{"id":36550,"date":"2026-06-08T13:16:40","date_gmt":"2026-06-08T13:16:40","guid":{"rendered":"https:\/\/lamarr-institute.org\/publication\/branching-fraction-measurement-of-the-lambda-to-pmu-overlinenu_mu-decay\/"},"modified":"2026-06-08T13:16:40","modified_gmt":"2026-06-08T13:16:40","slug":"branching-fraction-measurement-of-the-lambda-to-pmu-overlinenu_mu-decay","status":"publish","type":"publication","link":"https:\/\/lamarr-institute.org\/de\/publication\/branching-fraction-measurement-of-the-lambda-to-pmu-overlinenu_mu-decay\/","title":{"rendered":"Branching fraction measurement of the $\\Lambda \\to p{\\mu}^{-}{\\overline{\\nu}}_{\\mu }$ decay"},"content":{"rendered":"<p>A measurement of the branching fraction for the decay $\\mathit{\\Lambda} \\to p \\mu^- \\overline{\\nu}_{\\mu}$ is presented using $pp$ collision data collected by the LHCb experiment at a centre-of-mass energy of 13 TeV. The analysis is based on data recorded between 2016 and 2018, corresponding to an integrated luminosity of 5.4 $fb^{-1}$. The result is obtained using $\\mathit{\\Lambda} \\to p \\pi^-$ decays as a normalisation channel. The measured branching fraction is $B(\\mathit{\\Lambda} \\to p \\mu^- \\overline{\\nu}_{\\mu})= (1.462 \\pm 0.016 \\pm 0.100 \\pm 0.011 ) \\times 10^{-4}$, where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalisation mode branching fraction, respectively. This result improves the precision of the branching fraction measurement by a factor of two compared to the previous best measurement and sets a more stringent bound on lepton flavour universality in $s \\to u$ quark transitions. It is consistent with previous measurements, and the extracted lepton flavour universality test observable, $R^{\\mu e} = \\frac{\\Gamma(\\mathit{\\Lambda} \\to p \\mu^- \\overline{\\nu}_\\mu)}{\\Gamma(\\mathit{\\Lambda} \\to p e^- \\overline{\\nu}_e)} = 0.175 \\pm 0.012$, agrees with the Standard Model prediction.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A measurement of the branching fraction for the decay $\\mathit{\\Lambda} \\to p \\mu^- \\overline{\\nu}_{\\mu}$ is presented using $pp$ collision data collected by the LHCb experiment at a centre-of-mass energy of 13 TeV. The analysis is based on data recorded between 2016 and 2018, corresponding to an integrated luminosity of 5.4 $fb^{-1}$. The result is obtained using $\\mathit{\\Lambda} \\to p \\pi^-$ decays as a normalisation channel. The measured branching fraction is [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"publication-type":[30],"class_list":["post-36550","publication","type-publication","status-publish","hentry","publication-type-article"],"acf":[],"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication\/36550","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication"}],"about":[{"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/types\/publication"}],"author":[{"embeddable":true,"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/users\/12"}],"version-history":[{"count":0,"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication\/36550\/revisions"}],"wp:attachment":[{"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/media?parent=36550"}],"wp:term":[{"taxonomy":"publication-type","embeddable":true,"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication-type?post=36550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}