Measurement of the Michel parameters and the v<inf>τ</inf> helicity in τ lepton decays

A. Heister; S. Schael; R. Barate; I. de Bonis; D. Decamp; C. Goy; J. P. Lees; E. Merle; M. N. Minard; B. Pietrzyk; S. Bravo; M. P. Casado; M. Chmeissani; J. M. Crespo; E. Fernandez; M. Fernandez-Bosman; Ll Garrido; E. Graugés; M. Martinez; G. Merino; R. Miquel; Ll M. Mir; A. Pacheco; H. Ruiz; A. Colaleo; D. Creanza; M. de Palma; G. Iaselli; G. Maggi; M. Maggi; S. Nuzzo; A. Ranieri; G. Raso; F. Ruggieri; G. Selvaggi; L. Silvestris; P. Tempesta; A. Tricomi; G. Zito; X. Huang; J. Lin; Q. Ouyang; T. Wang; Y. Xie; R. Xu; S. Xue; J. Zhang; L. Zhang; W. Zhao; D. Abbaneo; P. Azzurri; G. Boix; O. Buchmüller; M. Cattaneo; F. Cerutti; B. Clerbaux; G. Dissertori; H. Drevermann; R. W. Forty; M. Frank; T. C. Greening; J. B. Hansen; J. Harvey; P. Janot; B. Jost; M. Kado; P. Mato; A. Moutoussi; F. Ranjard; L. Rolandi; D. Schlatter; O. Schneider; P. Spagnolo; W. Tejessy; F. Teubert; E. Tournefier; J. Ward; Z. Ajaltouni; F. Badaud; A. Falvard; P. Gay; P. Henrard; J. Jousset; B. Michel; S. Monteil; J. C. Montret; D. Pallin; P. Perret; F. Podlyski; J. D. Hansen; J. R. Hansen; P. H. Hansen; B. S. Nilsson; A. Wäänänen; A. Kyriakis; C. Markou; E. Simopoulou; A. Vayaki; K. Zachariadou; A. Blondel

Measurement of the Michel parameters and the v<inf>τ</inf> helicity in τ lepton decays

A. Heister, S. Schael, R. Barate, I. de Bonis, D. Decamp, C. Goy, J. P. Lees, E. Merle, M. N. Minard, B. Pietrzyk, S. Bravo, M. P. Casado, M. Chmeissani, J. M. Crespo, E. Fernandez, M. Fernandez-Bosman, Ll Garrido, E. Graugés, M. Martinez, G. MerinoR. Miquel, Ll M. Mir, A. Pacheco, H. Ruiz, A. Colaleo, D. Creanza, M. de Palma, G. Iaselli, G. Maggi, M. Maggi, S. Nuzzo, A. Ranieri, G. Raso, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, A. Tricomi, G. Zito, X. Huang, J. Lin, Q. Ouyang, T. Wang, Y. Xie, R. Xu, S. Xue, J. Zhang, L. Zhang, W. Zhao, D. Abbaneo, P. Azzurri, G. Boix, O. Buchmüller, M. Cattaneo, F. Cerutti, B. Clerbaux, G. Dissertori, H. Drevermann, R. W. Forty, M. Frank, T. C. Greening, J. B. Hansen, J. Harvey, P. Janot, B. Jost, M. Kado, P. Mato, A. Moutoussi, F. Ranjard, L. Rolandi, D. Schlatter, O. Schneider, P. Spagnolo, W. Tejessy, F. Teubert, E. Tournefier, J. Ward, Z. Ajaltouni, F. Badaud, A. Falvard, P. Gay, P. Henrard, J. Jousset, B. Michel, S. Monteil, J. C. Montret, D. Pallin, P. Perret, F. Podlyski, J. D. Hansen, J. R. Hansen, P. H. Hansen, B. S. Nilsson, A. Wäänänen, A. Kyriakis, C. Markou, E. Simopoulou, A. Vayaki, K. Zachariadou, A. Blondel

