Measurement of the charged-hadron multiplicity in proton-proton collisions at LHC with the CMS detector

Charged-hadron pseudorapidity densities and multiplicity distributions in protonproton collisions at [the square root of sigma] = 0.9, 2.36, 7.0 TeV were measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield was obtained by counting the number of hit-pairs (tracklets). The charged-particle multiplicity per unit of pseudorapidity dNch/d[eta] [eta]<0.5 at [the square root of sigma] = 7.0 TeV is 5.78 i 0.01(stat.) i 0.23(syst.) for nonsingle- diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from [the square root of sigma] = 0.9 to 7 TeV is 66.1% ± 1.0%(stat.) ± 4.2%(syst.) and strong KNO violation is observed in the multiplicity distributions. Results are compared with low energy measurements.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2011

Author dc:creator

• Lee, Yen-Jie

Advisor dc:contributor.advisor

• Wit Busza.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/68876

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/68876