Precise measurements of direct CP violation, CPT symmetry, and other parameters in the neutral kaon system

E. Abouzaid, M. Arenton, A. R. Barker, M. Barrio, L. Bellantoni, E. Blucher, G. J. Bock, C. Bown, E. Cheu, R. Coleman, M. D. Corcoran, B. Cox, A. R. Erwin, C. O. Escobar, A. Glazov, A. Golossanov, R. A. Gomes, P. Gouffon, J. Graham, J. HammY. B. Hsiung, D. A. Jensen, R. Kessler, K. Kotera, J. Ladue, A. Ledovskoy, P. L. McBride, E. Monnier, H. Nguyen, R. Niclasen, D. G. Phillips, V. Prasad, X. R. Qi, E. J. Ramberg, R. E. Ray, M. Ronquest, A. Roodman, E. Santos, P. Shanahan, P. S. Shawhan, W. Slater, D. Smith, N. Solomey, E. C. Swallow, S. A. Taegar, P. A. Toale, R. Tschirhart, Y. W. Wah, J. Wang, H. B. White, J. Whitmore, M. J. Wilking, B. Winstein, R. Winston, E. T. Worcester, T. Yamanaka, E. D. Zimmerman, R. F. Zukanovich

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123 Scopus citations


We present precise tests of CP and CPT symmetry based on the full data set of K→ππ decays collected by the KTeV experiment at Fermi National Accelerator Laboratory during 1996, 1997, and 1999. This data set contains 16×106 K→π0π0 and 69×106 K→π+π - decays. We measure the direct CP violation parameter Re(ε/ε)=(19.2±2.1)×10-4. We find the KL-KS mass difference Δm=(5270±12) ×106hs-1 and the KS lifetime τS=(89. 62±0.05)×10-12s. We also measure several parameters that test CPT invariance. We find the difference between the phase of the indirect CP violation parameter ε and the superweak phase: φε- φSW=(0.40±0.56)°. We measure the difference of the relative phases between the CP violating and CP conserving decay amplitudes for K→π+π-+-) and for K→π0π0 (φ00): Δφ=(0.30±0.35)°. From these phase measurements, we place a limit on the mass difference between K0 and K̄0: ΔM<4.8×10-19GeV/c2 at 95% C.L. These results are consistent with those of other experiments, our own earlier measurements, and CPT symmetry.

Original languageEnglish (US)
Article number092001
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number9
StatePublished - May 5 2011

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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