Precise Measurement of Nuclear Fragmentation Cross Sections for the Understanding of Particle Production in the Galaxy

• Applicant: Dr. Michael Unger
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Astrophysics and Astronomy
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426579465

Project objectives A new generation of space-based cosmic-ray detectors has measured the fluxes of Galactic cosmic rays to an unprecedented precision at the percent-level. These measurements provide a unique diagnostic of cosmic-ray propagation in the Galaxy and an opportunity to find signatures of dark matter annihilation in the Galaxy and new physics phenomena beyond the Standard Model of Particle Physics.The origin of the excess of the measured fluxes of anti-protons and positrons with respect to the expectations from standard astrophysical backgrounds has attracted a lot of speculation recently. However, a firm establishment of a non-standard component of particle production in the Galaxy relies on a good knowledge of fragmentation cross sections of cosmic-ray interactions with the interstellar medium.In this proposal we suggest to perform a precise measurement of all the fragmentation channels important for the interpretation ofsecondary cosmic rays in the Galaxy. With the proposed measurement campaign, the fragmentation-related uncertainties of predictions of the fluxes of Galactic cosmic rays at Earth can be decreased from the current 20% to the percentage level matching the precision of cosmic-ray data.MethodologyWe propose to use the NA61/SHINE facility at the SPS at CERN to perform the needed cross section measurements at isotope level. The program will perform measurements of the fragmentation of Li, Be, B, C and N nuclei, which are the elements that are of particular importance to constrain the propagation of cosmic rays in the Galaxy. To reach the desired statistical accuracy of the measurements within a realistic amount of SPS beam time, we will contribute to the ongoing upgrade of the NA61/SHINE detector system and aim at a tenfold increase of the maximal readout rate of the detector system. Moreover, we will develop a new beam detector system that will assure a precise measurement of the beam particles.Expected impact of the research project on the development of science The proposed measurement campaign will lead toa unique reaction database for present and future studies of cosmic rays. This data will not only be essential for the understanding of the origin of Galactic cosmic rays, but also for a precise prediction of the astrophysical background for searches for the signatures of dark matter annihilation in the Galaxy and new physics phenomena beyond the Standard Model of Particle Physics.Added value of bilateral cooperation The German group is part of one of the world-leading institutes for the study of cosmic rays, whereas the Polish group has a experience in the heavy ion physics and the constructions of beam detectors. The collaboration will open a new scientific topic at the Polish institute and the joint analysis of the fragmentation data will combine the physics and hardware expertise of both institutes needed to archive the desired precision of the measurement.

• DFG Programme: Research Grants
• International Connection: Poland
• Partner Organisation: Narodowe Centrum Nauki (NCN)
• Cooperation Partner: Dr. Seweryn Kowalski