UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-22 2:16

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Conference: Bucharest University Faculty of Physics 2013 Meeting


Section: Nuclear and Elementary Particles Physics


Title:
Search of parity violation effects in neutron reactions on Lead nucleus (I)


Authors:
A. I. Oprea, C. Oprea, P.V. Sedyshev, Yu. M. Gledenov


Affiliation:
Frank Laboratory for Neutron Physics (FLNP)

Joint Institute for Nuclear Research (JINR)

141980 Dubna, Moscow Region, Russian Federation


E-mail
ionica@nf.jinr.ru


Keywords:
slow neutrons, parity violation effects, polarization, spin rotation


Abstract:
Parity violation effects (PV) in nuclear reaction were discovered in the ’60 years of the last century in the capture of thermal transversal polarized neutrons by 113Cd nucleus. In this reaction experimentally was measured a non zero asymmetry of emitted gamma quanta and the results was interpreted by the existence of weak non leptonic interaction between nucleons in the compound nucleus. This first experimental result gave a serious impulse of theoretical and experimental developments of parity violation question in nuclear reactions. The weak interaction acts in the background of strong interaction (with order of magnitude higher) and therefore it is very difficult to observe and evidence it. One possibility is the evaluation of asymmetry effects induced by PV phenomena.For neutrons scattering there are a few asymmetry effects (like polarization of incident neutron beam, spin rotation and emitted neutrons asymmetry of incident transversal polarized neutrons) explained by the presence of weak interaction.In natural Lead were observed an unexpected high value of neutron spin rotation due to the PV phenomena. The natural Lead contains four isotopes and the main contribution to the PV effects is given by 204Pb. Further to explain the high value of neutron spin rotation it was supposed the existence of a new negative P resonance with energy EP = - 16 eV.In this work were estimated the PV effects in scattering in order to extract the weak matrix element and to verify the existence of the new negative resonance of 204Pb nucleus.