Nuclear Experiment·nucl-ex
5 papers—2 primary·3 cross-listed·reconstructed*
Beta decays of mirror nuclei differ in Q-value, but will otherwise proceed with transitions of similar strength. The current status is reviewed: Fermi transitions are all very similar, whereas Gamow-Teller transitions can differ in strength by more than a factor two. The main cause of the asymmetries appears to be binding energy differences between the mirror systems.
A. Jhingan🇮🇳 · C. Schmitt🇫🇷 · A. Lemasson🇫🇷 · S. Biswas🇫🇷 · Y.H. Kim🇰🇷 · D. Ramos🇫🇷 · A.N. Andreyev🇬🇧 · D. Curien🇫🇷 · M. Ciemala🇵🇱 · E. Clément🇫🇷 · O. Dorvaux🇫🇷 · B. De Canditiis🇫🇷 and 18 other authors
Fission at low excitation energy is an ideal playground to probe the impact of nuclear structure on nuclear dynamics. While the importance of structural effects in the nascent fragments is well-established in the (trans-)actinide region, the observation of asymmetric fission in several neutron-deficient pre-actinides can be explained by various mechanisms. To deepen our insight into that puzzle, an innovative approach based on inverse kinematics and an enhanced version of the VAMOS++ heavy-ion spectrometer was implemented at the GANIL facility, Caen. Fission of Hg was induced by fusion of Xe and Fe. The two fragments were detected in coincidence using VAMOS++ supplemented with a new SEcond Detection arm. For the first time in the pre-actinide region, access to the pre-neutron mass and total kinetic energy distributions, and the simultaneous isotopic identification of one the fission fragment, was achieved. The present work describes the experimental approach, and discusses the pre-neutron observables in the context of an extended asymmetric-fission island located south-west of $^{208}Pb. A comparison with different models is performed, demonstrating the importance of this "new" asymmetric-fission island for elaborating on driving effects in fission.
M. Wang🇨🇳 · M. Zhang🇨🇳 · X. Zhou🇨🇳 · Y. H. Zhang🇨🇳 · Yu. A. Litvinov🇩🇪 · H. S. Xu🇨🇳 · R. J. Chen · H. Y. Deng🇨🇳 · C. Y. Fu🇨🇳 · W. W. Ge · H. F. Li · T. Liao and 17 other authors
A novel technique for broadband high-precision mass measurements of short-lived exotic nuclides is reported. It is based on the isochronous mass spectrometry (IMS) and realizes simultaneous determinations of revolution time and velocity of short-lived stored ions at the cooler storage ring CSRe in Lanzhou. The new technique, named as the -defined IMS or -IMS, boosts the efficiency, sensitivity, and accuracy of mass measurements, and is applied here to measure masses of neutron-deficient -shell nuclides. In a single accelerator setting, masses of Cr, Fe and Ni are determined with relative uncertainties of (5~-~6), thereby improving the input data for testing the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. This is the technique of choice for future high-precision measurements of the most rarely produced shortest-lived nuclides.
A. Grassi🇵🇱 · J. Golak🇵🇱 · W. N. Polyzou🇺🇸 · R. Skibiński🇵🇱 · H. Witała🇵🇱 · H. Kamada🇯🇵
We build a relativistic model to perform calculations of exclusive, semi-exclusive and inclusive unpolarized cross sections and various polarization observables in electron and neutrino scattering experiments with deuteron targets. The strong interaction dynamics is defined by an explicit dynamical unitary representation of the Poincaré group, where representations of space translations and rotations in the interacting and non-interacting representations are the same. The Argonne V18 potential is used to construct a relativistic nucleon-nucleon interaction reproducing the experimental deuteron binding energy and nucleon-nucleon scattering observables. Our formalism does not include the pion production channel and neglects two-body contributions in the electromagnetic as well as in the weak nuclear current operator. We show that it is applicable to processes at kinematics, where the internal two-nucleon energy remains below the pion production threshold but the magnitude of the three-momentum transfer extends at least to several GeV.
N.N. Arsenyev🇷🇺 · A.P. Severyukhin🇷🇺
The properties of the isoscalar giant monopole resonance (ISGMR) for the double magic Ca are analyzed in the framework of a microscopic model based on Skyrme-type interactions. A method for simultaneously taking into account the coupling between one-, two-, and three-phonon terms in the wave functions of states has been developed. The inclusion of three-phonon configurations leads to a substantial redistribution of the ISGMR strength to lower energy states and also higher energy tail. Our results demonstrate that the developed approach enables to us to describe a gross structure of the ISGMR spreading width.
* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.