Speaker
Description
Summary
In this work we performed a systematic study of the
inclusive muon capture rates for the nuclei 12C,
20Ne, 32Mg, 28Si, 40Ar, 52Cr, 54Cr, 56Fe, and 58Ni
using the Projected Random Quase-particle Phase
Approximation (PQRPA) as nuclear model.
The theoretical formalism for the muon capture rates
shown in Ref. [1] is used with the delta
interaction as the residual interaction in nuclear
structure calculations.
The theoretical results of the capture rates within
the PQRPA have been compared with those
obtained in other works using the models of
RPA+BCS [2] and RQRPA (relativistic QRPA) [3].
This leads to a modification of the axial coupling
constant gA = 1 to gA = 1.135, resulting in
one better agreement with the experimental data.
The influence of the CVC (Conserved Vector
Current) in the muon capture rates for the presented
nuclei was explicitly verified for the first time
in the literature. This showed to be more significant
in lighter nuclei, still more when the Coulomb
term of muon-nucleus interaction is disrespected.
A final comparison was carried through inclusive
capture and exclusive muon capture rates in
12C showing that the PQRPA did not present a good
experimental agreement for the exclusive
capture, only for the inclusive one. We reckon
that the comparison between theory and data for
the inclusive muon capture is not a fully
satisfactory test on the nuclear model that is used.
The exclusive muon transitions are more robust for
such a purpose. Therefore, it would be necessary
more experimental data for the exclusive capture
rates in other nuclei, beyond 12C, to test if a
nuclear model is satisfactory [4].
References
[1] F. Krmpotic, A. Mariano and A. Samana,
Phys. Rev. C 71, 044319 (2005).
[2] N.T. Zinner, K. Langanke e P. Vogel,
Phys. Rev. C 74, 024326 (2006).
[3] N. Paar, T. Niksic, D. Vretenar, and P. Ring,
Phys. Rev. C 69, 054303 (2004); N. Paar, D.
Vretenar, T. Marketin and P. Ring, Phys. Rev. C 77, 024608 (2008).
[4] Danilo Sande Santos,Captura de mons usando PQRPA,
thesis presented for the degree of Master
of Physics Science, unpublished, Universidade
Estadual de Santa Cruz, February 2012, Bahia,
Brazil.