arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1301.7623hep-ex
收藏

用KLOE实验对KS -> 3 π 0破坏衰变的新极限

A new limit on the CP violating decay KS -> 3pi0 with the KLOE experiment

D. Babusci, D. Badoni, I. Balwierz-Pytko, G. Bencivenni, C. Bini, C. Bloise, F. Bossi, P. Branchini, A. Budano, L. Caldeira Balkestahl, G. Capon, F. Ceradini, P… 展开作者

D. Babusci, D. Badoni, I. Balwierz-Pytko, G. Bencivenni, C. Bini, C. Bloise, F. Bossi, P. Branchini, A. Budano, L. Caldeira Balkestahl, G. Capon, F. Ceradini, P. Ciambrone, F. Curciarello, E. Czerwinski, E. Dane, V. De Leo, E. De Lucia, G. De Robertis, A. De Santis, A. Di Domenico, C. Di Donato, R. Di Salvo, D. Domenici, O. Erriquez, G. Fanizzi, A. Fantini, G. Felici, S. Fiore, P. Franzini, P. Gauzzi, G. Giardina, S. Giovannella, F. Gonnella, E. Graziani, F. Happacher, L. Heijkenskjold, B. Hoistad, L. Iafolla, M. Jacewicz, T. Johansson, K. Kacprzak, A. Kupsc, J. Lee-Franzini, B. Leverington, F. Loddo, S. Loffredo, G. Mandaglio, M. Martemianov, M. Martini, M. Mascolo, R. Messi, S. Miscetti, G. Morello, D. Moricciani, P. Moskal, F. Nguyen, A. Passeri, V. Patera, I. Prado Longhi, A. Ranieri, C. F. Redmer, P. Santangelo, I. Sarra, M. Schioppa, B. Sciascia, M. Silarski, C. Taccini, L. Tortora, G. Venanzoni, W. Wislicki, M. Wolke, J. Zdebik

摘要:

我们利用φ工厂DAFNE的KLOE探测器收集的1.7 fb^-1的e+e碰撞,对CP破坏衰变KS -> 3 pi 0进行了新的直接搜索。我们在一个约为5.9 × 10^8 KS KL事件的样本中寻找这种衰变,该样本通过量热计中的KL相互作用标记KS,并且需要6个瞬发光子。相对于我们以前的搜索,分析已得到改善,增加了四个因素的标记的样本,并通过更有效的背景拒绝假KS标签和虚假集群。我们在数据和模拟背景样本中没有发现候选事件,而我们预计有0.12个标准模型事件。对同一样本中KS -> 2 pi 0事件的数量进行归一化,我们设定BR的上限(KS -> 3 pi 0 < 2.6 x 10^-8,90% C.L.,比以前的限额低五倍。我们还设置了eta_000参数的上限,|eta_000|在90% C.L.时< 0.0088,将最新的直接测量结果提高了两倍。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