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14 pages, 317 KB

Open AccessArticle

Beta Decay Properties of Waiting-Point N = 50 and 82 Isotopes

by Necla Çakmak and Najm Abdullah Saleh

Particles 2025, 8(2), 56; https://doi.org/10.3390/particles8020056 - 6 May 2025

Viewed by 2440

We performed the microscopic calculation of

β

-decay properties for waiting-point nuclei with neutron-closed magic shells. Allowed Gamow–Teller (GT) and first-forbidden (FF) transitions were simulated using a schematic model (SM) for waiting-point N =

50, 82

isotopes in the framework of a [...] Read more.

We performed the microscopic calculation of

β

50, 82

isotopes in the framework of a proton–neutron quasiparticle random phase approximation (

p n

-QRPA). The Woods–Saxon (WS) potential basis was used in our calculations. The

p n

-QRPA equations of allowed (GT) and (FF) transitions were utilized in both the particle–hole (

p h

) and particle–particle (

p p

) channels in the SM. We solved the secular equations of the GT and FF transitions for eigenvalues and eigenfunctions of the corresponding Hamiltonians. A spherical shape was assigned to each waiting-point nucleus in all simulations. Significantly, this study marks the first time that

β

-decay analysis has been applied to certain nuclei, including ⁸²Ge₅₀, ⁸³As₅₀, ⁸⁴Se₅₀, ⁸⁵Br₅₀ and ⁸⁷Rb₅₀ with

N = 50

isotones, and ¹³²Sn₈₂, ¹³³Sb₈₂, ¹³⁴Te₈₂, ¹³⁵I₈₂ and ¹³⁷Cs₈₂ with

N = 82

isotones. Since there is no prior theoretical research on these nuclei, this work is a unique addition to the field. We compared our results with the previous calculations and measured data, and our calculations agree with the experimental data and the other theoretical results. Full article

10 pages, 399 KB

Open AccessArticle

Correlating the 0νββ-Decay Amplitudes of ¹³⁶Xe with the Ordinary Muon Capture (OMC) Rates of ¹³⁶Ba

by Aagrah Agnihotri, Vikas Kumar and Jouni Suhonen

Universe 2025, 11(5), 138; https://doi.org/10.3390/universe11050138 - 27 Apr 2025

Cited by 1 | Viewed by 970

Abstract

The potential correlation between the ordinary muon capture (OMC) on ¹³⁶Ba and

0 ν β β

decay of ¹³⁶Xe is explored. For this, we compute

0 ν β β

-decay amplitudes for intermediate states in ¹³⁶Cs below 1 MeV of [...] Read more.

The potential correlation between the ordinary muon capture (OMC) on ¹³⁶Ba and

0 ν β β

decay of ¹³⁶Xe is explored. For this, we compute

0 ν β β

-decay amplitudes for intermediate states in ¹³⁶Cs below 1 MeV of excitation and for angular-momentum values

J \leq 5

by using the proton–neutron quasiparticle random-phase approximation (pnQRPA) and nuclear shell model (NSM). We compare these amplitudes with the corresponding OMC rates, computed in a previous Universe article (Universe 2023, 9, 270) for the same energy and angular-momentum ranges. The obtained results suggest that an extension of the present analysis to a wider energy and angular-momentum region could be highly beneficial for probing the

0 ν β β

-decay nuclear matrix elements using experimental data on OMC rates to intermediate states of

0 ν β β

decays. Full article

(This article belongs to the Special Issue Exploring Double Beta Decay: Probing Fundamental Properties of Neutrinos and Beyond)

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26 pages, 643 KB

Open AccessArticle

Re-Examination of the Effect of Pairing Gaps on Gamow–Teller Strength Distributions and β-Decay Rates

by Jameel-Un Nabi, Muhammad Riaz and Arslan Mehmood

Universe 2024, 10(3), 128; https://doi.org/10.3390/universe10030128 - 6 Mar 2024

Cited by 7 | Viewed by 2214

Abstract

β

-decay is one of the key factors for understanding the r-process and evolution of massive stars. The Gamow–Teller (GT) transitions drive the

β

-decay process. We employ the proton–neutron quasiparticle random phase approximation (pn-QRPA) model to calculate terrestrial and stellar

β

[...] Read more.

