We have found the first evidence for the Cabibbo suppressed, color suppressed decay
B
− →
ψπ
− in a data sample of 4 million
B decays obtained by the CLEO detector at the Cornell Electron Storage ...Ring (CESR). The branching ratio is found to be (4.3±2.3)% of the Cabibbo allowed
B
− →
ψK
− decay mode, which is consistent with theoretical expectations.
The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This ...provides charged particle identification over a wide momentum range, from 2-100 GeV/c. The operation and control software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (pion, kaon and proton) is achieved.
We have observed two new decay modes of the charmed baryon
Ξ
c
+ into
Σ
+
K
−
π
+ and
Σ
+
K
∗0
using data collected with the CLEO II detector. We also present the first measurement of the branching ...fraction for the previously observed decay mode
Ξ
c
+ →
ΛK
−
π
+
π
+. The branching fractions for these three modes relative to
Ξ
c
+ →
Ξ
−
π
+
π
+ are measured to be 1.18 ± 0.26 ± 0.17, 0.92 ± 0.27 ± 0.14, and 0.58 ± 0.16 ± 0.07, respectively.
We have measured the weak decay asymmetry parameters (
α
Λ
c
) for two
Λ
c
+ decay modes. Our measurements are
α
Λ
c
= −0.94
−0.06−0.06
+0.21+0.12 for the decay mode
Λ
c
+ →
Λπ
+ and
α
Λ
c
= −0.45 ...±0.31 ±0.06 for the decay mode
Λ
c
→
Σ
+
π
0. By combining these measurements with the previously measured decay rates, we have extracted the parity-violating and parity-conserving amplitudes. These amplitudes are used to test models of nonleptonic charmed baryon decay.
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