A model-independent study of
C
P
violation in
B
0
→
D
K
∗
0
decays is presented using data corresponding to an integrated luminosity of 9
\,fb
-
1
collected by the LHCb experiment at centre-of-mass ...energies of
s
=
7
,
8
and 13
\,Te
V
. The CKM angle
γ
is determined by examining the distributions of signal decays in phase-space bins of the self-conjugate
D
→
K
S
0
h
+
h
-
decays, where
h
=
π
,
K
. Observables related to
C
P
violation are measured and the angle
γ
is determined to be
γ
=
(
49
-
19
+
22
)
∘
. Measurements of the amplitude ratio and strong-phase difference between the favoured and suppressed
B
0
decays are also presented.
A
bstract
An amplitude analysis of the
D
+
→ π
−
π
+
π
+
decay is performed with a sample corresponding to 1.5 fb
−
1
of integrated luminosity of
pp
collisions at a centre-of-mass energy
s
= 8 TeV ...collected by the LHCb detector in 2012. The sample contains approximately six hundred thousand candidates with a signal purity of 95%. The resonant structure is studied through a fit to the Dalitz plot where the
π
−
π
+
S-wave amplitude is extracted as a function of
π
−
π
+
mass, and spin-1 and spin-2 resonances are included coherently through an isobar model. The S-wave component is found to be dominant, followed by the
ρ
(770)
0
π
+
and
f
2
(1270)
π
+
components. A small contribution from the
ω
(782)
→ π
−
π
+
decay is seen for the first time in the
D
+
→ π
−
π
+
π
+
decay.
A
bstract
Four decay modes of the
B
c
+
meson into a
J/ψ
meson and multiple charged kaons or pions are studied using proton-proton collision data, collected with the LHCb detector at centre-of-mass ...energies of 7, 8, and 13 TeV and corresponding to an integrated luminosity of 9 fb
−
1
. The decay
B
c
+
→ J/ψK
+
K
−
π
+
π
+
π
−
is observed for the first time, and evidence for the
B
c
+
→ J/ψ
4
π
+
3
π
−
decay is found. The decay
B
c
+
→ J/ψ
3
π
+
2
π
−
is observed and the previous observation of the
B
c
+
→ ψ
(2
S
)
π
+
π
+
π
−
decay is confirmed using the
ψ
(2
S
) →
J/ψπ
+
π
−
decay mode. Ratios of the branching fractions of these four
B
c
+
decay channels are measured.
A
bstract
A first search for the lepton-flavour violating decays
B
0
→
K
*0
τ
±
μ
∓
is presented. The analysis is performed using a sample of proton-proton collision data, collected with the LHCb ...detector at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018, corresponding to an integrated luminosity of 9 fb
−
1
. No significant signal is observed, and upper limits on the branching fractions are determined to be
B
B
0
→
K
∗
0
τ
+
μ
−
<
1.0
1.2
×
10
−
5
and
B
B
0
→
K
∗
0
τ
−
μ
+
<
8.2
9.8
×
10
−
6
at the 90% (95%) confidence level.
A
bstract
The first observation of the
Λ
b
0
→
D
s
−
p
decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of
s
= 13 TeV, corresponding ...to a total integrated luminosity of 6 fb
−
1
. Using the
Λ
b
0
→
Λ
c
+
π
−
decay as the normalisation mode, the branching fraction of the
Λ
b
0
→
D
s
−
p
decay is measured to be
B
Λ
b
0
→
D
s
−
p
=
12.6
±
0.5
±
0.3
±
1.2
×
10
−
6
, where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the
Λ
b
0
→
Λ
c
+
π
−
,
D
s
−
→
K
−
K
+
π
−
and
Λ
c
+
→
p
K
−
π
+
decays.
Amplitude analysis of the Ds+→ π−π+π+ decay Amhis, Y.; Andersson, M.; Bachmann, S. ...
