Direct measurement of the phi (1020) leptonic branching ratio

Authors
Achasov, MN Beloborodov, KI Berdyugin, AV Bogdanchikov, AG Bozhenok, AV Bukin, AD Bukin, DA Burdin, SV Dimova, TV Drozdetsky, AA Druzhinin, VP Dubrovin, MS Gaponenko, IA Golubev, VB Ivanchenko, VN Ivanov, PM Korol, AA Koshuba, SV Lysenko, AP Nesterenko, IN Pakhtusova, EV Perevedentsev, EA Salnikov, AA Serednyakov, SI Shary, VV Shatunov, YM Sidorov, VA Silagadze, ZK Skrinsky, AN Usov, YV Vasiljev, AV
Citation
Mn. Achasov et al., Direct measurement of the phi (1020) leptonic branching ratio, PHYS REV L, 86(9), 2001, pp. 1698-1701
Citations number
31
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW LETTERS
ISSN journal
00319007 → ACNP
Volume
86
Issue
9
Year of publication
2001
Pages
1698 - 1701
Database
ISI
SICI code
0031-9007(20010226)86:9<1698:DMOTP(>2.0.ZU;2-Q
Abstract
The process e(+)e(-) --> mu (+)mu (-) has been studied by the SND detector at the VEPP-2M e(+)e(-) collider in the phi (1020)-resonance energy region. The measured effective phi meson leptonic branching ratio B(phi --> l(+)l( -)) = rootB(phi --> e(+)e(-))B(phi --> mu (+)mu (-)) = (2.89 +/- 0.10 +/- 0 .06) x 10(-4) agrees well with the Particle Data Group value B(phi --> e(+) e(-)) = (2.91 +/- 0.07) x 10(-4), confirming mu -e universality. Without ad ditional assumption of mu -e universality the branching ratio B(phi --> mu (+)mu (-)) = (2.87 +/- 0.20 +/- 0.14) x 10(-4) was obtained.