Excited States of 71Ge above the Neutron Emission Threshold and Solar Neutrino Capture Rates for Ga Detectors

1997 ◽  
Vol 12 (30) ◽  
pp. 2279-2285
Author(s):  
Kamales Kar ◽  
Sukhendusekhar Sarkar ◽  
Srubabati Goswami ◽  
Amitava Raychaudhuri
Keyword(s):  
Excited States ◽  
Neutron Emission ◽  
Capture Rate ◽  
Solar Neutrinos ◽  
Additional Contribution ◽  
Isobaric Analog ◽  
Isobaric Analog State ◽  
Emission Threshold ◽  
Gamow Teller ◽  
Capture Rates

In Gallium detectors for solar neutrinos, the capture rate due to Gamow–Teller transitions to excited states of 71Ge beyond the neutron emission threshold is usually neglected. We make a model calculation to estimate its effect and find that this yields an additional contribution which may be as much as 0.4 SNU, even larger than that from the Isobaric Analog State in 71 Ge reached by Fermi transitions, which is normally included in the standard predictions.

scholarly journals Analogous Gamow-Teller and M1 Transitions in Tz = ±½ Mirror Nuclei and in Tz = ±1, 0 Triplet Nuclei relevant to Low-energy Super GT state

2018 ◽  
Vol 178 ◽  
pp. 05001
Author(s):  
Yoshitaka Fujita ◽  
Hirohiko Fujita ◽  
Yusuke Tanumura
Keyword(s):  
Nuclear Spin ◽  
Ground State ◽  
Degrees Of Freedom ◽  
Main Part ◽  
Low Energy ◽  
Magnetic Interactions ◽  
Isobaric Analog ◽  
Isobaric Analog State ◽  
Electro Magnetic ◽  
Gamow Teller

Nuclei have spin- and isospin-degrees of freedom. Therefore, Gamow-Teller (GT) transitions caused by the στ operator (spin-isospin operator) are unique tools for the studies of nuclear structure as well as nuclear interactions. They can be studied in β decays as well as charge-exchange (CE) reactions. Similarly, M1 γ decays are mainly caused by the στ operator. Combined studies of these transitions caused by Weak, Strong, and Electro-Magnetic interactions provide us a deeper understanding of nuclear spin-isospin-type transitions. We first compare the strengths of analogous GT and M1 transitions in the A = 27, Tz = ±½ mirror nuclei 27Al and 27Si. The comparison is extended to the Tz = ±1, 0 nuclei. The strength of GT transition from the ground state (g.s.) of 42Ca to the 0.611 MeV first Jπ = 1+ state in 42Sc is compared with that of the analogous M1 transition from the 0.611 MeV state to the T = 1, 0+ g.s. (isobaric analog state: IAS) in 42Sc. The 0.611 MeV state has the property of Low-energy Super GT (LeSGT) state, because it carries the main part of the GT strength of all available transitions from the g.s. of 42Ca (and 42Ti) to the Jπ = 1+ GT states in 42Sc.

scholarly journals Single and Double Charge Exchange Excitations of Spin-Isospin Mode

2019 ◽  
Vol 223 ◽  
pp. 01053
Author(s):  
Hiroyuki Sagawa
Keyword(s):  
Cross Section ◽  
Charge Exchange ◽  
Sum Rules ◽  
Transition Strength ◽  
Double Charge Exchange ◽  
Double Spin ◽  
Isobaric Analog ◽  
Isobaric Analog State ◽  
Double Charge ◽  
Gamow Teller

We study the sum rules of double Gamow-Teller (DGT) excitations through double spin-isospin operator (σt­)2 In general, 2+states in the granddaughter nuclei have dominant transition strength in DGT excitations and 0+states are weak, except in T = 1 mother nuclei in which 0+strength is competitive with 2+strength. A possibility to extract the unit cross section for the DGT transition strength is pointed out in the (#x03C3;t­)2 excitation of double isobaric analog state (DIAS) in T = 1 nuclei.

Feeding of hole states by proton decay of Gamow-Teller and isobaric analog state resonances

1996 ◽  
Vol 53 (4) ◽  
pp. 2001-2003 ◽  
Author(s):  
J. Blomqvist ◽  
O. Civitarese ◽  
E. D. Kirchuk ◽  
R. J. Liotta ◽  
T. Vertse
Keyword(s):  
Proton Decay ◽  
Isobaric Analog ◽  
Isobaric Analog State ◽  
Gamow Teller

scholarly journals RELATIVISTIC DESCRIPTION OF EXOTIC COLLECTIVE EXCITATION PHENOMENA IN ATOMIC NUCLEI

2005 ◽  
Vol 14 (01) ◽  
pp. 29-37 ◽  
Author(s):  
N. PAAR ◽  
T. NIKŠIĆ ◽  
D. VRETENAR ◽  
P. RING
Keyword(s):  
Neutron Emission ◽  
Collective Excitation ◽  
Random Phase ◽  
Canonical Basis ◽  
Neutron Skin ◽  
Excitation Energies ◽  
Quasiparticle Random Phase Approximation ◽  
Isobaric Analog ◽  
Emission Threshold ◽  
Radiative Neutron Capture

The low-lying dipole and quadrupole states in neutron rich nuclei are studied within the fully self-consistent relativistic quasiparticle random-phase approximation (RQRPA), formulated in the canonical basis of the Relativistic Hartree–Bogoliubov model (RHB), which is extended to include the density dependent interactions. In heavier nuclei, the low-lying E1 excited state is identified as a pygmy dipole resonance (PDR), i.e. as a collective mode of excess neutrons oscillating against a proton–neutron core. Isotopic dependence of the PDR is characterized by a crossing between the PDR and one-neutron separation energies. Already at moderate proton–neutron asymmetry the PDR peak is calculated above the neutron emission threshold, indicating important implications for the observation of the PDR in (γ, γ′) scattering, and on the theoretical predictions of the radiative neutron capture rates in neutron-rich nuclei. In addition, a novel method is suggested for determining the neutron skin of nuclei, based on measurement of excitation energies of the Gamow–Teller resonance relative to the isobaric analog state.

scholarly journals Isobaric analog state energy in deformed nuclei: A toy model

2020 ◽  
Vol 102 (6) ◽  
Author(s):  
X. Roca-Maza ◽  
H. Sagawa ◽  
G. Colò
Keyword(s):  
State Energy ◽  
Deformed Nuclei ◽  
Isobaric Analog ◽  
Isobaric Analog State
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