Search results for "mirror nuclei"
showing 10 items of 24 documents
Charge symmetry breaking inA= 4 hypernuclei
2016
Charge symmetry breaking in the A = 4 hypernuclear system is reviewed. The data on binding energies of the mirror nuclei and hypernuclei are examined. At the Mainz Microtron MAMI the high-resolution spectroscopy of decay-pions in strangeness electro-production is used to extract the Λ hyperon ground state binding energy in 4 Λ H. This binding energy is used together with the 4 Λ He ground state binding energy from nuclear emulsion experiments and with energy levels of the 1 + excited state for both hypernuclei from γ-ray spectroscopy to address the charge symmetry breaking in the strong interaction. The binding energy difference of the ground states in the mirror pair is reduced from its lo…
Lifetime measurements in mirror nuclei31S and31P: A test for isospin mixing
2011
Using the 20Ne + 12C fusion-evaporation reaction at E20Ne = 33 MeV and the multidetector array GASP in conjuction with the EUCLIDES charged particle detector, angular correlations of coincident pairs of γ transitions and lifetimes in mirror nuclei 31S and 31P have been measured at the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. A comparison of the determined B(E1) strengths of the analog mirror 7/2− → 5/2+ transitions indicates the presence of a violation of isospin symmetry.
Nuclear weak response from the combined study of beta-decay and charge-exchange reaction
2009
Studying the weak nuclear response, especially the Gamow-Teller (GT) transitions, of stable as well as unstable pf-shell nuclei, is one of the key issues in nuclear and astro-nuclear physics. We study the decay half-lives and the GT transitions starting from Tz = ±1 and ±2 mirror nuclei, respectively, by means of β decays and complementary hadronic (3 He , t) charge-exchange reactions. Under the assumption that isospin is a good quantum number, symmetry is expected for mirror nuclei and the GT transitions starting from the mirror nuclei. The half-lives and branching ratios and the measured strength distributions of GT transitions are compared and also combined for the understanding of the …
Beta Decay Study of the Tz=−2 56Zn Nucleus and the Determination of the Half-Lives of a Few fp-shell Nuclei
2014
Abstract This paper concerns the experimental study of the β decay properties of few proton-rich fp -shell nuclei. The nuclei were produced at GANIL in fragmentation reactions, separated with the LISE spectrometer and stopped in an implantation detector surrounded by Ge detectors. The β -delayed gammas, β -delayed protons and the exotic β -delayed gamma-proton emission have been studied. Preliminary results are presented. The decay of the T z = − 2 nucleus 56 Zn has been studied in detail. Information from the β -delayed protons and β -delayed gammas has been used to deduce the decay scheme. The exotic beta-delayed gamma-proton decay has been observed for the first time in the fp -shell. Th…
Tz = ±1 → 0 ISOSPIN SYMMETRY GAMOW-TELLER TRANSITIONS IN pf-SHELL NUCLEI
2010
Studying the Gamow-Teller (GT) transitions of stable as well as unstable pf-shell nuclei is one of the key issues in nuclear and astro-nuclear physics. Under the assumption that isospin T is a good quantum number, symmetry is expected for mirror nuclei and the GT transitions starting from the mirror nuclei. We study the GT transitions starting from Tz = ±1 mirror nuclei, respectively, by means of hadronic (3 He , t) charge-exchange reactions and complementary β decays.
Isospin-breaking corrections to superallowed Fermi beta-decay in isospin- and angular momentum-projected nuclear Density Functional Theory
2012
Background: The superallowed beta-decay rates provide stringent constraints on physics beyond the Standard Model of particle physics. To extract crucial information about the electroweak force, small isospin-breaking corrections to the Fermi matrix element of superallowed transitions must be applied. Purpose: We perform systematic calculations of isospin-breaking corrections to superallowed beta-decays and estimate theoretical uncertainties related to the basis truncation, time-odd polarization effects related to the intrinsic symmetry of the underlying Slater determinants, and to the functional parametrization. Methods: We use the self-consistent isospin- and angular-momentum-projected nuc…
Nuclear moments of neon isotopes in the range fromNe17at the proton drip line to neutron-richNe25
2005
Nuclear moments of odd-A neon isotopes in the range 17 ≤ A ≤ 25 have been determined from optical hyperfine structures measured by collinear fast-beam laser spectroscopy. The magnetic dipole moments of 17 Ne, 23 Ne and 25 Ne, as well as the electric quadrupole moment of 23 Ne are either reported for the first time or improved considerably. The measurements also decide for a 1/2 + ground state of 25 Ne. The behavior of the magnetic moments of the proton drip-line nucleus 17 Ne and its mirror partner 17 N suggests isospin symmetry. Thus, no clear indication of an anomalous nuclear structure is found for 17 Ne. The magnetic moments of the investigated nuclei are discussed in a shell-model appr…
Reevaluation of theP30(p,γ)S31astrophysical reaction rate from a study of theT=1/2mirror nuclei,S31andP31
2006
The $^{30}\mathrm{P}$($p,\ensuremath{\gamma}$)$^{31}\mathrm{S}$ reaction rate is expected to be the principal determinant for the endpoint of nucleosynthesis in classical novae. To date, the reaction rate has only been estimated through Hauser-Feschbach calculations and is unmeasured experimentally. This paper aims to remedy this situation. Excited states in $^{31}\mathrm{S}$ and $^{31}\mathrm{P}$ were populated in the $^{12}\mathrm{C}$($^{20}\mathrm{Ne}$,$n$) and $^{12}\mathrm{C}$($^{20}\mathrm{Ne}$,$p$) reactions, respectively, at a beam energy of 32 MeV, and their resulting $\ensuremath{\gamma}$decay was detected with the Gammasphere array. Around half the relevant proton unbound states …
Mirror energy differences in theA=31mirror nuclei,S31andP31, and their significance in electromagnetic spin-orbit splitting
2005
Excited states in $^{31}\mathrm{S}$ and $^{31}\mathrm{P}$ were populated in the $^{12}\mathrm{C}$($^{20}\mathrm{Ne}$,n) and $^{12}\mathrm{C}$($^{20}\mathrm{Ne}$,p) reactions, respectively, at a beam energy of 32 MeV. High spin states of positive and negative parity have been observed in $^{31}\mathrm{S}$ for the first time, and the yrast scheme of $^{31}\mathrm{P}$ has been extended. Large mirror energy differences between the first $9/{2}^{\ensuremath{-}}$ and $13/{2}^{\ensuremath{-}}$ states were observed, but only small differences for the first $7/{2}^{\ensuremath{-}}$ and $11/{2}^{\ensuremath{-}}$ levels. The significance of these observations is discussed in relation to the electromag…
Coulomb displacement energies as a probe for nucleon pairing in the $f_{7/2}$ shell
2014
Coulomb displacement energies of $T=1/2$ mirror nuclei have been studied via a series of high-precision $Q_\mathrm{EC}$-value measurements with the double Penning trap mass spectrometer JYFLTRAP. Most recently, the $Q_\mathrm{EC}$ values of the $f_{7/2}$-shell mirror nuclei $^{45}$V ($Q_\mathrm{EC}=7123.82(22)$ keV) and $^{49}$Mn ($Q_\mathrm{EC}=7712.42(24)$ keV) have been measured with an unprecedented precision. The data reveal a 16-keV ($1.6\sigma$) offset in the adopted Atomic Mass Evaluation 2012 value of $^{49}$Mn suggesting the need for further measurements to verify the breakdown of the quadratic form of the isobaric multiplet mass equation. Precisely measured $Q_\mathrm{EC}$ values…