Evidence for exclusive ηc production in γγ interactions

doi:10.1016/0370-2693(86)90558-7

Physics Letters B

Volume 167, Issue 1, 30 January 1986, Pages 120-126

https://doi.org/10.1016/0370-2693(86)90558-7 Get rights and content

Abstract

We observe for evidence for γγ → η_c production in the reaction e⁺e⁻ → e⁺e⁻K_S⁰K^±π^∓. The product Γ_γγ(η_c)·B(η_c → K_S⁰K^±π^∓) is measured to be 0.5_−0.15^+0.2±0.1 keV.

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Cited by (31)

First-principle calculation of the η<inf>c</inf>→2γ decay width from lattice QCD
2023, Science Bulletin
We perform a lattice QCD calculation of the $η_{c} \to 2 γ$ decay width using a model-independent method that requires no momentum extrapolation of the off-shell form factors. This method also provides a straightforward and simple way to examine the finite-volume effects. The calculation is accomplished using $N_{f} = 2$ twisted mass fermion ensembles. The statistically significant excited-state effects are observed and eliminated using a multi-state fit. The impact of fine-tuning the charm quark mass is also examined and confirmed to be well-controlled. Finally, using three lattice spacings for the continuum extrapolation, we obtain the decay width $Γ_{η_{c} γ γ} = 6.67 {(16)}_{stat} {(6)}_{syst}$ keV, which differs significantly from the Particle Data Group’s reported value of $Γ_{η_{c} γ γ} = 5.4 (4)$ keV (2.9 $σ$ tension). We provide insight into the comparison between our findings, previous theoretical predictions, and experimental measurements.
Charmonium resonance formation in γγ collisions with the L3 detector
2000, Nuclear Physics A
Charmonium resonance production in γγ collisions with the L3 detector
1999, Nuclear Physics B - Proceedings Supplements
The production of cc states in two-photon collisions has been studied with the L3 detector at LEP. We present results on the two-photon partial widths for the resonances η_c and χ_c2, measured at √ ≅ 91 GeV with an integrated luminosity of 140 pb⁻¹ and at √ ≅ 183 GeV with an integrated luminosity of 50 pb⁻¹. The studied decay channels are η_c → 4π, K⁺K⁻, π⁺ π⁻, K⁰K^∓ π^±, π⁰ K⁺K⁻, ηπ⁺π⁻, η^lπ⁺π⁻, ρρ and gc_c2 → J /Ψγ.
Formation of the η<inf>c</inf> in two-photon collisions at LEP
1999, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
The two-photon width Γ_γγ of the η_c meson has been measured with the L3 detector at LEP. The η_c is studied in the decay modes π⁺π⁻π⁺π⁻, π⁺π⁻K⁺K⁻, K⁰_sK^±π^∓, K⁺K⁻π⁰, π⁺π⁻η, π⁺π⁻η′, and ρ⁺ρ⁻ using an integrated luminosity of 140 pb⁻¹ at $s ≃91$ GeV and of 52 pb⁻¹ at $s ≃183$ GeV. The result is $Γ_{γγ} (η_{c})=6.9±1.7 stat ±0.8 sys ±2.0$ (BR) keV. The Q² dependence of the η_c cross section is studied for Q²<9 GeV². It is found to be better described by a Vector Meson Dominance model form factor with a J-pole than with a ρ-pole. In addition, a signal of 29±11 events is observed at the χ_c0 mass. Upper limits for the two-photon widths of the χ_c0, χ_c2, and η_c′ are also given.
Observation of exclusive η<inf>c</inf> production in two photon interactions at TRISTAN
1998, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Determination of the radiative decay width of the η<inf>c</inf> meson
1994, Physics Letters B
An analysis of the reaction γ → η_c was performed in five different decay channels of the η_c: K_S⁰K^±π^∓, K⁺K⁻π⁺π⁻, 2π⁺2π⁻, φφ and 2K⁺2k⁻. A value Γ_γγ(η_c) = (11.3±4.2) keV was obtained for the radiative decay width by combining the results from the first four channels. Using our result on the two-photon width we also determined the branching ratio for the decay η_c → 2K⁺2K⁻.

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³: Supported by the BMFT, Fed. Rep. Germany.

¹: Deceased.

²: Present address: University of California at Davis, Davis, CA 95616, USA.

⁴: Partially supported by the Norwegian Council for Science and the Humanities.

⁵: Rome University, partially supported by INFN, Sezione di Roma, I-00135 Rome, Italy.

⁶: Institute of Nuclear Physics, PL-30 059 Cracow, Poland.

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Evidence for exclusive ηc production in γγ interactions

Abstract

Resonances Summary Talk

Resonances I

Resonances II

Search for two-photon production of resonances decaying into KK and KKπ,

ISR R704 experiment

Phys. Rep.

Internal Report DESY-PLUTO-84/04

Thesis

Phys. Lett.

Phys. Rep.

Phys. Lett.

Evidence for exclusive η_c production in γγ interactions

Search for two-photon production of resonances decaying into K $K$ and K $K$ π,