Biomedical subjects

O Lebedev

Publications and source records attributed to O Lebedev.

4 recordsLinked to original sources

PubMed2002

Additional stringy sources for electric dipole moments.

We show that string models with low energy supersymmetry which accommodate the fermion mass hierarchy generally give nonuniversal soft trilinear couplings (A terms). In conjunction with the apparently large Cabibbo-Kobayashi-Maskawa (CKM) phase, this results in large fermion electric dipole moments (EDMs) even in the absence of CP violating phases in the supersymmetry breaking auxiliary fields and the micro term. Nonobservation of the EDMs therefore implies that strings select special flavor and/or supersymmetry breaking patterns.

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PubMed2001

Electric dipole moment cancellations in D-brane models.

We analyze the possibility of simultaneous electron, neutron, and mercury electric dipole moment (EDM) cancellations in the mSUGRA and D-brane models. We find that the mercury EDM constraint practically rules out the cancellation scenario in D-brane models, whereas in the context of mSUGRA it is still allowed with some fine tuning.

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PubMed2000

Universal torsion-induced interaction from large extra dimensions

We consider the Kaluza-Klein (KK) scenario in which only gravity exists in the bulk. Without the assumption of symmetric connection, the presence of brane fermions induces torsion. The result is a universal axial contact interaction that dominates those induced by KK gravitons. This enhancement arises from a large spin density on the brane. Using a global fit to Z-pole observables, we find the 3sigma bound on the scale of quantum gravity to be 28 TeV for n = 2. If Dirac or light sterile neutrinos are present, the data from SN1987A increase the bound to sqrt[n] M(S)>/=210 TeV.

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PubMed2000

Can flavor-independent supersymmetric soft phases Be the source of all CP violation?

Recently it has been demonstrated that large phases in softly broken supersymmetric (SUSY) theories are consistent with electric dipole moment constraints, and are motivated in some (type I) string models. Here we consider whether large flavor-independent soft phases may be the dominant (or only) source of all CP violation. In this framework, epsilon and epsilon(')/epsilon can be accommodated, and the SUSY contribution to the B system mixing can be large and dominant. An unconventional flavor structure of the squark mass matrices (with enhanced super-Cabibbo-Kobayashi-Maskawa mixing) is required for consistency with B and K system observables.

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