Search for B+ c → π+μ+μ− decays and measurement of the branching fraction ratio B(B+ c → ψ(2S)π+)/B(B+ c → J/ψπ+)
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10052_2024_Article_12669.pdf
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Author(s) • • • • • • • • •
Aaij, R.
Abdelmotteleb, A.S.W.
Beteta, C. Abellan
Abudinén, F.
Ackernley, T.
Adeva, B.
Adinolfi, M.
Adlarson, P.
Agapopoulou, C.
Aidala, C. A.
Date Issued
May 7, 2024
Journal
The European Physical Journal C
Publisher
Springer Science and Business Media LLC
Citation
The European Physical Journal C. 2024 May 07;84(5):468
Version
Final published version
Abstract
The first search for nonresonant $${{B} _{c} ^+} \!\rightarrow {{\pi } ^+} {\mu ^+\mu ^-} $$
B c + → π + μ + μ - decays is reported. The analysis uses proton–proton collision data collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9$$\,\text {fb} ^{-1}$$ fb - 1 . No evidence for an excess of signal events over background is observed and an upper limit is set on the branching fraction ratio $${\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {{\pi } ^+} {\mu ^+\mu ^-} )/{\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} {{\pi } ^+} ) < 2.1\times 10^{-4}$$ B ( B c + → π + μ + μ - ) / B ( B c + → J / ψ π + ) < 2.1 × 10 - 4 at $$90\%$$ 90 % confidence level. Additionally, an updated measurement of the ratio of the $${{B} _{c} ^+} \!\rightarrow {\psi {(2S)}} {{\pi } ^+} $$ B c + → ψ ( 2 S ) π + and $${{B} _{c} ^+} \!\rightarrow {{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} {{\pi } ^+} $$ B c + → J / ψ π + branching fractions is reported. The ratio $${\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {\psi {(2S)}} {{\pi } ^+} )/{\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} {{\pi } ^+} )$$ B ( B c + → ψ ( 2 S ) π + ) / B ( B c + → J / ψ π + ) is measured to be $$0.254\pm 0.018 \pm 0.003 \pm 0.005$$ 0.254 ± 0.018 ± 0.003 ± 0.005 , where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the leptonic $${J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }$$ J / ψ and $$\psi {(2S)}$$ ψ ( 2 S ) decays. This measurement is the most precise to date and is consistent with previous LHCb results.
B c + → π + μ + μ - decays is reported. The analysis uses proton–proton collision data collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9$$\,\text {fb} ^{-1}$$ fb - 1 . No evidence for an excess of signal events over background is observed and an upper limit is set on the branching fraction ratio $${\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {{\pi } ^+} {\mu ^+\mu ^-} )/{\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} {{\pi } ^+} ) < 2.1\times 10^{-4}$$ B ( B c + → π + μ + μ - ) / B ( B c + → J / ψ π + ) < 2.1 × 10 - 4 at $$90\%$$ 90 % confidence level. Additionally, an updated measurement of the ratio of the $${{B} _{c} ^+} \!\rightarrow {\psi {(2S)}} {{\pi } ^+} $$ B c + → ψ ( 2 S ) π + and $${{B} _{c} ^+} \!\rightarrow {{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} {{\pi } ^+} $$ B c + → J / ψ π + branching fractions is reported. The ratio $${\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {\psi {(2S)}} {{\pi } ^+} )/{\mathcal {B}} ({{B} _{c} ^+} \!\rightarrow {{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} {{\pi } ^+} )$$ B ( B c + → ψ ( 2 S ) π + ) / B ( B c + → J / ψ π + ) is measured to be $$0.254\pm 0.018 \pm 0.003 \pm 0.005$$ 0.254 ± 0.018 ± 0.003 ± 0.005 , where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the leptonic $${J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }$$ J / ψ and $$\psi {(2S)}$$ ψ ( 2 S ) decays. This measurement is the most precise to date and is consistent with previous LHCb results.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
10.1140/epjc/s10052-024-12669-x