ANALYSIS OF THE DECAY TAU--]PI-PI-TAU AND DETERMINATION OF THE A1 (1260) RESONANCE PARAMETERS(NU)

Authors
ALBRECHT H EHRLICHMANN H HAMACHER T HOFMANN RP KIRCHHOFF T NAU A NOWAK S SCHRODER H SCHULZ HD WALTER M WURTH R APPUHN RD HAST C KOLANOSKI H LANGE A LINDNER A MANKEL R SCHIEBER M SIEGMUND T SPAAN B THURN H TOPFER D WALTHER A WEGENER D BITTNER M ECKSTEIN P PAULINI M REIM K WEGENER H MUNDT R OEST T REIMER R SCHMIDTPARZEFALL W FUNK W STIEWE J WERNER S EHRET K HOFMANN W HUPPER A KHAN S KNOPFLE KT SPENGLER J BRITTON DI CHARLESWORTH CEK EDWARDS KW HYATT ERF KAPITZA H KRIEGER P MACFARLANE DB PATEL PM PRENTICE JD SAULL PRB TZAMARIUDAKI K VANDEWATER RG YOON TS RESSING D SCHMIDTLER M SCHNEIDER M SCHUBERT KR STRAHL K WALDI R WESELER S KERNEL G KRIZAN P KRIZNIC E PODOBNIK T ZIVKO T BALAGURA V BELYAEV I CHECHELNITSKY S DANILOV M DROUTSKOY A GERSHTEIN Y GOLUTVIN A GORELOV I KOSTINA G LUBIMOV V PAKHLOV P RATNIKOV F SEMENOV S SHIBAEV V SOLOSHENKO V TICHOMIROV I ZAITSEV Y
Citation
H. Albrecht et al., ANALYSIS OF THE DECAY TAU--]PI-PI-TAU AND DETERMINATION OF THE A1 (1260) RESONANCE PARAMETERS(NU), Zeitschrift fur Physik. C, Particles and fields, 58(1), 1993, pp. 61-70
Citations number
34
Journal title
Zeitschrift fur Physik. C, Particles and fields → ACNP
ISSN journal
01709739
Volume
58
Issue
1
Year of publication
1993
Pages
61 - 70
Database
ISI
SICI code
0170-9739(1993)58:1<61:AOTDTA>2.0.ZU;2-C
Abstract
Using the ARGUS detector at the DORIS II e+e- storage ring we have stu died the three-pion hadronic final state in the decay tau- --> pi- pi- pi+ nu(tau). From about 7500 events we conclude that the three-pion s ystem is dominated by the J(P)=1+ resonance a1 (1260) decaying prefere ntially via rho0pi-. Our data restrict a possible rhopi contribution o f three-pion states without intermediate resonances to less than 6% at 95% CL. Fitting a model by Isgur et al. to the data yields m(a1) = (1 .211 +/- 0.007 +/- 0.0(0.050)) GeV/c2 and GAMMA(a1) = (0.446 +/- 0.021 +/- 0.0(0.140)) GeV/c2. The second errors reflect the model dependenc e of the result. This is the currently most significant determination of the a1 resonance parameters. The ratio of S- and D-wave amplitudes for the rho0pi- intermediate state of the a1- decay at the nominal a1- mass was found to be D/S = -0.11 +/- 0.02. Using this D/S ratio we up date our former measurement of the parity violating asymmetry paramete r gamma(AV) = 2g(A)g(V)/(g(A)2 + g(V)2) to 1.25 +/- 0.23 +/- 0.15/0.08 . The branching ratio of the decay tau- --> pi- pi- pi+ nu(tau) is det ermined to be Br(tau- --> pi- pi- pi+ nu(tau)) = (6.8 +/- 0.1 +/- 0.5) %.