Peter Shawhan

Peter S. Shawhan
Associate Professor of Physics
The University of Maryland

pshawhan @
Office: Physical Sciences Complex (PSC), room 2120
Address: Department of Physics
The University of Maryland
College Park, MD 20742-4111
(301) 405 1580

Peter Shawhan Peter Shawhan

My Research

LIGO logoI am working on a major project called LIGO (short for Laser Interferometer Gravitational-wave Observatory) which is designed to detect gravitational waves coming from distant astrophysical objects such as black holes, neutron stars, cosmic strings, or the core of a massive star when it collapses and creates a supernova.  Gravitational waves are distortions in the geometry of space-time which are predicted, by Einstein's general theory of relativity, to be emitted when massive bodies change their shape or orientation rapidly.  Direct searches for gravitational waves began with Joe Weber here at the University of Maryland in the 1960s and have continued with increasingly sensitive detectors, but the expected distortions are incredibly tiny when they reach the Earth, and consequently have not yet been directly detected.  Technological advancements over the years have finally made it feasible to construct detectors based on very large laser interferometers, and after many years of design, construction, and commissioning, LIGO and a few similar detectors (GEO, VIRGO) are listening for gravitational waves with sensitivities which should allow us to finally detect them in the not-too-distant future. In fact, all of the gravitational-wave detector projects work cooperatively so that we can do the best science with our combined data.

LSC logoWhereas the construction and operation of the LIGO observatories are co-led by Caltech (where I spent 7 years as a postdoctoral fellow and staff scientist) and MIT, the scientific mission of LIGO is carried out by the LIGO Scientific Collaboration, which includes scientists at the University of Maryland along with a few dozen other institutions.  You can get an overview of many of the scientific activities by visiting the LIGO Science Links web page I maintain (though some of the links are restricted to collaboration members). I served for several years as Co-Chair of the LSC Burst Analysis Working Group. I have also been a member of the LSC Executive Committee and served on the LIGO Program Advisory Committee (PAC). Currently I am Co-Chair of the LIGO Academic Affairs Council (LAAC).

I am grateful to the National Science Foundation for financial support of my research through grants PHY-0653421, PHY-0738032, PHY-0757957 and PHY-1068549, as well as for the overall funding of the LIGO program.

My Ph.D. Thesis Research (1991-1999)

KTeV logo As a graduate student at the University of Chicago, I worked on a particle physics experiment called KTeV which studied the decays of neutral K mesons produced in a fixed-target beam at Fermilab.  The neutral K meson system is remarkable in that two neutral K meson states are observed, one of which lives (on average) about 580 times longer than the other before it decays.  This is the result of mixing of the quantum eigenstates due to particle interactions, and it turns out that there is a small particle-antiparticle asymmetry in the mixing, referred to as "CP violation".  One of the main goals of KTeV was to measure an even more subtle effect, direct CP violation in the decay process itself, by comparing the decays of the short- and long-lived K mesons.  My thesis research was the measurement of direct CP violation using the first part of the data collected by KTeV; we found a clear nonzero effect, and published the results in  Phys. Rev. Lett. 83, 22 (1999).  (For anyone who may be interested, my Ph.D. thesis is available in PostScript or PDF format.)