{"id":39039,"date":"2026-08-21T15:28:53","date_gmt":"2026-08-21T15:28:53","guid":{"rendered":"https:\/\/lamarr-institute.org\/publication\/observation-of-the-decay-chi_c13872rightarrow-jmskip-3mu-mskip-2mupsi-mumu\/"},"modified":"2026-09-17T11:19:19","modified_gmt":"2026-09-17T11:19:19","slug":"observation-of-the-decay-chi_c13872rightarrow-jmskip-3mu-mskip-2mupsi-mumu","status":"publish","type":"publication","link":"https:\/\/lamarr-institute.org\/de\/publication\/observation-of-the-decay-chi_c13872rightarrow-jmskip-3mu-mskip-2mupsi-mumu\/","title":{"rendered":"Observation of the decay $\\chi_{c1}$(3872)$\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\mu^+\\mu^-$"},"content":{"rendered":"<p>The first observation of the $\\chi_{c1}$(3872)$\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\mu^+\\mu^-$ decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of 9 $fb^{-1}$. The decay mode is observed for the first time, with a significance of 6.5\\sigma. Its branching fraction is measured relative to the $\\chi_{c1}$(3872)$\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\pi^+\\pi^-$ decay mode<\/p>\n<p>$\\frac{\\cal{BF}(\\chi_{c1}(3872)\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\mu^+\\mu^-)}{\\cal{BF}(\\chi_{c1}(3872)\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\pi^+\\pi^-)} = \\left(1.68\\pm 0.32\\pm 0.05\\right)\\times10^{-3}$,<\/p>\n<p>where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The first observation of the $\\chi_{c1}$(3872)$\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\mu^+\\mu^-$ decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of 9 $fb^{-1}$. The decay mode is observed for the first time, with a significance of 6.5\\sigma. Its branching fraction is measured relative to the $\\chi_{c1}$(3872)$\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\pi^+\\pi^-$ decay mode $\\frac{\\cal{BF}(\\chi_{c1}(3872)\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\mu^+\\mu^-)}{\\cal{BF}(\\chi_{c1}(3872)\\rightarrow J\\mskip -3mu\/\\mskip -2mu\\psi \\pi^+\\pi^-)} = \\left(1.68\\pm [&hellip;]<\/p>\n","protected":false},"author":14,"featured_media":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"publication-type":[30],"class_list":["post-39039","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\/39039","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\/14"}],"version-history":[{"count":0,"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication\/39039\/revisions"}],"wp:attachment":[{"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/media?parent=39039"}],"wp:term":[{"taxonomy":"publication-type","embeddable":true,"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication-type?post=39039"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}