2023 Articles

Search for single vector-like B quark production and decay via 𝐵 → 𝒃𝐻 (𝒃𝒃̄) in𝑝𝑝 collisions at √𝑠 = 13 TeV with the ATLAS detector

Aad, G.; Abbott, B.; Abbott, D. C.; Abed Abud, A.; Abeling, K.; Abhayasinghe, D. K.; Abidi, S. H.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Abusleme Hoffman, A. C.; Acharya, B. S.; Achkar, B.; Adam, L.; Adam Bourdarios, C.; Adamczyk, L.; Adamek, L.; Adelman, J.; Adiguzel, A.; Adorni, S.; Adye, T.; Affolder, A. A.; Afik, Y.; Agapopoulou, C.; Agaras, M. N.; Agarwala, J.; Aggarwal, A.; Agheorghiesei, C.; Aguilar-Saavedra, J. A.; Ahmad, A.; Ahmadov, F.; Ahmed, W. S.; Ai, X.; Aielli, G.; Akatsuka, S.; Akbiyik, M.; Åkesson, T. P. A.; Akimov, A. V.; Al Khoury, K.; Alberghi, G. L.

A search is presented for single production of a vector-like 𝐵 quark decaying into a Standard Model 𝒃-quark and a Standard Model Higgs boson, which decays into a 𝒃𝒃̄ pair. The search is carried out in 139 fb⁻¹ of √𝑠= 13 TeV proton-proton collision data collected by the ATLAS detector at the LHC between 2015 and 2018. No significant deviation from the Standard Model background prediction is observed, and mass-dependent exclusion limits at the 95% confidence level are set on the resonance production cross-section in several theoretical scenarios determined by the couplings 𝑐_𝑊, 𝑐_𝑍 and 𝑐_𝐻 between the 𝐵 quark and the Standard Model 𝑊, 𝑍 and Higgs bosons, respectively. For a vector-like B occurring as an isospin singlet, the search excludes values of 𝑐_𝑊 greater than 0.45 for a 𝐵 resonance mass (𝑚_𝐵) between 1.0 and 1.2 TeV. For 1.2 TeV < 𝑚_𝐵 < 2.0 TeV, 𝑐_𝑊 values larger than 0.50–0.65 are excluded. If the 𝐵 occurs as part of a (𝐵,𝑌) doublet, the smallest excluded 𝑐_𝑍 coupling values range between 0.3 and 0.5 across the investigated resonance mass range 1.0 TeV < 𝑚_𝐵 < 2.0 TeV.