V. Yu. Denisov

Interaction potential between heavy ions

Abstract The semi-microscopic potential between heavy ions is evaluated for various colliding ions in the approach of frozen densities in the framework of the extended Thomas–Fermi approximation with ℏ2 correction terms in the kinetic energy density functional. The proton and neutron densities of each ion are obtained in the Hartree–Fock–Bogoliubov approximation with SkM ∗ parameter set of the Skyrme force. An expression for the ion–ion potential well fits the semi-microscopic potentials in the wide range of both colliding ions and distances between them.

Search for the nucleon and di-nucleon decay into invisible channels

Data collected deep underground at the Gran Sasso National Laboratory of INFN by using the similar or equal to 6.5 kg DAMA liquid Xenon scintillator have been analysed to search for nucleon and di-nucleon decays into invisible channels (decay to nu (i) )over bar>(i) or to nu (i) )over bar>(i)nu (i) or to 5 nu (i), etc., with i = e, mu, tau) or disappearance. The considered statistics has been 2257.7 kg x day. The new obtained limits are: tau (p) = 1.9 x 10(24) yr, tau (nn), = 1.2 x 10(25) yr and tau (pp) = 5.5 X 10(23) yr at 90% C.L. The latter values are the same or better than those previously established by the Frejus Collaboration; in particular, the limits for the NN decay into nu (tau) )over bar>(tau) are set for the first time

Density distributions in nuclei

Density distribution across the nuclear surface is obtained in the approximation of relatively sharp nuclear edge. It is used to determine dynamical parts of the density relevant to density vibration resonances. Results of the simple calculations are in close agreement with detailed microscopic theories.

Search for long-lived superheavy eka-tungsten with radiopure ZnWO4 crystal scintillator

The data collected with a radioactively pure ZnWO4 crystal scintillator (699 g) in low background measurements during 2130 h at the underground (3600 m w.e.) Laboratori Nazionali del Gran Sasso (INFN, Italy) were used to set a limit on possible concentration of superheavy eka-W (seaborgium Sg, Z = 106) in the crystal. Assuming that one of the daughters in a chain of decays of the initial Sg nucleus decays with emission of high energy ? particle ( MeV) and analyzing the high energy part of the measured ? spectrum, the limit N(Sg)/N(W) atoms/atom at 90% C.L. was obtained (for Sg half-life of 109 yr). In addition, a limit on the concentration of eka-Bi was set by analysing the data collected with a large BGO scintillation bolometer in an experiment performed by another group (Cardani et al 2012 JINST?7 P10022): N(eka-Bi)/N(Bi) atoms/atom with 90% C.L. Both the limits are comparable with those obtained in recent experiments which instead look for spontaneous fission of superheavy elements or use the accelerator mass spectrometry.

Polarized electric dipole moment of well-deformed reflection asymmetric nuclei

The expression for polarized electric dipole moment of well-deformed reflection asymmetric nuclei is obtained in the framework of the liquid-drop model in the case of geometrically similar proton and neutron surfaces. The expression for polarized electric dipole moment consists of the first- and second-order terms. It is shown that the second-order correction terms of the polarized electric dipole moment are important for well-deformed nuclei.

New limits on dinucleon decay into invisible channels

Data of the radiochemical experiment [E.L.Fireman, 1978] with 1.7 t of KC_2H_3O_2, accumulated deep underground during ~1 yr, were reanalyzed to set limits on di-nucleons (nn and np) decays into invisible channels (disappearance, decay into neutrinos, etc.). The obtained lifetime bounds tau_np>2.1 10^25 yr and tau_nn>4.2 10^25 yr (at 90% C.L.) are better (or competitive) than those established in the recent experiments.Data of the radiochemical experiment (E.L. Fireman, 1978) with 1.7 t of KC2H3O2, accumulated deep underground during ≃ 1 yr, were reanalyzed to set limits on dinucleon (nn and np) decays into invisible channels (disappearance, decay into neutrinos, etc.). The obtained lifetime bounds τnpτ; 2.1×1025 yr and τnnτ;4.2×1025 yr (at 90% C.L.) are better (or competitive) than those established in the recent experiments.