Perspectives of scalar- and vector-meson production in hadron-nucleus reactions

Abstract

The production and decay of vector mesons ($\rho ,\omega$) in $pA$ reactions at COSY energies is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations, if hadronic in-medium decays like ${\pi }^{+}{\pi }^{-}$ or ${\pi }^0\gamma$ might provide complementary information to their dilepton ($e^{+}{e}^{-}$) decays. Whereas the ${\pi }^{+}{\pi }^{-}$ signal from the $\rho$-meson is found to be strongly distorted by pion rescattering, the $\omega$-meson Dalitz decay to ${\pi }^0\gamma$ appears promising even for more heavy nuclei. The perspectives of scalar meson ($f_0,a_0$) production in $pp$ reactions are investigated within a boson-exchange model indicating that the $f_0$-meson might hardly be detected in these collisions in the $K\bar{K}$ or $\pi \pi$ decay channels whereas the exclusive channel $pp\to d{a}_0^{+}$ looks very promising.

Comments: invited talk presented at MESON2000, Cracow, May 2000; to appear in Acta Phys. Pol. B