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High Energy Physics Seminar University of Connecticut 7 February 2005 Konstantin Goulianos The Rockefeller University QCD ASPECTS OF HADRONIC DIFFRACTION.

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Presentation on theme: "High Energy Physics Seminar University of Connecticut 7 February 2005 Konstantin Goulianos The Rockefeller University QCD ASPECTS OF HADRONIC DIFFRACTION."— Presentation transcript:

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2 High Energy Physics Seminar University of Connecticut 7 February 2005 Konstantin Goulianos The Rockefeller University QCD ASPECTS OF HADRONIC DIFFRACTION  CDF results  Comparison with HERA  QCD aspects  Tev2LHC

3 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos2 What is Dark Energy? * * * H He E M * * * H He E M

4 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos3 Rapidity Gaps Gaps are exponentially suppressed From Poisson statistics: (  =particle density in rapidity space) Rapidity gaps are formed by multiplicity fluctuations. Non-diffractive interactions Bj, PRD 47 (1993) 101: regions of (pseudo)rapidity devoid of particles Rapidity gaps at t=0 grow with  y. Diffractive interactions 2  : negative particle density!

5 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos4 Forty Years of Diffraction 1960’sBNL: first observation of pp -> pX 1970’sFermilab fixed target, ISR, SPS  Regge theory & factorization Review: KG, Phys. Rep. 101 (1983) 169 1980’sUA8: diffractive dijets  hard diffraction 1990’sTev Run-I: Regge factorization breakdown Tev/ HERA: QCD factorization breakdown 21 st C Multigap diffraction: restoration of factorization Ideal for diffractive studies @ LHC http://physics.rockefeller.edu/dino/my.html

6 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos5 The First 20 Years KG, Phys. Rep. 101 (1983) 171 X POMERON: color singlet w/vacuum quantum numbers y 

7 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos6 The Last 20 Years 93(2004)141601

8 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos7 valence quarks antiproton x=x= Diffraction in QCD proton  g =0.20  q =0. 04  R =-0.5 g =0.5 q =0.3 SOFTHARD deep sea Derive diffractive from inclusive PDFs and color factors antiproton valence quarks p p

9 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos8 CDF in Run I-0 (1988-89) Elastic, single diffractive, and total cross sections @ 546 and 1800 GeV Roman Pot Spectrometers Roman Pot Detectors  Scintillation trigger counters  Wire chamber  Double-sided silicon strip detector Results  Total cross section  tot ~ s   Elastic cross section d  /dt ~ exp[2  ’ ln s ]  shrinking forward peak  Single diffraction Breakdown of Regge factorization Additional Detectors Trackers up to |  | = 7

10 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos9 Regge Theory

11 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos10  Unitarity problem: With factorization and std pomeron flux  SD exceeds  T at  Renormalization: normalize the pomeron flux to unity Renormalization KG, PLB 358 (1995) 379 ~10

12 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos11 A Scaling Law in Diffraction KG&JM, PRD 59 (1999) 114017 Factorization breaks down in favor of M 2 -scaling renormalization 1

13 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos12 The QCD Connection y  The exponential rise of  T (  y’) is due to the increase of wee partons with  y’ (see E. Levin, An Introduction to Pomerons,Preprint DESY 98-120) y  Total cross section: power law rise with energy Elastic cross section forward scattering amplitude  s

14 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos13 2 independent variables: Gap probability Renormalization removes the s-dependence SCALING QCD Basis of Renormalization t color factor (KG, hep-ph/0205141)

15 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos14 The Factors  and  Experimentally: KG&JM, PRD 59 (114017) 1999 g =0.20 q =0.04 R =-0.5 f g =gluon fraction f q =quark fraction Color factor: Pomeron intercept: CTEQ5L

16 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos15 Run-I A,B: Rapidity Gap Studies Forward Detectors BBC 3.2<  <5.9 FCAL 2.4<  <4.2

17 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos16  Double Diffraction Dissociation  One central gap  Double Pomeron Exchange  Two forward gaps  SDD: Single+Double Diffraction  One forward + one central gap Central and Double Gaps

18 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos17 Gap probabilitySub-energy cross section (for regions with particles) Multigap Renormalization Same suppression as for single gap! 5 independent variables color factors (KG, hep-ph/0205141)

19 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos18  One-gap cross sections are suppressed  Two-gap/one-gap ratios are Central & Double-Gap Results Differential shapes agree with Regge predictions DDSDDDPE

20 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos19 Gap Survival Probability S = Results similar to predictions by: Gotsman-Levin-Maor Kaidalov-Khoze-Martin-Ryskin Soft color interactions

