Constraint on the mass scale of a left-right-symmetric electroweak theory from the KL-KS mass difference

The KL-KS mass difference provides a stringent constraint on the mass (MR) of the charged right-handed gauge field occurring in a "manifest" left-right-symmetric electroweak theory, yielding MR1.6 TeV. Taken in the context of a grand-unifying gauge theory, e.g., O(10), such a large bound on MR, along with the measured value of sin2θW, implies that MR109 GeV. © 1982 The American Physical Society