The Astrophysical r-process

Kratz, K. L.; Möller, P.; Pfeiffer, B.; Thielemann, F. K.

doi:10.1007/0-306-46927-8_11

Cited by 3 publications

(3 citation statements)

References 73 publications

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“…QRPA-FRDM calculation comprises of both allowed GT and first-forbidden (FF) contributions where allowed GT part was computed via QRPA approximation and gross theory was used for the computation of FF part. It is to be noted that the experimental evaluations in [5] were taken from [32,33]. The SM computed the half-lives (including allowed GT and FF transitions) employing a quenching factor of 0.7.…”

Section: Resultsmentioning

confidence: 99%

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β-decay of N = 126 isotones for the r-process nucleosynthesis

Nabi¹,

Çakmak²,

Ullah³

et al. 2021

Phys. Scr.

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The β-decay properties of nuclei with neutron number N = 126 is investigated in this paper. Two different versions of the proton-neutron quasi particle random phase (pn-QRPA) model were employed to compute β-decay rates and half-lives for the N = 126 isotones. The first set of calculation solves the pn-QRPA equations using the schematic model (SM) approach. The Woods-Saxon potential was employed as a mean-field basis. A spherical shape assigned for each waiting point nuclei throughout all simulations. Both allowed Gamow-Teller (GT) and first-forbidden (FF) transitions were considered in the particle-hole (ph) channel. The second set uses the pn-QRPA model in deformed Nilsson basis to calculate β-decay rates for allowed GT and unique first-forbidden (U1F) transitions under terrestrial and stellar conditions. Our results are in agreement with shell model findings that first-forbidden transitions lead to a considerable decrement in the calculated half-lives of the isotones. Inclusion of the first-forbidden contribution led to a decent agreement of our computed terrestrial β-decay half-lives with measured ones, much better than the previous calculations. The possible implication of the waiting point nuclei on r-process nucleosynthesis is discussed briefly.

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Section: Resultsmentioning

confidence: 99%

“…where j′ indicates the energy levels of the daughter nucleus with E j′ > S n . The λ ij(′) in equation (31) and equation (32), represents the sum of positron capture and β-decay rates, for transition from i → j( j′) state.…”

Section: The Pn-qrpa (N) Modelmentioning

confidence: 99%

β-decay of N = 126 isotones for the r-process nucleosynthesis

Nabi¹,

Çakmak²,

Ullah³

et al. 2021

Phys. Scr.

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“…KHF is a simple phenomenological expression for delayed-neutron emission probability, P n , which was initially developed by Kratz and Herrman in 1972 [52]. Later, Pfeiffer and collaborators [53] suggested to fit the T 1/2 of neutron-rich nuclides according to the underlying concepts of KHF and developed an expression for half-life calculations. Based on new non-linear least-squares fit parameters, with the inclusion of new experimental values available at that time, the authors Pfeiffer et al [48] used KHF to predict the unknown P n values and unknown T 1/2 .…”

Section: Resultsmentioning

confidence: 99%

β-Decay properties of neutron-rich yttrium isotopes

Farooq¹,

Nabi²,

Shehzadi³

2021

Phys. Scr.

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In this study, we have reported key nuclear properties of weak β-decay processes on Yttrium isotopes for the mass number range A = 101 − 108. This mass region has importance while dealing with astrophysical r-process abundances. Our study might be helpful in r-process simulations. We have computed charge-changing strength distributions, β-decay half-lives, β-delayed neutron emission probabilities and β − (EC) weak rates under stellar conditions. We have performed microscopic calculations based on deformed proton-neutron quasi-particle random phase approximation (p-n-QRPA) over a wide temperature (10 7 − 3 × 10 10 ) K and density (10 − 10 11 ) g/cm 3 domain. Unique first-forbidden (U1F) transitions have been included in the calculations in addition to the allowed transitions. A significant decrease in calculated half-lives in ceratin cases, e.g., in 107 Y ( 108 Y) by about 67% (42%), has been observed because of the contribution from U1F transitions. We have compared present results with measured and theoretical works. A good agreement of our half-lives with experimental data is observed.

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