3 papers
astro-ph1996
Implications of a Possible Clustering of Highest Energy Cosmic Rays
Guenter Sigl, David N. Schramm, Sangjin Lee +2
Very recently, a possible clustering of a subset of observed ultrahigh energy cosmic rays above about 40EeV (4x10^19eV) in pairs near the supergalactic plane was reported. We show…
astro-ph1995
HELIUM PHOTODISINTEGRATION AND NUCLEOSYNTHESIS: IMPLICATIONS FOR TOPOLOGICAL DEFECTS, HIGH ENERGY COSMIC RAYS, AND MASSIVE BLACK HOLES
G. Sigl, K. Jedamzik, D. N. Schramm +1
We consider the production of He and H by He photodisintegration initiated by non-thermal energy releases during early cosmic epochs. We find that this process cannot b…
hep-ph1993
Could a nearby supernova explosion have caused a mass extinction?
John Ellis, David N. Schramm
We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by palaeontologists. We discuss the likely rate of suc…