Particle Dark Matter and Solar Axion Searches with a small germanium detector at the Canfranc Underground Laboratory

A. Morales, F. T. Avignone III, R. L. Brodzinski, S. Cebrian, E. Garcia, D. Gonzalez, I. G. Irastorza, H. S. Miley, J. Morales, A. Ortiz de Solorzano, J. Puimedon, J. H. Reeves, M. L. Sarsa, S. Scopel, J. A. Villar

Published 2001-01-22Version 1

A small, natural abundance, germanium detector (COSME) has been operating recently at the Canfranc Underground Laboratory (Spanish Pyrenees) in improved conditions of shielding and overburden with respect to a previous operation of the same detector. An exposure of 72.7 kg day in these conditions has at present a background improvement of about one order of magnitude compared to the former operation of the detector. These new data have been applied to a direct search for WIMPs and solar axions. New WIMP exclusion plots improving the current bounds for low masses are reported. The paper also presents a limit on the axion-photon coupling obtained from the analysis of the data looking for a Primakoff axion-to-photon conversion and Bragg scattering inside the crystal.