Journal article

Disoriented sleptons

We discuss some fundamental concerns regarding the recent proposal of Dimopoulos, Giudice and Tetradis for dynamically aligning the soft masses of the sfermions in the minimal supersymmetric standard model (MSSM) with the corresponding fermion masses to suppress flavor-changing neutral currents. We show that the phenomenologically-favored presence of right-handed neutrinos in the theory, even if only at very high scales, generically disaligns the slepton mass matrices. Further suppression is then needed to meet the current upper bound on the rate for mu --> rho gamma. Planned improvements in the search for mu --> rho gamma should easily detect this rare mode. (With improved sensitivity mu --> 3 rho may also be seen.) By measuring the helicity of the amplitude for mu --> rho gamma such experiments could distinguish between unified and non-unified models at very high energies; by inserting the various MSSM parameters as they become available, the mixing in the leptonic Yukawa couplings can be extracted; and by combining the results with those of various neutrino experiments some information about the right-handed neutrino Majorana matrices can also be gained.

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