Experimental Nuclear Physics at UC Davis

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Experimental Nuclear Physics at UC Davis
Come visit us on the fifth floor - WEST end

• FACULTY
• Jim Draper (emeritus)
• Paul Brady (emeritus)
• Daniel Cebra
• Ramona Vogt
• STAFF
• Juan Romero
• Tom Gutierrez

• GRAD STUDENTS
• Roppon Picha (2005)
• Brooke Haag (2006)
• UNDERGRADS
• David Cherney
• Stephen Baumgarten
• Matt Searle
• Orpheus Mall

PS Check out our web page at
http//nuclear.ucdavis.edu
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Recent Graduates

• Ian Johnson (2002) Postdoc LBNL
• Jenn Klay (2001) Postdoc LBNL
• Mike Heffner (2000) Postdoc LLNL
• Tom Gutierrez (2000) Postdoc UCD
• Bill Caskey (1999) Z-World, Davis CA
• Lynn Wood (1998) Z-World, Davis CA
• Doug Mayo (1997) Staff Scientist LANL
• Jason Dunn (1997) Professor - Idaho Christian
• Isaac Huang (1997) FunMail.com
• Jack Osbourn (1995) Professor - Sac State
• Jessica Kintner (1995) Professor - St. Marys

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What Do We Do?
Condensed Matter
High Energy
Relativistic Heavy Ion Physics
Cosmology
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Basics
Hadrons Made of quarks Baryon 3 q meson q
q p uud n udd p ud K us
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Relativistic Heavy Ion PhysicsCreating
Mini-Big Bangs in the Laboratory
1) Goal Use relativistic collisions of nuclear
to create hot dense matter which reproduces the
earliest stages of the universe
2) Now, how do we do this? (In Theory)
PS Check out our web page at
http//nuclear. ucdavis.edu
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Brief History of the RHIC Project

• 1947 BNL founded
• 1952 Cosmotron
• 1960 AGS
• 1970 Tandem
• 1979 ISABELLE
• 1983 CBA canceled
• 1983 RHIC proposed
• 1991 RHIC approved
• 1992 STAR approved
• 1999 First Beams
• 2000 First collisions
• 2001 200 GeV collisions
• 2003 dAu collisions

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3) How do we really do this?
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Data sets
hot partonic/nuclear matter
pp un-polarized vertical pol. 391/nb
longitudinal pol. 373/nb (spin flip snake)
Level-3 trigger, rare probes EMC jet trigger

• AuAu ?s130 GeV NEvent0.7 M
• AuAu ?s200 GeV NEvent 3.2 M
• AuAu ?s19.6 GeV NEvent20k
• dAu ?s200 GeV NEvent35 M

Particle Identification dE/dx
?
resolution 8
jet
cold partonic/nuclear matter
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The Relevant Questions

• First, have we created Matter?
• Local Kinetic Equilibrium
• Bulk Properties
• If so, does it have the properties of the QGP
• low T, high entropy (compared to hadron gas)
• opaque to jets
• large fluctuations/droplets at transition
• low pressure
• chiral symmetry

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Local Thermal Equilibrium?
thermal source
explosive source
½mltvgt2

• Fits assuming a hubble-like expansion yields
  temperatures of 90 MeV and average radial
  expansion velocities of 0.6c

Conclusion The Final freeze-out state has
reached a local thermal equilibrium.
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The Hottest matter in the Universe
Hottest
Relativistic Heavy Ion Collider Brookhaven
National Laboratory Upton, New York
Scientists have recently set records for both the
highest and lowest measured temperatures. The
high temperatures approach those of the early
stage of the Big Bang.

• Relativistic Heavy Ion Collisions 1.3x1012 K
  (2002)
• Thermonuclear Fusion Device 3x106 K
• The surface of the Sun 5800 K
• The hottest place in the Solar system (Io) 2000 K
• The highest recorded temperature on earth (Libya)
  330 K

• Room Temperature 300 K
• Coldest place on Earth 184 K (Vostock Station -
  Antarctica)
• Air turns to liquid 73 K
• Coldest place in the solar system (Triton) 38K
• Helium turns to liquid 4.2 K
• Dilution Refrigeration .002 K
• Magnetic Cooling 90 mK
• Ion Trapping 10 nK (1999)

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Is it the Right Temperature ?
Tc160?3.5 MeVmb725?35 MeVe0.3-1.3 GeV/fm3
Statistical fit Result T176 MeV ?B41 MeV (130
GeV), T177 MeV ?B29 MeV (200 GeV)
Phase boundary lattice QCDAllton et
al.hep-lat/0204010

hep-lat/0106002
T2.11012 KSun 15.6106 K Supernova 109
K Plasma fusion 55106 K Laser fusion 4106 K
At RHIC, we see evidence that the quarks
freeze-out at the expected QPG transition
temperature
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Bulk Properties 1 Directed Flow or V1

• Developed early - pre - equilibrium !
• Sensitive to the EOS
• As important as radial flow
• Well studied at lower energies
• Hard to be measured at RHIC because it is small

STAR Data
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Bulk Properties 2 Elliptic Flow or V2
Expected Hydrodynamical Behavior
Profile of Source
Hard Scattering dominated region, but still
showing some V2
f
Significant v2 up to 7 GeV/c in pt, the region
where hard scattering begins to dominate.
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Jets at RHIC
pQCD estimateETgt1 GeVNJet500
Find this.in this
pp ?jetjet (STAR_at_RHIC)
AuAu ???? (STAR_at_RHIC)
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Azimuthal distributions in AuAu
Near-side peripheral and central AuAu similar
to pp
AuAu peripheral
AuAu central
pedestal and flow subtracted
Phys Rev Lett 90, 082302
Strong suppression of back-to-back correlations
in central AuAu
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Have we found the Quark Gluon Plasma at RHIC?

• We now know that AuAu collisions generate a
  medium that
• is hot gt 175 MeV gt the QGP transition
  temperature
• is dense (pQCD theory many times cold nuclear
  matter density)
• is dissipative, jets lose energy.
• exhibits strong collective behavior

This represents significant progress in our
understanding of strongly interacting matter

• We have yet to do
• Study the properties of the QGP matter
• Relate these properties to the nature of the
  Universe (Big Bang)

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The Bozons 2002 Softball Champions IM -
Grad-Staff-Faculty League
Record Undeated! outscored opponents 75-21