Measurement of the [ital CP]-violation parameter [eta][sub +[minus][gamma]] in neutral kaon decays

Journal Article · Mon Apr 26 04:00:00 EDT 1993 · Physical Review Letters; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.70.2529· OSTI ID:6582915

Ramberg, E J; Bock, G J; Coleman, R; Enagonio, J; Hsiung, Y B; Stanfield, K; Tschirhart, R; Yamanaka, T ^[1]; Barker, A R; Briere, R A; Gibbons, L K; Makoff, G; Papadimitriou, V; Patterson, J R; Somalwar, S; Wah, Y W; Winstein, B; Winston, R; Woods, M; Yamamoto, H ^[2] ; Swallow, E C ^[3]; Blair, G; Gollin, G D; Karlsson, M; Okamitsu, J K ^[4]; Debu, P; Payaud, B; Turlay, R; Vallage, B ^[5]

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1. Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)
2. The Enrico Fermi Institute and the Department of Physics, The University of Chicago, Chicago, Illinois 60637 (United States)
3. Department of Physics, Elmhurst College, Elmhurst, Illinois 60126 (United States) The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)
4. Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)
5. Department de Physique des Particules Elementaires, Centre d'Etudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette CEDEX (

Interference between [ital K][sub [ital S]] and [ital K][sub [ital L]] decays into the final state [pi][sup +][pi][sup [minus]][gamma] has been observed in experiment 731 at Fermilab. By fitting the distribution of decays downstream of a regenerator, a new CP-violation parameter [eta][sub +[minus][gamma]], analogous to [eta][sub +[minus]], has been measured, with its magnitude equal to (2.15[plus minus]0.26[plus minus]0.20)[times]10[sup [minus]3], and [phi][sub +[minus][gamma]], the associated phase angle, equal to (72[plus minus]23[plus minus]17)[degree]. Assuming that any difference between this fit value for [eta][sub +[minus][gamma]] and the previously measured value for [eta][sub +[minus]] can be attributed to direct CP violation in this decay, a limit of [vert bar][ital e][sub +[minus][gamma]][sup [prime]][vert bar]/[epsilon][lt]0.3 at the 90% confidence level has been made.

• OSTI ID: 6582915
• Journal Information: Physical Review Letters; (United States), Journal Name: Physical Review Letters; (United States) Vol. 70:17; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

662120 -- General Theory of Particles & Fields-- Symmetry
Conservation Laws
Currents & Their Properties-- (1992-)
662350* -- Decays of Mesons-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOSONS
CP INVARIANCE
DECAY
ELEMENTARY PARTICLES
HADRONS
INTERFERENCE
INVARIANCE PRINCIPLES
KAONS
KAONS NEUTRAL
KAONS NEUTRAL LONG-LIVED
KAONS NEUTRAL SHORT-LIVED
MASSLESS PARTICLES
MESONS
PHOTONS
PIONS
PIONS MINUS
PIONS PLUS
PSEUDOSCALAR MESONS
STRANGE MESONS
STRANGE PARTICLES
SYMMETRY BREAKING