Department of Physics

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16 Citations (Scopus)

Abstract

A measurement of the Michel parameters and the average vτ helicity in τ lepton decays is described. The data was collected with the ALEPH detector at LEP during the years 1991 to 1995. A total integrated luminosity of 155 pb-1 is analysed. The Michel parameters ρl, ξl, (ξδ)l (l = e, μ), and ημ are determined for the leptonic decays, and the chirality parameters ξπ, ξρ, and ξa1 for the hadronic final states. Under the assumptions of e-μ universality and ξπ = ξρ = ξa1, the values ρl = 0.742 ± 0.016, ηl = 0.012 ± 0.026, (ξδ)l = 0.776 ± 0.051, ξl = 0.986 ± 0.074, and ξh = 0.992 ± 0.011 are obtained. No significant deviation is observed from the Standard Model assumption of the V - A structure of the charged weak interaction.

Original language	English
Pages (from-to)	217-230
Journal	European Physical Journal C
Volume	22
Issue number	2
Publication status	Published - 1 Jan 2001

Cite this

Heister, A., Schael, S., Barate, R., de Bonis, I., Decamp, D., Goy, C., Lees, J. P., Merle, E., Minard, M. N., Pietrzyk, B., Bravo, S., Casado, M. P., Chmeissani, M., Crespo, J. M., Fernandez, E., Fernandez-Bosman, M., Garrido, L., Graugés, E., Martinez, M., ... Blondel, A. (2001). Measurement of the Michel parameters and the v<inf>τ</inf> helicity in τ lepton decays. European Physical Journal C, 22(2), 217-230.

@article{fdee0349df4f4a0cac3c7cd1b4d27e6a,

title = "Measurement of the Michel parameters and the vτ helicity in τ lepton decays",

abstract = "A measurement of the Michel parameters and the average vτ helicity in τ lepton decays is described. The data was collected with the ALEPH detector at LEP during the years 1991 to 1995. A total integrated luminosity of 155 pb-1 is analysed. The Michel parameters ρl, ξl, (ξδ)l (l = e, μ), and ημ are determined for the leptonic decays, and the chirality parameters ξπ, ξρ, and ξa1 for the hadronic final states. Under the assumptions of e-μ universality and ξπ = ξρ = ξa1, the values ρl = 0.742 ± 0.016, ηl = 0.012 ± 0.026, (ξδ)l = 0.776 ± 0.051, ξl = 0.986 ± 0.074, and ξh = 0.992 ± 0.011 are obtained. No significant deviation is observed from the Standard Model assumption of the V - A structure of the charged weak interaction.",

author = "A. Heister and S. Schael and R. Barate and {de Bonis}, I. and D. Decamp and C. Goy and Lees, {J. P.} and E. Merle and Minard, {M. N.} and B. Pietrzyk and S. Bravo and Casado, {M. P.} and M. Chmeissani and Crespo, {J. M.} and E. Fernandez and M. Fernandez-Bosman and Ll Garrido and E. Graug{\'e}s and M. Martinez and G. Merino and R. Miquel and Mir, {Ll M.} and A. Pacheco and H. Ruiz and A. Colaleo and D. Creanza and {de Palma}, M. and G. Iaselli and G. Maggi and M. Maggi and S. Nuzzo and A. Ranieri and G. Raso and F. Ruggieri and G. Selvaggi and L. Silvestris and P. Tempesta and A. Tricomi and G. Zito and X. Huang and J. Lin and Q. Ouyang and T. Wang and Y. Xie and R. Xu and S. Xue and J. Zhang and L. Zhang and W. Zhao and D. Abbaneo and P. Azzurri and G. Boix and O. Buchm{\"u}ller and M. Cattaneo and F. Cerutti and B. Clerbaux and G. Dissertori and H. Drevermann and Forty, {R. W.} and M. Frank and Greening, {T. C.} and Hansen, {J. B.} and J. Harvey and P. Janot and B. Jost and M. Kado and P. Mato and A. Moutoussi and F. Ranjard and L. Rolandi and D. Schlatter and O. Schneider and P. Spagnolo and W. Tejessy and F. Teubert and E. Tournefier and J. Ward and Z. Ajaltouni and F. Badaud and A. Falvard and P. Gay and P. Henrard and J. Jousset and B. Michel and S. Monteil and Montret, {J. C.} and D. Pallin and P. Perret and F. Podlyski and Hansen, {J. D.} and Hansen, {J. R.} and Hansen, {P. H.} and Nilsson, {B. S.} and A. W{\"a}{\"a}n{\"a}nen and A. Kyriakis and C. Markou and E. Simopoulou and A. Vayaki and K. Zachariadou and A. Blondel",

