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Title: Implication of the running mass of the {rho}{sup 0} meson for the dilepton mass spectrum and the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio in K{sup +}{r_arrow}{pi}{sup +}l{sup +}l{sup {minus}} decays

Abstract

We make an attempt to resolve the discrepancy of the observed e{sup +}e{sup {minus}} mass spectrum in the K{sup +}{r_arrow}{pi}{sup +}e{sup +}e{sup {minus}} decay with that predicted by meson dominance. To this end we investigate the properties of the {rho}{sup 0} propagator. We use dispersion relations to evaluate the running mass m{sub {rho}}{sup 2}(t) of the {rho}{sup 0} resonance without adjustable parameters. To improve the convergence of the dispersion integral, the momentum dependence of strong vertices is taken from the flux-tube-breaking model of Kokoski and Isgur. The obtained behavior of m{sub {rho}}{sup 2}(t) at small momentum squared {ital t} makes the K{sup +}{r_arrow}{pi}{sup +}e{sup +}e{sup {minus}} form factor rise faster with increasing {ital t} than in the original meson dominance calculation and more in agreement with the published data. As a consequence, the meson dominance prediction of the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio changes slightly, from 0.224 to 0.236. We do not see any possibility to accommodate into the meson dominance approach an even steeper e{sup +}e{sup {minus}} spectrum, indicated by the preliminary data of the E865 Collaboration at BNL AGS. {copyright} {ital 1999} {ital The American Physical Society}

Authors:
 [1]
  1. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)|[Institute of Physics, Silesian University, 746-01 Opava (Czech Republic)
Publication Date:
OSTI Identifier:
362722
Resource Type:
Journal Article
Journal Name:
Physical Review, D
Additional Journal Information:
Journal Volume: 60; Journal Issue: 5; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; KAONS PLUS; LEPTONIC DECAY; PIONS PLUS; ELECTRONS; POSITRONS; MUONS PLUS; MUONS MINUS; MASS SPECTRA; VECTOR DOMINANCE MODEL; DISPERSION RELATIONS

Citation Formats

Lichard, P. Implication of the running mass of the {rho}{sup 0} meson for the dilepton mass spectrum and the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio in K{sup +}{r_arrow}{pi}{sup +}l{sup +}l{sup {minus}} decays. United States: N. p., 1999. Web. doi:10.1103/PhysRevD.60.053007.
Lichard, P. Implication of the running mass of the {rho}{sup 0} meson for the dilepton mass spectrum and the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio in K{sup +}{r_arrow}{pi}{sup +}l{sup +}l{sup {minus}} decays. United States. doi:10.1103/PhysRevD.60.053007.
Lichard, P. Wed . "Implication of the running mass of the {rho}{sup 0} meson for the dilepton mass spectrum and the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio in K{sup +}{r_arrow}{pi}{sup +}l{sup +}l{sup {minus}} decays". United States. doi:10.1103/PhysRevD.60.053007.
@article{osti_362722,
title = {Implication of the running mass of the {rho}{sup 0} meson for the dilepton mass spectrum and the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio in K{sup +}{r_arrow}{pi}{sup +}l{sup +}l{sup {minus}} decays},
author = {Lichard, P.},
abstractNote = {We make an attempt to resolve the discrepancy of the observed e{sup +}e{sup {minus}} mass spectrum in the K{sup +}{r_arrow}{pi}{sup +}e{sup +}e{sup {minus}} decay with that predicted by meson dominance. To this end we investigate the properties of the {rho}{sup 0} propagator. We use dispersion relations to evaluate the running mass m{sub {rho}}{sup 2}(t) of the {rho}{sup 0} resonance without adjustable parameters. To improve the convergence of the dispersion integral, the momentum dependence of strong vertices is taken from the flux-tube-breaking model of Kokoski and Isgur. The obtained behavior of m{sub {rho}}{sup 2}(t) at small momentum squared {ital t} makes the K{sup +}{r_arrow}{pi}{sup +}e{sup +}e{sup {minus}} form factor rise faster with increasing {ital t} than in the original meson dominance calculation and more in agreement with the published data. As a consequence, the meson dominance prediction of the {mu}{sup +}{mu}{sup {minus}}/e{sup +}e{sup {minus}} ratio changes slightly, from 0.224 to 0.236. We do not see any possibility to accommodate into the meson dominance approach an even steeper e{sup +}e{sup {minus}} spectrum, indicated by the preliminary data of the E865 Collaboration at BNL AGS. {copyright} {ital 1999} {ital The American Physical Society}},
doi = {10.1103/PhysRevD.60.053007},
journal = {Physical Review, D},
number = 5,
volume = 60,
place = {United States},
year = {1999},
month = {9}
}