Abstract
The time-dependent CP asymmetries of B0→ π+π− and $$ {B}_s^0 $$
B
s
0
→ K+K− decays are measured using a data sample of pp collisions corresponding to an integrated luminosity of 1.9 fb−1, collected with the LHCb detector at a centre-of-mass energy of 13 TeV. The results are$$ {\displaystyle \begin{array}{c}{C}_{\pi \pi}=-0.311\pm 0.045\pm 0.015,\\ {}{S}_{\pi \pi}=-0.706\pm 0.042\pm 0.013,\\ {}{C}_{KK}=0.123\pm 0.034\pm 0.015,\\ {}{S}_{KK}=0.164\pm 0.034\pm 0.014,\\ {}{\mathcal{A}}_{KK}^{\Delta \varGamma }=-0.83\pm 0.05\pm 0.09,\end{array}} $$
C
ππ
=
−
0.311
±
0.045
±
0.015
,
S
ππ
=
−
0.706
±
0.042
±
0.013
,
C
KK
=
0.123
±
0.034
±
0.015
,
S
KK
=
0.164
±
0.034
±
0.014
,
A
KK
Δ
Γ
=
−
0.83
±
0.05
±
0.09
,
where the first uncertainties are statistical and the second systematic. The same data sample is used to measure the time-integrated CP asymmetries of B0→ K + π− and $$ {B}_s^0 $$
B
s
0
→K−π+ decays and the results are$$ {\displaystyle \begin{array}{c}{A}_{CP}^{B^0}=-0.0824\pm 0.0033\pm 0.0033,\\ {}{A}_{CP}^{B_s^0}=0.236\pm 0.013\pm 0.011.\end{array}} $$
A
CP
B
0
=
−
0.0824
±
0.0033
±
0.0033
,
A
CP
B
s
0
=
0.236
±
0.013
±
0.011
.
All results are consistent with earlier measurements. A combination of LHCb measurements provides the first observation of time-dependent CP violation in $$ {B}_s^0 $$
B
s
0
decays.
Measurement of
CP
asymmetries in two-body
B(s)0
-meson decays to charged pions and kaons