Search for Solar Dark Matter Particles with Crystal micro-pendulum.

We report the direct detection of dark neutral massive particles (MP) emitted by the Sun. The estimated rest mass is (3.15 ±1) PeV/C² and the local mass-energy density is (0.64 ±0.2) GeV/cm³. They were detected by using a novel mechano-optical method, which does not require any electromagnetic or nuclear interaction of MP with detector elements. The sensor is a crystal pendulum (CP) with a microgram crystalline bob. It starts to oscillate when MP carrying momentum knocks CP. The Laser-Doppler-Vibrometer (LDV) detects these oscillations. A laser beam of LDV is focused on the crystal-bob and is reflected to LDV optical sensor. It allows for measuring the speed, amplitude, and frequency of CP oscillations. Theoretical calculations of CP oscillations are then compared to experimental data registered by LDV. The solar MP was detected by 8 CP with different quartz crystals in 30 runs of the experiments completed at different seasons. The data obtained allowed us to estimate the rest mass and local mass-energy density of solar MP. The MP particles do not interact with electromagnetic radiation and are dark to contemporary astrophysical and particle physics detectors. That is why detected MP is a part of dark matter by definition, despite MP are not a part of matter produced during the Big Bang period. Discovered MP is a new part of solar/star wind. They contribute their mass to the total mass of the galaxy and universe. Possibly, other stars also can emit similar MP and it may shed light on astrophysical problems in mass distribution in the universe.