21 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos20 Soft Diffraction Summary  M 2 – scaling  Non-suppressed double-gap to single-gap ratios Experiment: Phenomenology:  Generalized renormalization  Obtain Pomeron intercept and tripe-Pomeron coupling from inclusive PDF’s and color factors

22 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos21  SOFT DIFFRACTION Hard Diffraction @ CDF  HARD DIFFRACTION Additional variables: (x, Q 2 )  dN/d   =  P L /P L  =fractional momentum loss of scattered (anti)proton Variables: ( , t) or ( , t) MXMX  =-ln  t dN/d  ln M X 2

23 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos22 All fractions ~ 1%  Factorization ~ OK @ Tevatron at fixed c.m.s. energy. Diffractive Fractions @ CDF 1.45 (0.25)J/  0.62 (0.25)b 0.75 (0.10)JJ 1.15 (0.55)W Fraction(%) X SD/ND fraction at 1800 GeV

24 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos23 Diffractive DIS @ HERA e Q2Q2 ** p jet  reorganize J. Collins: Factorization should hold e **  t p IP Pomeron exchangeColor reorganization

25 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos24 Inclusive vs Diffractive DIS  P (0)-1 (  q  )/2 F 2 ~ x  qq KG, “Diffraction: a New Approach,” J.Phys.G26:716-720,2000 e-Print Archive: hep-ph/0001092

26 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos25  diff /  incl DIS at HERA At fixed x: flat Q 2 -dependence At fixed Q 2 : flat x-dependence

27 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos26 Diffractive Dijets @ Tevatron p jet reorganize jet

28 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos27 CDF-IC Run-ICRun-IA,B Forward Detectors BBC 3.2<  <5.9 FCAL 2.4<  <4.2

29 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos28 Roman Pot tracking

30 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos29 Diffractive Structure F‘n @CDF SD/ND Rates vs Measure ratio of SD/ND dijet rates as a f’n of In LO-QCD ratio of rates equals ratio of structure fn’s

31 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos30 F D JJ ( , Q 2 ) @ Tevatron

32 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos31 Tevatron vs HERA: Factorization Breakdown dN/d  gap dN/d  gap pp IP CDF H1 pp IP e **  t p IP Predicted in KG, PLB 358 (1995) 379

33 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos32 Restoring Factorization R(SD/ND) R(DPE/SD) DSF from two/one gap: factorization restored!

34 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos33 CDF-II Tag leading p-bar @ 0.02 <  < 0.1 Reject (retain) 95% of ND (SD)events detect forward particles

35 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos34 MiniPlug Calorimeter About 1500 wavelength shifting fibers of 1 mm dia. are ‘strung’ through holes drilled in 36x¼” lead plates sandwiched between reflective Al sheets and guided into bunches to be viewed individually by multi-channel photomultipliers.

36 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos35 Artist’s View of MiniPlug 25 in 5.5 in 84 towers

37 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos36 Diffractive dijets   =   all  towers)  E T e  ss  momentum loss fraction of pbar Approx. flat at  <0.1 const overlap events SD region MP energy scale: ±25% → Δ log ξ = ±0.1 RP acceptance (0.03< ξ < 0.1) ~ 80% (Run I)

38 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos37  : RP vs calorimeter overlap events signal region  cal distribution for slice of  RP  from RP  cal = (0.94 ± 0.03)  RP  /mean ~ 30%

39 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos38 Q 2 -dependence of SD/ND ratio  No appreciable Q 2 dependence within 100 < Q 2 < 10,000 GeV 2  Pomeron evolves similarly to proton

40 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos39 Exclusive Dijets in DPE Interest in diffractive Higgs production Calibrate on exclusive dijets Dijet mass fraction no peak! Upper limit for excl DPE-jj consistent with theory: KMR  60 pb @ 25<E T J <35 GeV

41 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos40 Gap Between Jets Question

42 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos41 CDF2LHC TOPICSTATUS  (Q 2, t) dependence of DSFclose to ready  Exclusive  c production close to ready  Low mass states in DPEneed good trigger  Exclusive b-bbar production in DPE need b-trigger   -dependence of DSFneed low lum run  Jet-gap-Jet w /jets in miniplugsneed low lum run

43 UC seminar, 7 Feb 2005 QCD Aspects of HadronicDiffraction K. Goulianos42 Summary  M 2 – scaling  Non-suppressed double-gap to single-gap ratios  Flavor-independent SD/ND ratio  Little or no Q 2 -dependence in SD/ND ratio SOFT DIFFRACTION Universality of gap prob. across soft and hard diffraction Pomeron evolves similarly to proton HARD DIFFRACTION Diffraction appears to be a low-x partonic exchange subject to color constraints


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