Measurement of the branching fraction of the $${{B} ^0} {\rightarrow }{{D} ^+_{s}} {{\pi } ^-} $$ B 0 → D s + π - decay

Abstract

Abstract A branching fraction measurement of the

$${{B} ^0} {\rightarrow }{{D} ^+_{s}} {{\pi } ^-} $$

B

0

→

D

s +

π

-

decay is presented using proton–proton collision data collected with the LHCb experiment, corresponding to an integrated luminosity of

$$5.0\,\text {fb} ^{-1} $$

5.0

fb

- 1

. The branching fraction is found to be

$${\mathcal {B}} ({{B} ^0} {\rightarrow }{{D} ^+_{s}} {{\pi } ^-} ) =(19.4 \pm $$

B

(

B

0

→

D

s +

π

-

)

= ( 19.4 ±

$$1.8\pm 1.3 \pm 1.2)\times 10^{-6}$$

1.8 ± 1.3 ± 1.2 ) ×

10

- 6

, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the

$${{B} ^0} {\rightarrow }{{D} ^-} {{\pi } ^+} $$

B

0

→

D

-

π

+

,

$${{D} ^+_{s}} {\rightarrow }{{K} ^+} {{K} ^-} {{\pi } ^+} $$

D

s +

→

K

+

K

-

π

+

and

$${{D} ^-} {\rightarrow }{{K} ^+} {{\pi } ^-} {{\pi } ^-} $$

D

-

→

K

+

π

-

π

-

branching fractions. This is the most precise single measurement of this quantity to date. As this decay proceeds through a single amplitude involving a

$$b{\rightarrow }u$$

b → u

charged-current transition, the result provides information on non-factorisable strong interaction effects and the magnitude of the Cabibbo–Kobayashi–Maskawa matrix element

$$V_{ub}$$

V

ub

. Additionally, the collision energy dependence of the hadronisation-fraction ratio

$$f_s/f_d$$

f s

/

f d

is measured through

$${{\overline{B}} {}^0_{s}} {\rightarrow }{{D} ^+_{s}} {{\pi } ^-} $$

B ¯

s 0

→

D

s +

π

-

and

$${{B} ^0} {\rightarrow }{{D} ^-} {{\pi } ^+} $$

B

0

→

D

-

π

+

decays.