Non-Spin * Physics Craig Ogilvie, ISU, [email protected] • high-density QCD • status of saturation at RHIC • intense proton beam as a neutrino source (J.

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Transcript Non-Spin * Physics Craig Ogilvie, ISU, [email protected] • high-density QCD • status of saturation at RHIC • intense proton beam as a neutrino source (J.

Non-Spin
*
Physics
Craig Ogilvie, ISU, [email protected]
• high-density QCD
• status of saturation at RHIC
• intense proton beam as a neutrino source (J. Nelson)
* disclaimer, thanks to all speakers for the help,
all omissions, mistakes my responsibility
Cold QCD
Gluon fields (occupation numbers) become large (Al Muller)
but coupling small, perturbative methods
Non-linear QCD evolution, new “form” of matter
ln(1/x)
High-density
QCD
Dilute parton
QCD
ln(Q)
Cold QCD: New Form of Matter
Tuchin
Properties
ln(1/x)
onset?
Jalilian-Marian,
Baker
Armesto
BK equ.
Ranier
Higher-twist
Vuzey: DGLAP
ln(Q)
Organize summary by approaches/attacks on this diagram
Exploring Non-Linear Evolution Region
Nestor Armesto: Challenge of non-linear evolution
Numerical solution of Balitsky-Kovchegov equation:
ln(1/x)
ln(Q)
Nuclear Structure function
DGLAP Evolution with Q: Vadim Guzey
10-1

10-1
Cuurrent data does not constrain available nuclearstructure functions sea-quarks, GA
Multiple-Interactions: Rainer Fries
Final state interaction
Scattered quark interacting with
nuclear matter.
Testing ground for higher-twist
Beyond double scattering:
triple, .... n-scattering
Move from lower to
higher Q2 to establish
role of higher twist
EIC Gluon Distribution: Antje Bruell
ln(1/x)
Key measurement
Across this phase-space
nuclear-modification factors GA/Gp
low-x and high Q2
High-density
QCD “CGC”
Dilute parton
QCD
ln(Q)
Gluon structure functions in A
- Q2 evolution
- open charm via photongluon fusion
- Fl (Caldwell)
Open charm via D => K p
Allen Caldwell FL => GA(x,Q2)
d2/dxdQ2=2p2/xQ4[ (1+(1-y)2)F2(x,Q2) - y2FL(x,Q2) ]
Fix x, Q2. Use
different beam
energies to vary y.
Critical issue: e/p
separation
FL can be measured
precisely in the
region of maximum
interest. This will be
a strong test of our
understanding of
QCD radiation.
Role of sea quarks at low-x in A: Rolf Ent
Strategy: Select Energy Loss n > 50 GeV
hadrons with large elasticity z (=Eh/n) to reduce space-time
effect complications
Use K- and lambda-bar
to pick apart nuclear effects on sea quarks?
Semi-inclusive DIS: Kirill Turchin

Beyond probing structure function
– radiation of gluon from parton evolution
k
e
Accesses correlations between gluons in dense QCD
Radiation of Gluons
d ( * A)
2
d
kdy
2
2
RDIS ( x, Q , k ) 
d ( * p)
A 2
d kdy
Measuring Structure Functions at eRHIC
Joseph Seele
Wonderful infrastructure => event generators => simulation
=> Common output independent of event generator
eRHIC Detector Performance
Juraj Sutiak
Si tracker + calorimetry
Electron method - standard
Raw acceptance:
# of positron found
# of generated
Acceptance:
# of reconstructed
# of generated
barrel – catcher border
catcher – endwall border
Efficiency:
9 GeV
# of generated & reconstructed
# of generated
9.9 GeV
Purity:
# of generated & reconstructed
# of reconstructed
Current Experiment Probes of Saturation
Gluon fields (occupation numbers) become large
classical =>CGC
Jamal Jalilian-Marian
• can CGC be applied from DIS to d+Au at RHIC ?
• towards universal properties of condensate
From DIS to d+Au @ RHIC
Fit DIS => dipole 
Functional form from saturation model
Iancu+Itakura+Munier
Use same dipole  in dAu collisions @ RHIC
RdAu
pt
Saturation at RHIC: Mark Baker
 Au+Au
– at y ~ 0, high-pt suppression is due to
dense matter formed after Au-Au passage
– not CGC, possibly QGP
 d-Au at forward rapidity
– Low-x in Au
Spectra in d+Au for h>0
Brahms DNP - submitted to PRL
G. Veres QM04 (PHOBOS)
This could be the CGC!?
CAVEAT:
Shape not perfect
Phenix
Brahms
Phobos dN/dh dA/pp scaled by 1.4 /(Npart/2)
Dominated by low-pt
Suppression at moderate pt is the same as low-pt
=> Challenge to CGC which has stronger suppression at lower pt.
Moving forward : Personal View


Internal questions: what luminosity and detector do we need?
While measurements of GA/Gp are key
– Cond. matter, HEP colleagues yawn with structure funcs
ln(1/x)
High-density
QCD
Dilute parton
QCD
ln(Q)

“Expand” the question to sell the physics
- what is unique/similar about non-linear QCD
–What qualitatively happens near the boarder regions?
–What are the correlations in the condensate?
»Links with BEC, correlations in condensed matter?