Elliptic flow of ν ands π 0 mesons in heavy-ion collisions at 2 A GeVmesons in heavy-ion collisions at 2 A GeV

Abstract

Azimuthal distributions of η and π 0 mesons emitted at midrapidity in collisions of 1.9 AGeV 58 Ni+ 58 Ni and 2 AGeV 40 Ca+ nat Ca are studied as a function of the number of projectile-like spectator nucleons. The observed anisotropy corresponds to a negative elliptic flow signal for η mesons, indicating a preferred emission perpendicular to the reaction plane. In contrast, only small azimuthal anisotropies are observed for π 0 mesons. This may indicate that η mesons freeze out earlier from the fire ball than pions.

Effects of nuclear symmetry energy on η meson production and its rare decay to the dark U-boson in heavy-ion reactions

“…In fact, η meson production in heavy-ion collisions has been studied extensively both theoretically and experimentally, especially by the TAPS and HADES Collaborations, see, e.g., refs. [66][67][68][69][70][71][72][73][74][75]. Moreover, as pointed out earlier [66,67], because of the hidden strangeness (the ss component), η mesons experience weaker final state interactions compared to pions.…”