A search for top-squark pair production, in final states containing a top quark, a charm quark and missing transverse momentum, using the 139 fb−1 of pp collision data collected by the ATLAS detector.

Autor: Aad, G., Abbott, B., Abeling, K., Abicht, N. J., Abidi, S. H., Aboulhorma, A., Abramowicz, H., Abreu, H., Abulaiti, Y., Acharya, B. S., Adam Bourdarios, C., Adamczyk, L., Addepalli, S. V., Addison, M. J., Adelman, J., Adiguzel, A., Adye, T., Affolder, A. A., Afik, Y., Agaras, M. N.
Zdroj: Journal of High Energy Physics; Jul2024, Vol. 2024 Issue 7, p1-49, 49p
Abstrakt: This paper presents a search for top-squark pair production in final states with a top quark, a charm quark and missing transverse momentum. The data were collected with the ATLAS detector during LHC Run 2 and correspond to an integrated luminosity of 139 fb−1 of proton-proton collisions at a centre-of-mass energy of s = 13 TeV. The analysis is motivated by an extended Minimal Supersymmetric Standard Model featuring a non-minimal flavour violation in the second- and third-generation squark sector. The top squark in this model has two possible decay modes, either t ~ 1 → c χ ~ 1 0 or t ~ 1 → t χ ~ 1 0 , where the χ ~ 1 0 is undetected. The analysis is optimised assuming that both of the decay modes are equally probable, leading to the most likely final state of tc + E T miss . Good agreement is found between the Standard Model expectation and the data in the search regions. Exclusion limits at 95% CL are obtained in the m t ~ 1 vs. m χ ~ 1 0 plane and, in addition, limits on the branching ratio of the t ~ 1 → t χ ~ 1 0 decay as a function of m( t ~ 1 ) are also produced. Top-squark masses of up to 800 GeV are excluded for scenarios with light neutralinos, and top-squark masses up to 600 GeV are excluded in scenarios where the neutralino and the top squark are almost mass degenerate. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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