Parton Physics – from Fermilab to RHIC. Mike Leitch – LANL Peter Barnes, Jan Boissevain(Eng), Melynda Brooks, Allan Hansen(PD), Dave Lee, Ming Liu, Pat McGaughey, Joel Moss, Andrea Palounek, Walter Sondheim(Eng), John Sullivan, Hubert vanHecke.
Mike Leitch – LANL
Peter Barnes, Jan Boissevain(Eng), Melynda Brooks, Allan Hansen(PD), Dave Lee, Ming Liu, Pat McGaughey, Joel Moss, Andrea Palounek, Walter Sondheim(Eng), John Sullivan, Hubert vanHecke
E772 - 1991
Anti-quark asymmetry in the Nucleon Sea
ACU, ANL, FNAL, GSU, IIT, LANL, LSU, NMSU, UNM, ORNL, TAMU, Valpo
PRL 84, 3256 (2000)
PT Broadening at 800 GeV
open charm: no A-dep
a(pT) shape is independent of xF & same for NA3 at a lower energy
Baier et al. NP B484, 265 (1987)
E866 – Preliminary
So energy loss associated with observed pT broadening is tiny, e.g. for W:
Johnson, Kopeliovich et al., PRL 86, 4483 (2001)
dE/dx = 0
dE/dx & Shadowing
Charged hadron and p0 production at PHENIX versus pT for central collisions which, when compared to pQCD models that work well for peripheral collisions, suggests that jet-quenching or energy-loss may be present.
Analysis of our p-A Drell-Yan data (E772 - PRL 64, 2479 (1990) using the Kopeliovich model. Dashed lines with shadowing only; solid lines with parton energy loss of,
dE/dz = 2.32 ± 0.52 ± 0.5 GeV/fm
Kopeliovich et al, hep-ph/0110221
“Light Cone Dipole” approach
DY as bremsstrahlung in the target rest frame
E866/NuSea – PRL 86, 2529 (2001).
However U(2S+3S), which should not suffer from feeddown, have maximal polarization consistent with the Octet model!
The February 2002 issue of Discover magazine based its cover story on the recent 105-page
public draft of the National Research Council Committee on Physics of the Universe report,
Connecting Quarks with the Cosmos: 11 Science Questions for the New Century.
7. Are there new states of matter at ultrahigh temperatures and densities?
The theory of how protons and neutrons form the atomic nuclei of the chemical elements is well developed. At extremely high densities and temperatures, protons and neutrons may "dissolve" into an undifferentiated "soup" of quarks and gluons, which can be probed in heavy-ion accelerators. Still higher densities occur and can be probed in neutron stars and the early universe. The Relativistic Heavy Ion Collider (RHIC) is in operation at the DOE's Brookhaven National Laboratory to study of extremely hot, dense nuclear matter. It collides beams of gold nuclei at energies sufficient to form brief microcosms of the hot, dense soup of elementary particles (quarks and gluons) that previously existed only for the first microseconds after the Big Bang origin of our universe. The experimental data to date have revealed unexpected characteristics and provide the first tantalizing clues of possible quark-gluon plasma formation.
Physicists around the world are interested in the RHIC collisions, which occur thousands of times per second. Each one acts as a microscopic pressure cooker, producing temperatures and pressures more extreme than exist now even in the cores of the hottest stars. In fact, the temperature inside a RHIC collision can exceed 1,000,000,000,000 degrees above absolute zero - about ten thousand times the temperature of the sun. Although RHIC collisions may be super-fast and super-hot, which makes them interesting to physicists, they're too small and too brief to be dangerous.
In a RHIC experiment using the massive PHENIX detector, the impact of two gold nuclei ejected fewer particles transverse to the collision axis than standard theory predicts. This is the first indicator of an exotic state of matter, but much more evidence is needed. By combining this finding with many to come in the next few years, researchers may be able to understand a state of matter that hasn't existed since the dawn of the universe.
From Science Highlights – DOE Office High Energy & Nuclear Physics.
J/Ψ suppression – an effective signature of Quark-gluon plasma (QGP) formation?
NA50 -- Anomalous J/ suppression. Evidence for QGP??
Eskola, Kolhinen, Vogt hep-ph/0104124
Kopeliovich, Tarasov, & Hufner
Expected statistical errors from a 2-week
d-A run at PHENIX and measurements form E866/NuSea
Gluon Shadowing for J/Ψ’s – predictions?
PHENIX μ+μ- (Au)
* Min-bias/RHIC-year for a = .92 (Nagle & Brooks)
** E866 nuclear dependence data only *** Upsilons from E772
PHENIX w/o MVD : | η | < 0.35
dN/dη from MVD
for 125 Au-Au events
dN/dη from MVD
for one Au-Au event
And also detect h in silicon
LANL LDRD supporting
R&D for us ($250K/yr)
Accurate projection to collision vertex
=> close, thin detector
E772 (1987 - …)
DY, J/Y, Y’, U Nuclear Dep.
NA44 (1990 - …)
Jacak, Sullivan,van Hecke
E789 (1990 - …)
sbb, sJ/Y, D0 Nuclear Dep.
SSC (GEM,SLD 1990 - …)
GEM Silicon tracker
(Brooks, Lee, Palounek)
E866/NuSea (1996 - …)
, J/Y, Y’, Nuclear Dep.
PHENIX (1990 - …)
Muons: J/Y, single-m, open-charm, spin, p-A, QGP
MVD: dN/dη, ZVERTEX
at high-x, parton dE/dz
Spokesman: Reimer (ANL)
Sm with Au-Au beams
Run Nm & Sm
1stmm physics (J/ suppression & single m’s)
Install Nm chambers
Build Nm chambers
Install Nm FEE
Start Building Nm FEE
Complete Nm FEE
1st MVD physics (dN/dη, vertex & fluctuations)
Si vertex upgrade R&D for charm physics
In FY2003 d-A, p-p and Au-Au collisions are all likely
South m arm
North m arm