Particle physicists have long been waiting for the discovery of new physics which will point the way beyond the standard model. To anticipate the new physics, theorist make educated guesses. Our expectation (not universally shared!) is that there are new gauge interactions at accessible energies which are not only responsible for the W and Z masses, but also shed light on the origin of quark and lepton masses. Naturalness helps to determine the appropriate dynamics and symmetries. In the past we have studied the dynamics of gauge theories with small beta functions. We have considered remnant family symmetries; one example is a U(1) gauge symmetry which leads to a decoupled second photon and millicharged particles. Another is a massive U(1) gauge field, not coupling to the lighter families, which mixes with the Z-boson. In other work effective field theory techniques have been applied to new physics corrections in the electroweak sector and to models for low energy QCD. Particle symmetries have also led to the consideration of domain walls and associated long-lived structures in the early universe.
We have developed a framework in which the questions of particle physics (origin of mass and flavor) are addressed on energy scales far below the scale of gravity. This bottom-up approach complements the currently fashionable top-down approach. We believe that the true theory of fermion mass will not involve elementary scalar fields and will involve non-QCD-like gauge interactions. In a particular picture, remnants of flavor gauge symmetries are found on TeV mass scales, involving the third and a fourth family. Effective 4-fermion operators of a chirality changing type are responsible for quark and lepton masses and mixings. In particular some understanding of both the large top mass and the small neutrino masses is achieved. Of particular interest for LHC physics is the prediction of a fourth family with masses just somewhat below a TeV.
The cosmological constant problem implies that there is a major missing link in our understanding, which seriously hinders the development of theories of gravity, cosmology, and fundamental physics. Higher derivative gravity theories offer one way to explore the effects of new gravitational dynamics and new gravitational degrees of freedom. We initially combined this with an investigation of extra dimensions where we found how a cosmological constant in higher dimensions is compatible with a flat 4 dimensional space-time. We were eventually led to the study of metrics with an oscillating time dependence of Planck-like frequencies, with the field oscillations being driven by the cosmological constant. Higher derivative theories are also invoked to soften curvature singularities present in solutions of general relativity. We found evidence of a transition to a Euclidean core in the interior of black holes.
A recent focus has been on the topological properties of the configuration space of gauge theories. This leads to a study of Gribov copies, and the explicit counting of these copies sheds light on the infrared properties of these theories.
"Approaching a strong fourth family", arXiv:1001.5321
"Mass gap without vacuum energy", arXiv:0907.0009
A complete list of my publications is available
here.
Varun Sahni 1987-1989
Takuya Morozumi 1992-1993
George Triantaphyllou 1993-1995
M. V. Ramana 1994-1996
Tibor Torma 1997-2000
Hael Collins 1999-2001
Takayuki Hirayama 2002-2004
Scott Watson 2005-2007
Qi-Shu Yan 2008-2010
John Terning PhD 1990
Randy Lewis PhD 1995
Cameron Wicentowich PhD 1995
Stefan Roux PhD 2000
Catalina Gomez present
This site is maintained by Bob Holdom.
