569 Jefferson Lab
617 496 9123
In fall 2016, I will be away at the Institute for Advanced Study as Junior Visiting Faculty. In spring 2016, I will be back at Harvard teaching Physics 143a: Quantum Mechanics I.
Harvard workshop on self-interacting dark matter, August 7-9, 2013
My recent work on dark matter with dissipative dynamics (with J. Fan, A. Katz, and L. Randall) has been highlighted in an APS Physics Synopsis.
I'm the John L. Loeb Associate Professor of the Natural Sciences at the Harvard Physics Department, High-Energy Theory Group. My research interests are in theoretical high-energy physics, with a particular focus on understanding possibilities for physics beyond the Standard Model. I am also interested, more generally, in exploring quantum field theories.
The discussion below is somewhat outdated; see my publications in the Inspire-HEP database for the latest.
Much of my recent work involves confronting various theories with LHC data. I'm also very interested in dark matter. A few recent papers:
Various things I have worked on in the past include:
With the Large Hadron Collider now taking data, we are entering an exciting time for the field of particle physics. I am very interested in understanding how to make the best use of the data that the LHC will give us. Some of the related topics I have studied include how to infer the spins of particles from data and how to make use of sophisticated timing and directional measurement capabilities of the ATLAS and CMS detectors to do precise measurements of the spectrum, lifetime, and even interactions of long-lived particles decaying to Z bosons.
The LHC is an exciting machine because it reaches the energy frontier, offering the first opportunity to produce new massive particles. At the same time, we shouldn't neglect other experiments that offer the chance to probe more weakly-interacting particles by reaching for the precision frontier. Work along these lines includes studying a light, very weakly-coupled gauge boson, and the development of an effective theory that describes all possible interactions of dark matter with nuclei in direct detection experiments.
One possible explanation for electroweak symmetry breaking is that there is no Higgs boson—at least, not an elementary one. After doing some model-building along these lines, I've invested more effort in trying to argue for why I think it's unlikely, by showing that all such (calculable) theories have an inherent fine-tuning to cancel the S parameter, and that they almost certainly contain new light string states that have not been included in the effective theory. The upshot is that while this scenario may be correct, any realistic version of it is, unfortunately, a theory that we currently aren't able to do precise calculations in.
Along similar lines, I have worked on the recent class of models known as "AdS/QCD," which use an extra dimension to mimic the effects of confinement in the strong interaction. This began as a model-building effort to incorporate a toy model of asymptotic freedom and of the effects of higher-dimension operators that had been integrated out. This did little to alleviate the largest underlying problems, which a further study of event shapes clarified. As with models of electroweak symmetry breaking, the failure to include string states is key.
Obligatory bit of not-physics from my favorite American writer (before he became an American):
"But sometimes I get the impression that all this is a rubbishy rumor, a tired legend, that it has been created out of those same suspicious granules of approximate knowledge that I use myself when my dreams muddle through regions known to me only by hearsay or out of books, so that the first knowledgeable person who has really seen at the time the places referred to will refuse to recognize them, will make fun of the exoticism of my thoughts, the hills of my sorrow, the precipices of my imagination, and will find in my conjectures just as many topographical errors as he will anachronisms."
(Any relevance this might have for physics is left as an exercise for the reader.)
You can reach me by e-mail: email@example.com