My research interests in experimental nuclear physics involve
low-energy, high-precision tests of fundamental symmetries as probed
in experiments utilizing ultracold neutrons (UCN). The driving central
theme of our research in these fundamental neutron physics experiments
is the search for new physics beyond the Standard Model of particle
physics. We are currently involved with two such initiatives. First,
we are carrying out a high-precision measurement of the neutron
beta-asymmetry at a new UCN source developed at the Los Alamos
National Laboratory. A value for this asymmetry, combined with the
neutron lifetime, permits an extraction of the CKM quark-mixing matrix
element Vud. The goal is to perform a high-precision test
of the unitarity of the CKM matrix. Second, we are involved with a
new U.S.-based search for the neutron electric dipole moment (EDM).
The existence of a neutron EDM requires violation of the Time-Reversal
Symmetry (T-violation). Additional sources of T-violation, equivalent
to CP-violation, are needed to explain the fundamental question of the
origin of the baryon asymmetry of the universe. This experiment will
be conducted at the Spallation Neutron Source at Oak Ridge National
Laboratory.
I am also interested in measurements of the
distribution of charge within the (neutral) neutron. Future
measurements to the smallest length scales ever will be conducted at
the Jefferson Laboratory.
Education
B.S. in Physics, Massachusetts Institute of Technology (1999)
Ph.D. in Physics, Massachusetts Institute of Technology (1999)
Postdoctoral Scholar, California Institute of Technology (2003-2007)
Selected Recent Publications
T.M. Ito et al., "A multiwire proportional chamber for precision studies
of neutron beta decay angular correlations", Nucl. Instrum. Methods
Phys. Res. A 571, 676 (2007).
B. Plaster et al., "Measurements of the neutron electric to magnetic form
factor ratio GEn/GMn via the
2H(e,e'n)1H reaction to Q2 = 1.45
(GeV/c)2", Phys. Rev. C 73, 025205 (2006).
J.W. Martin et al., "New measurements and quantitative analysis of electron
backscattering in the energy range of neutron beta-decay",
Phys. Rev. C 73, 015501 (2006).
B. Plaster, "A new search for a neutron electric dipole moment",
Int. J. Mod. Phys. A 20, 3331 (2005).
F.E. Maas et al., "Evidence for strange quark contributions to the
nucleon's form factors at Q2 = 0.108 (GeV/c)2",
Phys. Rev. Lett. 94, 152001 (2005).
F.E. Maas et al., "Measurement of strange quark contributions to the
nucleon's form factors at Q2 = 0.230 (GeV/c)2",
Phys. Rev. Lett. 93, 022002 (2004).
T.M. Ito et al., "Parity violating electron deuteron scattering and the
proton's neutral weak axial vector form-factor",
Phys. Rev. Lett. 92, 102003 (2004).
R. Madey, A. Yu. Semenov, S. Taylor, B. Plaster et al., "Measurements
of GEn/GMn from the
2H(e,e'n)1H reaction to Q2 = 1.45
(GeV/c)2", Phys. Rev. Lett. 91, 122002 (2003).
