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Title: Chiral Approach to {phi} radiative decays

Abstract

Rare decays of the {phi} vector meson, to {pi}{pi}{gamma} and {pi}{eta}{gamma}, have been measured in the last few years. We give some background about why these decays are of interest in that they may provide some insights about the puzzling light scalar mesons. We then present our approach to studying strong and radiative decays involving light scalar mesons more generally, pointing out that it has the advantage of potentially relating many radiative decays at tree-level. Finally we discuss the rare radiative {phi} decays and comparison with recent experimental data in more detail.

Authors:
 [1];  [2];  [3]
  1. Department of Physics, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 OHE (United Kingdom)
  2. Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)
  3. Department of Physics, Syracuse University, Syracuse, New York 13244-1130 (United States)
Publication Date:
OSTI Identifier:
21056823
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 892; Journal Issue: 1; Conference: QCHS7: 7. conference on quark confinement and the hadron spectrum, Ponta Delgada, Acores (Portugal), 2-7 Sep 2006; Other Information: DOI: 10.1063/1.2714386; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHIRAL SYMMETRY; CHIRALITY; COMPARATIVE EVALUATIONS; ETA MESONS; HADRONIC PARTICLE DECAY; PHI MESONS; PHOTONS; PIONS; RADIATIVE DECAY; SCALAR MESONS; VECTOR DOMINANCE MODEL

Citation Formats

Black, Deirdre, Harada, Masayasu, and Schechter, Joseph. Chiral Approach to {phi} radiative decays. United States: N. p., 2007. Web. doi:10.1063/1.2714386.
Black, Deirdre, Harada, Masayasu, & Schechter, Joseph. Chiral Approach to {phi} radiative decays. United States. doi:10.1063/1.2714386.
Black, Deirdre, Harada, Masayasu, and Schechter, Joseph. Tue . "Chiral Approach to {phi} radiative decays". United States. doi:10.1063/1.2714386.
@article{osti_21056823,
title = {Chiral Approach to {phi} radiative decays},
author = {Black, Deirdre and Harada, Masayasu and Schechter, Joseph},
abstractNote = {Rare decays of the {phi} vector meson, to {pi}{pi}{gamma} and {pi}{eta}{gamma}, have been measured in the last few years. We give some background about why these decays are of interest in that they may provide some insights about the puzzling light scalar mesons. We then present our approach to studying strong and radiative decays involving light scalar mesons more generally, pointing out that it has the advantage of potentially relating many radiative decays at tree-level. Finally we discuss the rare radiative {phi} decays and comparison with recent experimental data in more detail.},
doi = {10.1063/1.2714386},
journal = {AIP Conference Proceedings},
number = 1,
volume = 892,
place = {United States},
year = {Tue Feb 27 00:00:00 EST 2007},
month = {Tue Feb 27 00:00:00 EST 2007}
}
  • The radiative decays of the phi meson are known to be a good source of information about the a{sub 0}(980) and f{sub 0}(980) scalar mesons. We discuss these decays starting from a nonlinear model Lagrangian which maintains the (broken) chiral symmetry for the pseudoscalar (P), scalar (S) and vector (V) nonets involved. The characteristic feature is derivative coupling for the SPP interaction. In an initial approximation which models all the scalar nonet radiative processes together with the help of a pointlike vertex, it is noted that the derivative coupling prevents the a{sub 0} and f{sub 0} resonance peaks from gettingmore » washed out (by falling phase space). However, the shapes of the invariant two final PP mass distributions do not agree well with the experimental ones. For improving the situation we verify that inclusion of the charged K meson loop diagrams in the model does reproduce the experimental spectrum shapes in the resonance region. The derivative coupling introduces quadratic as well as logarithmic divergences in this calculation. Using dimensional regularization we show in detail that these divergences actually cancel out among the four diagrams, as expected from gauge invariance. We point out the features which are expected to be important for further work on this model and for learning more about the puzzling scalar mesons.« less
  • The KLOE experiment at the electron-positron collider DAPHNE has collected in the 2001-2002 running period an integrated luminosity of 450 pb-1. Through the radiative {phi} decays, large samples of the light scalar mesons f0(980) and a0(980) are available. The f0 meson is clearly observed in {pi}+{pi}- and {pi}0{pi}0 final states, the a0 in the {eta}{pi}0 final states. Invariant mass spectra and Dalitz plot densities are analyzed to investigate the controversial structure of these particels.
  • The potentialities of the production of the scalar K{bar K} molecules in {phi} radiative decays are considered beyond the narrow resonance width approximation. It is shown that B{bold (}{phi}{r_arrow}{gamma}f{sub 0}(a{sub 0}){r_arrow}{gamma}{pi}{pi}({pi}{eta}){bold )} {approx}(1{minus}2){times}10{sup {minus}5}, B{bold (}{phi}{r_arrow}{gamma}(f{sub 0}+a{sub 0}){r_arrow}{gamma}K{sup +}K{sup {minus}}{bold )}{approx_lt}10{sup {minus}6}, and B{bold (}{phi}{r_arrow}{gamma}(f{sub 0}+a{sub 0}){r_arrow}{gamma}K{sub S}K{sub S}{bold )}{lt}5{times}10{sup {minus}8}. The mass spectra in the {pi}{pi}, {pi}{eta}, K{sup +}K{sup {minus}} channels are calculated. The imaginary part of the amplitude {phi}{r_arrow}{gamma}f{sub 0}(a{sub 0}) is calculated analytically. The phase of the scalar resonance production amplitude that causes the interference patterns in the reaction e{sup +}e{sup {minus}}{r_arrow}{gamma}{pi}{sup +}{pi}{sup {minus}} in the {phi}more » meson mass region is obtained. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We discuss the status and future prospects of a program to study radiative {phi} decays in at Jefferson Lab. {copyright} {ital 1997 American Institute of Physics.}