Amplitude analysis and branching fraction measurement of B⁺→ D⁻Dₛ⁺π⁺ decays

A bstract The decays of the B + meson to the final state D⁻Dₛ⁺π⁺ D ∗ − D s + π + are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb − 1 . The ratio of branching fractions of the B⁺→ D⁻Dₛ⁺π⁺ B + → D ∗ − D s + π + and B⁰→ D⁻Dₛ⁺ B 0 → D ∗ − D s + decays is measured to be 0 . 173 ± 0 . 006 ± 0 . 010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed Dₛ⁺→ Dₛ⁺γ D s ∗ + → D s + γ and Dₛ⁺π⁰ D s + π 0 decays, the ratio of branching fractions between the B⁺→ D⁻Dₛ⁺π⁺ B + → D ∗ − D s ∗ + π + and B⁺→ D⁻Dₛ⁺π⁺ B + → D ∗ − D s + π + decays is determined as 1 . 31 ± 0 . 07 ± 0 . 14. An amplitude analysis of the B⁺→ D⁻Dₛ⁺π⁺ B + → D ∗ − D s + π + decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D * − π + final state. No significant evidence of exotic contributions in the Dₛ⁺π⁺ D s + π + or D⁻Dₛ⁺ D ∗ − D s + channels is found. The fit fraction of the scalar state Tcs̄0(2900)⁺⁺ T c s ¯ 0 ∗ 2900 + + observed in the B⁺→ D⁻Dₛ⁺π⁺ B + → D − D s + π + decay is determined to be less than 2.3% at a 90% confidence level.