Browsing by Author "Aygör H.A."

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    Calculation of the log(ft) values for the allowed gamow-teller transitions in deformed nuclei using the basis of woods-saxon wave functions
    (2003) Salamov D.I.; Kücükbursa A.; Maras I.; Aygör H.A.; Babacan T.; Bircan H.
    The present study investigates the log(ft) values of the allowed β± decay between odd-A deformed nuclei in the atomic mass regions of 125 ≤ A ≤ 131 and 159 ≤ A ≤ 181. Single particle energies and wave functions have been calculated with a deformed Woods-Saxon potential. Calculations have been performed within the framework of a proton-neutron quasi-particle random phase approximation (QRPA), including the schematic residual spinisospin interaction between nucleons in the particle-hole and particle-particle channels. It has been seen that the results obtained by using the values for the fixed particle-hole and particle-particle interaction strengths, ΧGTph = 5.2/A0.7 MeV and ΧGTpp = 0.58/A0.7 MeV, have good agreement with the experimental observations.
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    Nuclear matrix elements of double beta decay in deformed nuclei
    (2003) Selam C.; Küçükbursa A.; Bircan H.; Aygör H.A.; Babacan T.; Maraş I.; Kökçe A.
    Nuclear matrix elements (MGT for two-neutrino double beta transitions of selected nuclei were calculated via a QRPA approach by considering the charge-exchange spin-spin interactions in the particle-hole channel among nucleons. Calculations were performed for both spherical and deformed cases of nuclei. As a result of these calculations, it has been seen that, although the value of the nuclear matrix elements in deformation case are 2-4 times smaller when compared with that of the spherical case, it is still 2-8 times greater than the experimental values.
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    The investigation of the log(ft) values for the allowed Gamow-Teller transitions of some deformed nuclei
    (Association for Scientific Research, 2004) Selam C.; Babacan T.; Aygör H.A.; Bircan H.; Küçükbursa A.; Maraş I.
    The log(ft) values of allowed β± decay between odd-A nuclei for 125≤A≤180 mass region are investigated. Single particle energies and wave functions are calculated by making use of a deformed Woods-Saxon potential. The calculations are performed in the framework of proton-neutron quasi particle random phase approximation (QRPA) including the schematic residual spin-isospin interaction among the nucleons in the particle hole channel. The calculations indicated that the results obtained through using the ΧGT=5.2/A0.7 are more in agreement with experimental observations.
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    The effect of the pairing interaction on the energies of isobar analogue resonances in 112-124Sb and isospin admixture in 100-124Sn isotopes
    (2004) Babacan T.; Salamov D.; Kücükbursa A.; Babacan H.; Maras I.; Aygör H.A.; Ünal A.
    In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analogue resonances (IAR) in 112-124Sb isotopes and the isospin admixture in 100-124Sn isotopes is investigated within the framework of the proton-neutron quasi-particle random phase approximation (pnQRPA). The form of the interaction strength parameter is related to the shell-model potential by restoring the isotopic invariance of the nuclear part of the total Hamiltonian. In this respect, the isospin admixtures in the 100-124Sn isotopes are calculated, and the dependence of the differential cross section and the volume integral JF for the Sn(3He,t)Sb reactions at E( 3He) = 200 MeV occurring by the excitation of IAR on mass number A is examined. Our results show that the calculated value for the isospin mixing in the 100Sn isotope is in good agreement with Colo et al's estimates (4-5%), and the obtained values for the volume integral change within the error range of the value reported by Fujiwara et al (53 ± 5 MeV fm 3). Moreover, it is concluded that although the differential cross section of the isobar analogue resonance for the (3He,t) reactions is not sensitive to pairing correlations between nucleons, a considerable effect on the isospin admixtures in N ≈ Z isotopes can be seen with the presence of these correlations.
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    An investigation of the influence of the pairing correlations on the properties of the isobar analog resonances in A = 208 nuclei
    (Indian Academy of Sciences, 2004) Kücükbursa A.; Salamov D.I.; Babacan T.; Aygör H.A.
    Within the quasi-particle random phase approximation (QRPA), the method of the self-consistent determination of the isovector effective interaction which restores a broken isotopic symmetry for the nuclear part of the Hamiltonian is given. The effect of the pairing correlations between nucleons on the following quantities were investigated for the A = 208 nuclei: energies of the isobar analog 0 + states, the isospin admixtures in the ground state of the even-even nuclei, and the differential cross-section for the 208 Pb( 3 He,t) 208 Bi reaction at E( 3 He) = 450 MeV. Both couplings of the excitation branches with T z = To ± 1, and the analog state with isovector monopole resonance (IVMR) in the quasi-particle representation were taken into account in our calculations. As a result of these calculations, it was seen that the pairing correlations between nucleons have no considerable effect on the T = 23 isospin admixture in the ground state of the 208 Pb nucleus, and they cause partially an increase in the isospin impurity of the isobar analog resonance (IAR). It was also established that these correlations have changed the isospin structure of the IAR states, and shifted the energies of the IVMR states to the higher values.