Distinguishing Between Hierarchical and Lop-sided SO(10) Models

Abstract

A comparative study of two predictive SO(10) models, namely the BPW model (proposed by Babu, Pati and Wilczek) and the AB model (proposed by Albright and Barr) is done based on their predictions regarding CP and flavor violations. The values of Δm_K, ε_K, Δm_{B_d} and S(B_d\to J/ψK_S) are found, in both models, to be close to SM predictions, in good agreement with data. Both models predict that S(B_d\to ϕK_S) should lie in the range +0.65-0.74, close to the SM prediction and that the EDM of the neutron \approx (few\times 10^{-26})e-cm. It is found that $Br(μ\to eγ)$ in the AB model is generically much larger than that in the BPW model, being consistent with the experimental limit only with a rather heavy SUSY spectrum. The BPW model, on the other hand, is consistent with a much lighter SUSY spectrum. In the AB model d_e lies in the range 10^{-27}-10^{-28}e-cm. The BPW model gives d_e to be typically 100 times lower than that in the AB case. Thus the two models can be distinguished based on their predictions regarding CP and flavor violating processes, and can be tested in future experiments.