Below we present the achievements of our department in recent years.
The possibility of detecting high-energy neutrinos, above 1017eV, by ground detectors of Pierre Auger Observatory was investigated. No neutrino candidate was found in the collected data, so the upper limits for the neutrino stream were determined. The determined limits impose strong limitations on models predicting production of neutrinos in astrophysical sources and during propagation of cosmic rays.
Pierre Auger Collab., A. Aab, et al., Probing the origin of ultra-high-energy cosmic rays with neutrinos in the EeV energy range using the Pierre Auger Observatory, J. Cosmol. Astropart. Phys., 10 (2019) 022, DOI: 10.1088/1475-7516/2019/10/022
Pierre Auger Collab., A. Aab, et al., Limits on point-like sources of ultra-high-energy neutrinos with the Pierre Auger Observatory, J. Cosmol. Astropart. Phys., 11 (2019) 004, DOI: 10.1088/1475-7516/2019/11/004
The technology of mounting scintillation detectors in IFJ PAN was developed. In close, multilateral international cooperation, a technique of assembly and testing of SSD detectors was developed for the Pierre Auger Observatory. The assembly and testing of 228 such detectors was completed at IFJ PAN.
The possibility of detecting tau-neutrinos by IACT (Imaging Atmospheric Cherenkov Telescope) detectors was investigated. Usually such detectors register large atmospheric bundles induced by high-energy photons. For the first time the method of identification of tau-neutrinos in this type of detectors is presented. The limit for the stream of tau-neutrinos was also determined using this new method.
MAGIC Collab., M.L. Ahnen, (D. Góra) et al., Limits on the flux of tau neutrinos from 1 PeV to 3 EeV with the MAGIC telescopes, Astropart. Phys., 102 (2018) 77-88
Observation of the dipole large-scale anisotropy of the directions of arrival of ultra-high energy cosmic rays (above 8x1018 eV) in the Pierre Auger Observatory. This anisotropy has an amplitude of about 6.5% at the level of 5.2 standard deviations. The direction of the dipole indicates the extra-agalactic origin of ultra-high energy cosmic rays (result indicated by Physics World (IoP) as one of Top 10 breakthroughs of 2017).
The Pierre Auger Collaboration, A. Aab, et al., Observation of large-scale anisotropy in the arrival directions of cosmic rays above 8x1018 eV, Science 357, 1266-1270 (2017)
Organization of the international project CREDO (Cosmic Ray Extremely Distributed Observatory). The aim of the project is the global analysis of data from all available cosmic ray detectors for the identification of vast cascades of cosmic radiation, which cannot be recorded in single observatories. The resolution of the existence of such cascades will allow to verify the hypothesis of the existence of superheavy particles of dark matter and exotic scenarios of the origin of cosmic rays of the highest energy. The inaugural meeting of the project took place on August 30, 2016 in IFJ PAN.
Investigating the possibility of radar detection of large atmospheric bundles (J. Stasielak et al., Astropart. Phys. 73 (2016) 14). The reflection of radio wave from the plasma produced in the air by charged particles of a large crack was analysed. It was found that the radar echo of the big bundle is too weak to be the basis for an efficient and cheap method of detecting cosmic ultra-high energy radiation.
The first measurement of the average number of muons in the great atmospheric bundles of ultra-high energy. Comparison with the predictions of crack development using different models of nuclear interactions shows that none of the existing models is reproducing the observations correctly. Observed number of muons is 30-80% higher than predicted by the models. This fact is fundamental for determining the composition of cosmic rays of the highest energies.
Pierre Auger Collaboration, A. Aab, et al., Muons in air showers at the Pierre Auger Observatory: mean number in highly inclined events, Phys. Rev. D 91, 032003 (2015)