Alternative theories of CP violation

Abstract

Recent improvements to the limit of ∆M Bs imply that pure superweak theories, while not excluded, no longer provide a good fit to the data. A class of general superweak theories is introduced in which all flavor changing interactions are governed by an approximate flavor symmetry which gives a "3 mechanism". These theories are in good agreement with data, and predict low values for |V td |, |V ub /V cb |, B(K + → π +ν ν), ǫ ′ /ǫ and CP asymmetries in B decays, and high values for ∆M Bs and f B √ B B . An important example of such a theory is provided by weak scale supersymmetric theories with soft CP violation. The CP violation originates in the squark mass matrix, and, with phases of order unity, flavor symmetries can yield a correct prediction for the order of magnitude of ǫ K .

A real CKM matrix?

“…With all the input data used, included those suggested in [1], that hypothesis is excluded at more than 95% Confidence Level. This result contradicts statements in [1] and agrees with the result indicated in [7] with an older input data set.…”

“…However it is unclear which was the statistical approach followed to come to that statement 1 and a completely different conclusion can be obtained with a standard method. In addition the claim of [1], although using a different input-data-set, contradicts what is reported in [7]. Assuming η = 0 and using exactly the same input parameters as [1] ( (10) and ρ V ub = ±(0.42 ± 0.07) (11) are obtained from eq.…”

“…To this purpose, the measurements of the CP violation parameter in neutral Kaon decay |ǫ k |, of the difference between the mass eigenstates in the B 0 d − B0 d system ∆m d and of the ratio V ub V cb and the lower limit on the difference between the mass eigenstates in the B 0 s − B0 s system ∆m s can be used. On the other hand, since the only direct experimental evidence for CP violation is given by the fact that |ǫ k | = 0 and the effect could be explained in terms of models proposed in alternative to the Standard Model (see, for instance, [7,8] and references therein), it is suggested to remove the constraint coming from the neutral Kaon system and to investigate the results on parameter η or to test the hypothesis of a real V CKM matrix. In this letter the latter hypothesis is tested with a different statistical approach with respect to [1] coming to a different conclusion.…”

Spontaneous CP violation

“…This value is much smaller than C (KM) bd , and negligible. This situation is similar to η = 0 in the standard model, which is not excluded by the experiment [16,23,24].…”

Supersymmetry and CP violating asymmetries in Bd,s decays

“…These recent analyses have shown [12] that LEP2 experiments pose a serious naturalness problem to all conventional mSUGRA models, motivating the search for different SUSY models. In addition, motivated by the recent claim [13] that the CP violating observable ǫ K may have a fully supersymmetric origin in general SUSY models, we feel encouraged to study the predictions of the full range of SUSY flavour models considered in literature on the CP asymmetries to be measured in the upcoming experiments.…”