Multigap Diffraction at the LHC

1. Multigap Diffraction at the LHC K. Goulianos The Rockefeller University DIS 2005 27 April – 1 May Madison, Wisconsin http://physics.rockefeller.edu/dino/my.html Multigap Diffraction at the LHC K. Goulianos

2. Multigap Diffraction (KG, hep-ph/0205141) f y Multigap Diffraction at the LHC K. Goulianos

3. f y Total cross section: power law rise with energy ~1/as The exponential rise of sT(Dy’) is due to the increase of wee partons with Dy’ (see E. Levin, An Introduction to Pomerons,Preprint DESY 98-120) f Elastic cross section: forward scattering amplitude y Elastic and Total Cross Sections QCD expectations Multigap Diffraction at the LHC K. Goulianos

4. t 2 independent variables: color factor Single Diffraction sub-energy x-section gap probability Gap probability MUST be normalized to unity! Multigap Diffraction at the LHC K. Goulianos

5. Grows slower than se  The Pumplin bound is obeyed at all impact parameters Single diffraction (re)normalized Multigap Diffraction at the LHC K. Goulianos

6. Total Single Diffractive x-Section • Unitarity problem: Using factorization and std pomeron flux sSD exceeds sT at • Renormalization: Normalize the Pomeron flux to unity KG, PLB 358 (1995) 379 Multigap Diffraction at the LHC K. Goulianos

7. Color factor: Pomeron intercept: lg=0.20 lq=0.04 lR=-0.5 The Factors k and e Experimentally: KG&JM, PRD 59 (114017) 1999 CTEQ5L fg=gluon fraction fq=quark fraction Multigap Diffraction at the LHC K. Goulianos

8. 5 independent variables color factors Gap probability Sub-energy cross section (for regions with particles) Multigap Cross Sections Same suppression as for single gap! Multigap Diffraction at the LHC K. Goulianos

9. Agreement with renormalized Regge predictions DD SDD DPE • One-gap cross sections are suppressed • Two-gap/one-gap ratios are Central and Two-Gap CDF Results Multigap Diffraction at the LHC K. Goulianos

10. S = Gap Survival Probability Results similar to predictions by: Gotsman-Levin-Maor Kaidalov-Khoze-Martin-Ryskin Soft color interactions Multigap Diffraction at the LHC K. Goulianos

11. jet p x x,t IP p g* e g* Q2 e reorganize Diffractive DIS @ HERA Factorization holds: J. Collins Pomeron exchange Color reorganization Multigap Diffraction at the LHC K. Goulianos

12. aP(0)-1= (eq+l)/2 eq Inclusive vs Diffractive DIS KG, “Diffraction: a New Approach,” J.Phys.G26:716-720,2000 e-Print Archive: hep-ph/0001092 F2 ~ x-l Multigap Diffraction at the LHC K. Goulianos

13. jet p jet reorganize Diffractive Dijets @ Tevatron Multigap Diffraction at the LHC K. Goulianos

14. FDJJ(x,b,Q2) @ Tevatron Multigap Diffraction at the LHC K. Goulianos

15. SD/ND Dijet Ratio vs xBj@ CDF 0.035 < x < 0.095 Flat x dependence Multigap Diffraction at the LHC K. Goulianos

16. R(SD/ND) R(DPE/SD) Restoring Factorization @ Tevatron DSF from two/one gap: factorization restored! Multigap Diffraction at the LHC K. Goulianos

17. Gap Between Jets Multigap Diffraction at the LHC K. Goulianos

18. p p valence quarks antiproton antiproton SOFT HARD eg=0.20 lg=0.5 eq=0. 04 lq=0.3 eR=-0.5 Low-x and Diffraction deep sea valence quarks Derive diffractive from inclusive PDFs and color factors x=x proton Multigap Diffraction at the LHC K. Goulianos

19. Summary • Multigap processes offer the opportunity of studying diffraction without complications arising from screening corrections, multi- Pomeron exchanges, rescattering, or other rapidity gap survival issues. • Run 1 results from the Tevatron, and those expected from Run 2, should be followed up by more studies at the LHC with the aim of advancing a successful phenomenology to a THEORY of diffraction. Multigap Diffraction at the LHC K. Goulianos

20. Anwar Luc Stefano Michele Mary Koji Christina Andrea Ken Thanks toThe Rockefeller HEP Group Multigap Diffraction at the LHC K. Goulianos