2022 Impact factor 4.4
Particles and Fields
Eur. Phys. J. C 27, 33-41 (2003)
DOI: 10.1140/epjc/s2002-01087-0

CP-violation in the production of $\tau$-leptons at TESLA with beam polarization

B. Ananthanarayan1, S.D. Rindani2 and A. Stahl3

1  Centre for Theoretical Studies, Indian Institute of Science, Bangalore 560 012, India
2  Theory Group, Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, India
3  DESY, Platanenallee 6, 15738 Zeuthen, Germany

(Received: 13 June 2002 / Revised version: 17 October 2002 Published online: 20 December 2002)

We study the prospects of discovering CP-violation in the production of $\tau$ leptons in the reaction $e^+ e^- \to \tau^+ \tau^-$ at TESLA, an e+e- linear collider with center-of-mass energies of 500 or even 800 GeV. Non-vanishing expectation values of certain correlations between the momenta of the decay products of the two $\tau$ leptons would signal the presence of CP-violation beyond the standard model. We study how longitudinal beam polarization of the electron and positron beams will enhance these correlations. We find that T-odd and T-even vector correlations are well suited for the measurements of the real and imaginary parts of the electric dipole form factors. We expect measurements of the real part with a precision of roughly 10-20 e cm and of the imaginary part of 10-17 e cm. This compares well with the size of the expected effects in many extensions of the standard model.

© Società Italiana di Fisica, Springer-Verlag 2003