β

-decay is one of the key factors for understanding the r-process and evolution of massive stars. The Gamow–Teller (GT) transitions drive the

β

-decay process. We employ the proton–neutron quasiparticle random phase approximation (pn-QRPA) model to calculate terrestrial and stellar

β

-decay rates for 50 top-ranked nuclei possessing astrophysical significance according to a recent survey. The model parameters of the pn-QRPA model affect the predicted results of

β

-decay. The current study investigates the effect of nucleon–nucleon pairing gaps on charge-changing transitions and the associated

β

decay rates. Three different values of pairing gaps, namely TF, 3TF, and 5TF, were used in our investigation. It was concluded that both GT strength distributions and half-lives are sensitive to pairing gap values. The 3TF pairing gap scheme, in our chosen nuclear model, resulted in the best prediction with around 80% of the calculated half-lives within a factor 10 of the measured ones. The 3TF pairing scheme also led to the calculation of the biggest

β

-decay rates in stellar matter. Full article

(This article belongs to the Special Issue Recent Advances in Double Beta Decay Investigations: In Honor of Prof. Sabin Stoica at His 70th Anniversary)

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13 pages, 613 KB

Open AccessArticle

Ordinary Muon Capture on ¹³⁶Ba: Comparative Study Using the Shell Model and pnQRPA

by Patricia Gimeno, Lotta Jokiniemi, Jenni Kotila, Marlom Ramalho and Jouni Suhonen

Universe 2023, 9(6), 270; https://doi.org/10.3390/universe9060270 - 5 Jun 2023

Cited by 15 | Viewed by 2665

Abstract

In this work, we present a study of ordinary muon capture (OMC) on

^{136}

Ba, the daughter nucleus of

^{136}

Xe double beta decay (DBD). The OMC rates at low-lying nuclear states (below 1 MeV of excitation energy) in

^{136}

Cs are assessed [...] Read more.

In this work, we present a study of ordinary muon capture (OMC) on

^{136}

Ba, the daughter nucleus of

^{136}

Xe double beta decay (DBD). The OMC rates at low-lying nuclear states (below 1 MeV of excitation energy) in

^{136}

Cs are assessed by using both the interacting shell model (ISM) and proton–neutron quasiparticle random-phase approximation (pnQRPA). We also add chiral two-body (2BC) meson-exchange currents and use an exact Dirac wave function for the captured s-orbital muon. OMC can be viewed as a complementary probe of the wave functions in

^{136}

Cs, the intermediate nucleus of the

^{136}

Xe DBD. At the same time, OMC can be considered a powerful probe of the effective values of weak axial-type couplings in a 100 MeV momentum exchange region, which is relevant for neutrinoless DBD. The present work represents the first attempt to compare the ISM and pnQRPA results for OMC on a heavy nucleus while also including the exact muon wave function and the 2BC. The sensitivity estimates of the current and future neutrinoless DBD experiments will clearly benefit from future OMC measurements taken using OMC calculations similar to the one presented here. Full article

(This article belongs to the Special Issue Recent Advances in Double Beta Decay Investigations: In Honor of Prof. Sabin Stoica at His 70th Anniversary)

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8 pages, 364 KB

Open AccessArticle

β⁻-Decay Half-Lives of Even-Even Nuclei Using the Recently Introduced Phase Space Recipe

by Jameel-Un Nabi, Mavra Ishfaq, Ovidiu Niţescu, Mihail Mirea and Sabin Stoica

Universe 2020, 6(1), 5; https://doi.org/10.3390/universe6010005 - 26 Dec 2019

Cited by 2 | Viewed by 3821

Abstract

In this paper, we present the

β

-decay half-lives calculation for selected even-even nuclei that decay through electron emission. The kinematical portion of the half-life calculation was performed using a recently introduced technique for computation of phase space factors (PSFs). The dynamical portion [...] Read more.

In this paper, we present the

β

^{20}

^{24}

Ne,

^{34}

Si,

^{54}

Ti,

^{62}

Fe and

^{98}

Zr) were selected for the present calculation. We compare the calculated PSFs for these cases against the traditionally used recipe. In our new approach, the Dirac equation was numerically solved by employing a Coulomb potential. This potential was adopted from a more realistic proton distribution of the daughter nucleus. Thus, the finite size of the nucleus and the diffuse nuclear surface corrections are taken into account. Moreover, a screened Coulomb potential was constructed to account for the effect of atomic screening. The power series technique was used for the numerical solution. The calculated values of half-lives, employing the recently developed method for computation of PSFs, were in good agreement with the experimental data. Full article

(This article belongs to the Special Issue Relativistic Astrophysics)

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