Measurement of <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mrow><mrow><msup><mrow><mi>ε</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></mrow><mrow><mi>ε</mi></mrow></mfrac></math></span> in the Neutral Kaon System

R. H. Bernstein; G. J. Bock; D. Carlsmith; D. Coupal; J. W. Cronin; G. D. Gollin; Wen Keling; K. Nishikawa; H. W. M. Norton; B. Winstein; B. Peyaud; R. Turlay; A. Zylberstejn

doi:10.1103/PhysRevLett.54.1631

Measurement of $\frac{ε^{'}}{ε}$ in the Neutral Kaon System

R. H. Bernstein, G. J. Bock, D. Carlsmith, D. Coupal, J. W. Cronin, G. D. Gollin, Wen Keling, K. Nishikawa, H. W. M. Norton, B. Winstein, B. Peyaud, R. Turlay, and A. Zylberstejn

Phys. Rev. Lett. 54, 1631 – Published 15 April 1985

Abstract

A measurement of the ratio of the $CP$ -nonconservation parameters, $\frac{ε^{'}}{ε}$ , in the $K^{0} {\bar{K}}^{0}$ system was performed through a study of two-pion decays with and without a regenerator. To reduce systematic effects, $K_{L}$ and $K_{S}$ decays were recorded simultaneously with a double beam. Over 3100 $K_{L} \to 2 π^{0}$ events were reconstructed leading to the result $\frac{ε^{'}}{ε} = - 0.0046 \pm 0.0053 \pm 0.0024$ (the first error is statistical, the second systematic). The measurement agrees with previous less precise determinations but, because of theoretical uncertainties, is not able to test decisively the Kobayashi-Maskawa mechanism.

Received 30 January 1985

DOI:https://doi.org/10.1103/PhysRevLett.54.1631

Authors & Affiliations

R. H. Bernstein^*, G. J. Bock^†, D. Carlsmith^‡, D. Coupal^§, J. W. Cronin, G. D. Gollin^∥, Wen Keling^¶, K. Nishikawa, H. W. M. Norton^**, and B. Winstein

The Enrico Fermi Institute and the Department of Physics, The University of Chicago, Chicago, Illinois 60637

B. Peyaud, R. Turlay, and A. Zylberstejn

Department de Physique des Particules Elementaires, Centre d'Etudes Nucléaires de Saclay, F-91191 Gif-sur-Yvette Cedex, France

^*Present address: Nevis Laboratories, P. O. Box 137, Irvington-on-Hudson, N.Y. 10533.
^†Present address: Fermilab, P. O. Box 500, Batavia, Ill. 60510.
^‡Present address: University of Wisconsin, Department of Physics, 1150 University of Avenue, Madison, Wis. 53706.
^§Present address: Stanford Linear Accelerator Center, P. O. Box 4349, Stanford, Cal. 94305.
^∥Present address: Department of Physics, Princeton University, P. O. Box 708, Princeton, N.J. 08544.
^¶Present address: Institute of High Energy Physics, Academia Sinica, P. O. Box 918, Beijing, China.
^**Present address: Lazard Freres Co., 31st Floor, 1 Rockefeller Plaza, New York, N.Y. 10020.