UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2007 Meeting


Section: Nuclear and Elementary Particles Physics


Title:
Angular correlations in the (n,p) reaction


Authors:
A.I. Oprea, C. Oprea


Affiliation:
FLNP JINR


E-mail
opreaalexandru492@yahoo.com


Keywords:


Abstract:
The asymmetry effects in the (n,p) reaction on 35Cl and 14N in the frame of the model of the mixing states of compound nucleus with the same spin and opposite parities were evaluated. The asymmetry effects are the forward – backward, left right and parity non conservation [1-3] in the neutron energy range up to 100 keV for 35Cl and to 1 MeV for 14N respectively. As suggested in [4] in the two level approximation it is possible to extract the weak matrix element of (n,p) reaction and other information about compound nucleus using only experimental data from the measured forward – backward, left – right and parity non conservation coefficients. In the case of 35Cl the forward – backward effect (aFB(En=300 eV)=0.17, En – the incident neutron energy, aLR(0.0253 eV)=-2.4 10-4, aPNC(0.0253 eV)=-1.5 10-4) were measured and applying the procedure described in [4] the weak matrix element WSP=(0.56±0.12) meV was extracted. For 14N until present exist only preliminary results on forward – backward coefficient, up to 10 percent [6], and of order of 10-4 for other two coefficients [7]. The weak matrix element obtained was very small, practically zero, as suggested in [7]. It is of interest to investigate these effects of asymmetry taking into account more than two resonances. In this paper we will take into account ten resonances for each nucleus (14N and 35Cl). As it is expected the contribution to the cross section of the each resonance will reduce the asymmetry effects but the interference between resonances with the same spin or opposite can increase or decrease the studied effects. Taking into account more than two resonances and two ore more pairs of resonances contributing to the asymmetry effect the procedure for the extraction of the weak matrix element becomes impossible to be applied because the partial reduced amplitudes are not known and these must be obtained from other reaction. References. [1]V.V. Flambaum, O.P. Sushkov, Nucl. Phys. A412 (1984) 3-13 [2] V. E. Bunakov,V. P. Gudkov, Nucl. Phys. A401(1983), 93-116 [3] G. Rigol, Preprint Dubna, P4-85-70 [4] S. V. Zenkin, N. A. Titov, Academya Nauk SSSR – Institut Yadernyh Issledovanii - P 0367 Moskva 1984- [5]. Yu.M. Gledenov, R. Mashrafi, A.I. Oprea, V.I. Salatsky, P.V. Sedyshev, P.I. Szalanski, V.A. Vesna, I.S. Okunev - Nuclear Physics A654 (1999), 943c-948c [6] A. Oprea et. all, Proceeding of ISINN 13, Dubna, 25-28 May 2005, p.153 [7] A. Antonov, V.A. Vesna, Yu. M. Gledenov et. all., Sov. J. Nucl. Phys. 48(2), 1988, p.193