1. Suppression of high P T hadron spectra in p+A collisions Wei-Tian Deng In Collaboration with: Rong Xu & Xin-Nian Wang arXiv:1204.1998

2. Nuclear Modification Factor: If R = 1 here, no any nuclear modification Suppression at High p T Phys.Lett. B696 (2011)30-39

3. Initial state?Final state? RHIC d+Au 200GeV LHC p+Pb 4.4TeV within HIJING Only initial cold nuclear effect +

4. Cronin effect Shadowing Energy-Momentum conservation Parton flavor composition Fragmentation …… Initial Cold Nuclear Effect in p+A parton level Final hadron

5. Cronin effect Cronin Effect P.R.L. 91, 072303 PHENIX P.R.L. 91, 072304 STAR If no nuclear modification Nuclear modification:

6. K T Broadening in HIJING Multiple inelastic scattering k T kick in p+A collisions: Energy dependence of the width in Gaussian distribution K T broadening of initial and final partons, with Gaussian distribution

7. Quark, fixed on DIS Gluon, fit to the RHIC Shadowing in HIJING Nuclear shadowing: Phys.Lett.B 527, 85 (2002) S.Y. Li & X.N. Wang Gluon uncertainty in EPS09 arXiv: 1205.5359

8. R pA on Parton level Cronin Effect at fix P T Shadowing suppress R pA at low p T region (small x region) There is suppression on large p T, why?

9. Momentum Correlation De-coherent Hard Collision (DHC) means: Soft-Hard is de-coupled in multiple scattering in HIJING 1st Hard Scattering 1st Soft Scattering 2nd Hard Scattering 2nd Soft Scattering …… 1st Hard Scattering 2nd Hard Scattering …… 1st Soft Scattering 2nd Soft Scattering ……

10. R pA on Parton level For DHC without shadowing, R pA is 1 at large p T Soft-Hard coupling suppress R pA at large p T

11. Flavor Correlation in projectile In HIJING, we push to the limit: If a quark has been scattered once, only gluon available for latter scattering Valence Quark Number Conservation Quark availability is less in multiple scattering …

12. Flavor Correlation the Q/G ratio in p+A is smaller at large p T. More gluon give softer hadron spectrum

13. This flavor correlation suppress R pA of final hadron at large p T RpA for Final Hadron Lund Fragmentation

14. Lund Frg Vs. Inde Frg Hard gluons are attached on the excited participants as a kink Hard gluons fragment into hadron independently Projectile in p+A Projectile in p+p

15. RpA for Final Hadron hadron spectra in Lund frag. is softer than Independent frag.

16. The suppression of High p T hadron comes from fragmentation mainly: More gluon jets Multiple gluon fragmentation model

17. Summary We studied the p+A collision within HIJING model. Cronin effect at intermediate p T due to K T broadening through multiple scattering. High p T suppression from initial nuclear effects: –parton shadowing, –soft-hard coupling, –enhanced gluon jets due to valence quark conservation –Fragmentation method Such effects in AA collisions need to be investigated

19. Rapidity density K T broadening Increase E T Increase the central rapidity density We have to tune the shadowing of gluon

20. HIJING Model: Two-Component Model in N+N Collisions Hard InteractionSoft Interaction PDF

21. Eikonal FormalismJet Independent Approximation The Eikonal Function: HIJING Model: Two-Component Model in N+N Collisions

22. Probability for event without jet: Probability for event with j≥1 number of jets HIJING Model: Two-Component Model in N+N Collisions

23. Non-Single-Diffractive events (NSD). The definition of NSD differs in different experiments. HIJING Model: Results for p+p Phys.Rev. C81 (2010) 024902 Wei-Tian Deng, X.-N. Wang & R. Xu

24. P+P at LHC Energies Phys.Rev.C83 (2011) 014915, Wei-Tian Deng, X.-N. Wang & R. Xu