Study of hard double-parton scattering in four-jet events in pp collisions at √ s = 7 TeV with the ATLAS experiment

Allbrooke, B M M, Asquith, L, Cerri, A, Chavez Barajas, C A, De Santo, A, Salvatore, F, Santoyo Castillo, I, Suruliz, K, Sutton, M R, Vivarelli, I and The ATLAS Collaboration, (2016) Study of hard double-parton scattering in four-jet events in pp collisions at √ s = 7 TeV with the ATLAS experiment. Journal of High Energy Physics, 2016 (11). p. 110. ISSN 1029-8479

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Abstract

Inclusive four-jet events produced in proton-proton collisions at a centre-of-mass energy of √ s = 7 TeV are analysed for the presence of hard double-parton scattering using data corresponding to an integrated luminosity of 37.3 pb −1, collected with the ATLAS detector at the LHC. The contribution of hard double-parton scattering to the production of four-jet events is extracted using an artificial neural network, assuming that hard double-parton scattering can be approximated by an uncorrelated overlaying of dijet events. For events containing at least four jets with transverse momentum p T ≥20 GeV and pseudorapidity η≤4.4 , and at least one having p T ≥42.5 GeV, the contribution of hard double-parton scattering is estimated to be f DPS =0.092 +0.005 −0.011 (stat.) +0.033 −0.037 (syst.) . After combining this measurement with those of the inclusive dijet and four-jet cross-sections in the appropriate phase space regions, the effective overlap area between the interacting protons, σ eff , was determined to be σ eff =14.9 +1.2 −1.0 (stat.) +5.1 −3.8 (syst.) mb. This result is consistent within the quoted uncertainties with previous measurements of σ eff, performed at centre-of-mass energies between 63 GeV and 8 TeV using various final states, and it corresponds to 21 +7 −6 % of the total inelastic cross-section measured at √ s = 7 TeV. The distributions of the observables sensitive to the contribution of hard double-parton scattering, corrected for detector effects, are also provided.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Experimental Particle Physics Research Group
Subjects: Q Science > QC Physics
Depositing User: Richard Chambers
Date Deposited: 19 Dec 2016 15:31
Last Modified: 22 Apr 2017 23:32
URI: http://sro.sussex.ac.uk/id/eprint/65952

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