Using pile-up collisions as an abundant source of low-energy hadronic physics processes in ATLAS and an extraction of the jet energy resolution

• Published in: The journal of high energy physics 2024-12, Vol.2024 (12), p.32
• Main Authors: Abramowicz, H., Affolder, A. A., Aikot, A., Amaral Coutinho, Y., Astrand, K. S. V., Bagnaia, P., Bai, K., Balz, J., Bandyopadhyay, A., Barton, A. E., Bellos, P., Biros, M., Boonekamp, M., Brandt, G., Brost, E., Camacho Toro, R., Carnesale, M., Carratta, G., Chen, X., Clarke Hall, N., Corpe, L. D., Damp, J., D’Auria, S., Deliot, F., Di Donato, C., Dumitriu, A. E., Ellinghaus, F., Farbin, A., Fernandez Luengo, S. I., Fernandez Martinez, P., Ferrari, P., Formica, A., Franklin, M., Garcia Alonso, A., Gilbert, B. J., Giugliarelli, G., Gnesi, I., Gonzalez-Sevilla, S., Gotz, S. A., Han, S., Hasegawa, Y., Heinlein, J. G., Hervas, L., Holm, T., Jeanty, L., Jia, J., Jinaru, A., Jones, K. S., Joshi, R., Karpova, Z. M., Ke, Y., Khan, R. A., Klein, S. B., Kluit, P., Koperny, S., Le Boulicaut, E. M., Lee, S., Liu, X., Lory, A. M., Maleev, V. P., Marjanovic, M., Meloni, F., Montella, M., Morinaga, M., Nikolaenko, V., Padilla Aranda, C., Pastore, F., Patel, U. M., Perrella, S., Pinfold, J. L., Pokharel, I., Richter, R., Ridouani, S., Robson, A., Roloff, J., Ruiz-Martinez, A., Sala, A., Sha, Q., Shipsey, I. P. J., Sicho, P., Siral, I., Soloshenko, A., Stevenson, T. J., Sumida, T., Tao, Z., Varouchas, D., Vergis, C., Viehhauser, G. H. A., Wagner, W., Wamorkar, T., Wang, T., Wilkens, H. G., Woźniak, K. W., Yao, W-M., Yildirim, T. P., Young, C., Zabinski, B., Zak, Z. K., Zenger, D. T., Zerradi, S.
• Format: Article
• Language: English
• Subjects: Algorithms; Classical and Quantum Gravitation; Collisions; Data analysis; Datasets; Elementary Particles; Energy resolution; Large Hadron Collider; Luminosity; Physics; Physics and Astronomy; Pile extraction; Protons; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Experimental Physics; Relativity Theory; String Theory
• ISSN: 1029-8479
• DOI: 10.1007/JHEP12(2024)032

A bstract During the 2015–2018 data-taking period, the Large Hadron Collider delivered proton-proton bunch crossings at a centre-of-mass energy of 13 TeV to the ATLAS experiment at a rate of roughly 30 MHz, where each bunch crossing contained an average of 34 independent inelastic proton-proton collisions. The ATLAS trigger system selected roughly 1 kHz of these bunch crossings to be recorded to disk. Offline algorithms then identify one of the recorded collisions as the collision of interest for subsequent data analysis, and the remaining collisions are referred to as pile-up. Pile-up collisions represent a trigger-unbiased dataset, which is evaluated to have an integrated luminosity of 1.33 pb − 1 in 2015–2018. This is small compared with the normal trigger-based ATLAS dataset, but when combined with vertex-by-vertex jet reconstruction it provides up to 50 times more dijet events than the conventional single-jet-trigger-based approach, and does so without adding any additional cost or requirements on the trigger system, readout, or storage. The pile-up dataset is validated through comparisons with a special trigger-unbiased dataset recorded by ATLAS, and its utility is demonstrated by means of a measurement of the jet energy resolution in dijet events, where the statistical uncertainty is significantly reduced for jet transverse momenta below 65 GeV.