Measurement of the Tm beta spectrum.

The beta spectrum of the main transition of the β decay of Tm was measured using a double focalizing spectrometer. The instrument was lately improved in order to reduce its low energy threshold to 34 keV. We used the spectrometer to measure the beta spectrum end-point energy of the main transition of Tm decay using the Kurie plot formalism.

A facility to search for hidden particles at the CERN SPS: the SHiP physics case.

This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, [Formula: see text] and to search for weakly-interacting sub-GeV dark matter candidates.

Long-range magnetic fields in the ground state of the Standard Model plasma.

In thermal equilibrium the ground state of the plasma of Standard Model particles is determined by temperature and exactly conserved combinations of baryon and lepton numbers. We show that at nonzero values of the global charges a translation invariant and homogeneous state of the plasma becomes unstable and the system transits into a new equilibrium state, containing a large-scale magnetic field. The origin of this effect is the parity-breaking character of weak interactions and chiral anomaly.

Self-consistent evolution of magnetic fields and chiral asymmetry in the early universe.

We show that the evolution of magnetic fields in a primordial plasma, filled with standard model particles at temperatures T≳10 MeV, is strongly affected by the chiral anomaly-an effect previously neglected. Although reactions, equilibrating left and right electrons, are in thermal equilibrium for T≲80 TeV, a left-right asymmetry develops in the presence of strong magnetic fields. This results in magnetic helicity transfer from shorter to longer scales and lepton asymmetry present in the plasma until T~10 MeV, which may strongly affect many processes in the early Universe.

Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds.

Previous fits of sterile neutrino dark matter (DM) models to cosmological data ruled out masses smaller than approximately 8 keV, assuming a production mechanism that is not the best motivated from a particle physics point of view. Here we focus on a realistic extension of the standard model with three sterile neutrinos, consistent with neutrino oscillation data and baryogenesis, with the lightest sterile neutrino being the DM particle. We show that for each mass >or= 2 keV there exists at least one model accounting for 100% of DM and consistent with Lyman-alpha and other cosmological, astrophysical, and particle physics data.