Search for B0 -> J/psi D0bar and B+ -> J/psi D0bar pi+ decays

TL;DR

This paper searches for specific B meson decay modes involving J/psi and D0bar particles, setting upper limits on their branching fractions, which constrains models of intrinsic charm in B mesons.

Contribution

The study provides the first upper limits on these decay modes, challenging previous explanations of J/psi spectrum excess as intrinsic charm.

Findings

No significant signals observed for the decay modes.

Upper limits set on branching fractions: < 2.0×10^{-5} and < 2.5×10^{-5}.

Results exclude intrinsic charm as the source of J/psi spectrum excess.

Abstract

We report the results of a search for the decay modes B0 -> J/psi D0bar and B+ -> J/psi D0bar pi+. The analysis is based on 140 $\rm fb^{-1}$ of data accumulated by the Belle detector at the KEKB asymmetric-energy $e^{+} e^{-}$ collider. No significant signals are observed and we determine the branching fraction upper limits B(B0 -> J/psi D0bar) < 2.0 10^{-5} and B(B+ -> J/psi D0bar pi+) < 2.5 10^{-5} at 90% confidence level. These results rule out the explanation of the excess in the low momentum region of the inclusive J/psi spectrum as intrinsic charm content in the B meson. The branching fractions of the corresponding non-resonant decay channels are also reported.