Measurement of the branching ratio for the decay [eta][r arrow][mu][sup +][mu][sup [minus]]

Journal Article · Fri Jul 01 00:00:00 EDT 1994 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.50.92· OSTI ID:7233347

Abegg, R; Baldisseri, A; Boudard, A; Briscoe, W; Fabbro, B; Garcon, M; Hermes, E A; Jacobs, W W; Kessler, R S; Lytkin, L; Mayer, B; Nefkens, B M.K.; Niebuhr, C; Petrov, A M; Poitou, J; Saudinos, J; Tippens, B; Tomasi-Gustafsson, E; van der Schaaf, A; van Oers, W T.H. ; Vigdor, S E; Wang, M; White, D ^[1]

---

1. TRIUMF; 4004 Wesbrook Mall; Vancouver; British Columbia; V6T 2A3 (Canada) Service de Physique Nucleaire; Centre d'Etudes de Saclay; F-91191 Gif-sur-Yvette (France) Center for Nuclear Studies and Department of Physics; The George Washington University; Washington; D.C. 20052 (United States) Physik-Institut der Universitaet Zuerich; CH-8057 Zuerich (Switzerland) Indiana University Cyclotron Facility; 2401 Milo B. Sampson Lane; Bloomington; Indiana 47408 (United States) Laboratoire National Saturne; F-91191 Gif-sur-Yvette (France) Department of Physics; University of California; Los Angeles; California 90024 (United States) Joint Institute for Nuclear Research; Dubna; RU-

A new measurement of the branching ratio for the decay [eta][r arrow][mu][sup +][mu][sup [minus]], made at the SATURNE II proton synchrotron, resulted in [Gamma]([eta][r arrow][mu][sup +][mu][sup [minus]])/[Gamma]([eta][r arrow]all)= [5.7[plus minus]0.7(stat.)[plus minus]0.5(syst.)][times]10[sup [minus]6]. The reaction [ital pd][r arrow][sup 3]He[eta] close to threshold yielded 800 s[sup [minus]1] tagged [eta]'s in a narrow momentum band around 257 MeV/[ital c]. Muon pairs were detected in two range telescopes. The data obtained consist of 114 events [eta][r arrow][mu][sup +][mu][sup [minus]] on a background of 14 events. The new value for the branching ratio is 1.3[plus minus]0.2 times the unitarity lower limit, consistent with most quark and vector meson dominance models which describe the decay as an electromagnetic transition with a two-photon intermediate state. The result resolves the discrepancy between the two previous measurements of this branching ratio.

• OSTI ID: 7233347
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 50:1; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

662350* -- Decays of Mesons-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATORS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
BOSONS
BRANCHING RATIO
CYCLIC ACCELERATORS
DECAY
ELEMENTARY PARTICLES
ETA MESONS
FERMIONS
HADRONS
INTERACTIONS
LEPTONIC DECAY
LEPTONS
MATHEMATICAL MODELS
MATTER
MESONS
MUONS
MUONS MINUS
MUONS PLUS
PARTICLE DECAY
PARTICLE MODELS
PSEUDOSCALAR MESONS
SATURNE II
SYNCHROTRONS
VECTOR DOMINANCE MODEL
WEAK INTERACTIONS
WEAK PARTICLE DECAY