Fri·Feb 18, 2022Friday·February 18, 2022

1. 01*

   Evidence of a dibaryon spectrum in coherent ${\pi }^0{\pi }^{0}d$ photoproduction at forward deuteron angles

   T.C. Jude · S. Alef · R. Beck · A. Braghieri · P.L. Cole · D. Elsner · R. Di Salvo · A. Fantini · O. Freyermuth · F. Frommberger · F. Ghio · A. Gridnev and 18 other authors

   The coherent reaction, $\gamma d\to {\pi }^0{\pi }^{0}d$ was studied with the BGOOD experiment at ELSA from threshold to a centre-of-mass energy of 2850\,MeV. A full kinematic reconstruction was made, with final state deuterons identified in the forward spectrometer and ${\pi }^0$ decays in the central BGO Rugby Ball. The strength of the differential cross section exceeds what can be described by models of coherent photoproduction and instead supports the three isoscalar dibaryon candidates reported by the ELPH collaboration at 2.38, 2.47 and 2.63\,GeV/c${}^2$. A low mass enhancement in the ${\pi }^0{\pi }^0$ invariant mass is also observed at the $d^{\ast }(2380)$ centre-of-mass energy which is consistent with the ABC effect. At higher centre-of-mass energies, a narrow peak in the ${\pi }^{0}d$ invariant mass at 2114\,MeV/c${}^2$ with a width of 20\,MeV/c${}^2$ supports a sequential two-dibaryon decay mechanism.

   nucl-exPLB(2022)·24 citations
2. 02*

   Final results on the $0\nu \beta \beta$ decay half-life limit of ${}^{100}$Mo from the CUPID-Mo experiment

   C. Augier · A. S. Barabash · F. Bellini · G. Benato · M. Beretta · L. Bergé · J. Billard · Yu. A. Borovlev · L. Cardani · N. Casali · A. Cazes · M. Chapellier and 67 other authors

   The CUPID-Mo experiment to search for 0$\nu \beta \beta$ decay in ${}^{100}$Mo has been recently completed after about 1.5 years of operation at Laboratoire Souterrain de Modane (France). It served as a demonstrator for CUPID, a next generation 0$\nu \beta \beta$ decay experiment. CUPID-Mo was comprised of 20 enriched Li${}_2$${}^{100}$MoO${}_4$ scintillating calorimeters, each with a mass of $\sim$ 0.2 kg, operated at $\sim$20 mK. We present here the final analysis with the full exposure of CUPID-Mo (${}^{100}$Mo exposure of 1.47 kg$\times$yr) used to search for lepton number violation via 0$\nu \beta \beta$ decay. We report on various analysis improvements since the previous result on a subset of data, reprocessing all data with these new techniques. We observe zero events in the region of interest and set a new limit on the ${}^{100}$Mo 0$\nu \beta \beta$ decay half-life of $T_{1/2}^{0\nu }>1.8\times 10^{24}$ year (stat.+syst.) at 90% CI. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of $⟨m_{\beta \beta }⟩<(0.28$--$0.49)$ eV, dependent upon the nuclear matrix element utilized.

   nucl-exphysics.ins-detEPJC(2022)·105 citations
3. 03*

   Effects of triaxiality and pairing interaction on fission barriers of actinide nuclei studied by density-dependence relativistic mean-field theory

   Taiki Kouno · Chikako Ishizuka🇯🇵 · Kazuki Fujio · Tsunenori Inakura🇯🇵 · Satoshi Chiba🇯🇵

   We employ density-dependent relativistic mean-field theory to study how the triaxiality and pairing interaction affect the inner fission barriers of actinide nuclei. It was found that triaxiality reduced the inner fission barriers and improved agreement with experimental values for many actinides. However, about 1-2 MeV discrepancy to the experimental values still remained for some of the considered nuclei. Such a discrepancy could be made further smaller by increasing the BCS pairing strength parameter. In this work, we demonstrated that adjusting the paring strength was effective to reproduce the experimental inner fission barriers as well as "pairing rotational energy" and binding energy in a consistent manner for nuclei where the effect of the triaxiality on the inner fission barriers was significant.

   ↳ nucl-thnucl-exIJMPE(2022)·1 citation
4. 04*

   Effects of isoscalar- and isovector-scalar meson mixing on neutron star structure

   Fan Li🇨🇳 · Bao-Jun Cai🇨🇳 · Ying Zhou🇨🇳 · Wei-Zhou Jiang🇨🇳 · Lie-Wen Chen🇨🇳

   Based on the accurately calibrated interaction FSUGold, we show that including isovector scalar $\delta$ meson and its coupling to isoscalar scalar $\sigma$ meson in the relativistic mean field (RMF) model can soften the symmetry energy $E_{\mathrm{sym}}(n)$ at intermediate densities while stiffen the $E_{\mathrm{sym}}(n)$ at high densities. We find this new RMF model can be simultaneously compatible with (1) the constraints on the equation of state of symmetric nuclear matter at suprasaturation densities from flow data in heavy-ion collisions, (2) the neutron skin thickness of ${}^{208}$Pb from the PREX-II experiment, (3) the largest mass of neutron star (NS) reported so far from PSR J0740+6620, (4) the limit of ${\Lambda }_{1.4}\le 580$ for the dimensionless tidal deformability of the canonical 1.4$M_{\odot }$ NS from the gravitational wave signal GW170817, (5) the mass-radius relation of PSR J0030+0451 and PSR J0740+6620 measured by NICER, and thus remove the tension between PREX-II and GW170817 observed in the conventional RMF model.

   ↳ nucl-thastro-ph.HEhep-phnucl-exApJ(2022)·49 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.