Off-mass-shell coupling constants and radiative decays of ψ particles in VDM
TL;DR: In this paper, a class of radiative decays of psi particles is studied in the vector-meson dominance model to determine the behavior of the off-shell vector meson-photon coupling constants, and it is found that these are suppressed by about a couple of orders of magnitude compared with their on-shell values.
Abstract: A class of radiative decays of psi particles is studied in the vector-meson dominance model to determine the behaviour of the off-shell vector-meson-photon coupling constants. It is found that these are suppressed by about a couple of orders of magnitude compared with their on-shell values and the suppression thus obtained may be much larger than is usually believed. Different approaches for the incorporation of the suppression in simple VDM are discussed, and the necessity of considering suppression due to off-shell effects at both the hadronic and photonic vertices is emphasised. While the authors' model is constructed in the constructive interference scheme, the parallel arguments in the cancellation hypothesis are closely examined in an appendix to the paper; it is found that in this hypothesis also off-shell suppression factors are necessary to give currently acceptable numbers, and some of the problems associated with this approach are indicated.
Citations
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TL;DR: In this article, it was shown that if the E(1440) is identified as a glueball with pseudoscalar quantum numbers then its decay width can be significantly large, about as broad as that of the ϱ meson, if not more.
Abstract: In this letter, we observe that if the E(1440) is identified as a glueball with pseudoscalar quantum numbers then its decay width can be significantly large, about as broad as that of the ϱ meson, if not more. However, the possiblity of a narrow width cannot be rigorously ruled out. We also examine the sensitivity of the decay widths to the off-shell corrections as well as to the sign of the intermediate coupling constants.
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391 citations
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TL;DR: The decay rates of ψdblac; (4.028)→ D D, D D ∗ + D D * ∗, D ∠, D * * ∆ D ∆ can be fairly well understood with the assignment this state as a second radial excitation of charmonium as mentioned in this paper.
Abstract: The decay rates of ψdblac; (4.028)→ D D, D D ∗ + D D ∗ , D ∗ , D ∗ D ∗ can be fairly well understood with the assignment this state as a second radial excitation of charmonium. The nodes of the wave function and the different Q -value in each of these decays allow to understand the failure of the simple quark spin counting prediction.
150 citations
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TL;DR: In this paper, the yield of single muons at a transverse momentum of 1.65 GeV/c with a bremsstrahlung beam of 20$ GeV was measured from beryllium and tantalum targets.
Abstract: $\frac{J}{\ensuremath{\psi}}$ photoproduction has been measured from beryllium and tantalum targets by observing the yield of single muons at a transverse momentum of 1.65 GeV/c with a bremsstrahlung beam of ${E}_{0}=20$ GeV. The results have been interpreted in terms of a nuclearoptics model to yield the $\ensuremath{\psi}$-nucleon total cross section. The result is ${\ensuremath{\sigma}}_{\ensuremath{\psi}N}=3.5\ifmmode\pm\else\textpm\fi{}0.8$ mb.
105 citations
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TL;DR: In this article, the decay widths of φ, f′, ψ and ψ′ are derived in the dual unitarisation scheme and the correct hierarchy of suppression associated with different topologies of the quark graphs and the observed pattern of SU(3) breaking are obtained.
Abstract: Decays of φ, f′, ψ and ψ′ which violate Zweig rule are discussed in the dual unitarisation scheme. One obtains the correct hierarchy of suppression associated with different topologies of the quark graphs and the observed pattern of SU(3) breaking. A simplified calculation already yields decay widths in semi-quantitative agreement with experiment.
34 citations