Physics of the tau lepton Jorge Portols Instituto de Fsica - PowerPoint PPT Presentation

Physics of the tau lepton Jorge Portolés Instituto de Física Corpuscular CSIC-UVEG, Valencia (Spain)

Leptons [1] Discovery of the tau lepton SLAC-LBL (SLAC,1975), PLUTO (DESY,1976) “anomalous” e  events [2] Momentum of e or   DONuT (Direct Observation of Nu Tau), 2000

P ª Pseudoscalar meson Decay spectrum    p, n   ’  K   [1.77682(16)]  e (GeV ) 1 2

Experiment Estimate Process

Outline  Leptonic decays  Hadron decays Inclusive tau decays:  S (M  ) and |V us | I. II. Exclusive tau decays: Hadronization of QCD currents E. g.

[3] Charged current universality 1. Lepton decays

[4] 2. Hadron decays

What can we get? 1. Inclusive decays: full hadron spectra. Precision physics. Study of Standard Model parameters :  S (M  ), |V us |, m S Approximate 2. Exclusive decays: specific hadron spectrum. physics P = pseudoscalar meson Study of form factors, resonance parameters (M R ,  R ), hadronization of QCD currents.

2 2.1 Inclusive hadron decays 2

2 [5]

A A + V V S=1 S=0

A A + V J [6] V

[7] [8]

Working on the theoretical prediction of …. to get , ..... analytic everywhere except on the positive real axis analytic [9] Im(s) OPE 2 M  Re(s) Quark-Hadron duality violation

Perturbative contribution [8,11,12] [3,10]

[14] [15] [13] Non-perturbative contributions [9, 13]

Reference Method Baikov et al. [12] CIPT, FOPT 0.1998 (43) - 0.332 (16) 0.1202 (19) Davier et al. [8] CIPT 0.2066 (70) -0.0059 (14) 0.344 (09) 0.1212 (11) Beneke-Jamin [16] BSR + FOPT 0.2042 (50) -0.007 (03) 0.316 (06) 0.1180 (08) Maltman-Yavin [17] PWM + CIPT - +0.012 (18) 0.321 (13) 0.1187 (16) Menke [18] CIPT, FOPT 0.2042 (50) - 0.342 (11) 0.1213 (12) Narison [19] CIPT, FOPT - - 0.324 (08) 0.1192 (10) Caprini-Fischer [20] BSR + CIPT 0.2037 (54) - 0.322 (16) - Abbas et al. [21] IFOPT 0.2037 (54) - 0.338 (10) -  exp + CIPT Cvetic et al. [22] 0.2040 (40) - 0.341 (08) 0.1211 (10) Boito et al. [23] CIPT, DV - -0.002 (12) 0.347 (25) 0.1216 (27) FOPT, DV - -0.004 (12) 0.325 (18) 0.1191 (22) Pich [24] CIPT, FOPT 0.1995 (33) -0.0059 (14) 0.329 (13) 0.1198 (15)  exp : Expansion in derivatives of  s CIPT : Contour-improved perturbation theory FOPT : Fixed-order perturbation theory PWM : Pinched-weight moments BSR : Borel summation of renormalon series DV : Duality violation IFOPT: Improved FOPT

m S and |V us | from inclusive tau data decays [25, 26]

[Gamiz, 05]

V us Unitarity (2005) RBC/UK (2009) 0.23 Expts QCD, 06 0.2275 (2005) V 0.225 (2007) us M = Maltman (2009) 0.2225 B CHPT+ P = Pich (2013) JOP LR 0.22 (2004) BT 0.2175 CHPT+ (2004) N C, (2005) M P LR = Leutwyler-Roos (1984) BT = Bijnens-Talavera (2003) Expts = FLAVIAnet WG (2010) JOP = Jamin-Oller-Pich (2004) CHPT+N C = Cirigliano et al (2006) B = A. Bazavov et al. (2012)

2.2 Exclusive hadron decays

Examples

[27,28] Phenomenological Lagrangians : Tree Level

[29,30,31] +

[32]

1. Inclusive decays: full hadron spectra. Precision physics. Study of Standard Model parameters :  S (M  ), |V us |, m S 2. Exclusive decays: specific hadron spectrum. Approximate physics P = pseudoscalar meson Study of form factors, resonance parameters (M R ,  R ), hadronization of QCD currents.

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