First observation of the phi -> pi(+)pi(-)gamma decay

Citation
Rr. Akhmetshin et al., First observation of the phi -> pi(+)pi(-)gamma decay, PHYS LETT B, 462(3-4), 1999, pp. 371-379
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICS LETTERS B
ISSN journal
0370-2693 → ACNP
Volume
462
Issue
3-4
Year of publication
1999
Pages
371 - 379
Database
ISI
SICI code
0370-2693(19990916)462:3-4<371:FOOTP->2.0.ZU;2-#
Abstract
Radiative decays of the phi mason have been studied using a data sample of about 20 million phi decays collected by the CMD-2 detector at VEPP-2M coll ider in Novosibirsk. From selected e(+)e(-)-->pi(+)pi(-)gamma events the ph i -->pi(+)pi(-)gamma decay has been observed for the first time. Under the assumption that the intermediate f(0)(980)gamma state dominates in the phi -->pi(+)pi(-)gamma decay, the corresponding branching ratio is Br(phi --> f (0)(980)gamma) = (1.93 +/- 0.46 +/- 0.50) x 10(-4). Selected e(+)e(-)-->mu( +)mu(-)gamma events were used to obtain Br(phi -->mu(+)mu(-)gamma) = (1.43 +/- 0.45 +/- 0.14) x 10(-5) for E gamma > 20 MeV. Using the same data sampl e, upper limits at 90% CL have been obtained for the C-violating decay of t he phi: Br(phi -->rho gamma) < 1.2 x 10(-5); and for the P- and CP-violatin g decay of the eta: Br(eta -->pi(+)pi(-)) < 3.3 x 10(-4). (C) 1999 Publishe d by Elsevier Science B.V. All rights reserved.