9 papers · 1 filter
Neutralino spectrum in top-down models of UHECR
Alejandro Ibarra, Ramon Toldra
We calculate the cosmic ray spectrum of ultra high energy neutralinos that one should expect provided that the observed ultra high energy cosmic rays are produced by the decay of s…
A C++ Code to Solve the DGLAP Equations Applied to Ultra High Energy Cosmic Rays
Ramon Toldra
We solve numerically the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations for the evolution of fragmentation functions using the Laguerre method. We extend this method…
The high energy cosmic ray spectrum from relic particle decay
Subir Sarkar, Ramon Toldra
It has been speculated that the recently detected ultra-high energy cosmic rays may originate from the decays of relic particles with mass of order GeV clustered in the h…
Gravitinos from Gravitational Collapse
J. A. Grifols, E. Masso, R. Toldra
We reanalyse the limits on the gravitino mass in superlight gravitino scenarios derived from arguments on energy-loss during gravitational collapse. We conclude that the…
Contact Interactions Involving Right-handed Neutrinos and SN1987A
J. A. Grifols, E. Masso, R. Toldra
We consider lepton-quark contact interactions in models with right-handed neutrinos, and find that observational data from SN1987A restricts the scale of such interactions to be at…
New Constraints on a Light Spinless Particle Coupled to Photons
Eduard Masso, Ramon Toldra
We obtain new stringent constraints on a light spinless particle phi coupled only to photons at low energies, considering its effects on the extragalactic photon background, the bl…