daniel cebra - physics 295 11-feb-04 experimental nuclear physics at uc davis ps… check out our...

Daniel Cebra - Physics 29511-Feb-0411-Feb-04

Experimental Experimental Nuclear Physics at Nuclear Physics at

UC DavisUC Davis

PS… Check out our web page at http://nuclear.ucdavis.edu

• 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

Come visit us on the fifth floor - WEST end


Recent GraduatesRecent 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. Mary’s


What Do We Do?What Do We Do?


BasicsBasics

Hadrons =Made of quarks

Baryon = 3 qmeson = q q

p = uudn = udd+ = udK+ = us


1) Goal: Use relativistic collisions of nuclear to create hot dense matter which reproduces the earliest stages of the universe

Relativistic Heavy Ion Physics:Relativistic Heavy Ion Physics:Creating Mini-`Big Bangs’ in the LaboratoryCreating Mini-`Big Bangs’ in the Laboratory

PS… Check out our web page at http://nuclear.ucdavis.edu

2)2) Now, Now, how do how do we do we do this?this?

(In Theory)(In Theory)

Daniel Cebra - Physics 295 111-Feb-0411-Feb-04

Brief History of the RHIC ProjectBrief 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 d+Au collisions

STAR

PHOBOSBRAHMS

PHENIX


3) How do we really do this?3) How do we really do this?


Data setsData sets Au+Au

s=130 GeV NEvent=0.7 M

Au+Au s=200 GeV NEvent= 3.2 M

Au+Au s=19.6

GeV NEvent=~20k

d+Au s=200 GeV NEvent=35 M

jet

pp• un-polarized• vertical pol. 391/nb• longitudinal pol. 373/nb (spin flip snake) Level-3 trigger, rare probesEMC jet trigger

Particle Identification: dE/dx

resolution ~8%

cold partonic/nuclear matter

hot partonic/nuclear matter

?


• 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

The Relevant Questions


Local Thermal Equilibrium?Local Thermal Equilibrium?

T

thermalsource

explosivesource

T,

pT

light

heavy

pT

light

heavy

T

mA

dm

dN

mT

TT

exp1

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

~½m<v>2

Conclusion: The Final freeze-out state has reached a local thermal equilibrium.


The The HottestHottest matter in the Universe matter in the UniverseScientists 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.

•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 K

•Ion Trapping 10 nK (1999)

•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

Relativistic Heavy Ion ColliderBrookhaven National Laboratory

Upton, New York


Is it the Right Temperature ?Is it the Right Temperature ?

Phase boundary lattice QCD:Allton et al.hep-lat/0204010

Tc=1603.5 MeVb=72535 MeV=0.3-1.3 GeV/fm3

At RHIC, we see evidence that the quarks freeze-out at the expected QPG transition temperature

hep-lat/0106002

Statistical fit Result: T=176 MeV B=41 MeV (130 GeV),

T=177 MeV B=29 MeV (200 GeV)

T=2.1·1012 K

Sun 15.6·106 K

Supernova~109 KPlasma fusion

55·106 KLaser fusion4·106 K


Bulk Properties 1: Directed Flow or V1 Bulk Properties 1: Directed Flow or V1 X

Z b

XZ – the reaction plane

Picture: © UrQMD

rapidity

<px> or v1

Developed early - pre - equilibrium !Sensitive to the EOSAs important as radial flowWell studied at lower energiesHard to be measured at RHIC because it is small

STAR Data


Bulk Properties 2: Elliptic Flow or V2Bulk Properties 2: Elliptic Flow or V2

Significant v2 up to ~7 GeV/c in pt, the region where hard scattering begins to dominate.

Expected Hydrodynamical Behavior

Hard Scattering dominated region, but still showing some V2

Profile of Source

v

dddP d

dddP d

T

T

2

2

2

2

2

2

2

cos( )

cos


Jets at RHICJets at RHIC

p+p jet+jet (STAR@RHIC)

Au+Au ??? (STAR@RHIC)

nucleon nucleonparton

jet

Find this……….in this

pQCD estimateET>1 GeVNJet~500


Strong suppression of back-to-back correlations in central Au+Au

Azimuthal distributions in Au+AuAzimuthal distributions in Au+AuAu+Au peripheral Au+Au central

Near-side: peripheral and central Au+Au similar to p+p

pedestal and flow subtracted

Phys Rev Lett 90, 082302

?


Have we found the Quark Gluon Have we found the Quark Gluon

Plasma at RHIC?Plasma at RHIC? We now know that Au+Au collisions generate a medium that• is hot => 175 MeV => the QGP transition temperature• is dense (pQCD theory: many times cold nuclear matter density)• is dissipative, jets lose energy.• exhibits strong collective behavior

We have yet to do:

• Study the properties of the QGP matter

• Relate these properties to the nature of the Universe (Big Bang)

This represents significant progress in our understanding of strongly interacting matter


The ‘Bozons’2002 Softball Champions

IM - Grad-Staff-Faculty League

Record: Undeated! [outscored opponents 75-21]

daniel cebra - physics 295 11-feb-04 experimental nuclear physics at uc davis ps… check out our...

Documents

daniel cebra physics

au au s

theory slide

experimental nuclear

gev n event

d au s

gev collisions

floor west end slide