1 / 34

Quark Pair Production in the Color Glass Condensate

Quark Pair Production in the Color Glass Condensate. Raju Venugopalan Brookhaven National Laboratory. RBRC Heavy Flavor Workshop, Dec. 12th-14th, 2005. Work done in collaboration with J.-P. Blaizot, H. Fujii and F. Gelis. Based on, a) F. Gelis and RV, PRD 69 : 014019, (2004)

sun
Download Presentation

Quark Pair Production in the Color Glass Condensate

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quark Pair Production in the Color Glass Condensate Raju Venugopalan Brookhaven National Laboratory RBRC Heavy Flavor Workshop, Dec. 12th-14th, 2005

  2. Work done in collaboration with J.-P. Blaizot, H. Fujii and F. Gelis. Based on, a) F. Gelis and RV, PRD 69: 014019, (2004) b) J.-P. Blaizot, F. Gelis and RV, NPA 743:57, (2004) c) H. Fujii, F. Gelis and RV, PRL 95:162002 (2005) d) H. Fujii, F. Gelis, and RV, in preparation. Also discuss related work of Kharzeev & Tuchin; Tuchin; Gelis, Kajantie and Lappi

  3. Outline of Talk • The kt factorization formalism for heavy quark production in the CGC • The breaking of kt factorization by higher twist effects in pA and AA scattering • Isolating multiple scattering & quantum evolution effects -results in MV & BK models • Summary and outlook

  4. McLerran, Ludlam

  5. Universality: collinear versus k_t factorization Collinear factorization: Heavy quark production at colliders

  6. Kt factorization: Are these “un-integrated gluon distributions” universal? In CGC, “Dipoles”- with evolution a la JIMWLK / BK RG equations

  7. HADRONIC COLLISIONS IN THE CGC FRAMEWORK Solve Yang-Mills equations for two light cone sources: For observables average over

  8. Breaks down at next order in Krasnitz,RV; Balitsky Inclusive gluon production in pp & p-A : Adjoint dipole -includes all twists • K_t factorization seen “trivially” in p-p • Also holds for inclusive gluon production lowest order inbut all orders in (Kovchegov, Mueller)

  9. Inclusive pair production in CGC framework Gelis, RV hep-ph/0310090 Abelian Non-Abelian Lipatov vertex To lowest order in sources:

  10. Identical to Collins-Ellis+ Catani-Ciafaloni-Hautmann k_t factorization result is the un-integrated gluon distribution in the Gaussian MV model K_t factorization compared to RHIC D-Au data by Kharzeev & Tuchin (hep-ph/0310358)

  11. Quark production to all orders in pA Blaizot, Gelis, RV Neither quark pair production nor single quark production is kt-factorizable

  12. Result can however still be “factorized” into novel multi-parton distributions These multi-parton distributions can be computed in closed form in the Gaussian (MV) approximation Quantum evolution of these distributions can be computed By solving the JIMWLK or BK renorm. group equations

  13. Blaizot, Gelis, RV; Tuchin Interpretation: Wilson line correlators - the last appears in pair production only Simplify greatly in large N_c limit x-evolution can be computed with Balitsky-Kovchegov eqn.

  14. Results I) Violation of k_t factorization in the MV model (multiple scattering only-no x evolution of target)

  15. Large N_c results - good approximation to exact result

  16. Cronin effect for quark production: (MV model- re-scattering but no evolution)

  17. Simple “Non-local” Gaussian model-simulates effects of quantum evolution

  18. Quark mass dependence…

  19. Q_s dependence…

  20. Pair cross-sections:

  21. R_pA: suppression Frankfurt, Strikman; Matsui, Fujii

  22. Kharzeev-Tuchin, Hep-ph/0510358 x_F dependence Need to also consider color octet contributions if matrix elements are large

  23. II) Rapidity dependence • No rapidity dependence in the MV model-multiple scattering but no x-evolution • Y-dependence via JIMWLK RG equations-simplified large N_c & Large A limit is the BK equation • Compute ``dipole” correlators solving BK with MV initial conditions • The 3-point and 4-point functions can also be computed at large N_c -factorize into products of 2-point functions

  24. Quark Production in A-A

  25. Solve Dirac equation in background field of two nuclei… Gelis,Kajantie,Lappi PRL 2005

  26. Ratio of quarks to glue roughly consistent with a chemically equilibrated QGP

  27. Outlook We can compute both small x evolution (shadowing) and multiple scattering effects in quark production on same footing. More detailed studies in progress for D-Au collisions Quark production in AA collisions can be computed at the earliest stages. Energy loss? Is NLO in this picture but recent theoretical developments suggest it can be computed consistently.

More Related