Observation of the decay B c + → ψ ( 2 S ) π Adrover, C.; Affolder, A.; Albrecht, J. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
04/2013, Letnik:
87, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The decay $B_c^+ \to \psi(2S)\pi^+$ with $\psi(2S) \to \mu^+\mu^-$ is observed with a significance of $5.2\,\sigma$ using $pp$ collision data corresponding to an integrated luminosity of ...$1.0\,\invfb$ collected by the LHCb experiment. The branching fraction of $B_c^+ \to \psi(2S)\pi^+$ decays relative to that of the $B_c^+ \to J/\psi\pi^+$ mode is measured to be \begin{equation*} \frac{\mathcal{B}(B_c^+ \to \psi(2S)\pi^+)}{\mathcal{B}(B_c^+ \to J/\psi\pi^+)} = 0.250 \pm 0.068 \,\text{stat} \pm 0.014 \,\text{\syst} \pm 0.006 \,(\mathcal{B}). \end{equation*} The last term is the uncertainty on the ratio $\mathcal{B}(\psi(2S) \to \mu^+\mu^-)/\mathcal{B}(J/\psi \to \mu^+\mu^-)$.
A
bstract
Measurements are presented of the branching fractions of the decays
B
S
0
→
D
S
∓
K
∓
and
B
0
→
D
S
−
K
+
relative to the decays
B
S
0
→
D
S
−
π
+
and
B
0
→
D
−
π
+
, respectively. ...The data used correspond to an integrated luminosity of 3
.
0 fb
−1
of proton-proton collisions. The ratios of branching fractions are
ℬ
B
s
0
→
D
s
∓
K
∓
ℬ
B
s
0
→
D
s
−
π
+
=
0.0752
±
0.0015
±
0.0019
and
ℬ
B
0
→
D
s
−
K
+
ℬ
B
0
→
D
−
π
+
=
0.0129
±
0.0005
±
0.0008
,
where the uncertainties are statistical and systematic, respectively.
Observation of the B s 0 → η ′ η ′ Decay Albrecht, J.; Aslanides, E.; Bedeschi, F. ...
Physical review letters,
07/2015, Letnik:
115, Številka:
5
Journal Article
A
bstract
We report on measurements of the time-dependent
CP
violating observables in
B
s
0
→
D
s
∓
K
±
decays using a dataset corresponding to 1
.
0 fb
−1
of
pp
collisions recorded with the LHCb ...detector. We find the
CP
violating observables
C
f
= 0
.
53±0
.
25±0
.
04,
A
f
ΔΓ
= 0.37 ± 0.42 ± 0.20,
A
f
¯
Δ
Γ
=
0.20
±
0.41
±
0.20
,
S
f
= −1
.
09±0
.
33±0
.
08,
S
f
¯
=
−
0.36
±
0.34
±
0.08
, where the uncertainties are statistical and systematic, respectively. Using these observables together with a recent measurement of the
B
s
0
mixing phase −2
β
s
leads to the first extraction of the CKM angle
γ
from
B
s
0
→
D
s
∓
K
±
decays, finding
γ
= (115
− 43
+ 28
)
°
modulo 180° at 68% CL, where the error contains both statistical and systematic uncertainties.
A full amplitude analysis of $\Lambda_b^0 \to J/\psi p \pi^-$ decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV $pp$ collisions, corresponding to an integrated ...luminosity of 3 fb$^{-1}$. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations $N\to p\pi^-$, either the $P_c(4380)^+$ and $P_c(4450)^+\to J/\psi p$ states, previously observed in $\Lambda_b^0 \to J/\psi p K^-$ decays, or the $Z_c(4200)^-\to J/\psi \pi^-$ state, previously reported in $B^0 \to J/\psi K^+ \pi^-$ decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the $P_c(4380)^+$ and $P_c(4450)^+$ production rates expected from their previous observation taking account of Cabibbo suppression.
A search is made for the highly-suppressed B meson decays B+→K+K+π− and B+→π+π+K− using a data sample corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb experiment in ...proton–proton collisions at centre-of-mass energies of 7 and 8 TeV. No evidence is found for the decays, and upper limits at 90% confidence level are determined to be B(B+→K+K+π−)<1.1×10−8 and B(B+→π+π+K−)<4.6×10−8.
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