Test of lepton flavor universality in semileptonic; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">; <mml:msubsup>; <mml:mi>B</mml:mi>; <mml:mi>c</mml:mi>; <mml:mo>+</mml:mo>; </mml:msubsup>; </mml:math>; meson decays in proton-proton collisions at; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">; <mml:msqrt>; <mml:mi>s</mml:mi>; </mml:msqrt>; <mml:mo>=</mml:mo>; <mml:mn>13</mml:mn>; <mml:mtext> </mml:mtext>; <mml:mtext> </mml:mtext>; <mml:mi>TeV</mml:mi>; </mml:math> | CU Experts

; A measurement of the ratio of branching fractions; ; R; (; ; J; /; ψ; ; ); =; B; (; ; B; c; +; ; →; ; J; /; ψ; ; ; τ; +; ; ; ν; τ; ; ); /; B; (; ; B; c; +; ; →; ; J; /; ψ; ; ; μ; +; ; ; ν; μ; ; ); ; in the; ; ; J; /; ψ; ; →; ; μ; +; ; ; μ; −; ; ; ,; ; ; ; ; τ; ; ; +; ; ; →; ; ; μ; ; ; +; ; ; ; ; ν; ; ; μ; ; ; ; ; ; ; ν; ; ; ¯; ; ; ; ; τ; ; ; ; ; decay channel is presented. This measurement uses a sample of proton-proton collision data collected at a center-of-mass energy of; ; ; 13; ; ; TeV; ; ; by the CMS experiment in 2018, corresponding to an integrated luminosity of; ; 59.7; ; ; ; fb; ; −; 1; ; ; ; . The measured ratio,; ; R; (; ; J; /; ψ; ; ); =; ; 0.1; ; 7; ; −; 0.17; ; ; +; 0.18; ; ; ; ; ; (; stat; ); ; ; ; −; 0.22; ; ; +; 0.21; ; ; ; ; ; (; syst; ); ; ; ; −; 0.18; ; ; +; 0.19; ; ; ; ; (; theo; ); ; ; =; 0.17; ±; 0.33; ; , agrees with the value of; ; 0.2582; ±; 0.0038; ; predicted by the standard model, which assumes lepton flavor universality. By testing lepton flavor universality, this measurement is a probe of new physics using; ; ; B; c; +; ; ; mesons, which are currently only produced at the LHC.;

Hayrapetyan A; Tumasyan A; Adam W; Andrejkovic JW; Bergauer T; Chatterjee S; Damanakis K; Dragicevic M; Hussain PS; Jeitler M

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