year = "2001",

month = jan,

day = "1",

language = "English",

volume = "22",

pages = "217--230",

number = "2",

}

Heister, A, Schael, S, Barate, R, de Bonis, I, Decamp, D, Goy, C, Lees, JP, Merle, E, Minard, MN, Pietrzyk, B, Bravo, S, Casado, MP, Chmeissani, M, Crespo, JM, Fernandez, E, Fernandez-Bosman, M, Garrido, L, Graugés, E, Martinez, M, Merino, G, Miquel, R, Mir, LM, Pacheco, A, Ruiz, H, Colaleo, A, Creanza, D, de Palma, M, Iaselli, G, Maggi, G, Maggi, M, Nuzzo, S, Ranieri, A, Raso, G, Ruggieri, F, Selvaggi, G, Silvestris, L, Tempesta, P, Tricomi, A, Zito, G, Huang, X, Lin, J, Ouyang, Q, Wang, T, Xie, Y, Xu, R, Xue, S, Zhang, J, Zhang, L, Zhao, W, Abbaneo, D, Azzurri, P, Boix, G, Buchmüller, O, Cattaneo, M, Cerutti, F, Clerbaux, B, Dissertori, G, Drevermann, H, Forty, RW, Frank, M, Greening, TC, Hansen, JB, Harvey, J, Janot, P, Jost, B, Kado, M, Mato, P, Moutoussi, A, Ranjard, F, Rolandi, L, Schlatter, D, Schneider, O, Spagnolo, P, Tejessy, W, Teubert, F, Tournefier, E, Ward, J, Ajaltouni, Z, Badaud, F, Falvard, A, Gay, P, Henrard, P, Jousset, J, Michel, B, Monteil, S, Montret, JC, Pallin, D, Perret, P, Podlyski, F, Hansen, JD, Hansen, JR, Hansen, PH, Nilsson, BS, Wäänänen, A, Kyriakis, A, Markou, C, Simopoulou, E, Vayaki, A, Zachariadou, K & Blondel, A 2001, 'Measurement of the Michel parameters and the v<inf>τ</inf> helicity in τ lepton decays', European Physical Journal C, vol. 22, no. 2, pp. 217-230.

TY - JOUR

T1 - Measurement of the Michel parameters and the vτ helicity in τ lepton decays

AU - Heister, A.

AU - Schael, S.

AU - Barate, R.

AU - de Bonis, I.

AU - Decamp, D.

AU - Goy, C.

AU - Lees, J. P.

AU - Merle, E.

AU - Minard, M. N.

AU - Pietrzyk, B.

AU - Bravo, S.

AU - Casado, M. P.

AU - Chmeissani, M.

AU - Crespo, J. M.

AU - Fernandez, E.

AU - Fernandez-Bosman, M.

AU - Garrido, Ll

AU - Graugés, E.

AU - Martinez, M.

AU - Merino, G.

AU - Miquel, R.

AU - Mir, Ll M.

AU - Pacheco, A.

AU - Ruiz, H.

AU - Colaleo, A.

AU - Creanza, D.

AU - de Palma, M.

AU - Iaselli, G.

AU - Maggi, G.

AU - Maggi, M.

