Amplitude analysis and branching fraction measurement of B + → D ∗ − D s + π + $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ decays

Abstract

Abstract The decays of the B + meson to the final state D ∗ − D s + π + $$ {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ 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 ∗ − D s + π + $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ and B 0 → D ∗ − D s + $$ {B}^0\to {D}^{\ast -}{D}_s^{+} $$ 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 D s ∗ + → D s + γ $$ {D}_s^{\ast +}\to {D}_s^{+}\gamma $$ and D s + π 0 $$ {D}_s^{+}{\pi}^0 $$ decays, the ratio of branching fractions between the B + → D ∗ − D s ∗ + π + $$ {B}^{+}\to {D}^{\ast -}{D}_s^{\ast +}{\pi}^{+} $$ and B + → D ∗ − D s + π + $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ decays is determined as 1.31 ± 0.07 ± 0.14. An amplitude analysis of the B + → D ∗ − D s + π + $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ 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 D s + π + $$ {D}_s^{+}{\pi}^{+} $$ or D ∗ − D s + $$ {D}^{\ast -}{D}_s^{+} $$ channels is found. The fit fraction of the scalar state T c s ¯ 0 ∗ 2900 + + $$ {T}_{c\overline{s}0}^{\ast }{(2900)}^{++} $$ observed in the B + → D − D s + π + $$ {B}^{+}\to {D}^{-}{D}_s^{+}{\pi}^{+} $$ decay is determined to be less than 2.3% at a 90% confidence level.

Keywords

• Branching fraction
• Charm Physics
• Hadron-Hadron Scattering
• Spectroscopy