The different stages of nucleus-nucleus collisions (parton
scattering, thermalization, expansion and hadronization) will be
studied by measuring the yield and spectral distribution of produced hadrons.
The formation of a QGP might be revealed through an enhancement of the relative
abundance of strange to non-strange quarks [[2]]. Considerable reduction
of the ratio of strange to anti-strange baryon production is also expected
with the formation of a QGP [[3]]. Measurements of
multiply strange baryon ratios
( e.g. 
) are very
sensitive to enhanced strange quark
density[[4], [5]]
which might result from chiral symmetry restoration in the QGP.
The addition of the SVT with its high position resolution
close to the production vertex allows the elimination of most of
the combinatoric background and drastically
improves the detection efficiency for strange particles. Fig. 1a shows
the tracking efficiency for secondary tracks in the SVT alone as a function
of momentum.
To illustrate the positive impact of the excellent SVT position
resolution we show in Fig. 1b an Armenteros scatter plot for 
and 
reconstructed from combined SVT and TPC tracks. Although
no particle identification information is used in this plot, a clean
separation of 
and 
is obtained.
Figure: a.) Secondary track reconstruction efficiency for the SVT alone
b.) Armenteros plot showing 
and 
separation based
on SVT information
The capability of the combined SVT and TPC detector for reconstructing
strange and multistrange particles is indicated by the invariant mass
spectra in Fig. 2 (see also [[6]]). To obtain the 
spectrum a complete tracking algorithm
in the SVT was employed, including momentum information from the TPC,
matching efficiency, and detector resolution factors derived from
simulations. The decay particles are identifiable via energy loss in the
combined tracking system. The 
spectrum assumes ideal tracking. Based
on the simulation for the 
, we expect a modest reduction of the
signal to noise ratio for the 
in the case of realistic tracking.
The ability of the SVT+TPC system to reconstruct multi-strange baryons coupled with the ability of STAR to study global event observables makes the proposed detector system unique among the RHIC experiments.
Modification of the mass and decay widths of certain very short lived
particles has been
predicted to occur in extremely dense hadronic matter and might also signal the
formation of a QGP and chiral symmetry restoration [[7]].
Because of its narrow width and simple decay schemes the 
meson has
received particular attention [[8]]. The excellent momentum
resolution and wide 
coverage of combined SVT and TPC detectors
will allow the study of possible medium modifications of the 
meson mass and width
through the 
decay channel.
Charm and in particular open charm production is currently believed to
be an excellent indicator of the initial parton scattering stage of heavy ion collisions
[[9]]. Because such particles must propagate through the medium they
might also be sensitive to the production of the QGP.
As the D-meson production cross section
(
) and lifetime (
200 
m) are
small and considering that most D decay channels are
complex, the detection capability of open charm with STAR SVT and TPC is
unclear at present. Strong enhancements in the D meson
production, predicted recently [[10]], will produce a cleaner
signal than that expected from previous estimates of the production cross
section. It is apparent however that such a
measurement cannot be achieved without the excellent position
resolution afforded by the SVT [[11]].
Figure: Invariant mass spectra of reconstructed strange and multi-strange
particles based on SVT and TPC tracking information
.