51 research outputs found
Nuclear charge radius of Al and its implication for V in the quark-mixing matrix
Collinear laser spectroscopy was performed on the isomer of the aluminium
isotope Al. The measured isotope shift to Al in the
3s^{2}3p\;^{2}\!P^\circ_{3/2} \rightarrow 3s^{2}4s\;^{2}\!S_{1/2} atomic
transition enabled the first experimental determination of the nuclear charge
radius of Al, resulting in =\qty{3.130\pm.015}{\femto\meter}. This
differs by 4.5 standard deviations from the extrapolated value used to
calculate the isospin-symmetry breaking corrections in the superallowed
decay of Al. Its corrected value, important for the
estimation of in the CKM matrix, is thus shifted by one standard
deviation to \qty{3071.4\pm1.0}{\second}.Comment: 5 pages, 2 figures, submitted to Phys. Rev. Let
Electromagnetic Properties of Indium Isotopes Elucidate the Doubly Magic Character of <sup>100</sup>Sn
Understanding the nuclear properties in the vicinity of 100Sn â suggested to be the heaviest doubly magic nucleus with equal proton number Z and neutron number N â has been a long-standing challenge for experimental and theoretical nuclear physics. In particular, contradictory experimental evidence exists regarding the role of nuclear collectivity in this region of the nuclear chart. Here, we provide additional evidence for the doubly-magic character of 100Sn by measuring the ground-state electromagnetic moments and nuclear charge radii of indium (Z = 49) isotopes as N approaches 50 from above using precision laser spectroscopy. Our results span almost the complete range between the two major neutron closed shells at N = 50 and N = 82 and reveal parabolic trends as a function of the neutron number, with a clear reduction toward these two neutron closed-shells. A detailed comparison between our experimental and numerical results from two complementary nuclear many-body frameworks, density functional theory and ab initio methods, exposes deficiencies in nuclear models and establishes a benchmark for future theoretical developments.<br/
High-precision measurements of the hyperfine structure of cobalt ions in the deep ultraviolet range
RAPTOR : A new collinear laser ionization spectroscopy and laser-radiofrequency double-resonance experiment at the IGISOL facility
RAPTOR, Resonance ionization spectroscopy And Purification Traps for Optimized spectRoscopy, is a new collinear resonance ionization spectroscopy device constructed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of JyvÀskylÀ, Finland. By operating at beam energies of under 10 keV, the footprint of the experiment is reduced compared to more traditional collinear laser spectroscopy beamlines. In addition, RAPTOR is coupled to the JYFLTRAP Penning trap mass spectrometer, opening a window to laser-assisted nuclear-state selective purification, serving not only the mass measurement program, but also supporting post-trap decay spectroscopy experiments. Finally, the low-energy ion beams used for RAPTOR will enable high-precision laser-radiofrequency double-resonance experiments, resulting in spectroscopy with linewidths below 1 MHz. In this contribution, the technical layout of RAPTOR and a selection of ion-beam optical simulations for the device are presented, along with a discussion of the current status of the commissioning experiments.peerReviewe
Direct determination of the atomic mass difference of the pairs As-Se and Tb-Gd rules out As and Tb as possible candidates for electron (anti)neutrino mass measurements
The first direct determination of the ground-state-to-ground-state values of the decay As Se and the electron-capture decay Tb Gd was performed utilizing the double Penning trap mass spectrometer JYFLTRAP. By measuring the atomic mass difference of the decay pairs via the phase-imaging ion-cyclotron-resonance (PI-ICR) technique, the values of As Se and Tb Gd were determined to be 2959.265(74) keV and 814.94(18) keV, respectively. The precision was increased relative to earlier measurements by factors of 12 and 57, respectively. The new values are 1.33 keV and 5 keV lower compared to the values adopted in the most recent Atomic Mass Evaluation 2020. With the newly determined ground-state-to-ground-state values combined with the excitation energy from -ray spectroscopy, the values for ground-state-to-excited-state transitions As (ground state) Se (2968.4(7) keV) and Tb (ground state) Gd (815.731(3) keV) were derived to be -9.13(70) keV and -0.79(18) keV. Thus we have confirmed that both of the -decay and EC-decay candidate transitions are energetically forbidden at a level of at least 4, thus definitely excluding these two cases from the list of potential candidates for the search of low--value or EC decays to determine the electron-(anti)neutrino mass
Direct determination of the atomic mass difference of the pairs <math><mrow><mmultiscripts><mi>As</mi><mprescripts/><none/><mn>76</mn></mmultiscripts><mtext>-</mtext><mmultiscripts><mi>Se</mi><mprescripts/><none/><mn>76</mn></mmultiscripts></mrow></math> and <math><mrow><mmultiscripts><mi>Tb</mi><mprescripts/><none/><mn>155</mn></mmultiscripts><mtext>-</mtext><mmultiscripts><mi>Gd</mi><mprescripts/><none/><mn>155</mn></mmultiscripts></mrow></math> rules out <math><mmultiscripts><mi>As</mi><mprescripts/><none/><mn>76</mn></mmultiscripts></math> and <math><mmultiscripts><mi>Tb</mi><mprescripts/><none/><mn>155</mn></mmultiscripts></math> as possible candidates for electron (anti)neutrino mass measurements
