Measurements ofhc(P11)inψ′Decays

2022

The Ξ++ cc → Ξ ′+ c π + decay is observed using proton-proton collisions collected by the LHCb experiment at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1. The Ξ++ cc → Ξ ′+ c π + decay is reconstructed partially, where the photon from the Ξ ′+ c → Ξ+ c γ decay is not reconstructed and the pK−π+ final state of the Ξ+ c baryon is employed. The Ξ ++ cc → Ξ ′+ c π + branching fraction relative to that of the Ξ++ cc → Ξ+ c π+ decay is measured to be 1.41±0.17±0.10, where the first uncertainty is statistical and the second systematic.

Physical Review D, 2010

We have searched for flavor-changing neutral current decays and lepton-number-violating decays of D + and D + s mesons to final states of the form h ± e ∓ e + , where h is either π or K. We use the complete samples of CLEO-c open-charm data, corresponding to integrated luminosities of 818 pb −1 at the center-of-mass energy E CM = 3.774 GeV containing 2.4×10 6 D + D − pairs and 602 pb −1 at E CM = 4.170 GeV containing 0.6 × 10 6 D * ± s D ∓ s pairs. No signal is observed in any channel, and we obtain 90% confidence level upper limits on branching fractions B(D + → π + e + e − ) < 5.9×10 −6 , B(D + → π − e + e + ) < 1.1×10 −6 , B(D + → K + e + e − ) < 3.0×10 −6 , B(D + → K − e + e + ) < 3.5×10 −6 , B(D + s → π + e + e − ) < 2.2 × 10 −5 , B(D + s → π − e + e + ) < 1.8 × 10 −5 , B(D + s → K + e + e − ) < 5.2 × 10 −5 , and B(D + s → K − e + e + ) < 1.7 × 10 −5 .

Physical Review D, 2007

Physical Review Letters, 2005

The h_c(1P1) state of charmonium has been observed in the reaction \psi(2S) -> \pi0 h_c -> (\gamma\gamma)(\gamma\eta_c) using 3.08 million \psi(2S) decays recorded in the CLEO detector. Data have been analyzed both for the inclusive reaction, where the decay products of the \eta_c are not identified, and for exclusive reactions, in which \eta_c decays are reconstructed in seven hadronic decay channels. We find M(h_c)=3524.4 +/- 0.6 +/- 0.4 MeV which corresponds to a hyperfine splitting \Delta M_{hf}(1P) \equiv <M(3PJ)>-M(1P1)=+1.0+/-0.6+/-0.4 MeV, and B(\psi(2S)->\pi0 h_c)xB(h_c->\gamma\eta_c)=(4. +/-0.8+/-0.7)x10^{-4}.

Physical Review D, 2004

Using data collected by the CLEO III detector at CESR, we report on measurements of Υ(1S) decays to charmonium final states. The data sample used for this analysis consists of 21.2 × 10 6 Υ(1S) decays, representing about 35 times more data than previous CLEO Υ(1S) data samples. We present substantially improved measurements of the branching fraction B(Υ(1S) → J/ψ + X) using J/ψ → µ + µ − and J/ψ → e + e − decays. The branching fractions for these two modes are averaged, thereby obtaining: B(Υ(1S) → J/ψ + X) = (6.4 ± 0.4(stat)±0.6(syst))×10 −4. A greatly improved measurement of the J/ψ momentum distribution is presented and indicates a spectrum which is much softer than predicted by the color-octet model and somewhat softer than the color-singlet model. First measurements of the J/ψ polarization and production angle are also presented. In addition, we report on the first observation of Υ(1S) → ψ(2S) + X and evidence for Υ(1S) → χ cJ + X. Their branching fractions are measured relative to B(Υ(1S) → J/ψ + X) and are found to be: B(Υ(1S)→ψ(2S)+X) B(Υ(1S)→J/ψ+X) = 0.41 ± 0.11(stat)±0.08(syst), B(Υ(1S)→χ c1 +X) B(Υ(1S)→J/ψ+X) = 0.35±0.08(stat)±0.06(syst), B(Υ(1S)→χ c2 +X) B(Υ(1S)→J/ψ+X) = 0.52±0.12(stat)±0.09(syst), and B(Υ(1S)→χ c0 +X) B(Υ(1S)→J/ψ+X) < 7.4 at 90% confidence level. The resulting feed-down contributions to J/ψ are (24±6(stat)±5(syst))% for ψ(2S), (11±3(stat)±2(syst))% for χ c1 , (10±2(stat)±2(syst))% for χ c2 , and < 8.2% at 90% confidence level for χ c0. These measurements (apart from χ c0) are about a factor of two larger than expected based on the color-octet model.