Proton structure, high energy neutrinos, and dark matter searches

• Applicant: Dr. Sergey Ostapchenko, Ph.D.
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Astrophysics and Astronomy
• Term: from 2018 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 394966107

The precise knowledge about forward particle production in hadronic collisions is of paramount importance for astrophysical studies of ultra-high energy cosmic rays (UHECRs), high energy neutrinos, and dark matter signals. While many valuable pieces of the relevant information are furnished by the present experiments at the Large Hadron Collider (LHC), one generally needs a self-consistent theoretical approach, including a treatment of the nonperturbative proton structure, to combine all the experimental data into a coherent picture and to provide reliable predictions outside the measured kinematic regions and for various interaction processes. The main goals of the present project are to develop an advanced Monte Carlo (MC) treatment of forward particle production, including charmed hadrons, in hadronic and nuclear collisions and to apply it to various astrophysical problems related to investigations of UHECRs, of high energy neutrinos, and to dark matter searches. The core element of the proposed scientific program is a coherent theoretical approach to the treatment of nonperturbative constituent parton Fock states, including those containing heavy quarks, and its incorporation into the QGSJET-II MC generator of hadronic collisions. Applications of the new model to the treatment of UHECR interactions in the atmosphere and to an analysis of the CR mass composition will allow the applicant to address many current puzzles related to UHECR studies, concerning both a self-consistent interpretation of the present and forthcoming cosmic ray data, and to a discrimination between various UHECR source models. A generalization of the MC generator for a treatment of charmed hadron production, including the nonperturbative intrinsic charm contribution, will form the basis for a reliable calculation of the atmospheric neutrino background and of astrophysical neutrino fluxes, for a number of UHECR source models. A generalization of the QGSJET-II model to treat the production of antinuclei, using a contemporary coalescence approach, will be an important step towards reliable calculations of backgrounds for indirect dark matter searches. The interdisciplinary character of the project is related to the fact that the proposed developments will form a bridge from the experiments at the Large Hadron Collider to the ones belonging to the high energy astrophysics field, thus allowing the latter to benefit from the vast and diverse experimental program at the LHC.

• DFG Programme: Research Grants