Fri·Mar 20, 2020Friday·March 20, 2020

1. 01*

   Refined scenario of the collinear cluster tri-partition mode with the greatest yield

   Yu.V. Pyatkov · D. V. Kamanin · Yu. M. Tchuvil'sky🇷🇺 · A. A. Alexandrov🇷🇺 · I. A. Alexandrova · Z. I. Goryainova · V. Malaza · E. A. Kuznetsova · A. O. Strekalovsky · O. V. Strekalovsky · Sh. Wyngaardt🇿🇦 · V. E. Zhuchko

   In our previous publications we discussed various manifestations of a new decay channel of the low excited heavy nuclei called collinear cluster tri-partition (CCT). The most populated CCT mode was revealed in the mass correlation distribution of fission fragments (FFs) as a local region ("bump") of increased yields below the loci linked to the conventional binary fission. The bump was dubbed "Ni-bump" because it is centered at the masses associated with the magic isotopes of Ni. Intriguing features of the CCT, especially high collinearity of the CCT partners and relatively high probability comparable with that typical for conventional ternary fission, have caused rather wide discussion. In the majority of dedicated publications, the FFs partitions from the Ni-bump have been analyzed from the different points of view. In our publications, we have underlined that Ni-bump manifests itself at the detectable level only in the spectrometer arm that faces the source backing. So far, this fact has been left beyond the scope of all known theoretical considerations, while the backing likely plays a crucial role in the observation of the CCT experimental pattern.

   nucl-exnucl-th0 citations
2. 02*

   Complete flavor decomposition of the spin and momentum fraction of the proton using lattice QCD simulations at physical pion mass

   C. Alexandrou (Univ. of Cyprus & The Cyprus Inst.)🇨🇾 · S. Bacchio (The Cyprus Inst.)🇨🇾 · M. Constantinou (Temple Univ.)🇺🇸 · J. Finkenrath (The Cyprus Inst.)🇨🇾 · K. Hadjiyiannakou (Univ. of Cyprus & The Cyprus Inst.)🇨🇾 · K. Jansen (DESY-Zeuthen)🇩🇪 · G. Koutsou (The Cyprus Inst.)🇨🇾 · H. Panagopoulos (Univ. of Cyprus)🇨🇾 · G. Spanoudes (Univ. of Cyprus)🇨🇾

   We evaluate the gluon and quark contributions to the spin of the proton using an ensemble of gauge configuration generated at physical pion mass. We compute all valence and sea quark contributions to high accuracy. We perform a non-perturbative renormalization for both quark and gluon matrix elements. We find that the contribution of the up, down, strange and charm quarks to the proton intrinsic spin is $\frac{1}{2}{\sum }_{q=u,d,s,c}\Delta {\Sigma }^{q^{+}}=0.191(15)$ and to the total spin ${\sum }_{q=u,d,s,c}{J}^{q^{+}}=0.285(45)$. The gluon contribution to the spin is $J^g=0.187(46)$ yielding $J=J^q+J^g=0.473(71)$ confirming the spin sum. The momentum fraction carried by quarks in the proton is found to be $0.618(60)$ and by gluons $0.427(92)$, the sum of which gives $1.045(118)$ confirming the momentum sum rule. All scale and scheme dependent quantities are given in the $\overline{\mathrm{MS}}$ scheme at 2 GeV.

   ↳ hep-lathep-exhep-phnucl-ex+1PRD(2020)·195 citations
3. 03*

   Addendum to: Global constraints on absolute neutrino masses and their ordering

   Francesco Capozzi🇺🇸 · Eleonora Di Valentino🇫🇷 · Eligio Lisi🇮🇹 · Antonio Marrone🇮🇹 · Alessandro Melchiorri🇮🇹 · Antonio Palazzo🇮🇹

