AbstractA measurement of the $$ B_{s}^{0} \rightarrow J/\psi \phi $$
B
s
0
→
J
/
ψ
ϕ
decay parameters using $$ 80.5\, \mathrm {fb^{-1}} $$
80.5
fb
-
1
of integrated luminosity collected with the ATLAS detector from 13 $$\text {Te}\text {V}$$
Te
proton–proton collisions at the LHC is presented. The measured parameters include the CP-violating phase $$\phi _{s} $$
ϕ
s
, the width difference $$ \Delta \Gamma _{s}$$
Δ
Γ
s
between the $$B_{s}^{0}$$
B
s
0
meson mass eigenstates and the average decay width $$ \Gamma _{s}$$
Γ
s
. The values measured for the physical parameters are combined with those from $$ 19.2\, \mathrm {fb^{-1}} $$
19.2
fb
-
1
of 7 and 8 $$\text {Te}\text {V}$$
Te
data, leading to the following: $$\begin{aligned} \phi _{s}= & {} -0.087 \pm 0.036 ~\mathrm {(stat.)} \pm 0.021 ~\mathrm {(syst.)~rad} \\ \Delta \Gamma _{s}= & {} 0.0657 \pm 0.0043 ~\mathrm {(stat.)}\pm 0.0037 ~\mathrm {(syst.)~ps}^{-1} \\ \Gamma _{s}= & {} 0.6703 \pm 0.0014 ~\mathrm {(stat.)}\pm 0.0018 ~\mathrm {(syst.)~ps}^{-1} \end{aligned}$$
ϕ
s
=
-
0.087
±
0.036
(
stat
.
)
±
0.021
(
syst
.
)
rad
Δ
Γ
s
=
0.0657
±
0.0043
(
stat
.
)
±
0.0037
(
syst
.
)
ps
-
1
Γ
s
=
0.6703
±
0.0014
(
stat
.
)
±
0.0018
(
syst
.
)
ps
-
1
Results for $$\phi _{s} $$
ϕ
s
and $$ \Delta \Gamma _{s}$$
Δ
Γ
s
are also presented as 68% confidence level contours in the $$\phi _{s} $$
ϕ
s
–$$ \Delta \Gamma _{s}$$
Δ
Γ
s
plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. $$\phi _{s} $$
ϕ
s
and $$ \Delta \Gamma _{s}$$
Δ
Γ
s
measurements are in agreement with the Standard Model predictions.
Measurement of the CP-violating phase $$\phi _s$$ in $$ B_{s}^{0} \rightarrow J/\psi \phi $$ decays in ATLAS at 13 TeV