/ hep-ex CERN-PH-EP-2015-143

Measurement of the production of neighbouring jets in lead-lead collisions at $\sqrt{s_{\mathrm{NN}}} = 2.76$ TeV with the ATLAS detector

Pages: 12

Abstract: This Letter presents measurements of correlated production of nearby jets in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 2.76$ TeV using the ATLAS detector at the Large Hadron Collider. The measurement was performed using 0.14 ${\rm nb}^{-1}$ of data recorded in 2011. The production of correlated jet pairs was quantified using the rate, $R_{\Delta R}$, of "neighbouring" jets that accompany "test" jets within a given range of angular distance, $\Delta R$, in the pseudorapidity--azimuthal angle plane. The jets were measured in the ATLAS calorimeter and were reconstructed using the anti-$k_{t}$ algorithm with radius parameters $d = 0.2$, $0.3$, and $0.4$. $R_{\Delta R}$ was measured in different Pb+Pb collision centrality bins, characterized by the total transverse energy measured in the forward calorimeters. A centrality dependence of $R_{\Delta R}$ is observed for all three jet radii with $R_{\Delta R}$ found to be lower in central collisions than in peripheral collisions. The ratios formed by the $R_{\Delta R}$ values in different centrality bins and the values in the 40-80 % centrality bin are presented.

Note: *Temporary entry*; 12 pages plus author list + cover pages (28 pages total), 6 figures, 2 tables, submitted to Physics Letters B, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2013-10/

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