Signatures of the d*(2380) Hexaquark in d(gamma,p(n)over-right-arrow)
Date Issued
2020-01-01
Author(s)
Bashkanov, M.
Watts, D. P.
Kay, S. J. D.
Abt, S.
Achenbach, P.
Adlarson, P.
Afzal, F.
Ahmed, Z.
Akondi, C. S.
Annand, J. R. M.
Arends, H. J.
Beck, R.
Biroth, M.
Borisov, N.
Braghieri, A.
Briscoe, W. J.
Cividini, F.
Collicott, C.
Costanza, S.
Denig, A.
Downie, E. J.
Drexler, P.
Fegan, S.
Fix, A.
Gardner, S.
Ghosal, D.
Glazier, I.
Gorodnov, I.
Gradl, W.
Guenther, M.
Gurevich, D.
Heijkenskjoeld, L.
Hornidge, D.
Huber, G. M.
Kaeser, A.
Kashevarov, V. L.
Korolija, M.
Lazarev, A.
Livingston, K.
Lutterer, S.
MacGregor, I. J. D.
Manley, D. M.
Martel, P. P.
Miskimen, R.
Mornacchi, E.
Mullen, C.
Neganov, A.
Neiser, A.
Ostrick, M.
Otte, P. B.
Paudyal, D.
Pedroni, P.
Powell, A.
Prakhov, S. N.
Ron, G.
Sarty, A.
Sfienti, C.
Sokhoyan, V.
Spieker, K.
Steffen, O.
Strakovsky, I. I.
Strub, T.
Supek, I.
Thiel, A.
Thiel, M.
Thomas, A.
Usov, Yu A.
Wagner, S.
Walford, N. K.
Werthmueller, D.
Wettig, J.
Wolfes, M.
Zachariou, N.
Zana, L. A.
A2, Collaboration
DOI
10.1103/physrevlett.124.132001
Abstract
We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E-gamma similar to 570 MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom. A Legendre polynomial decomposition suggests this behavior could be related to the excitation of the d*(2380) hexaquark.