arXiv subjects

D. Demir

Publications and source records attributed to D. Demir.

3 recordsLinked to original sources

arXiv2022

A quantum cosmology approach to cosmic coincidence and inflation

This work studies the quantum cosmology of a closed, spatially homogeneous, and isotropic FLRW minisuperspace model with electromagnetic radiation as a matter content. We solve the associated Wheeler-DeWitt (WDW) equation using the holographic regularization method and show that the electromagnetic zero-point energy forms the vacuum energy and provides a unified resolution to the horizon, flatness, singularity, and cosmic coincidence problems. This quantum cosmology approach composes an alternative to the usual inflationary paradigm and can be extended to more general matter contents and emergent gravity schemes.

gr-qc↗

arXiv2006

Correlating Mu Parameter and Right-Handed Neutrino Masses in N=1 Supergravity

The minimal supersymmetric standard model, when extended to embed the seesaw mechanism, obtains two dimensionful parameters in its superpotential: the mu parameter and the right-handed neutrino mass M_N. These mass parameters, belonging to the supersymmetric sector of the theory, pose serious naturalness problems as their scales are left completely undetermined. In fact, for correct phenomenology, mu must be stabilized at the electroweak scale while M_N lies at an intermediate scale. In this work we construct an explicit model of the hidden sector of N=1 supergravity for inducing both mu and M_N at their right scales. The model we build utilizes lepton number conservation and continuous R invariance as two fundamental global symmetries to forbid bare mu and M_N appearing in the superpotential, and induces them at phenomenologically desired scales via spontaneous breakdown of the global symmetries and the supergravity. We discuss briefly various phenomenological implications of the model.

hep-ph↗

arXiv2005

Can Measurements of Electric Dipole Moments Determine the Seesaw Parameters?

In the context of the supersymmetrized seesaw mechanism embedded in the Minimal Supersymmetric Standard Model (MSSM), complex neutrino Yukawa couplings can induce Electric Dipole Moments (EDMs) for the charged leptons, providing an additional route to seesaw parameters. However, the complex neutrino Yukawa matrix is not the only possible source of CP violation. Even in the framework of Constrained MSSM (CMSSM), there are additional sources, usually attributed to the phases of the trilinear soft supersymmetry breaking couplings and the mu-term, which contribute not only to the electron EDM but also to the EDMs of neutron and heavy nuclei. In this work, by combining bounds on various EDMs, we analyze how the sources of CP violation can be discriminated by the present and planned EDM experiments.

hep-ph↗