After a short review of Q-balls properties, in this paper, we discuss their
interaction with matter, and their energy losses in the earth, for a large
range of velocities. These calculations are used to compute the fractional
angular acceptance of a detector at Gran Sasso laboratory. Furthermore, we
computed the light yield in liquid scintillators, the ionization in stream
er tubes and the restricted energy loss in the CR39 nuclear track detector.
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