Predictions of Diffractive Cross Sections in Proton-Proton Collisions

1. Predictions of Diffractive Cross Sections in Proton-Proton Collisions Konstantin Goulianos* The Rockefeller University Diffractive Cross Sections in pp Collisions K. Goulianos

2. CONTENTS • Introduction • Cross Sections • (Event Generation) • (Implementation in PYTHIA8) • Conclusions For details on the phenomenology of the predictions see: DIFFRACTION 2010 “Diffractive and total ppcross sections at the LHC and beyond” (KG) http://link.aip.org/link/doi/10.1063/1.3601406 This talk: an implementation of these cross sections in PYTHIA8. Diffractive Cross Sections in pp Collisions K. Goulianos

3. INTRODUCTION • The RENORM (renormalization model) soft pp cross sections previously used in MBR (Minimum Bias Rockefeller) simulation are adapted to PYTHIA8. • MBR was successful at Fermilab in fixed target and collider experiments. • RENORM predictions are based on a parton-model approach in which diffraction is derived from inclusive PDFs and color factors. • Diffractive cross sections and final states are both predicted: • Cross sections vs gap width or vs forward momentum loss of proton(s): • Absolutenormalization! • Hadronization of dissociated proton: • A (non-perturbative) “quark string” is introduced and tuned to reproduce the MBR multiplicity and pT distributions. • dN/dh, pT, and particle ID: new in this PYTHIA8 implementation • (the original MBR simulation produced only p± and p0). • Unique unitarization based on a saturated “glue-ball” exchange. • Total Cross section ~ln2s based on a glue-ball-like saturated-exchange. • Immune to eikonaalization-model dependences. Diffractive Cross Sections in pp Collisions K. Goulianos

4. p Incident hadrons acquire color and break upart POMERON CONFINEMENT STUDIES OF DIFFRACTION IN QCD • Non-diffractive • color-exchange  gaps exponentially suppressed • Diffractive • Colorless vacuum exchange •  large-gap signature rapidity gap Incident hadrons retain their quantum numbers remaining colorless p p p p Goal: probe the QCD nature of the diffractive exchange Diffractive Cross Sections in pp Collisions K. Goulianos

5. MX p’ p’ DEFINITIONS SINGLE DIFFRACTION x,t xp p p MX dN/dh Rap-gap Dh=-lnx 0 ln Mx2 ln s ln s since no radiation no price paid for increasingdiffractive gap size Diffractive Cross Sections in pp Collisions K. Goulianos

6. SDD DIFFRACTION AT CDF sT=Im fel (t=0) Elastic scattering Total cross section OPTICAL THEOREM gap f f h h DD SD DPE /CD Single Diffraction or Single Dissociation Double Diffraction or Double Dissociation Double Pom. Exchange or Central Dissociation Single + Double Diffraction (SDD) exclusive JJ…ee…mm...gg p p JJ, b, J/y,W Diffractive Cross Sections in pp Collisions K. Goulianos

7. p’ p x,t p M 540 GeV 1800 GeV see KG, PLB 358, 379 (1995) FACTORIZATION BREAKING IN SOFT DIFFRACTION diffractive x-section suppressed relative to Regge prediction as √s increases Regge Factor of ~8 (~5) suppression at √s = 1800 (540) GeV RENORMALIZATION CDF √s=22 GeV Diffractive Cross Sections in pp Collisions K. Goulianos

8. DD at CDF gap probability x-section renormalized Diffractive Cross Sections in pp Collisions K. Goulianos

9. SDD at CDF • Excellent agreement between data and MBR (MinBiasRockefeller) MC Diffractive Cross Sections in pp Collisions K. Goulianos

10. CD (DPE) at CDF • Excellent agreement between data and MBR  low and high masses are correctly implemented Diffractive Cross Sections in pp Collisions K. Goulianos