   We revisit our previous work [Phys. Rev. D 95, 096014 (2017)] where neutrino oscillation and nonoscillation data were analyzed in the standard framework with three neutrino families, in order to constrain their absolute masses and to probe their ordering (either normal, NO, or inverted, IO). We include updated oscillation results to discuss best fits and allowed ranges for the two squared mass differences $\delta m^2$ and $\Delta m^2$, the three mixing angles ${\theta }_{12}$, ${\theta }_{23}$ and ${\theta }_{13}$, as well as constraints on the CP-violating phase $\delta$, plus significant indications in favor of NO vs IO at the level of $\Delta {\chi }^2=10.0$. We then consider nonoscillation data from beta decay, from neutrinoless double beta decay (if neutrinos are Majorana), and from various cosmological input variants (in the data or the model) leading to results dubbed as default, aggressive, and conservative. In the default option, we obtain from nonoscillation data an extra contribution $\Delta {\chi }^2=2.2$ in favor of NO, and an upper bound on the sum of neutrino masses $\Sigma <0.15$ eV at $2\sigma$; both results - dominated by cosmology - can be strengthened or weakened by using more aggressive or conservative options, respectively. Taking into account such variations, we find that the combination of all (oscillation and nonoscillation) neutrino data favors NO at the level of $3.2-3.7\sigma$, and that $\Sigma$ is constrained at the $2\sigma$ level within $\Sigma <0.12-0.69$ eV. The upper edge of this allowed range corresponds to an effective $\beta$-decay neutrino mass $m_{\beta }=\Sigma /3=0.23$ eV, at the sensitivity frontier of the KATRIN experiment.

   ↳ hep-phastro-ph.COhep-exnucl-exPRD(2017)·511 citations
4. 04*

   Challenge for describing the cluster states starting with realistic interaction

   Naoyuki Itagaki🇯🇵 · Tokuro Fukui🇯🇵 · Akihiro Tohsaki🇯🇵

   We aim to describe the cluster states of nuclear systems starting with a realistic interaction, which is a challenge of modern nuclear theories. Here, the short-range correlation of realistic interaction is treated by employing the damping factor, and the resultant interaction can be applied to the cluster structure of light nuclei. We start with a realistic interaction (G3RS) and transform it in this way, and the $\alpha$-$\alpha$ energy curve is compared with the results of phenomenological interactions. The attractive effect between two $\alpha$'s is found to be not enough even with a damping factor for the short-range repulsion, and the necessity of a finite-range three-body term is discussed. With this three-body term, the resonance energy of the ground state and the scattering phase shift of two $\alpha$'s can be reproduced. Also, the binding energy of ${}^{16}$O from the four $\alpha$ threshold is reasonably reproduced. The linear-chain structure of three and four $\alpha$ clusters in ${}^{12}$C and ${}^{16}$O are calculated with this interaction and compared with the results of the conventional approaches including the density functional theories.

   ↳ nucl-thnucl-ex2 citations
5. 05*

   The Continuum Spectrum of Hypernuclear Trios

   M. Schäfer🇨🇿 · B. Bazak🇮🇱 · N. Barnea🇮🇱 · J. Mareš🇨🇿

   The spectrum of hypernuclear trios composed of a $\Lambda$ baryon and two nucleons is the subject of an ongoing experimental campaign, aiming to study the interaction of the $\Lambda$ particle with a neutron, and the 3-body $\Lambda$-nucleon-nucleon force. In this manuscript we utilize baryonic effective field theory at leading order, constrained to reproduce the available low energy light hypernuclear data, to study the continuum spectrum of such hypernuclear trios. Using the complex scaling method and the inverse analytic continuation in the coupling constant method we find the existence of a virtual state in the $\Lambda np$ $J^{\pi }={\frac{3}{2}}^{+}$ channel, leading to cross-section enhancement near threshold. For the $\Lambda nn$ $J^{\pi }={\frac{1}{2}}^{+}$ channel we predict a resonance state. Depending, however, on the value of the $\Lambda N$ scattering length, the resonance pole moves from the physical to the unphysical complex energy sheet within the experimental bounds.

   ↳ nucl-thnucl-exPLB(2020)·25 citations
6. 06*

   Actinides measurements on environmental samples of the Garigliano Nuclear Power Plant (Italy) during the decommissioning phase

   Antonio Petraglia · Carmina Sirignano🇮🇹 · Raffaele Buompane · Antonio D'Onofrio · Carlo Sabbarese · Alfonso Maria Esposito · Filippo Terrasi

   An environmental survey was carried out in order to provide an adequate and updated assessment of the radiological impact that the decommissioning operations of the Garigliano NNP may have procured to the environment of the surrounding area. Some isotopes of uranium (235U, 236U, 238U) and plutonium (239Pu, 240Pu) and some {\gamma}-emitter radionuclides (60Co, 137Cs and 40K,) were measured to quantify the possible contamination and identify the origin source. Actinides isotopes were measured with the AMS technique that is able to detect elements in traces and reach sensitivity that cannot be obtained with other methods. The results show that the anthropogenic component is essentially due to the atmospheric fallout and no contamination can be charged to the NPP. Data are represented in geo-referenced maps to highlight the distribution area and some particular aspects of each measured radionuclide.

   ↳ physics.geo-phnucl-exProceedings of the 4 th International Con…·0 citations

* 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.