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Predictions of Diffraction at the LHC Compared to Experimental Results Konstantin Goulianos The Rockefeller University 1 http://physics.rockefeller.edu/dino/my.html ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos International Conference on New Frontiers in Physics (ICNFP-2013) Aug 28 – Sep 5, 2013, Kolymbari, Crete, Greece http://indico.cern.ch/event/icnfp2013
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Total pp cross section: predicted in a unitarized parton model approach, which does not employ eikonalization and does not depend on the -value. Diffractive cross sections: SD - single dissociation: one of the protons dissociates. DD - double dissociation: both protons dissociate. CD – central diffraction: neither proton dissociates, but there is central diffractive production of particles. Triple-Pomeron coupling: uniquely determined. ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 2 This is an updated version of a talk presented at EDS-2013. CONTENTS
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DIFFRACTION IN QCD Diffractive events Colorless vacuum exchange -gaps not suppressed Non-diffractive events color-exchange -gaps exponentially suppressed POMERONPOMERON Goal : probe the QCD nature of the diffractive exchange rapidity gap p ppp p ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 3
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DEFINITIONS MXMX dN/d ,t,t p’ rap-gap =-ln 0 ln s ln Mx 2 ln s since no radiation no price paid for increasing diffractive-gap width pp p MXMX p p’ SINGLE DIFFRACTION ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 4 Forward momentum loss
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DIFFRACTION AT CDF Single Diffraction or Single Dissociation Double Diffraction or Double Dissociation Double Pom. Exchange or Central Dissociation Single + Double Diffraction (SDD) SD DD DPE/CD SDD Elastic scatteringTotal cross section T =Im f el (t=0) OPTICAL THEOREM gap JJ, b, J/ W p p JJ …ee… exclusive ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 5
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Basic and combined diffractive processes 4-gap diffractive process-Snowmass 2001- http://arxiv.org/pdf/hep-ph/0110240http://arxiv.org/pdf/hep-ph/0110240 gap SD DD ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 6
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KG-PLB 358, 379 (1995) Regge theory – values of s o & g PPP ? Parameters: s 0, s 0 ' and g(t) set s 0 ‘ = s 0 (universal IP ) determine s 0 and g PPP – how? ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 7 (t)= (0)+ ′t (0)=1+
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A complicatiion… Unitarity! A complication … Unitarity! sd grows faster than t as s increases unitarity violation at high s (similarly for partial x-sections in impact parameter space) the unitarity limit is already reached at √s ~ 2 TeV ! need unitarization ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 8
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Factor of ~8 (~5) suppression at √s = 1800 (540) GeV diffractive x-section suppressed relative to Regge prediction as √s increases see KG, PLB 358, 379 (1995) 1800 GeV 540 GeV M ,t,t p p p’ √s=22 GeV RENORMALIZATION Regge FACTORIZATION BREAKING IN SOFT DIFFRACTION CDFCDF ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 9 Interpret flux as gap formation probability that saturates when it reaches unity
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Gap probability (re)normalize to unity Single diffraction renormalized - 1 2 independent variables: t color factor gap probability sub-energy x-section KG CORFU-2001: http://arxiv.org/abs/hep-ph/0203141 ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 10
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Single diffraction renormalized - 2 color factor Experimentally: KG&JM, PRD 59 (114017) 1999 QCD: ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 11
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Single diffraction renormalized - 3 set to unity determines s o ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 12
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M2 distribution: data KG&JM, PRD 59 (1999) 114017 factorization breaks down to ensure M 2 scaling! Regge 1 Independent of s over 6 orders of magnitude in M 2 M 2 scaling d dM 2 | t=-0.05 ~ independent of s over 6 orders of magnitude ! data ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 13
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Scale s 0 and PPP coupling ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 14 Two free parameters: s o and g PPP Obtain product g PPP s o from SD Renormalized Pomeron flux determines s o Get unique solution for g PPP Pomeron-proton x-section Pomeron flux: interpret as gap probability set to unity: determines g PPP and s 0 KG, PLB 358 (1995) 379
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Saturation at low Q 2 and small x figure from a talk by Edmond Iancu ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 15
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DD at CDF renormalized gap probabilityx-section ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 16
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 17 Rapidity gaps in fireworks! Fermilab1989 Opening night at Chez Leon Rapidity Gaps in Fireworks
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SDD at CDF Excellent agreement between data and MBR (MinBiasRockefeller) MC ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 18
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Total, elastic & inelastic cross sections GeV 2 ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 19 KG Moriond 2011, arXiv:1105.1916 el p±p = tot ×( el tot ), with el tot from CMG small extrapol. from 1.8 to 7 and up to 50 TeV ) CMG
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 20 The total x-section √s F =22 GeV 98 ± 8 mb at 7 TeV 109 ±12 mb at 14 TeV Main error from s 0
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Reducing the uncertainty in s 0 ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 21 glue-ball-like object “superball” mass 1.9 GeV m s 2 = 3.7 GeV agrees with RENORM s o =3.7 Error in s 0 can be reduced by factor ~4 from a fit to these data! reduces error in t.