AU - Nuzzo, S.

AU - Ranieri, A.

AU - Raso, G.

AU - Ruggieri, F.

AU - Selvaggi, G.

AU - Silvestris, L.

AU - Tempesta, P.

AU - Tricomi, A.

AU - Zito, G.

AU - Huang, X.

AU - Lin, J.

AU - Ouyang, Q.

AU - Wang, T.

AU - Xie, Y.

AU - Xu, R.

AU - Xue, S.

AU - Zhang, J.

AU - Zhang, L.

AU - Zhao, W.

AU - Abbaneo, D.

AU - Azzurri, P.

AU - Boix, G.

AU - Buchmüller, O.

AU - Cattaneo, M.

AU - Cerutti, F.

AU - Clerbaux, B.

AU - Dissertori, G.

AU - Drevermann, H.

AU - Forty, R. W.

AU - Frank, M.

AU - Greening, T. C.

AU - Hansen, J. B.

AU - Harvey, J.

AU - Janot, P.

AU - Jost, B.

AU - Kado, M.

AU - Mato, P.

AU - Moutoussi, A.

AU - Ranjard, F.

AU - Rolandi, L.

AU - Schlatter, D.

AU - Schneider, O.

AU - Spagnolo, P.

AU - Tejessy, W.

AU - Teubert, F.

AU - Tournefier, E.

AU - Ward, J.

AU - Ajaltouni, Z.

AU - Badaud, F.

AU - Falvard, A.

AU - Gay, P.

AU - Henrard, P.

AU - Jousset, J.

AU - Michel, B.

AU - Monteil, S.

AU - Montret, J. C.

AU - Pallin, D.

AU - Perret, P.

AU - Podlyski, F.

AU - Hansen, J. D.

AU - Hansen, J. R.

AU - Hansen, P. H.

AU - Nilsson, B. S.

AU - Wäänänen, A.

AU - Kyriakis, A.

AU - Markou, C.

AU - Simopoulou, E.

AU - Vayaki, A.

AU - Zachariadou, K.

AU - Blondel, A.

PY - 2001/1/1

Y1 - 2001/1/1

N2 - A measurement of the Michel parameters and the average vτ helicity in τ lepton decays is described. The data was collected with the ALEPH detector at LEP during the years 1991 to 1995. A total integrated luminosity of 155 pb-1 is analysed. The Michel parameters ρl, ξl, (ξδ)l (l = e, μ), and ημ are determined for the leptonic decays, and the chirality parameters ξπ, ξρ, and ξa1 for the hadronic final states. Under the assumptions of e-μ universality and ξπ = ξρ = ξa1, the values ρl = 0.742 ± 0.016, ηl = 0.012 ± 0.026, (ξδ)l = 0.776 ± 0.051, ξl = 0.986 ± 0.074, and ξh = 0.992 ± 0.011 are obtained. No significant deviation is observed from the Standard Model assumption of the V - A structure of the charged weak interaction.

AB - A measurement of the Michel parameters and the average vτ helicity in τ lepton decays is described. The data was collected with the ALEPH detector at LEP during the years 1991 to 1995. A total integrated luminosity of 155 pb-1 is analysed. The Michel parameters ρl, ξl, (ξδ)l (l = e, μ), and ημ are determined for the leptonic decays, and the chirality parameters ξπ, ξρ, and ξa1 for the hadronic final states. Under the assumptions of e-μ universality and ξπ = ξρ = ξa1, the values ρl = 0.742 ± 0.016, ηl = 0.012 ± 0.026, (ξδ)l = 0.776 ± 0.051, ξl = 0.986 ± 0.074, and ξh = 0.992 ± 0.011 are obtained. No significant deviation is observed from the Standard Model assumption of the V - A structure of the charged weak interaction.

M3 - Article

VL - 22

SP - 217

EP - 230

IS - 2

ER -

Measurement of the Michel parameters and the v<inf>τ</inf> helicity in τ lepton decays

Abstract

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