Meson Multiplicities Ca + Ca

Romain's explanation

In order to estimate the expected yields of vector mesons in 1-2 AGeV A+A
I have done a calculation based on mt-scaling of known pi0 and eta cross sections
(Taps and KaoS data measured at GSI and also some old Bevalac data).

I had shown the systematics of the data on previous occasions (Fig. 1).  From this
the omega and phi production can be computed assuming mt-scaling, i.e. assuming
that the production scales only with the available energy above threshold. Fig. 2
shows the cross sections for C+C.
For details see e.g. Bratkovskaya et al. Phys. Lett. B424 (1998) p. 244.

Lately some phi data have become available from FOPI measurements in Ni+Ni and Ru+Ru (phi -> K+ + K-).
The FOPI people claim now that the phi/K- ratio is between 0.4 and 1.8!  The large
uncertainty is due to their poor knowledge of the phi phase-space distribution.
In my Fig. 2 I show therefore also the C+C K- data from KaoS for comparison.  The yellow
shaded area indicates the possible range of phi cross sections according to the
FOPI phi/K- ratio.

Finally, Fig. 3 shows meson multiplcities as function of Ebeam for the 3 systems
C+C, Si+Si and Ca+Ca.