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TOTEM results vs PYTHIA8-MBR ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 22 inrl 7 TeV = 72.9 ±1.5 mb inrl 8 TeV = 74.7 ±1.7 mb TOTEM, G. Latino talk at MPI@LHC, CERN 2012 MBR: 71.1±5 mb superball ± 1.2 mb RENORM: 72.3±1.2 mb RENORM: 71.1±1.2 mb
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SD and DD cross sections vs predictions ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 23 KG*: from CMS measurements after extrapolation into low using the KG model. Includes ND background KG*
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CD/DPE at CDF Excellent agreement between data and MBR low and high masses are correctly implemented ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 24
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Difractive cross sections 1 =0.9, 2 =0.1, b 1 =4.6 GeV -2, b 2 =0.6 GeV -2, s′=s e - y, =0.17, 2 (0)= 0, s 0 =1 GeV 2, 0 =2.82 mb or 7.25 GeV -2 ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 25
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 26 Inelastic cross sections at LHC vs predictions TOTE PYTHIA8+MBR
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Monte Carlo Strategy for the LHC … tot from SUPERBALL model optical theorem Im f el ( t=0 ) dispersion relations Re f el ( t=0 ) el using global fit inel = tot - el differential SD from RENORM use nesting of final states for pp collisions at the P-p sub-energy √s' Strategy similar to that of MBR used in CDF based on multiplicities from: K. Goulianos, Phys. Lett. B 193 (1987) 151 pp “A new statistical description of hardonic and e + e − multiplicity distributios “ T optical theorem Im f el (t=0) dispersion relations Re f el (t=0) MONTE CARLO STRATEGY ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 27
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 28 Monte Carlo algorithm - nesting y'cy'c Profile of a pp inelastic collision y‘ < y' min hadronize y′ > y' min generate central gap repeat until y' < y' min ln s′ = y′ evolve every cluster similarly gap no gap final state of MC w /no-gaps t gap t t t1t1 t2t2
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 29 SUMMARY Introduction Diffractive cross sections: basic: SD1,SD2, DD, CD (DPE) combined: multigap x-sections ND no diffractive gaps: this is the only final state to be tuned Total, elastic, and total inelastic cross sections Monte Carlo strategy for the LHC – “nesting” derived from ND and QCD color factors Thank you for your attention
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 30 Images
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 31 Fermilab 1971 First American-Soviet Collaboration Elastic, diffractive and total cross sections
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 32 At the gorge of Samaria (1980)-I
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 33 At the gorge of Samaria (1980)-II with R. Feynman – a day of jokes!
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 34 Opening night at Chez Leon Fermilab1989 Opening night at Chez Leon
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ICNFP-2013, Kolymbari Predictions of Diffraction at the LHC K. Goulianos 35 The End The End!
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