학술논문
Measurement of CKM matrix elements in single top quark t-channel production in proton-proton collisions at s = 13 TeV
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article
Author
Sirunyan, AM; Tumasyan, A; Adam, W; Ambrogi, F; Bergauer, T; Dragicevic, M; Erö, J; Del Valle, A Escalante; Flechl, M; Frühwirth, R; Jeitler, M; Krammer, N; Krätschmer, I; Liko, D; Madlener, T; Mikulec, I; Rad, N; Schieck, J; Schöfbeck, R; Spanring, M; Waltenberger, W; Wulz, C-E; Zarucki, M; Drugakov, V; Mossolov, V; Gonzalez, J Suarez; Darwish, MR; De Wolf, EA; Di Croce, D; Janssen, X; Kello, T; Lelek, A; Pieters, M; Sfar, H Rejeb; Van Haevermaet, H; Van Mechelen, P; Van Putte, S; Van Remortel, N; Blekman, F; Bols, ES; Chhibra, SS; D'Hondt, J; De Clercq, J; Lontkovskyi, D; Lowette, S; Marchesini, I; Moortgat, S; Python, Q; Tavernier, S; Van Doninck, W; Van Mulders, P; Beghin, D; Bilin, B; Clerbaux, B; De Lentdecker, G; Delannoy, H; Dorney, B; Favart, L; Grebenyuk, A; Kalsi, AK; Moureaux, L; Popov, A; Postiau, N; Starling, E; Thomas, L; Velde, C Vander; Vanlaer, P; Vannerom, D; Cornelis, T; Dobur, D; Khvastunov, I; Niedziela, M; Roskas, C; Skovpen, K; Tytgat, M; Verbeke, W; Vermassen, B; Vit, M; Bruno, G; Caputo, C; David, P; Delaere, C; Delcourt, M; Giammanco, A; Lemaitre, V; Prisciandaro, J; Saggio, A; Vischia, P; Zobec, J; Alves, GA; Silva, G Correia; Hensel, C; Moraes, A; Chagas, E Belchior Batista Das; Carvalho, W; Chinellato, J; Coelho, E; Da Costa, EM; Da Silveira, GG; De Jesus Damiao, D
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Abstract
The first direct, model-independent measurement is presented of the modulus of the Cabibbo–Kobayashi–Maskawa (CKM) matrix elements |η|Vtb, |η|Vtd, and |η|Vts, in final states enriched in single top quark t-channel events. The analysis uses proton-proton collision data from the LHC, collected during 2016 by the CMS experiment, at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. Processes directly sensitive to these matrix elements are considered at both the production and decay vertices of the top quark. In the standard model hypothesis of CKM unitarity, a lower limit of |η|Vtb>0.970 is measured at the 95% confidence level. Several theories beyond the standard model are considered, and by releasing all constraints among the involved parameters, the values |η|Vtb=0.988±0.024, and |η|Vtd2+|η|Vts2=0.06±0.06, where the uncertainties include both statistical and systematic components, are measured.