Decays [eta][sub [ital c]][r arrow][gamma][gamma] and [eta][sub [ital b]][r arrow][gamma][gamma]: A test for potential models

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.51.141· OSTI ID:6707889

Ahmady, M R; Mendel, R R ^[1]

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1. Department of Applied Mathematics, The University of Western Ontario, London, Ontario, N6A 5B9 (Canada)

We use a simple perturbation theory argument and measurements of charmonium leptonic widths [Gamma]([psi][sub [ital N][ital S]][r arrow][ital e][sup +][ital e][sup [minus]]) to estimate the ratio [ital R][sub 0][equivalent to][vert bar][Psi][sub [eta][ital c]1[ital S]](0)[vert bar][sup 2]/[vert bar][Psi][sub [psi]1[ital S]](0)[vert bar][sup 2] in the general context of nonrelativistic potential models. We obtain [ital R][sub 0]=1.4[plus minus]0.1. We then apply well known potential model formulas, which include lowest order QCD corrections, to find [Gamma]([eta][sub [ital c]][r arrow][gamma][gamma])/[Gamma]([psi][sub 1[ital S]][r arrow][ital e][sup +][ital e][sup [minus]])[approx]2.2[plus minus]0.2. The central value for [Gamma]([psi][sub 1[ital S]][r arrow][ital e][sup +][ital e][sup [minus]]) in the 1992 Particle Data Group Tables then leads to a (nonrelativistic) prediction [Gamma]([eta][sub [ital c]][r arrow][gamma][gamma])[approx]11.8[plus minus]0.8 keV. This prediction is in good agreement with a recent measurement by the ARGUS Collaboration, is consistent with a recent measurement by the L3 Collaboration, but is significantly higher than several other measurements and previous theoretical estimates, which usually assume [ital R][sub 0]=1. The correction to [ital R][sub 0]=1 is estimated to be smaller but non-negligible for the [ital b[bar b]] system. Using the current central measurement for [Gamma]([Upsilon][sub 1[ital S]][r arrow][ital e][sup +][ital e][sup [minus]]) we find [Gamma]([eta][sub [ital b]][r arrow][gamma][gamma])[approx]0.58[plus minus]0.03 keV. A rough estimate of relativistic corrections reduces the expected two photon rates to about 8.8 and 0.52 keV for the [eta][sub [ital c]] and [eta][sub [ital b]] mesons, respectively. Such corrections, however, are not expected to significantly affect our estimates of [ital R][sub 0]. An estimate of [Gamma]([eta][sub [ital c]](2[ital S])[r arrow][gamma][gamma]) is given as well.

• OSTI ID: 6707889
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 51:1; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BASIC INTERACTIONS
BOSONS
CHARMONIUM
CORRECTIONS
DECAY
DIMENSIONS
ELEMENTARY PARTICLES
ETA MESONS
FIELD THEORIES
HADRONS
INTERACTIONS
LEPTONIC DECAY
MATHEMATICAL MODELS
MESONS
PARTICLE DECAY
PARTICLE MODELS
PERTURBATION THEORY
POTENTIALS
PSEUDOSCALAR MESONS
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARKONIUM
RADIATIVE DECAY
TESTING
WEAK INTERACTIONS
WEAK PARTICLE DECAY
WIDTH