A method of η′ decay product selection to detect partial chiral symmetry restoration

In case of chiral U_A(1) symmetry restoration the mass of the η′ boson (the ninth, would-be Goldstone boson) is decreased, thus its production cross section is heavily enhanced [1], The η′ decays (through one of its decay channels) into five pions. These pions will not be correlated in terms of Bose-Einstein correlations, thus the production enhancement changes the strength of two-pion correlation functions at low momentum [2). Preliminary results strongly support the mass decrease of the η′ boson [3–5]. In this paper we propose a method to select pions coming from η′ decays. We investigate the efficiency of the proposed kinematical cut in several collision systems and energies with several simulators. We prove that our method can be used in all investigeted collision systems.