 2013 by the CMS experiment at the LHC. Upsilons that decay into muons are reconstructed within the rapidity interval abs(y[CM])<1.93 in the nucleon-nucleon centre-of-mass frame. Their production is studied as a function of two measures of event activity, namely the charged-particle multiplicity measured in the pseudorapidity interval abs(eta)<2.4, and the sum of transverse energy deposited at forward pseudorapidity, 4.0<abs(eta)<5.2. The Y cross sections normalized by their event activity integrated values, Y(nS)/<Y((nS)>, are found to rise with both measures of the event activity in pp and pPb. In both collision systems, the ratios of the excited to the ground state cross sections, Y(nS)/Y(1S), are found to decrease with the charged-particle multiplicity, while as a function of the transverse energy the variation is less pronounced. The event activity integrated double ratios, [Y(nS)/Y(1S)][pPb] / [Y(nS)/Y(1S)][pp], are also measured and found to be 0.83 +/- 0.05 (stat.) +/- 0.05 (syst.) and 0.71 +/- 0.08 (stat.) +/- 0.09 (syst.) for Y(2S) and Y(3S), respectively.

Statistics

Citations

30 citations in Web of Science®
34 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

0 downloads since deposited on 19 Feb 2014
11 downloads since 12 months

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Language:English
Date:2014
Deposited On:19 Feb 2014 09:50
Last Modified:08 Dec 2017 03:52
Publisher:Springer
ISSN:1029-8479
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1007/JHEP04(2014)103
Official URL:http://arxiv.org/abs/1312.6300

Download

Download PDF  'Event activity dependence of  Y (nS) production in  $\sqrt{{{s_{NN }}}}$  = 5.02 TeV pPb and  $\sqrt{s}$  = 2.76 TeV pp collisions'.
Preview
Content: Published Version
Filetype: PDF
Size: 693kB
View at publisher
Licence: Creative Commons: Attribution 4.0 International (CC BY 4.0)
Download PDF  'Event activity dependence of  Y (nS) production in  $\sqrt{{{s_{NN }}}}$  = 5.02 TeV pPb and  $\sqrt{s}$  = 2.76 TeV pp collisions'.
Preview
Content: Accepted Version
Filetype: PDF
Size: 696kB