Charm rescattering contribution in rare Bc+→K+K−π+ decay

Following the experimental results from LHCb on the rare decay Bc+→K−K+π+, we investigate the possibility where this process is dominated by a double charm rescattering. The Bc decay to double charm channels have a weak topology that is favored in comparison with the direct production of K−K+π+ in the final state, suppressed by quark annihilation. The decay amplitude for Bc+→K−K+π+ with Bc decaying first to double charm channels is described by charm hadronic triangle loops, which reach the final state of interest after DD¯→KK¯ or D+Ds−→π+K− transitions. We show that these processes give rise to non-resonant amplitudes with a clear signature in the Dalitz plot. In a near future, the new data from LHCb run II will be able to confirme if the main hypotheses of this work is correct and the dominant mechanism to produce K+K+π− from the decay of Bc+ is through charm rescattering.