International audienceThe first direct determination of the ground-stateâtoâground-state Q values of the ÎČâ decay As76âSe76 and the electron-capture decay Tb155âGd155 was performed utilizing the double Penning trap mass spectrometer JYFLTRAP. By measuring the atomic mass difference of the decay pairs via the phase-imaging ion-cyclotron-resonance technique, the Q values of As76âSe76 and Tb155âGd155 were determined to be 2959.265(74)Â keV and 814.94(18) keV, respectively. The precision was increased relative to earlier measurements by factors of 12 and 57, respectively. The new Q values are 1.33 keV and 5 keV lower compared to the values adopted in the most recent Atomic Mass Evaluation 2020. With the newly determined ground-stateâtoâground-state Q values combined with the excitation energy from Îł-ray spectroscopy, the Q values for ground-stateâtoâexcited-state transitions As76 (ground state) âSe*76 (2968.4(7) keV) and Tb155 (ground state) âGd*155 (815.731(3) keV) were derived to be â9.13(70) keV and â0.79(18) keV. Thus we have confirmed that both of the ÎČâ-decay and EC-decay candidate transitions are energetically forbidden at a level of at least 4Ï, thus definitely excluding these two cases from the list of potential candidates for the search of low-Q-value ÎČâ or EC decays to determine the electron-(anti)neutrino mass
Direct measurement of the mass difference of As-Ge rules out As as a promising -decay candidate to determine the neutrino mass
We report the first direct determination of the ground-state to ground-state electron-capture Q value for the As72 to Ge72 decay by measuring their atomic mass difference utilizing the double Penning trap mass spectrometer, JYFLTRAP. The Q value was measured to be 4343.596(75) keV, which is more than a fiftyfold improvement in precision compared to the value in the most recent Atomic Mass Evaluation 2020. Furthermore, the new Q value was found to be 12.4(40) keV (3.1 Ï) lower. With the significant reduction of the uncertainty of the ground-state to ground-state Q value combined with the level scheme of Ge72 from Îł-ray spectroscopy, we confirm that the five potential ultralow Q-value ÎČ+ decay or electron capture transitions are energetically forbidden, thus precluding all the transitions as possible candidates for the electron neutrino mass determination. However, the discovery of small negative Q values opens up the possibility to use As72 for the study of virtual ÎČ-Îł transitions
Direct determination of the atomic mass difference of the pairs As-Se and Tb-Gd rules out As and Tb as possible candidates for electron (anti)neutrino mass measurements
International audienceThe first direct determination of the ground-state-to-ground-state values of the decay As Se and the electron-capture decay Tb Gd was performed utilizing the double Penning trap mass spectrometer JYFLTRAP. By measuring the atomic mass difference of the decay pairs via the phase-imaging ion-cyclotron-resonance (PI-ICR) technique, the values of As Se and Tb Gd were determined to be 2959.265(74) keV and 814.94(18) keV, respectively. The precision was increased relative to earlier measurements by factors of 12 and 57, respectively. The new values are 1.33 keV and 5 keV lower compared to the values adopted in the most recent Atomic Mass Evaluation 2020. With the newly determined ground-state-to-ground-state values combined with the excitation energy from -ray spectroscopy, the values for ground-state-to-excited-state transitions As (ground state) Se (2968.4(7) keV) and Tb (ground state) Gd (815.731(3) keV) were derived to be -9.13(70) keV and -0.79(18) keV. Thus we have confirmed that both of the -decay and EC-decay candidate transitions are energetically forbidden at a level of at least 4, thus definitely excluding these two cases from the list of potential candidates for the search of low--value or EC decays to determine the electron-(anti)neutrino mass
Direct high-precision measurement of the mass difference of As-Se related to neutrino mass determination
International audienceThe first direct determination of the ground-state-to-ground-state -decay -value of As to Se was performed by measuring their atomic mass difference utilizing the double Penning trap mass spectrometer, JYFLTRAP. The resulting -value is 684.463(70) keV, representing a remarkable 24-fold improvement in precision compared to the value reported in the most recent Atomic Mass Evaluation (AME2020). With the significant reduction of the uncertainty of the ground-state-to-ground-state -value and knowledge of the excitation energies in Se from -ray spectroscopy, the ground-state-to-excited-state -value of the transition As (3/2, ground state) Se (5/2, 680.1035(17) keV) was refined to be 4.360(70) keV. We confirm that this potential low -value -decay transition for neutrino mass determination is energetically allowed at a confidence level of about 60. Nuclear shell-model calculations with two well-established effective Hamiltonians were used to estimate the partial half-life for the low -value transition. The half-life was found to be of the order of 10 years, which makes this candidate a potential source for rare-event experiments searching for the electron antineutrino mass
Proton-neutron pairing correlations in the self-conjugate nucleus 42Sc
Collinear laser spectroscopy of the N=Z=21 self-conjugate nucleus 42Sc has been performed at the JYFL IGISOL IV facility in order to determine the change in nuclear mean-square charge radius between the IÏ=0+ ground state and the IÏ=7+ isomer via the measurement of the 42g,42mSc isomer shift. New multi-configurational Dirac-Fock calculations for the atomic mass shift and field shift factors have enabled a recalibration of the charge radii of the 42â46Sc isotopes which were measured previously. While consistent with the treatment of proton-neutron, proton-proton and neutron-neutron pairing on an equal footing, the reduction in size for the isomer is observed to be of a significantly larger magnitude than that expected from both shell-model and ab-initio calculations. The measured nuclear magnetic dipole moment and electric quadruple moment, on the other hand, are in good agreement with simple empirical estimates and shell-model calculations.peerReviewe
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