# Lepton Flavor Universality Tests Using B_c+ Decays at LHCb

- Institution: CERN
- Speaker: Emily Jiang
- Year: 2026
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3025690)
- Licence: [CERN](https://copyright.web.cern)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

Lepton flavor universality ratios have been the source of much interest in the search for beyond the Standard Model physics, with longstanding anomalies in the R(D(*)) measurements at 3.8 standard deviations above the Standard Model value. A measurement of the ratio of semileptonic branching fractions R(J/psi), defined as R}(J/psi) = B(B_c^+ \to J/psi tau^+ nu_{tau})/B(B_c^+ \to J/\psi mu^+ nu_{mu}), is reported using a sample of proton-proton collision data corresponding to an integrated luminosity of 5.4fb^{-1} (Run-2) recorded by the LHCb experiment in 2016--2018 at a center-of-mass energy of 13 TeV.

Coffee will be served at 10h30

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## Lectures

1. [Lepton Flavor Universality Tests Using B_c+ Decays at LHCb](https://invisiblenetwork.ai/learn/cern/3025690/c88f6928f5a0), 52 min (CERN's player)