Helicity-flip bremsstrahlung and the measurement of CP-violating form factors in polarized e+e- collisions.
Helicity-flip bremsstrahlung and the measurement of CP-violating form factors in polarized e+e- collisions.
复制标题
螺旋翻转轫致辐射和偏振电子碰撞中 CP 破坏形状因子的测量。
DOI：
10.1103/physrevd.52.2684
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Rindani
中科院分区：
文献类型：
--
作者：
Ananthanarayan;Rindani
在{电子e}{sup +}{电子e}{sup{负}}碰撞中，重费米子对的产生和随后的衰变中的某些动量关联增加了费米子在{电子e}{sup +}{电子e}{sup{负}}光束纵向极化存在下对违反{电子CP}的电和“弱”偶极子形式因子的敏感性。然而，除非{ital e}{sup +}和{ital e}{sup{-}}的极化相等且相反，否则伴随螺旋翻转的共线初始态辐射会导致{ital CP}不变的贡献，并作为背景，必须计算和减去，以便隔离由于偶极子形状因素导致的{ital CP}违反贡献。我们计算这种相关性的背景贡献，排序为{alpha}，在{ital e}{sup +}{ital e}{sup{负}}{r_arrow}{tau}{sup +}{tau}{sup{负}}和{ital e}{sup +}{ital e}{sup{负}}{r_arrow}{ital t{bar t}}。对于{tau}符码工厂和SLC的预期亮度，对于{tau}，以及未来的线性对撞机，顶夸克的质心能量为500 GeV，这些背景比统计背景小，可以安全忽略。
Certain momentum correlations in the production and subsequent decay of heavy fermion pairs in {ital e}{sup +}{ital e}{sup {minus}} collisions have increased sensitivity to {ital CP}-violating electric and ``weak`` dipole form factors of the fermion in the presence of longitudinal polarization of the {ital e}{sup +}{ital e}{sup {minus}} beams. However, unless the polarizations of {ital e}{sup +} and {ital e}{sup {minus}} are equal and opposite, collinear initial-state radiation accompanied by helicity flip results in a {ital CP}-invariant contribution to these and acts as a background, and must be calculated and subtracted in order to isolate the {ital CP}-violating contribution due to the dipole form factor. We calculate this background contribution to such correlations, to order {alpha}, in {ital e}{sup +}{ital e}{sup {minus}}{r_arrow}{tau}{sup +}{tau}{sup {minus}} and {ital e}{sup +}{ital e}{sup {minus}}{r_arrow}{ital t{bar t}}. For the anticipated luminosities at {tau}-charm factories and the SLC, for the {tau}, and at a future linear collider with a center-of-mass energy of 500 GeV for the top quark, these backgrounds are smaller than the statistical background and may be safely neglected.