A new limit on the CP violating decay KS -> 3pi0 with the KLOE experiment
Abstract
We have carried out a new direct search for the CP violating decay KS -> 3pi0 with 1.7 fb^-1 of e+e- collisions collected by the KLOE detector at the phi-factory DAFNE. We have searched for this decay in a sample of about 5.9 x 10^8 KS KL events tagging the KS by means of the KL interaction in the calorimeter and requiring six prompt photons. With respect to our previous search, the analysis has been improved by increasing of a factor four the tagged sample and by a more effective background rejection of fake KS tags and spurious clusters. We find no candidates in data and simulated background samples, while we expect 0.12 standard model events. Normalizing to the number of KS -> 2pi0 events in the same sample, we set the upper limit on BR(KS -> 3pi0 < 2.6 x 10^-8 at 90% C.L., five times lower than the previous limit. We also set the upper limit on the eta_000 parameter, |eta_000 | < 0.0088 at 90% C.L., improving by a factor two the latest direct measurement.
Keywords
Cite
@article{arxiv.1301.7623,
title = {A new limit on the CP violating decay KS -> 3pi0 with the KLOE experiment},
author = {D. Babusci and D. Badoni and I. Balwierz-Pytko and G. Bencivenni and C. Bini and C. Bloise and F. Bossi and P. Branchini and A. Budano and L. Caldeira Balkestahl and G. Capon and F. Ceradini and P. Ciambrone and F. Curciarello and E. Czerwinski and E. Dane and V. De Leo and E. De Lucia and G. De Robertis and A. De Santis and A. Di Domenico and C. Di Donato and R. Di Salvo and D. Domenici and O. Erriquez and G. Fanizzi and A. Fantini and G. Felici and S. Fiore and P. Franzini and P. Gauzzi and G. Giardina and S. Giovannella and F. Gonnella and E. Graziani and F. Happacher and L. Heijkenskjold and B. Hoistad and L. Iafolla and M. Jacewicz and T. Johansson and K. Kacprzak and A. Kupsc and J. Lee-Franzini and B. Leverington and F. Loddo and S. Loffredo and G. Mandaglio and M. Martemianov and M. Martini and M. Mascolo and R. Messi and S. Miscetti and G. Morello and D. Moricciani and P. Moskal and F. Nguyen and A. Passeri and V. Patera and I. Prado Longhi and A. Ranieri and C. F. Redmer and P. Santangelo and I. Sarra and M. Schioppa and B. Sciascia and M. Silarski and C. Taccini and L. Tortora and G. Venanzoni and W. Wislicki and M. Wolke and J. Zdebik},
journal= {arXiv preprint arXiv:1301.7623},
year = {2013}
}
Comments
Accepted for publication in Physics Letters B (15 pages, 13 figures)