11. Scale s0 and triple-pom coupling Pom. flux: interpret as gap probability set to unity: determines gPPP and s0 Slide #16 Ddffr. 2012 KG, PLB 358 (1995) 379 Pomeron-proton x-section • Two free parameters: s0 and gPPP • Obtain product gPPP•s0e / 2 from sSD • Renormalized Pomeron flux determines s0 • Get unique solution for gPPP gPPP=0.69 mb-1/2=1.1 GeV -1 So=3.7±1.5 GeV2 Diffractive Cross Sections in pp Collisions K. Goulianos

12. Reduce the uncertainty in s0 Diffractive Cross Sections in pp Collisions K. Goulianos

13. Cross Sections el tot CD SD SD DD • SD  single diffraction (single dissociation) • DD  double dissociation (double diffraction) • CD  central dissociation (double pomeron exchange) Diffractive Cross Sections in pp Collisions K. Goulianos

14. Total, elastic, and inelastic x-sections GeV2 Diffractive Cross Sections in pp Collisions K. Goulianos

15. Total, elastic, and inelastic x-sections versus √s Diffractive Cross Sections in pp Collisions K. Goulianos

16. TOTEM vs PYTHIA8-MBR Diffractive Cross Sections in pp Collisions K. Goulianos

17. ALICE tot-inel vs PYTHIA8-MBR Diffractive Cross Sections in pp Collisions K. Goulianos

18. More on cross sections 136 Diffractive Cross Sections in pp Collisions K. Goulianos

19. Difractive x-sections a1=0.9, a2=0.1, b1=4.6 GeV-2, b2=0.6 GeV-2, s′=s e-Dy, k=0.17, kb2(0)=s0, s0=1 GeV2, s0=2.82 mb or 7.25 GeV-2 Diffractive Cross Sections in pp Collisions K. Goulianos

20. Difractive x-sections of √s • Supress x-sections at small gaps by a factor S using the error function with DyS=2 for SD and DD, and Dy=Dy1+Dy2 =2 for CD (DPE). Diffractive Cross Sections in pp Collisions K. Goulianos

21. ALICE SD and DD vs PYTHIA8-MBR Diffractive Cross Sections in pp Collisions K. Goulianos

22. SD and DD at 7 TeV MBR vs PYTHIA8-4C • The differences between the PYTHIA8(4C) and MBR predictions are mainly due to the (1/M2)1+e behavior, with e=1.104 in MBR vs 1,08 in PYTHIA8(4C). Diffractive Cross Sections in pp Collisions K. Goulianos

23. CD (DPE) x-sections at 7 TeV versus (a) Dy=Dy1+Dy2 and (b) Dy1 • Both figures are MBR predictions with a Dy=2 cut-off in the error function. • The normalization is absolute with no model uncertainty other than that due to the determination of the parameters in the formulas as determined from data Diffractive Cross Sections in pp Collisions K. Goulianos

24. SUMMARY  introduction • The ENORM (renormalization model) soft pp cross sections previously used in MBR (Minimum Bias Rockefeller) simulation are adapted to PYTHIA8. • MBR was successful at Fermilab in fixed target and collider experiments. • RENORM predictions are based on a parton-model approach, in which diffraction is derived from inclusive PDFs and color factors. • Diffractive cross sections and final states are both predicted: • Cross sections vs gap width or vs forward-momentum loss of proton(s): • Absolutenormalization! • Hadronization of dissociated proton: • A (non-perturbative) “quark string” is introduced and tuned to reproduce the MBR multiplicity and pT distributions. • dN/dh, pT, and particle ID: new in this PYTHIA8 implementation • (the original MBR simulation produced only p± and p0). • Unique unitarization based on a saturated “glue-ball” exchange. • Total Cross section ~ln2s based on a glue-ball-like saturated-exchange. • Immune to eikonaalization-model dependences. Thank you for your attention Diffractive Cross Sections in pp Collisions K. Goulianos

25. References in arXiv:1205.1446v2 [hep-ph] multiplicities Diffractive Cross Sections in pp Collisions K. Goulianos