Measurement of the nuclear modification factor of b-jets in 5.02 TeV Pb+Pb collisions with the ATLAS detector

• Published in: The European physical journal. C, Particles and fields Vol. 83; no. 5; p. 438
• Main Authors: Åkesson, T. P. A., Allaire, C., Aloisio, A., Angerami, A., Arling, J.-H., Assamagan, K., Balaji, S., Balek, P., Barton, A. E., Batool, B., Bayirli, A., Beddall, A. J., Behera, A., Beringer, J., Bi, R., Bindi, M., Birch-sykes, C. J., Bobbink, G. J., Bruni, G., Buttar, C. M., Cairo, V. M. M., Cardenas, J. C. J., Gimenez, V. Castillo, Chekulaev, S. V., Cheremushkina, E., Choi, K., Christopher, L. D., Ciesla, K. M., Cole, B., Cristoforetti, M., Dai, T., Rio, F. Del, Delitzsch, C. M., Diehl, E. B., Cornell, S. Díez, Dodsworth, D., D’Onofrio, M., Durglishvili, A., Fayard, L., Gabrielli, A., Gagnon, L. G., Gargiulo, S., Gazis, E. N., George, W. F., Gorasia, N. A., Grivaz, J.-F., Guan, W., Guindon, S., Hamano, K., Heim, S., Herten, G., Hinchliffe, I., Hinterkeuser, F., Hirschbuehl, D., Jessiman, C. E., Jia, J., Karpov, S. N., Kozhin, A. S., Kuechler, J. T., Kvita, J., Lammers, S., Lefebvre, H. P., Lohwasser, K., Luci, C., Mancini, G., Da Costa, A. M. Mendes Jacques, Meroni, C., Morii, M., Mosidze, M., Nguyen, H. D. N., Nikiforou, N., Parrish, E. W., Pascuzzi, V. R., Penc, O., Garcia, Y. Rodriguez, Roland, B., Scutti, F., Seiden, A., Sharma, A. S., Sickles, A. M., Simpson, E. L., Singh, S., Smirnov, S.Yu, Solovyanov, O. V., Stamen, R., Su, S., Sutton, M. R., Swiatlowski, M., Tskhadadze, E. G., Tuts, P. M., Vannicola, D., Vermeulen, J. C., Viehhauser, G. H. A., Vogel, F., Wang, S., Wendland, B., Winklmeier, F., Xella, S., Zakharchuk, N., Zeitnitz, C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2023; Springer; Springer Nature B.V; Springer Nature
• Subjects: Algorithms; Astronomy; Astrophysics and Cosmology; Collaboration; Detectors; Elementary Particles; Energy; Fysik; Hadrons; Heavy Ions; Ionic collisions; Jets; Large Hadron Collider; Mathematical analysis; Measurement Science and Instrumentation; Muons; Natural Sciences; Naturvetenskap; Nuclear Energy; Nuclear Physics; Physical Sciences; Physics; Physics and Astronomy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Quantum Field Theories; Quantum Field Theory; Quarks; Radiation; Regular Article - Experimental Physics; Sensors; String Theory; Subatomic Physics; Subatomär fysik; Transverse momentum
• ISSN: 1434-6044; 1434-6052; 1434-6052
• DOI: 10.1140/epjc/s10052-023-11427-9

This paper presents a measurement of b -jet production in Pb+Pb and pp collisions at s NN = 5.02  TeV with the ATLAS detector at the LHC. The measurement uses 260  pb - 1 of pp collisions collected in 2017 and 1.4  nb - 1 of Pb+Pb collisions collected in 2018. In both collision systems, jets are reconstructed via the anti- k t algorithm. The b -jets are identified from a sample of jets containing muons from the semileptonic decay of b -quarks using template fits of the muon momentum relative to the jet axis. In pp collisions, b -jets are reconstructed for radius parameters R = 0.2 and R = 0.4 , and only R = 0.2 jets are used in Pb+Pb collisions. For comparison, inclusive R = 0.2 jets are also measured using 1.7  nb - 1 of Pb+Pb collisions collected in 2018 and the same pp collision data as the b -jet measurement. The nuclear modification factor, R AA , is calculated for both b -jets and inclusive jets with R = 0.2 over the transverse momentum range of 80–290 GeV. The nuclear modification factor for b -jets decreases from peripheral to central collisions. The ratio of the b -jet R AA to inclusive jet R AA is also presented and suggests that the R AA for b -jets is larger than that for inclusive jets in central Pb+Pb collisions. The measurements are compared with theoretical calculations and suggest a role for mass and colour-charge effects in partonic energy loss in heavy-ion collisions.