Search for excited Bc(+) states

Journal article

A search is performed in the invariant mass spectrum of the $B_c^{+}\pi^{+}\pi^{-}$ system for the excited $B_c^{+}$ states $B_c(2^{1}S_{0})^+$ and $B_c(2^{3}S_{1})^+$ using a data sample of $pp$ collisions collected by the LHCb experiment at the centre-of-mass energy of $\sqrt{s} = 8 \,{\mathrm{TeV}}$, corresponding to an integrated luminosity of $2 \,{\mathrm{fb^{-1}}}$. No evidence is seen for either state. Upper limits on the ratios of the production cross-sections of the $B_c(2^{1}S_{0})^+$ and $B_c(2^{3}S_{1})^+$ states times the branching fractions of ${B_c(2^{1}S_{0})^+} \to {B_c^{+}\pi^{+}\pi^{-}}$ and ${B_c(2^{3}S_{1})^+} \to {B_c^{*+}\pi^{+}\pi^{-}}$ over the production cross-section of the $B_c^{+}$ state are given as a function of their masses. They are found to be between 0.02 and 0.14 at $95\%$ confidence level for $B_c(2^{1}S_{0})^+$ and $B_c(2^{3}S_{1})^+$ in the mass ranges $[6830, 6890] \,{\mathrm{MeV}}/c^{2}$ and $[6795,6890] \,{\mathrm{MeV}}/c^{2}$, respectively.

Authors: LHCb Collaboration; Aaij, R; Adeva, B; Bjørn, M; Cheung, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer Verlag
• Journal: Journal of High Energy Physics
• Volume: 2018
• Issue: 1
• Article number: 138
• Publication date: 2018-01-29
• Acceptance date: 2018-01-18
• DOI: 10.1007/JHEP01(2018)138
• EISSN: 1029-8479
• ISSN: 1029-8479
• Keywords: Hadron-Hadron scattering (experiments); Spectroscopy; B physics