Department of Physics

Symmetries and reactions involving polarized particles

My current research involves three projects.

1. I am part of the aCORN Collaboration whose goal is to measure the correlation between the directions of the electron and anti-neutrino momenta in the decay of the neutron. This parameter (known as "little a") will be determined to a precision of about 1% and represent a significant test of the electroweak theory of beta decay. The apparatus will be built at IUCF, and production running will occur at NIST.
2. I am part of a collaboration to measure a relatively complete set of observables for the four-body system starting in the d+d channel with a polarized deuteron beam. This set of data will test new models of the four-body interaction.
3. I participate in a collaboration to develop a search for an electric dipole moment on the deuteron using the large electric fields (in the particle frame) available in a storage ring. If such a moment exists, its signature is the precession of the deuteron polarization out of the ring plane. My duties in this collaboration are to develop the polarimeters necessary to make this search.

Charge Symmetry Breaking and QCD, Gerald A. Miller, Allena K. Opper, and Edward J. Stephenson, Ann. Rev. Nucl. Part. Sci. 56, 253 (2006).

Measurement of the Analyzing Power A_N in pp Elastic Scattering in the CNI Region with a Polarized Atomic Hydrogen Gas Jet Target, H. Okada, I.G. Alekseev, A. Bravar, G. Bunce, S. Dhawan, R. Gill, W. Haeberli, O. Jinnouchi, A. Khodinov, Y. Makdisi, A. Nass, N. Saito, E. J. Stephenson, D.N. Svirida, T. Wise, and A. Zelenski, Phys. Lett. B 638, 450 (2006).

Inclusion of non-spherical components of the Pauli blocking operator in (p,p) reactions, E.J. Stephenson, R.C. Johnson, and F. Sammarruca, Phys. Rev. C 71, 014612 (2005).

Reaction mechanism for natural parity (p,p') transitions in 10B, A.C. Betker, S. Chang, E.J. Stephenson, A.D. Bacher, S.M. Bowyer, W.A. Franklin, J. Liu, C. Olmer, D.L. Prout, S.P. Wells, S.W. Wissink, C. Yu, R.A. Lindgren, H. Baghaei, V. Gladyshev, J.A. Carr, S.K. Yoon, F. Petrovich, B.L. Clausen, and J. Lisantti, Phys. Rev. C 71, 064607 (2005).

New Method of Measuring Electric Dipole Moments in Storage Rings, F.J.M. Farley, K. Jungmann, J.P. Miller, W.M. Morse, Y.F. Orlov, B.L. Roberts, Y.K. Semertzidis, A. Silenko, and E.J. Stephenson, Phys. Rev. Lett. 93, 052001 (2004).

Observation of the Charge Symmetry Breaking d+d->4He+pi0 Reaction near Threshold, E.J. Stephenson, A.D. Bacher, C.E. Allgower, A. G'rdestig, C.M. Lavelle, G.A. Miller, H. Nann, J. Olmsted, P.V. Pancella, M.A. Pickar, J. Rapaport, T. Rinckel, A. Smith, H.M. Spinka, and U. van Kolck, Phys. Lett. 91, 142302.