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Looking for the Color Glass Condensate. in an electron-ion collider. Maria Simone Kugeratski. F.S.N. (Univ. São Paulo). Victor P. Gonçalves. (Univ. Fed. de Pelotas). Introduction. Evidence for the Color Glass Condensate at HERA and RHIC. The existence of the CGC still needs confirmation.
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Looking for the Color Glass Condensate in an electron-ion collider Maria Simone Kugeratski F.S.N (Univ. São Paulo) Victor P. Gonçalves (Univ. Fed. de Pelotas)
Introduction Evidence for the Color Glass Condensate at HERA and RHIC The existence of the CGC still needs confirmation New high energy experiments at Fermilab, LHC and AUGER Another possibility: eRHIC eRHIC: electron-ion collider at RHIC Deshpande,Milner,Venugopalan,Vogelsang, hep-ph/0506148, Ann.Rev.Nucl.Part.Sci, 55, 165, (2005) (x,Q2) coverage comparable toHERA Nuclear targets: higher saturation scales
Outline Continue the analysis started by Deshpande et al. Color dipole approach to eA Recent Ansatz for the dipole cross section: Iancu,Itakura,Munier, PLB (2004) Extend to the nuclear case Nuclear structure function F2 Diffractive cross section Diffractive nuclear structure function FD2 Iancu,Itakura,Munier, PLB (2004)
Color dipole approach Nikolaev, Zakharov, ZPC (1991) A. Müller, NPB (1994)
Photon wave function Nikolaev, Zakharov, ZPC (1991)
Dipole cross section linear saturation Iancu,Itakura,Munier, PLB (2004)
Nuclear inclusive DIS We assume that
Conclusions I Saturation reduces the growth of all considered observables in the low x and low Q2 region This happens more in eA than in ep In the saturation region F2 is reduced with respect to the linear case by: 20 % in ep 50 % in eA R=F2A /F2p : EKS with DGLAP is in qualitative agreement with IIMn Saturation reduces more in eA than in ep Saturation reduces more in eA than in ep
Nuclear diffractive DIS Golec-Biernat and Wüsthoff, PRD(1999) (plus new dipole cross section and extension to eA) Diffractive overlap function:
Saturation suppresses larger dipoles (even more for larger nuclei)
Ratio of cross sections Very slow growth with the energy W Very slow fall with x Fall with Q2 Growth with A
Nuclear diffractive structure functions Wüsthoff, PRD (1997); Golec-Biernat and Wüsthoff, PRD(1999) Forshaw,Sandapen,Shaw, PLB(2004)
A=2 A=197
A=2 A=197
The ratio grows weakly with W and falls weakly with x falls strongly with A; becomes flat in strongly changed by saturation effects becomes less important for large A is very flat in this is due to saturation ! Conclusions II Falls with Q2 and grows with A up to 0.37 ! Levin, Lublinsky, (2002) ; Nikolaev, Zakharov (1995)
eA collider seems promising! Estimates should be improved! References: M.S. Kugeratski, V.P. Gonçalves, F.S. Navarra, Eur. Phys. J. C 44 (2005) 577 Eur. Phys. J. C 46 (2006) 413 Eur. Phys. J. C 46 (2006) 465 Thanks to the organizers !!! I hope to see you soon...