Recently it has been shown that models which consider self-interacting particles as dark matter candidates can be able to account with practically all the discrepancies between N-body simulations and astronomical observations of the galactic structure. In the present work we show that the 3-3-1 electroweak model can provide a realistic candidate to this kind of dark matter. This dark matter particle is not arbitrarily imposed and no new symmetry is needed to stabilize it.

We investigate the possible decay of protons in geodesic circular motion around neutral compact objects. Weak and strong decay rates and the associated emitted powers are calculated using a semiclassical approach. Our results are discussed with respect to distinct ones in the literature, which consider the decay of accelerated protons in electromagnetic fields. A number of consistency checks are presented along the paper.

We consider here the decay of unstable particles in geodesic circular motion around compact objects. For the neutron, in particular, strong and weak decay are calculated by means of a semiclassical approach. Noticeable effects are expected to occur as one approaches the photonic circular orbit of realistic black-holes. We argue that, in such a limit,the quasi-thermal spectrum inherent to extremely relativistic observers in circular motion plays a role similar to the Unruh radiation for uniformly accelerated observers.Comment: 6 pages, 4 figures. Final version to appear in PR

By using rather conservative estimates based on the simplest polar cap model, we search the ATNF Pulsar Catalogue for strongly magnetized stars that could accelerate relativistic protons up to the curvature pion production threshold. The best candidate turns out to be the 16 ms pulsar J0537-6910, but the corresponding characteristic parameter χ = a/m p is yet too small to give origin to observable signals. We show that, for pulsars with period P ≈ 1 ms, a surface polar magnetic field B ≈ 10 12 G is required in order to induce detectable curvature pion radiation from accelerated protons in the magnetosphere. Some other emission processes are also considered.

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