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Measurement of the ratio of the B$_c^+$ → J / ψ τ$^+$ ν$_τ$ and B$_c^+$ → J / ψ μ$^+$ ν$_μ$ branching fractions using three-prong τ lepton decays

CMS Collaboration; Chekhovsky, V.; Hayrapetyan, A.; Makarenko, V.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Benato, L.; Bergauer, T.; Damanakis, K.; Dragicevic, M.; Giordano, C.; Hussain, P. S.; Jeitler, M.; Krammer, N.; Li, A.; Liko, D.; Mikulec, I.; Schieck, J.; ... mehr

Abstract:

The ratio between the 𝐵$^+_𝑐$→𝐽/𝜓⁢𝜏$^+$⁢𝜈$_𝜏$ and 𝐵$^+_𝑐$→𝐽/𝜓⁢𝜇$^+$⁢𝜈$_𝜇$ branching fractions is measured using a data sample of proton-proton collisions collected by CMS at a center-of-mass energy of 13  TeV in the years 2016–2018 and corresponding to an integrated luminosity of 138  fb$^{−1}$. The 𝐽/𝜓 meson is identified through its 𝐽/𝜓 →𝜇$^+$⁢𝜇$^−$ decay and the tau lepton is reconstructed in the hadronic three-prong final state. The measured ratio of branching fractions in this tau decay mode, ℛ$^{had}_{𝐽/𝜓}$ =1.0⁢4$^{+0.50}_{−0.44}$, is combined with the previous analysis based on the 𝜏$^+$→𝜇$^+$⁢𝜈$_𝜇$⁢$\overline{𝜈}$$_𝜏$ leptonic decay channel, leading to ℛ$_{𝐽/𝜓}$ =0.49±0.26. As this result is consistent with the standard model prediction of 0.258 ±0.004, no evidence of lepton flavor universality violation is found.


Verlagsausgabe §
DOI: 10.5445/IR/1000195281
Veröffentlicht am 16.07.2026
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Astroteilchenphysik (IAP)
Institut für Experimentelle Teilchenphysik (ETP)
Institut für Prozessdatenverarbeitung und Elektronik (IPE)
Scientific Computing Center (SCC)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 06.2026
Sprache Englisch
Identifikator ISSN: 2470-0010, 2470-0029
KITopen-ID: 1000195281
Erschienen in Physical Review D
Verlag American Physical Society (APS)
Band 113
Heft 11
Seiten L111101
Vorab online veröffentlicht am 04.06.2026
Nachgewiesen in OpenAlex
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