Journal Article

Nuclear physics. Momentum sharing in imbalanced Fermi systems

Niculescu, G, Niculescu, I, Hicks, K, Ireland, D G, Mineeva, T, Weinstein, L B, Girod, F X, Markov, N, Gevorgyan, N, Jiang, H, Kubarovsky, V, Pasyuk, E, Adhikari, K P, Kuhn, S E, Isupov, E L, Fegan, S, Pappalardo, L L, Bertozzi, W, Cole, P L, Osipenko, M, May-Tal Beck, S, Holtrop, M, Hanretty, C, Movsisyan, A, Jo, H S, Battaglieri, M, Hattawy, M, Piasetzky, E, Crede, V, El Alaoui, A, Arrington, J, Bedlinskiy, I, Guidal, M, Beck, A, Gothe, R W, El Fassi, L, Gilad, S, Koirala, S, Munoz Camacho, C, Gilfoyle, G P, Avakian, H, Dupre, R, Mayer, M, Hen, O, Keller, D, Guo, L, Garcon, M, Griffioen, K A, Fedotov, G, Niccolai, S, Levine, W I, Celentano, A, Mokeev, V, Carman, D S, Ishkanov, B I, Ilieva, Y, Garillon, B, Djalali, C, MacGregor, I J D, Lenisa, P, Phelps, W, Burkert, V D, McKinnon, B, Khandaker, M, Livingston, K, Biselli, A, Goetz, J T, Asryan, G, Baltzell, N A, Kim, W, Higinbotham, D W, Egiyan, H, Deur, A, Klein, F J, Ghandilyan, Y, Hakobyan, H, Korover, I, Braverman, M, Chandavar, S, Hafidi, K, Forest, T, Lowry, M, Doughty, D, Kim, A, Cao, T, Ball, J, Sargsian, M, Paremuzyan, R, De Vita, R, Dugger, M, Elouadrhiri, L, Colaneri, L, D'Angelo, A, Hyde, C E, Nadel-Turonski

2014

Overview

The atomic nucleus is composed of two different kinds of fermions: protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority of fermions (usually neutrons) to have a higher average momentum. Our high-energy electron-scattering measurements using (12)C, (27)Al, (56)Fe, and (208)Pb targets show that even in heavy, neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few-body systems to neutron stars and may also be observable experimentally in two-spin-state, ultracold atomic gas systems.