Abstract
From 64492 selected τ-pair events, produced at the Z0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and π0s, and the removal of fake photons. A detailed study of the systematics entering the π0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test τ-μ, universality in hadronic decays, ${cal G}_{∢u}/{cal G}_{ώ}=1.0013pm 0.0095$, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic τ decay width: Rτ,V = 1.788 ± 0 0.025 and Rτ,A = 1.694 ± 0.027. The ratio (Rτ,V − Rτ,A)/(Rτ,V + Rτ,A), equal to (2.7 ± 1.3) %, is a measure of the importance of QCD non-perturbative contributions to the hadronic τ decay width.
Similar content being viewed by others
References
Proceedings of the third Workshop on Tau Lepton Physics, Montreux 1994, L. Rolandi ed., Nucl. Phys. (Proc. Suppl.) B40 (1995).
CELLO Collaboration, H.J. Behrend et al., Zeit. für Physik C46 (1990) 537.
ALEPH Collaboration, D. Decamp et al., Zeit. für Physik C54 (1992) 211.
ALEPH Collaboration,’ Tau leptonic branching ratios’, D. Buskulic et al., preceeding article.
ALEPH Collaboration, D. Buskulic et al., Phys. Lett. B332 (1994) 209.
ALEPH Collaboration, D. Buskulic et al., Phys. Lett. B332 (1994) 219.
ALEPH Collaboration, D. Decamp et al., Nucl. Instr. Methods A294 (1990) 127.
ALEPH Collaboration, D. Buskulic et al., Nucl. Instr. Methods A360 (1995) 481.
S. Jadach, B.F.L. Ward, and Z. Was, Comp. Phys. Comm. 79 (1994) 503.
S. Jadach et al., Comp. Phys. Comm. 76 (1993) 361.
ALEPH Collaboration, D. Decamp et al., Zeit. für Physik C62 (1994) 539.
CLEO Collaboration, D. Bortoletto et al., Phys. Rev. Lett. 71 (1993) 1791.
CLEO Collaboration, M. Artuso et al., Phys. Rev. Lett. 69 (1992) 3278.
DELCO Collaboration, G. Mills et al., Phys. Rev. Lett. 54 (1985) 624.
TPC/Two-Gamma Collaboration, D. Bauer et al., Phys. Rev. D50 (1994) R13.
R. Decker et al., Zeit. für Physik C58 (1993) 445.
P. Bourdon, (ALEPH Collaboration), Proceedings of the third Workshop on Tau Lepton Physics, Montreux 1994, L. Rolandi ed., Nucl. Phys. (Proc. Suppl.) B40 (1995).
S. Snow, Proceedings of the 2nd International Workshop on τ Lepton Physics, Columbus 1992, K.K. Gan ed., World Scientific (1993).
ALEPH Collaboration, D. Buskulic et al., Zeit. für Physik C59 (1993) 369.
N. Isgur et al., Phys. Rev. D39 (1989) 1357.
ARGUS Collaboration, H. Albrecht et al., Zeit. für Physik C58 (1993) 61.
OPAL Collaboration, R. Akers et al., CERN-PPE/95-22.
Z. Was, private communication.
R. Decker and M. Finkemeier, Phys. Rev. D48 (1993) 4203.
W.J. Marciano and A. Sirlin, Phys. Rev. Lett. 61 (1988) 1815.
ALEPH Collaboration, D. Buskulic et al., CERN-PPE/95-128.
Particle Data Group, L. Montanet et al., Phys. Rev. D50 (1994) 1173.
CLEO Collaboration, M. Artuso et al., Phys. Rev. Lett. 72 (1994) 3762.
OPAL Collaboration, R. Akers et al., CERN-PPE/94-42.
L3 Collaboration, M. Acciarri et al., CERN-PPE/94-178.
S. Eidelman et al, Proceedings of the third Workshop on Tau Lepton Physics, Montreux 1994, L. Rolandi ed., Nucl. Phys. (Proc. Suppl.) B40 (1995).
T. Das, V. Mathur and S. Okubo, Phys. Rev. Lett. 18 (1967) 761.
E. Floratos, S. Narison and E. De Rafael, Nucl. Phys. B155 (1979).
OPAL Collaboration, R. Akers et al., CERN-PPE/95-70.
M. Davier, Proceedings of the 2nd International Workshop on τ Lepton Physics, Columbus 1992, K.K. Gan ed., World Scientific (1993).
S. Narison and A. Pich, Phys. Lett. B304 (1993) 359.
E. Braaten, S. Narison and A. Pich, Nucl. Phys. B373 (1992) 581.
CLEO Collaboration, M. Procario et al., Phys. Rev. Lett. 70 (1993) 1207.
CLEO Collaboration, D. Gibaut et al., Phys. Rev. Lett. 73 (1994) 934.
T.N. Pham, C. Roiesnel, and T.N. Truong, Phys. Lett. B78 (1978) 623.
CLEO Collaboration, M. Battle et al., Phys. Rev. Lett. 73 (1994) 1079.
L3 Collaboration, M. Acciarri et al., CERN-PPE/95-42.
A. Pich, Proceedings of the QCD Workshop, Montpellier 1994, S. Narison ed., Nucl. Phys. (Proc. Suppl.) B39 (1995).
DELPHI Collaboration, P. Abreu et al., CERN-PPE/94-88.
CLEO Collaboration, M. Athanas et al., CLEO CONF 94-23, Submitted to Int. Conf. on High Energy Physics, Glasgow, Scotland, July, 1994.
CLEO Collaboration, J. Gronberg et al., CLEO CONF 94-24, Submitted to Int. Conf. on High Energy Physics, Glasgow, Scotland, July, 1994.
CLEO Collaboration, R. Balest et al., CLEO CONF 94-25, Submitted to Int. Conf. on High Energy Physics, Glasgow, Scotland, July, 1994.
Author information
Consortia
Rights and permissions
About this article
Cite this article
ALEPH Collaboration. Tau hadronic branching ratios. Z Phys C - Particles and Fields 70, 579–608 (1996). https://doi.org/10.1007/s002880050134
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s002880050134