Physical Sciences and Mathematics Commons^™

Precision E- Beam Polarimetry At An E-E+ B Factory Using Tau-Pair Events, J. P. Lees, V. Poireau, V, Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu. G. Kolomensky, M. Fritsch, H. Koch, R. Cheaib, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, Milind Purohit, Et. Al.

Faculty Publications

We present a new technique, “tau polarimetry,” for measuring the longitudinal beam polarization present in an e⁺e⁻ collider through the analysis of e⁺e⁻ → τ⁺τ⁻ events. By exploiting the sensitivity of τ decay kinematics to the longitudinal polarization of the beams, we demonstrate that the longitudinal polarization can be measured with a 3 per mil systematic uncertainty at the interaction point using a technique that is independent of spin and beam transport modeling. Using 424.2 ± 1.8 fb⁻¹ of BABAR data at √ s = 10.58 GeV, the average longitudinal …