Observation of χcJ Radiative Decays to Light Vector Mesons

Physical Review Letters, 2008

Using a total of 2.74 ×10 7 decays of the ψ(2S) collected with the CLEO-c detector, we present a study of χ cJ → γV , where V = ρ 0 , ω, φ. The transitions χ c1 → γρ 0 and χ c1 → γω are observed with B(χ c1 → γρ 0 ) = (2.43 ± 0.19 ± 0.22) × 10 −4 and B(χ c1 → γω) = (8.3 ± 1.5 ± 1.2) × 10 −5 . In the χ c1 → γρ 0 transition, the final state meson is dominantly longitudinally polarized. Upper limits on the branching fractions of other χ cJ states to light vector mesons are presented.

Physical Review D - Particles, Fields, Gravitation and Cosmology, 2011

The decays χcJ → γV (V = φ, ρ 0 , ω) are studied with a sample of radiative ψ ′ → γχcJ events in a sample of (1.06 ± 0.04) × 10 8 ψ ′ events collected with the BESIII detector. The branching fractions are determined to be: B(χc1 → γφ) = (25.8±5.2±2.3)×10 −6 , B(χc1 → γρ 0 ) = (228±13±22)×10 −6 , and B(χc1 → γω) = (69.7 ± 7.2 ± 6.6) × 10 −6 . The decay χc1 → γφ is observed for the first time. Upper limits at the 90% confidence level on the branching fractions for χc0 and χc2 decays into these final states are determined. In addition, the fractions of the transverse polarization component of the vector meson in χc1 → γV decays are measured to be 0.29 +0.13+0.10 −0.12−0.09 for χc1 → γφ, 0.158±0.034 +0.015 −0.014 for χc1 → γρ 0 , and 0.247 +0.090+0.044 −0.087−0.026 for χc1 → γω, respectively. The first errors are statistical and the second ones are systematic.

Physical Review D, 2011

The decays $\chi_{cJ}\to\gamma V$ ($V=\phi, \rho^0, \omega$) are studied with a sample of radiative $\psip\to\gamma\chi_{cJ}$ events in a sample of $(1.06\pm0.04)\times 10^{8} \psip$ events collected with the BESIII detector. The branching fractions are determined to be: ${\cal B}(\chi_{c1}\to \gamma\phi)=(25.8\pm 5.2\pm 2.3)\times 10^{-6}$, ${\cal B}(\chi_{c1}\to \gamma\rho^0)=(228\pm 13\pm 22)\times 10^{-6}$, and ${\cal B}(\chi_{c1}\to \gamma\omega)=(69.7\pm 7.2\pm 6.6)\times 10^{-6}$. The decay $\chi_{c1}\to \gamma\phi$ is observed for the first time. Upper limits at the 90% confidence level on the branching fractions for $\chi_{c0}$ and $\chict$ decays into these final states are determined. In addition, the fractions of the transverse polarization component of the vector meson in $\chi_{c1}\to \gamma V$ decays are measured to be $0.29_{-0.12-0.09}^{+0.13+0.10}$ for $\chi_{c1}\to \gamma\phi$, $0.158\pm 0.034^{+0.015}_{-0.014}$ for $\chi_{c1}\to \gamma\rho^0$, and $0.247_{-0.087-0.026}^{+0.090+0.044}$ for $\chi_{c1}\to \gamma\omega$, respectively. The first errors are statistical and the second ones are systematic.

Physical Review D, 2009

1 Abstract Using a sample of 2.59 × 10 7 ψ(2S) decays collected by the CLEO-c detector, we present results of a study of χ c0 and χ c2 decays into two-meson final states. We present the world's most precise measurements of the χ cJ,(J=0,2) → π + π − , π 0 π 0 , K + K − , K 0 S K 0 S , ηη and η ′ η ′ branching fractions, and a search for χ c decays into ηη ′ . These results shed light on the mechanism of charmonium decays into pseudoscalar mesons.

Physical Review D, 2008

2000

Using a sample of 9.7 × 10 BB meson pairs collected with the CLEO detector, we study B decays to the χc1 and χc2 charmonia states, which are reconstructed via their radiative decays to J/ψ. We first measure the branching fraction for inclusive χc1 production in B decays to be B(B → χc1X) = (4.14 ± 0.31 ± 0.40) × 10 , where the first uncertainty is statistical and the second one is systematic. We derive the branching fractions for direct χc1 and χc2 production in B decays by subtracting the known contribution of the decay chain B → ψ(2S)X with ψ(2S) → χc1,2γ. We obtain B[B → χc1(direct)X] = (3.83±0.31±0.40)×10 −3 . No statistically significant signal for χc2 production is observed in either case. Using the Feldman-Cousins approach, we determine the 95% confidence intervals to be [0.2, 2.0] × 10 for B(B → χc2X), [0.0, 1.7] × 10 −3 for B[B → χc2(direct)X], and [0.00, 0.44] for the ratio Γ[B → χc2(direct)X]/Γ[B → χc1(direct)X]. We also measure the branching ratio Γ[B → χc2(direct)Xs]/Γ[...

