Evidence for the decay $X(3872)\rightarrow\psi(2S)\gamma$ - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Journal Articles Nuclear Physics B Year : 2014

Evidence for the decay $X(3872)\rightarrow\psi(2S)\gamma$

R. Aaij
  • Function : Author
J. He
J. Cogan
O. Leroy
J. Serrano


Evidence for the decay mode $X(3872)\rightarrow\psi(2S)\gamma$ in $B^+\rightarrow X(3872)K^+$ decays is found with a significance of 4.4 standard deviations. The analysis is based on a data sample of proton-proton collisions, corresponding to an integrated luminosity of 3fb$^{-1}$ collected with the LHCb detector, at centre-of-mass energies of 7 and 8TeV. The ratio of the branching fraction of the $X(3872)\to\psi(2S)\gamma$ decay to that of the $X(3872)\rightarrow J/\psi \gamma$ decay is measured to be $$ \frac{Br(X(3872)\rightarrow\psi(2S)\gamma)}{Br(X(3872)\rightarrow J/\psi\gamma)} = 2.46\pm0.64\pm0.29, %\pm0.06,$$ where the first uncertainty is statistical and the second is systematic. The measured value agrees with expectations for a pure charmonium interpretation of the $X(3872)$ state and a mixture of charmonium and molecular interpretations. However, it does not support a pure $D\bar{D}^{*}$ molecular interpretation of the $X(3872)$state.

Dates and versions

in2p3-00969243 , version 1 (02-04-2014)



R. Aaij, Y. Amhis, S. Barsuk, O. Callot, J. He, et al.. Evidence for the decay $X(3872)\rightarrow\psi(2S)\gamma$. Nuclear Physics B, 2014, 886, pp.665-680. ⟨10.1016/j.nuclphysb.2014.06.011⟩. ⟨in2p3-00969243⟩
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