Gregor Bregar: Measurements of dark matter particle collisions

Gregor Bregar,  Oddelek za fiziko FMF Univerze v Ljubljani

Measurements of dark matter particle collisions

The dark matter is on of the great puzzles of contemporary physics.
Only recently have the experiments that probe the microscopic properties
been proposed. Until then only distribution and mass measurements existed.
In 1990 a preposition to detect scintilations of dark
matter particles colliding in highly shielded detector was made.

Among all experiments one is chosen for presentation: DAMA/LIBRA.
It differs from other experiments by scintillator size, threshold
of detection, operating time and a positive detection of dark
matter collisions with 8.2 $\sigma$ confidence level. Scientific community
did not accept the results as unambiguous since one experiment
contradicts the results of DAMA/LIBRA.

When accepting the results limitations for the ratio of cross section
for low energy elastic scattering of dark matter particles on nuclei and
their mass follows. The approach unifying spins and charges offers
a dark matter realisation. From DAMA/LIBRA an interval for mass
of stable new quarks of fifth family follows.