2009

1 Abstract Using a sample of 2.59 × 10 7 ψ(2S) decays collected by the CLEO-c detector, we present results of a study of χ c0 and χ c2 decays into two-meson final states. We present the world's most precise measurements of the χ cJ,(J=0,2) → π + π − , π 0 π 0 , K + K − , K 0 S K 0 S , ηη and η ′ η ′ branching fractions, and a search for χ c decays into ηη ′ . These results shed light on the mechanism of charmonium decays into pseudoscalar mesons.

Physical Review D, 2001

Using a sample of 9.7 × 10 6 BB meson pairs collected with the CLEO detector, we study B decays to the χ c1 and χ c2 charmonia states, which are reconstructed via their radiative decays to J/ψ. We first measure the branching fraction for inclusive χ c1 production in B decays to be B(B → χ c1 X) = (4.14 ± 0.31 ± 0.40) × 10 −3 , where the first uncertainty is statistical and the second one is systematic. We derive the branching fractions for direct χ c1 and χ c2 production in B decays by subtracting the known contribution of the decay chain B → ψ(2S)X with ψ(2S) → χ c1,2 γ. We obtain B[B → χ c1 (direct)X] = (3.83 ± 0.31 ± 0.40) × 10 −3 . No statistically significant signal for χ c2 production is observed in either case. Using the Feldman-Cousins approach, we determine the 95% confidence intervals to be [0.2, 2.0] × 10 −3 for B(B → χ c2 X), [0.0, 1.7] × 10 −3 for B[B → χ c2 (direct)X], and [0.00, 0.44] for the ratio Γ[B → χ c2 (direct)X]/Γ[B → χ c1 (direct)X]. We also measure the branching ratio Γ[B → χ c2 (direct)X s ]/Γ[B → χ c1 (direct)X s ] for different X s configurations by reconstructing B decays into exclusive final states with J/ψ, γ, a kaon, and up to four pions. For all the X s configurations we observe a strong χ c1 signal yet no statistically significant χ c2 signal. We discuss how our results compare with theoretical predictions in different models of charmonium production.

2012

Using 106 ×10 6 ψ ′ decays collected with the BESIII detector at the BEPCII, three decays of χ cJ (J = 0, 1, 2) with baryon pairs (ΛΛ, Σ 0Σ0 , Σ +Σ−) in the final state have been studied. The branching fractions are measured to be B(χ c0,1,2 → ΛΛ) = (33.3 ± 2.0 ± 2.6) × 10 −5 , (12.2 ± 1.1 ± 1.1) × 10 −5 , (20.8 ± 1.6 ± 2.3)×10 −5 ; B(χ c0,1,2 → Σ 0Σ0) = (47.8±3.4±3.9)×10 −5 , (3.8±1.0±0.5)×10 −5 , (4.0±1.1±0.5)×10 −5 ; and B(χ c0,1,2 → Σ +Σ−) = (45.4 ± 4.2 ± 3.0) × 10 −5 , (5.4 ± 1.5 ± 0.5) × 10 −5 , (4.9 ± 1.9 ± 0.7) × 10 −5 , where the first error is statistical and the second is systematic. Upper limits on the branching fractions for the decays of χ c1,2 → Σ 0Σ0 , Σ +Σ− , are estimated to be B(χ c1 → Σ 0Σ0) < 6.2 × 10 −5 , B(χ c2 → Σ 0Σ0) < 6.5 × 10 −5 , B(χ c1 → Σ +Σ−) < 8.7 × 10 −5 and B(χ c2 → Σ +Σ−) < 8.8 × 10 −5 at the 90% confidence level.

Physical Review D, 2011

The angular distributions of the decay products in the successive decays χc(χ b ) → J/ψ(Υ) γ and J/ψ(Υ) → + − are calculated as a function of the angular momentum composition of the decaying χ meson and of the multipole structure of the photon radiation, using a formalism independent of production mechanisms and polarization frames. The polarizations of the χ states produced in high energy collisions can be derived from the dilepton decay distributions of the daughter J/ψ or Υ mesons, with a reduced dependence on the details of the photon reconstruction or simulation. Moreover, this method eliminates the dependence of the polarization measurement on the actual details of the multipole structure of the radiative transition. Problematic points in previous calculations of the χc decay angular distributions are identified and clarified.