BE ISOTOPE MEASUREMENT WITH AMS-02 TO REDUCE ASTROPHYSICAL UNCERTAINTY IN DARK MATTER MODELS

The p̄/p ratio published by AMS-02 shows an excess of p̄ at rigidities above 60 GV , which can potentially be from WIMP annihilation. To that end, one has to decouple the contribution of secondary p̄ coming from standard p + He/H → p̄ + X process. However models computing the latter component are affected by astrophysical and nuclear uncertainties. To reduce the former, the 10 Be/ 9 Be ratio is calculated by analysing 10 years of AMS-02 Be data. A set of selection criteria is developed to extract a pure sample of Be, and a fit model is constructed to extract the counts of the Be isotopes viz. 7 Be, 9 Be, and 10 Be. Additionally, the detector acceptance is computed using the AMS-MC datasets for Be, and the RTI information from the AMS-02 data is employed to calculate the exposure time. Using these components, the detector level fluxes are calculated for each of the isotopes which is then unfolded using a Bayesian iterative unfolding procedure to extract the particle level fluxes. These fluxes are then utilised to compute the ratios, 10 Be/ 9 Be and 7 Be/Total Be. The former is compared with various theoretical models for computation of galactic halo sizes from the 10 Be/ 9 Be ratio; which suggests that the AMS-02 results severely challenges our understanding of halo sizes. Furthermore, for the measurement of the p̄ production cross-section, p beam at various energies from the CERN Super Proton Synchrotron are directed at a liquid He target within the COMPASS++/AMBER experimental hall. For this purpose, the COMPASS-RICH detector is used for p̄ identification. As such, a Monte-Carlo simulation of the detector is developed in Geant4, and a reconstruction algorithm is written. This work is presented as an appendix to the thesis.