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.

Measurement of CKM matrix elements in single top quark t-channel production in proton-proton collisions at s=13 TeV

Amapane N.;Argiro S.;Bellan R.;Bellora A.;Cappati A.;Costa M.;Covarelli R.;Kiani B.;Migliore E.;Monaco V.;Monteil E.;Obertino M. M.;Pacher L.;Pinna Angioni G. L.;Romero A.;Salvatico R.;Sola V.;Solano A.;Soldi D.;Shchelina K.;Rumerio P.;Ravera F.;
2020-01-01

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.
2020
808
135609
135640
CKM matrix; CMS; Physics; Top quark
Sirunyan A.M.; Tumasyan A.; Adam W.; Ambrogi F.; Bergauer T.; Dragicevic M.; Ero J.; Escalante Del Valle A.; Flechl M.; Fruhwirth R.; Jeitler M.; Kram...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1779938
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