The journal of high energy physics,
07/2023, Letnik:
2023, Številka:
7
Journal Article
Recenzirano
Odprti dostop
A
bstract
A Dalitz plot analysis of the
D
s
+
→
π
−
π
+
π
+
decay is presented. The analysis is based on proton-proton collision data recorded by the LHCb experiment at a centre-of-mass energy of 8 ...TeV and corresponding to an integrated luminosity of 1.5 fb
−
1
. The resonant structure of the decay is obtained using a quasi-model-independent partial-wave analysis, in which the
π
+
π
−
S-wave amplitude is parameterised as a generic complex function determined by a fit to the data. The S-wave component is found to be dominant, followed by the contribution from spin-2 resonances and a small contribution from spin-1 resonances. The latter includes the first observation of the
D
s
+
→ ω
(782)
π
+
channel in the
D
s
+
→ π
−
π
+
π
+
decay. The resonant structures of the
D
s
+
→ π
−
π
+
π
+
and
D
+
→ π
−
π
+
π
+
decays are compared, providing information about the mechanisms for the hadron formation in these decays.
Observation of the Bs0→ D+D− decay Alessio, F.; Aliouche, Z.; Artamonov, A. ...
The journal of high energy physics,
07/2023, Letnik:
2023, Številka:
7
Journal Article
Recenzirano
Odprti dostop
A
bstract
The first observation of the
B
s
0
→ D
∗+
D
∗
−
decay and the measurement of its branching ratio relative to the
B
0
→ D
∗+
D
∗
−
decay are presented. The data sample used corresponds to an ...integrated luminosity of 9 fb
−
1
of proton-proton collisions recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018. The decay is observed with more than 10 standard deviations and the time-integrated ratio of branching fractions is determined to be
B
B
s
0
→
D
∗
+
D
∗
−
B
B
0
→
D
∗
+
D
∗
−
=
0.269
±
0.032
±
0.011
±
0.008
,
where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the fragmentation fraction ratio
f
s
/f
d
. The
B
s
0
→ D
*+
D
*
−
branching fraction is calculated to be
B
B
s
0
→
D
∗
+
D
∗
−
=
2.15
±
0.26
±
0.09
±
0.06
±
0.16
×
10
−
4
,
where the fourth uncertainty is due to the
B
0
→ D
*
+
D
*−
branching fraction. These results are calculated using the average
B
s
0
meson lifetime in simulation. Correction factors are reported for scenarios where either a purely heavy or a purely light
B
s
0
eigenstate is considered.
A
bstract
A search for
CP
violation in D
0
→
π
−
π
+
π
0
decays is reported, using
pp
collision data collected by the LHCb experiment from 2015 to 2018 corresponding to an integrated luminosity of 6 ...fb
−
1
. An unbinned model-independent approach provides sensitivity to local
CP
violation within the two-dimensional phase space of the decay. The method is validated using the Cabibbo-favoured channel D
0
→ K
−
π
+
π
0
and background regions of the signal mode. The results are consistent with
CP
symmetry in this decay.
A
bstract
The ratio of branching fractions between
B
0
→
J/ψπ
0
and
B
+
→
J/ψK
*+
decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated ...luminosity of 9 fb
−
1
. The measured value is
B
B
0
→
J
/
ψ
π
0
B
B
+
→
J
/
ψ
K
∗
+
=
1.153
±
0.053
±
0.048
×
10
−
2
,
where the first uncertainty is statistical and the second is systematic. The branching fraction for
B
0
→
J/ψπ
0
decays is determined using the branching fraction of the normalisation channel, resulting in
B
B
0
→
J
/
ψ
π
0
=
1.670
±
0.077
±
0.069
±
0.095
×
10
−
5
,
where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date.
A
bstract
A measurement of
CP
-violating observables associated with the interference of
B
0
→ D
0
K
⋆
(892)
0
and
B
0
→
D
¯
0
K
⋆
892
0
decay amplitudes is performed in the
D
0
→ K
∓
π
±
(
π
+
π
−
...),
D
0
→ π
+
π
−
(
π
+
π
−
), and
D
0
→ K
+
K
−
final states using data collected by the LHCb experiment corresponding to an integrated luminosity of 9 fb
−
1
.
CP
-violating observables related to the interference of
B
s
0
→
D
0
K
¯
⋆
892
0
and
B
s
0
→
D
¯
0
K
¯
⋆
892
0
are also measured, but no evidence for interference is found. The
B
0
observables are used to constrain the parameter space of the CKM angle
γ
and the hadronic parameters
r
B
0
DK
⋆
and
δ
B
0
DK
⋆
with inputs from other measurements. In a combined analysis, these measurements allow for four solutions in the parameter space, only one of which is consistent with the world average.
