Charge-exchange reactions with pion and kaon beams in the NA64h experiment at CERN

Abstract

We discuss a new approach to search for dark sector coupled to quarks in the invisible decays and oscillations of light neutral mesons produced in the charge-exchange (CEX) reactions with pion and kaon beams $\pi^-(K^-)+ (A, Z) \to \pi^0, \eta, \eta' (\bar K^0) + (A,Z-1)$ at nuclei target $(A,Z)$ in the NA64h experiment at CERN for $P_{\rm Lab}$ running in the interval from 5 to 50 GeV. For estimating of the projection sensitivity for the proposed searches the knowledge of the meson yield is crucial. This work is dedicated to the accurate evaluation of CEX cross sections for the wide range of energies and target nuclei which could be also useful for other experiments.