학술논문
Measurement of the jet mass in high transverse momentum Z ( → b b ‾ ) γ production at s = 13 TeV using the ATLAS detector
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article
Author
Aad, G; Abbott, B; Abbott, DC; Abdinov, O; Abud, A Abed; Abeling, K; Abhayasinghe, DK; Abidi, SH; AbouZeid, OS; Abraham, NL; Abramowicz, H; Abreu, H; Abulaiti, Y; Acharya, BS; Achkar, B; Adachi, S; Adam, L; Bourdarios, C Adam; Adamczyk, L; Adamek, L; Adelman, J; Adersberger, M; Adiguzel, A; Adorni, S; Adye, T; Affolder, AA; Afik, Y; Agapopoulou, C; Agaras, MN; Aggarwal, A; Agheorghiesei, C; Aguilar-Saavedra, JA; Ahmadov, F; Ahmed, WS; Ai, X; Aielli, G; Akatsuka, S; Åkesson, TPA; Akilli, E; Akimov, AV; Al Khoury, K; Alberghi, GL; Albert, J; Verzini, MJ Alconada; Alderweireldt, S; Aleksa, M; Aleksandrov, IN; Alexa, C; Alexandre, D; Alexopoulos, T; Alfonsi, A; Alhroob, M; Ali, B; Alimonti, G; Alison, J; Alkire, SP; Allaire, C; Allbrooke, BMM; Allen, BW; Allport, PP; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Alshehri, AA; Estevez, M Alvarez; Piqueras, D Álvarez; Alviggi, MG; Coutinho, Y Amaral; Ambler, A; Ambroz, L; Amelung, C; Amidei, D; Dos Santos, SP Amor; Amoroso, S; Amrouche, CS; An, F; Anastopoulos, C; Andari, N; Andeen, T; Anders, CF; Anders, JK; Andreazza, A; Andrei, V; Anelli, CR; Angelidakis, S; Angerami, A; Anisenkov, AV; Annovi, A; Antel, C; Anthony, MT; Antonelli, M; Antrim, DJA; Anulli, F; Aoki, M; Pozo, JA Aparisi; Bella, L Aperio; Arabidze, G; Araque, JP; Ferraz, V Araujo
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Abstract
The integrated fiducial cross-section and unfolded differential jet mass spectrum of high transverse momentum Z→bb‾ decays are measured in Zγ events in proton–proton collisions at s=13TeV. The data analysed were collected between 2015 and 2016 with the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 36.1fb−1. Photons are required to have a transverse momentum pT>175GeV. The Z→bb‾ decay is reconstructed using a jet with pT>200GeV, found with the anti-kt R=1.0 jet algorithm, and groomed to remove soft and wide-angle radiation and to mitigate contributions from the underlying event and additional proton–proton collisions. Two different but related measurements are performed using two jet grooming definitions for reconstructing the Z→bb‾ decay: trimming and soft drop. These algorithms differ in their experimental and phenomenological implications regarding jet mass reconstruction and theoretical precision. To identify Z bosons, b-tagged R=0.2 track-jets matched to the groomed large-R calorimeter jet are used as a proxy for the b-quarks. The signal yield is determined from fits of the data-driven background templates to the different jet mass distributions for the two grooming methods. Integrated fiducial cross-sections and unfolded jet mass spectra for each grooming method are compared with leading-order theoretical predictions. The results are found to be in good agreement with Standard Model expectations within the current statistical and systematic uncertainties.