DANSS is a highly segmented 1 m 3 plastic scintillator detector. Its 2500 one meter long scintillator strips have a Gdloaded reflective cover. The DANSS detector is placed under an industrial 3.1 GW th reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 ν e per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detectν e . Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the ∆m 2 14 , sin 2 2θ 14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactorν e spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to sin 2 2θ 14 < 0.01 in the most sensitive region.Published in the Phys.Lett.B as

Recent progress in the field of topological states of matter has largely been initiated by the discovery of bismuth and antimony chalcogenide bulk topological insulators (TIs; refs ,,,), followed by closely related ternary compounds and predictions of several weak TIs (refs ,,). However, both the conceptual richness of Z2 classification of TIs as well as their structural and compositional diversity are far from being fully exploited. Here, a new Z2 topological insulator is theoretically predicted and experimentally confirmed in the β-phase of quasi-one-dimensional bismuth iodide Bi4I4. The electronic structure of β-Bi4I4, characterized by Z2 invariants (1;110), is in proximity of both the weak TI phase (0;001) and the trivial insulator phase (0;000). Our angle-resolved photoemission spectroscopy measurements performed on the (001) surface reveal a highly anisotropic band-crossing feature located at the  point of the surface Brillouin zone and showing no dispersion with the photon energy, thus being fully consistent with the theoretical prediction.

Theoretical calculations predict 270Hs (Z=108, N=162) to be a doubly magic deformed nucleus, decaying mainly by alpha-particle emission. In this work, based on a rapid chemical isolation of Hs isotopes produced in the 26Mg+248Cm reaction, we observed 15 genetically linked nuclear decay chains. Four chains were attributed to the new nuclide 270Hs, which decays by alpha-particle emission with Qalpha=9.02+/-0.03 MeV to 266Sg which undergoes spontaneous fission with a half-life of 444(-148)(+444) ms. A production cross section of about 3 pb was measured for 270Hs. Thus, 270Hs is the first nucleus for which experimental nuclear decay properties have become available for comparison with theoretical predictions of the N=162 shell stability.

The semiclassical formalism for numerical calculation of the rate of tunneling transitions induced by N particles with total energy E of order or higher than the height of the barrier is developed. The formalism is applied to the induced false vacuum decay in the massive four-dimensional −λφ 4 model. The decay rate, as a function of E and N , is calculated numerically in the range 0.4 ∼ < E/E sph ∼ < 3.5 and 0.25 ∼ < N/N sph ∼ < 1.0, where E sph and N sph are the energy and the number of particles in the analog of the sphaleron configuration. The results imply that the two-particle cross section of the false vacuum decay is exponentially suppressed at least up to energies of order 10E sph . At E ∼ E sph , this exponential suppression is estimated as about 80% of the zero energy suppression.

The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles (6 < or = Z < or = 18) and actinide targets suggests a disappearance of the 3n exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction (248)Cm ((26)Mg,xn)(274-x)Hs and the observation of the new nuclide (271)Hs produced in the 3n evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the 4n and 5n channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.