Study of the dynamics of soft interactions with two-particle angular correlations at ATLAS

Oropeza Barrera, Cristina (2012) Study of the dynamics of soft interactions with two-particle angular correlations at ATLAS. PhD thesis, University of Glasgow.

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Measurements of inclusive two-particle angular correlations in proton-proton collisions at centre-of-mass energies of 900 GeV and 7 TeV are presented. The events were collected with the ATLAS detector at the LHC, using a single-arm minimum-bias trigger, during 2009 and 2010. Correlations are measured for charged particles in the kinematic range defined by pT > 100 MeV and |eta| < 2.5. In total, integrated luminosities of 7 1/ub and 190 1/ub are analysed for 900 GeV and 7 TeV data, respectively. At 900 GeV only events with a charged particle multiplicity n_ch >= 2 are analysed whereas at 7 TeV, a second phase-space region of n_ch >= 20, with a suppressed contribution from diffractive events, is also explored.

Data is corrected using a novel approach in which the detector effects are applied repeatedly to the observable distribution and then extrapolated to a detector effect of zero.

A complex structure in pseudorapidity and azimuth is observed for the correlation function at both collision energies. Projections of the two-dimensional correlation distributions are compared to the Monte Carlo generators Pythia 8 and Herwig++ as well as the AMBT2B, DW and Perugia 2011 tunes of Pythia 6. The strength of the correlations seen in the data is not reproduced by any of the models.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Particle Physics, Minimum Bias, Monte Carlo Generators, Soft QCD, Two-Particle Correlations, HBOM Method, ATLAS
Subjects: Q Science > QC Physics
Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
Supervisor's Name: Buttar, Dr. Craig M.
Date of Award: 2012
Depositing User: Cristina Oropeza Barrera
Unique ID: glathesis:2012-3185
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 13 Feb 2012
Last Modified: 10 Dec 2012 14:04

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