Hadronic structure in the decay tau(-) -> nu(tau)pi(-) pi(0) pi(0) and thesign of the tau neutrino helicity - art. no. 012002

Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, HN Nelson, TK Roberts, D Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Boisvert, V Cassel, DG Crowcroft, DS Dickson, M von Dombrowski, S Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescot, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Briere, RA Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JI Williams, J Edwards, KW Bellerive, A Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhao, X Zhou, L Anderson, S Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lorenc, J Schwarthoff, H Wolf, A Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Glenn, S Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, S Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonivicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V
Dm. Asner et al., Hadronic structure in the decay tau(-) -> nu(tau)pi(-) pi(0) pi(0) and thesign of the tau neutrino helicity - art. no. 012002, PHYS REV D, 6101(1), 2000, pp. 2002
Citations number
Categorie Soggetti
Journal title
ISSN journal
0556-2821 → ACNP
Year of publication
SICI code
Based on a sample corresponding to 4.3 x 10(6) produced tau-pair events, we have studied hadronic dynamics in the decay tau(-)--> nu(tau) pi(-) pi(o)p i(o) in data recorded by the CLEO II detector operating at the CESR e(+)e(- ) collider. The decay is dominated by the process tau(-)-->nu(tau)a(1)(-)(1 260), with the a(1)(-) meson decaying to three pions predominantly via the lowest dimensional (mainly S-wave) rho(-)pi(o) Born amplitude. From model-d ependent fits to the Dalitz plot and angular observables in bins of 3 pi ma ss, we find significant additional contributions from amplitudes for a(1) d ecay to sigma pi, f(o)(1370) pi, and f(2)(1270) pi, as well as higher dimen sional a(1)-->rho pi and rho' pi amplitudes. Notably, the squared sigma pi amplitude accounts for approximately 15% of the total tau(-)-->nu(tau)pi(-) pi(o)pi(o) rate in the models considered. The data are well described using couplings to these amplitudes that are independent of the 3 pi mass. These amplitudes also provide a good description for the tau(-) -->nu(tau)pi(-)p i(+)pi(-) Dalitz plot distributions. We have searched for additional contri butions from tau(-)-->nu(tau)pi' -(1300). We place 90% confidence level upp er limits on the branching fraction for this channel of between 1.0 x 10(-4 ) and 1.9 x 10(-4), depending on the pi' decay mode considered. The pi(-)pi (o)pi(o) mass spectrum is parametrized by a Breit-Wigner form with a mass-d ependent width which is specified according to the results of the Dalitz pl ot fits plus an unknown coupling to an a(1)-->K*K amplitude. From a chi(2) fit using this parametrization, we extract the pole mass and width of the a (1), as well as the magnitude of the K*K coupling. We have also investigate d the impact of a possible contribution from the a(1)'(1700) meson on this spectrum. Finally, exploiting the parity-violating angular asymmetry in a(1 )-->3 pi decay, we determine the signed value of the tau neutrino helicity to be h(nu tau) = - 1.02+/-0.13 (stat) +/- 0.03 (syst + model), confirming the left-handedness of the tau neutrino.