Measurement of the jet mass in high transverse momentum Z(→ <i>b</i>(<i>b</i>)over-bar)γ production at √<i>s</i>=13 TeV using the ATLAS detector

Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H
et al (show 2918 more authors) (2021) Measurement of the jet mass in high transverse momentum Z(→ <i>b</i>(<i>b</i>)over-bar)γ production at √<i>s</i>=13 TeV using the ATLAS detector. PHYSICS LETTERS B, 812. 135991-.

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The integrated fiducial cross-section and unfolded differential jet mass spectrum of high transverse momentum $Z\rightarrow b\overline{b}$ decays are measured in $Z\gamma$ events in proton-proton collisions at $\sqrt{s} = 13$ TeV. 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 36.1 fb$^{-1}$. Photons are required to have a transverse momentum $p_{\mathrm{T}}>175$ GeV. The $Z\rightarrow b\overline{b}$ decay is reconstructed using a jet with $p_{\mathrm{T}} > 200$ GeV, found with the anti-$k_{t}$ $R = 1.0$ 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 $Z\rightarrow b\overline{b}$ 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 background templates extracted from the data 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.

Item Type: Article
Additional Information: 37 pages in total, author list starting page 21, 3 figures, 5 tables, submitted to Phys. Lett. B. All figures including auxiliary figures are available at
Uncontrolled Keywords: hep-ex, hep-ex
Depositing User: Symplectic Admin
Date Deposited: 24 Feb 2021 17:10
Last Modified: 05 Oct 2023 11:34
DOI: 10.1016/j.physletb.2020.135991
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