Peeking through the Colored Looking Glass

1. Peeking through the Colored Looking Glass A perspective on Future Directions Color Glass Condensate as a Media Whatever-ons: Little wiggles of the CGC Pomerons, Odderons, Reggeons Ploops: (Pomeron loops) How a little fluctuation becomes a big problem The CGC and the QGP: Is the sQGP really the CGC? Is rapid “thermalization” due to the CGC? Does flow arise largely from the CGC? Comments about the LHC: The CGC Machine 1

2. Reggeons, Pomerons and Odderons Reggeons: Mathematical objects which which allow the computation of scattering of hadrons. Found in complex angular momentum analysis of scattering matrix Pomeron: That Reggeon which controls the total cross section at high energy. Universal dependence of energy at high energy. Imaginary part of T matrix Odderon: Pomerons peculiar brother Real part of T matrix at high energy 2

3. The Pomeron: A Modern Perspective Describes total cross section Original version After growing cross sections: Pomeron: Vacuum quantum numbers Two gluon exchange Bare Pomeron related to growth of gluon densities Saturation <=> High density of pomerons 3

4. The Growth of Gluon Density Explains Slow Growth of Total Cross Section Transverse distribution of gluons: Transverse profile set by initial conditions Size is determined when probe sees a fixed number of particles at some transverse distance 4

5. The Pomeron and the CGC Separation between fast and slow degrees of freedom => Renormalization group Weight for source fluctuations JIMWLK Equation: H is Hamiltonian with No potential, assumes strong fields For weak fields: Pomeron: Weak field excitation 5

6. Pomeron: Saturation effects The real part of O is the Pomeron amplitude Balitsky-Kovchegov equation BK equation has exponential growth in y for transverse momentum scales greater than the saturation momenta; Power law growth for momenta less than the saturation moments. The saturation momentum never saturates 6

7. Odderon: C odd partner to Pomeron Real part of O when z -> y For SU(3): Topological Baryon number Pomeron: Simplest excitation of CGC Odderon: Next simplest excitation Implications: Signals for odderon in polarized pp Relative cross sections Baryon stopping 7

8. Reggeons: Equivalent to an N body problem with only two particle interactions. In large Nc, two body interactions form a chain If amplitude vanishes when any xi -> xj, theory is equivalent to 2d conformal field theory. (FKL) Is this many body problem solvable? What happens when quarks are included? Spin and baryon number transport? 8

9. Ploops: Problem: JIMWLK allows decreasing fusion of Pomerons at high density Strong field limit => No loops Weak field limit has only splitting Duality relation between field and derivative of fields Weak field => strong Dipole-dipole scattering must be self dual theory. A complete CGC description of evolution in QCD? 9

10. sQGP or CGC? How can one generate the flow? Requires strong interactions at very short times 10

11. sQGP or CGC? sQGP: Many resonances near Tc. Consistency with duality? Strength? CGC: Even though coupling is weak, coherence of interactions 1/g x g ~ O(1) Rapid isotropization of matter: KKMLV boost invariantclassical solution is unstable against small longitudinal perturbations Isotropy => P = 1/3 E => flow Thermalization? Classical yes. Quantum by Kharzeev-Tuchin method? Maybe not thermal in sense of transport equations, but consequences largely the same 11

12. Perspectives for the LHC: LHC is a CGC machine: Central region, typical particles Forward region: very small x and large Q^2 Excellent tests of evolution and universality Will need detailed comparison of pp pA and AA. dN/dy, centrality, jet correlations become much more quantitative tests 12