Measurement of the CKM angle γ using the B± → D*h± channels

Abstract

A measurement of the CP-violating observables from B± → D*K± and B± → D*π± decays is presented, where D*(D) is an admixture of D*0 and

D ¯

∗ 0

$$ {\overline{D}}^{\ast 0} $$ (D0 and

D ¯

0

$$ {\overline{D}}^0 $$ ) states and is reconstructed through the decay chains D* → Dπ0/γ and

D →

K S 0

π +

π −

/

K S 0

K +

K −

$$ D\to {K}_S^0{\pi}^{+}{\pi}^{-}/{K}_S^0{K}^{+}{K}^{-} $$ . The measurement is performed by analysing the signal yield variation across the D decay phase space and is independent of any amplitude model. The data sample used was collected by the LHCb experiment in proton-proton collisions and corresponds to a total integrated luminosity of 9 fb−1 at centre-of-mass energies of 7, 8 and 13 TeV. The CKM angle γ is determined to be

69

− 14

+ 13

∘

$$ {\left({69}_{-14}^{+13}\right)}^{\circ } $$ using the measured CP-violating observables. The hadronic parameters

r B

D ∗

K ±

,

r B

D ∗

π ±

,

δ B

D ∗

K ±

,

δ B

D ∗

π ±

$$ {r}_B^{D^{\ast }{K}^{\pm }},{r}_B^{D^{\ast }{\pi}^{\pm }},{\delta}_B^{D^{\ast }{K}^{\pm }},{\delta}_B^{D^{\ast }{\pi}^{\pm }} $$ , which are the ratios and strong phase differences between favoured and suppressed B± decays, are also reported.