Alavi-Harati A, Alexopoulos T, Arenton M, Barbosa R F, Barker A R, Barrio M, Bellantoni L, Bellavance A, Blucher E, Bock G J, Bown C, Bright S, Cheu E, Coleman R, Corcoran M D, Cox B, Erwin A R, Escobar C O, Ford R, Glazov A, Golossanov A, Gomes R A, Gouffon P, Graham J, Hamm J, Hanagaki K, Hsiung Y B, Huang H, Jejer V, Jensen D A, Kessler R, Kobrak H G E, Kotera K, LaDue J, Lai N, Ledovskoy A, McBride P L, Monnier E, Nelson K S, Nguyen H, Ping H, Prasad V, Qi X R, Quinn B, Ramberg E J, Ray R E, Ronquest M, Santos E, Senyo K, Shanahan P, Shields J, Slater W, Smith D E, Solomey N, Swallow E C, Taegar S A, Tesarek R J, Toale P A, Tschirhart R, Velissaris C, Wah Y W, Wang J, White H B, Whitmore J, Wilking M, Winstein B, Winston R, Worcester E T, Yamanaka T, Zukanovich R F
University of Wisconsin, Madison, Wisconsin 53706, USA.
Phys Rev Lett. 2004 Jul 9;93(2):021805. doi: 10.1103/PhysRevLett.93.021805.
The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay K(L)-->pi(0)e(+)e(-). This mode is expected to have a significant CP violating component. The measurement of its branching ratio could support the standard model or could indicate the existence of new physics. This Letter reports new results from the 1999-2000 data set. One event is observed with an expected background at 0.99+/-0.35 events. We set a limit on the branching ratio of 3.5x10(-10) at the 90% confidence level. Combining with the previous result based on the data set taken in 1997 yields the final KTeV result: BR(K(L)-->pi(0)e(+)e(-))<2.8x10(-10) at 90% C.L.
费米实验室的KTeV/E799实验搜寻了罕见的K介子衰变K(L)-->π(0)e(+)e(-)。预计这种模式会有显著的CP破坏成分。对其分支比的测量可能支持标准模型，也可能表明新物理的存在。本信函报告了1999 - 2000数据集的新结果。观测到一个事例，预期本底为0.99±0.35个事例。我们在90%置信水平下对分支比设定了3.5×10(-10)的上限。结合基于1997年数据集的先前结果，得到了KTeV的最终结果：在90%置信水平下，BR(K(L)-->π(0)e(+)e(-))<2.8×10(-10) 。
