Cosmic Rays Observed by the Resonant Gravitational Wave Detector NAUTILUS

The passage of,cosmic rays has been observed to excite mechanical vibrations in the resonant gravitational wave detector NAUTILUS operating at temperature of 100 mK. A very significant correlation (more than 10 standard deviations) is found.

Cosmic ray showers interacting with the resonant mass gravitational wave antenna NAUTILUS have been detected. The experimental results show large signals at a rate much greater than expected. The largest signal corresponds to an energy release in NAUTILUS of 87 TeV. We remark that a resonant mass gravitational wave detector used as particle detector has characteristics different from the usual particle detectors, and it could detect new features of cosmic rays. Among several possibilities, one can invoke unexpected behaviour of superconducting Aluminium as particle detector, producing enhanced signals, the excitation of non-elastic modes with large energy release or anomalies in cosmic rays (for instance, the showers might include exotic particles as nuclearites or Q-balls). Suggestions for explaining these observations are solicited.