EDUCATION:

Ph.D. 2000, University of Maryland-CollegePark

RESEARCH:

My main interest is in the area of physics beyond the standard model. In spite of the great success of the standard model of particle physics, the precise nature of the electroweak symmetry breaking sector remains rather mysterious. In the past few years I have concentrated on extensions of the standard model that can shed light on the "hierarchy problem", i.e. the great sensitivity of the electroweak scale to higher energy scales. Naturality considerations lead us to propose the existence of new physics at the electroweak scale, that should be observable in the near future by experiments such as the LHC. Among the leading candidate theories for the new physics at the TeV scale are supersymmetry and extra-dimensional scenarios.

I have worked on supersymmetric extensions of the standard model, in particular on scenarios for the mediation of supersymmetry breaking. As it turns out, the manner in which this breaking is transmitted to the observable sector is crucial in maintaining the agreement of the low-energy predictions with constraints on flavor violation. The pattern of supersymmetry breaking also determines the spectrum of superpartners and their collider phenomenology. Thus, the measurement of the properties of the superpartners can provide a window into the physics of supersymmetry breaking, that itself may lie at energies we cannot probe directly.

More recently, I have focused my attention on scenarios with extra dimensions at the TeV scale. A very attractive solution to the hierarchy problem, known as the Randall-Sundrum scenario, relies on the high curvature of a 5-dimensional spacetime. This setup explains the exponential hierarchy between the Planck and electroweak scales as the result of a gravitational red-shift when different positions along the fifth dimension are compared. If the standard model gauge and fermions fields propagate in the 5-dimensional bulk, these scenarios become consistent with gauge coupling unification, and also allow an understanding of the observed fermion mass hierarchies as the result of the localization of the fermions along the extra dimension. An additional attractive  possibility is that the Higgs field be part of a higher dimensional gauge field (corresponding to the polarizations in the fifth dimension). These "warped gauge-Higgs unification" scenarios can elegantly give rise to the weak scale, and predict new physics accessible at colliders, while being consistent with all electroweak precision and other low-energy measurements.

These are exciting times, as during the following years high-energy experiments will probe in great detail the energy range where the electroweak symmetry is broken, and have the potential to discover or rule out these and other scenarios.

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