The CP asymmetry and branching fraction of the CKM-suppressed decay $B^+ \\to J\/\\psi \\pi^+$ are precisely measured relative to the favoured decay $B^+ \\to J\/\\psi K^+$, using a sample of proton-proton collision data corresponding to an integrated luminosity of $5.4~\\text{fb}^{-1}$ recorded at a center-of-mass energy of $13~\\text{TeV}$ during 2016–2018.<\/p>\n
The results of the CP asymmetry difference and branching fraction ratio are<\/p>\n
$\\Delta A_{CP} \\equiv A_{CP}(B^+ \\to J\/\\psi \\pi^+) – A_{CP}(B^+ \\to J\/\\psi K^+) = (1.29 \\pm 0.49 \\pm 0.08) \\times 10^{-2},$<\/p>\n
$R_{\\pi\/K} \\equiv \\frac{\\mathcal{B}(B^+ \\to J\/\\psi \\pi^+)}{\\mathcal{B}(B^+ \\to J\/\\psi K^+)} = (3.852 \\pm 0.022 \\pm 0.018) \\times 10^{-2},$<\/p>\n
where the first uncertainties are statistical and the second systematic.<\/p>\n
A combination with previous LHCb results based on data collected at $7~\\text{TeV}$ and $8~\\text{TeV}$ in 2011 and 2012 yields<\/p>\n
$\\Delta A_{CP} = (1.42 \\pm 0.43 \\pm 0.08) \\times 10^{-2} \\quad \\text{and} \\quad R_{\\pi\/K} = (3.846 \\pm 0.018 \\pm 0.018) \\times 10^{-2}.$<\/p>\n
The combined $\\Delta A_{CP}$ value deviates from zero by $3.2$ standard deviations, providing the first evidence for direct CP violation in the amplitudes of beauty decays to charmonium final states.<\/p>\n","protected":false},"excerpt":{"rendered":"
The CP asymmetry and branching fraction of the CKM-suppressed decay $B^+ \\to J\/\\psi \\pi^+$ are precisely measured relative to the favoured decay $B^+ \\to J\/\\psi K^+$, using a sample of proton-proton collision data corresponding to an integrated luminosity of $5.4~\\text{fb}^{-1}$ recorded at a center-of-mass energy of $13~\\text{TeV}$ during 2016–2018. The results of the CP asymmetry difference and branching fraction ratio are $\\Delta A_{CP} \\equiv A_{CP}(B^+ \\to J\/\\psi \\pi^+) – A_{CP}(B^+ […]<\/p>\n","protected":false},"author":12,"featured_media":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"publication-type":[30],"class_list":["post-32496","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\/32496","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\/32496\/revisions"}],"wp:attachment":[{"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/media?parent=32496"}],"wp:term":[{"taxonomy":"publication-type","embeddable":true,"href":"https:\/\/lamarr-institute.org\/de\/wp-json\/wp\/v2\/publication-type?post=32496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}