Physics of the FVTX
The FVTX upgrade will enhance the physics program of the PHENIX experiment in all of its
main areas of study. The list below is taken from the
FVTX Technical Design Reviw Document.
A+A collisions and the Quark Gluon Plasma:
- Study of energy loss and flow
of heavy quarks into very forward and backward rapidity regions using robust charm and bottom measurements
over a broader x range than available with the barrel VTX detector alone and with greater precision than
is possible with the muon detectors alone. This allows the extension of studies of the geometrical and
dynamical effects of the hot-dense matter created in high-energy heavy ion collisions into the forward
and backward rapidity regions and will allow for the first time separate measurements for charm and
bottom.
- Precise open charm and bottom
measurements will provide a solid "denominator" for comparison with production of bound states of heavy
quarks (J/Psi and Upsilon). These comparisons will allow for the isolation of common physics, e.g., initial-state
effects such as those on the gluon structure function and physics that only affects the bound states,
e.g., final-state absorption. These measurements will also provide strong constraints on production of
J/Psi's from recombination by determining a precise open-charm cross section over a broad rapidity range.
- Direct measurement of Upsilons at
mid-rapidity will be possible by eliminating the large random backgrounds from light-meson decays.
Will also improve the mass resolution and signal/background for J/Psi production and enable improved
separation of the J/Psi from the Psi’.
- Unambiguous measurement of
the Drell-Yan and heavy-flavor dimuon continuum by separating background muons from light meson decays,
muons from heavy flavor decay and prompt muons.
- An accurate reaction plane
measurement will be provided by the FVTX.
- Flow in the forward and
backward regions will be able to be measured.
p(d)+A collisions and small-x or gluon saturation physics:
- The study of the gluon structure
function modification in nuclei at small (and large) x values, where gluon saturation or shadowing
(anti-shadowing) is thought to be important will be possible, by adding precision open charm and bottom
measurements at forward rapidity.
- Determine the initial state
for AA collisions and provide a robust baseline for cold-nuclear matter effects in studies of hot-dense
matter in heavy ion collisions, again by adding precision heavy flavor measurements at forward rapidity.
- Help untangle the intricate
physics of J/Psi and Upsilon production in cold nuclear matter by providing robust measurements of open-heavy
quark production that can, by contrast, separate initial and final-state physics for these resonances.
- Allow for a clean measurement
of Drell-Yan which can further help untangle production issues for the J/Psi.
Polarized p+p collisions, and the contributions to the spin of the
nucleon:
- Provide an increased x range
(up to x ˜ 0.2 and down to 10-3) over which the mostly unknown gluon polarization (Delta-G/G) can be determined
through open heavy flavor measurements. Without the FVTX the range covered is likely to be insufficient
to study the shape of any polarization or to determine its peak value.
- Allow for a direct measurement
of the spin asymmetry in bottom production, which is expected to be different from open charm and light
hadrons, thus providing much-needed cross checks.
- Add background rejection
capabilities for W and Z bosons measurements (which give information about the sea-quark contributions
to the spin) by rejecting muons from light and heavy hadron decays which contribute to the high pT muon
spectra and by adding the possibility of event topology cuts.
- Enable Drell-Yan asymmetry
measurements, which can give information about the sea quark polarization distributions.
Medium Energy Physics
