Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - NewPhysicsInSpace (Indirect Probes of New Physical Phenomena in Space)

Teaser

\"The project was devoted understanding the signals of new physical phenomena in space. Also, an extra topic of the project was the interplay between terrestrial experiments and space probes. In the project we analysed and modelled cosmic rays (charged energetic particles in...

Summary

\"The project was devoted understanding the signals of new physical phenomena in space. Also, an extra topic of the project was the interplay between terrestrial experiments and space probes. In the project we analysed and modelled cosmic rays (charged energetic particles in space), cosmic gamma-rays, neutrinos and gravitational waves.

The project belongs to fundamental physics, witch targets the very basic questions about Nature: the fundamental microstructure of matter; the properties of dark matter; why there are a certain amout of matter, dark matter and dark energy in the Universe; the properties of the very early Universe and so on. The project was on phenomenological physics, in the joint field between the experimental, observational and theoretical physics. The main purpose of the project was to acquire new knowledge about physical Nature. However, the project produced extra benefit for society in many ways: (i) training master and doctoral students; (ii) producing new research methods can be used beyond fundamental physics; (iii) motivating some new technologies for industry. For example, within the project period we had regular meetings with the developers of industrial radiation detectors using (secondary) cosmic rays from atmosphere.

The overall objectives of the project were to understand of:
-- anomalies in cosmic rays
-- \"\"standard\"\" astrophysics of cosmic rays
-- new probes of physics: gravitational waves from black hole and neutron star mergers, 21 cm radio wave signal from neutral atomic hydrogen in the young Universe
-- interplay between the cosmic signals and terrestrial experiments: colliders (Large Hadron Collider in Geneva), direct detection and g-2 experiments etc

The main conclusions of the action: (i) the standard picture of cosmic ray production and propagation in the Galaxy needs serious considerations; (ii) to find evidences of new physical phenomena one should merge the information from the known cosmic messengers (cosmic rays, neutrinos, photons form radio to gamma-ray) and new arising messengers (gravitational waves, 21-cm signatures). We can also conclude that the collaborations between this project and the researches working on the topics of data science, detector development and machine learning were beneficial for the both sides. Indirectly, the project initiated a new startup company, Nosob OÜ, operating in the topics of machine learning in medicine.\"

Work performed

The project was designed to follow the state of the art of indirect probes of new physical phenomena in space. Accordingly, the objectives and results were dynamically synced with arising possible signals of new physics. Below the objectives are directly linked withe the list of the research publication, which contain the main results of the project. (The citations of the publications counted by the INSPIRE database as of 28 Mar 2018, http://inspirehep.net/)

O1: The hint of di-photon excess at the LHC detectors CMS and ATLAS. The excess appeared in the beginning of the project period. In the following paper we related the excess to the other physical phenomenas. In Pub1 we related the excess with an other “anomaly”, the gamma-ray excess at the Galactic Centre in the energy range 2-5 GeV. In Pub2 we related the excess to a possible model of dark matter.
Publ1: A.Hektor and L.Marzola, JCAP 1607 (2016) no.07, 042, doi:10.1088/1475-7516/2016/07/042, arXiv:1602.00004 (20 citations)
Pub2: S.Di Chiara, A.Hektor, K.Kannike, L.Marzola and M.Raidal, Nucl. Phys. B 917 (2017) 31, doi:10.1016/j.nuclphysb.2017.02.001, arXiv:1603.07263 (18 citations)

O2: Some collusions of galaxy clusters show an anomalous feature, a possible dark matter concentration at the collusion area. It seems to hint that dark matter can be more strongly interaction than expected by most popular scenarios, e.g. WIMPs etc. In Pub3 we offered explanation of the features by collusionless shocks of “dark plasma”, which are similar to collusionless shocks in cosmic plasma.
Pub3: C.Spethmann, H.Veermäe, T.Sepp, M.Heikinheimo, B.Deshev, A.Hektor and M.Raidal, Astron. Astrophys. 608 (2017) A125, doi:10.1051/0004-6361/201731299, arXiv:1603.07324 (11 citations)

O3: The objective follows the study line of cosmic rays, gamma ray signals hinting new physics. In Pub4 we calculated and estimated the strength of a new interesting phenomena, a line feature in cosmic gamma-ray spectrum. So far the line feature in a certain set of dark matter models had been neglected by previous authors. We estimated the constraints from the gamma-ray line signal for the set of models.
Pub4: A.Hektor, L.Marzola and T.Tuvi, Phys. Rev. D 95 (2017) no.12, 121301, doi:10.1103/PhysRevD.95.121301, arXiv:1702.02580 (8 citations)

O4: A new exiting observational window appeared in the beginning of the project period, directly observed gravitational waves. The LISA, and later Virgo, experiments measured gravitational waves radiated by the mergers of black hole and neutron star binaries. It is one of the most exiting discovery in physics of last decades. It allows to test gravitational physics very directly. It sheds light to stellar and galaxy evolution, some cosmological problems. We had one of the first paper, Pub5, showing that the gravitational wave signal from merge of neutron stars can hint the accreted dark matter by neutron stars. In the second related paper, Pub6, we studied the effects of electroweak phase transition on the freeze-out of dark matter in the early Universe. We showed that those models predicts gravitational waves reachable for the next generation gravitational wave experiments.
Pub5: J.Ellis, A.Hektor, G.Hütsi, K.Kannike, L.Marzola, M.Raidal and V.Vaskonen, arXiv:1710.05540 (3 citations)
Pub6: A.Hektor, K.Kannike and V.Vaskonen, arXiv:1801.06184

O5: Within the project period we started to sharpen our knowledge on the cosmic 21 cm signal from neutral atomic hydrogen in the young Universe (from the recombination to reionization). The preprints of the publications appeared after the project period, but based strongly on the work done within the project.
Pub7: S.Fraser, A.Hektor, G.Hütsi, K.Kannike, C.Marzo, L.Marzola, C.Spethmann, A.Racioppi, M.Raidal, V.Vaskonen and H.Veermäe, arXiv:1803.03245 (11 citations)
Pub8: A.Hektor, G.Hütsi, L.Marzola, M.Raidal, V.Vaskonen and H.Veermäe, arXiv:1803.09697

Final results

\"The most interesting results of the project are related to the new \"\"observational windows\"\" of space: gravitational waves and 21 cm radio astronomy. In the project we showed that both of them can hint and/or constrain the properties of dark matter. An interesting result was that the large class of particle physical models of dark matter can be constrained/probed by a line feature in cosmic gamma ray spectrum. Also, we showed that the \"\"standard\"\" freeze-out of dark matter (the most popular production mechanism of dark matter) can be strongly modified if one takes account of the effects of the electro-weak phase transition.

The most direct impact of the project is the acquired new knowledge about physical Nature. In addition, the project produced extra benefit for society in many ways: (i) training master and doctoral students; (ii) producing new research methods can be used beyond fundamental physics; (iii) motivating some new technologies for industry. Within the project we had a very beneficial collaboration with the developers of industrial radiation detectors using (secondary) cosmic rays from atmosphere.\"

Website & more info

More info: https://hep.kbfi.ee/.