CMS &ATLAS were designed and optimised to look beyond the SM

2. CMS &ATLAS were designed and optimised to look beyond • the SM • High -pt signatures in the central region • But… ‘incomplete’(from the ILC motivation list) • Main physics ‘goes Forward’ • Difficult background conditions. • The precision measurements are limited by systematics • (luminosity goal of δL ≤5%) • Lack of : • Threshold scanning • ILC chartered territory • Quantum number analysing • Handle on CP-violating effects in the Higgs sector • Photon – photon reactions p p p RG Is there a way out? ☺YES-> Forward Proton Tagging Rapidity Gaps  Hadron Free Zones Δ Mx ~δM (Missing Mass) X RG p p

3. PLAN • 1. Introduction • (a gluonic Aladdin’s lamp) • 2.Basicelements of Durham approach • (a qualitative guide) • 3. Prospects for CED Higgs production. • the SM case • MSSM Higgses in the troublesome regions • MSSM with CP-violation • (difficult oreven impossible with conventional methods) • 4. Exotics • Conclusion • 6. Ten commandments of Physics with • Forward Protons at the LHC • .

4. Forward Proton Taggersas a gluonic • Aladdin’s Lamp • (rich Old and NewPhysics menu) • Higgs Hunting (currently a key selling point). • Photon-Photon Physics. K.Piotrzkowski • ‘Light’ SUSY ( sparticle ‘threshold’ scan). KMR-02 • Various aspects of Diffractive Physics • (strong interest from cosmic rays people) • Luminometry KMOR-01 • High intensity Gluon Factory. • (lower lumi run, RG trigger…) Helsinki Group, VAK • Searches for new heavy gluophilic states KMR-02 • FPT • Would provide a unique additional tool tc complement the conventionalstrategies at theLHCandILC. • a ‘ time machine’ • Many of the studies can be done with L~10³³ (or lower) • Higgs is only a part of a broad diffractive program@LHC

5. The basic ingredients of the KMR approach(1997-2005) Interplay between the soft and hard dynamics Sudakov suppression • Bialas-Landshoff-91 rescattering/absorptive • ( Born -level ) effects • Main requirements: • inelastically scattered protons remain intact • active gluons do not radiate in the course of evolution up to the scale M • <Qt> >>/\QCDin order to go by pQCD book

6. High price to pay for such aclean environment: σ (CEDP) ~ 10 -4 σ( Incl) Rapidity Gapsshould survive hostile hadronic radiation damages and ‘partonic pile-up ‘ W = S² T² • Colour charges of the ‘digluon dipole’ are screened • only at rd ≥ 1/ (Qt)ch • GAP Keepers (Survival Factors) , protecting RG against: • the debris of QCD radiation with 1/Qt≥ ≥ 1/M(T) • soft rescattering effects (necessitated by unitariy) (S) Forcing two (inflatable) camels to go through the eye of a needle H P P

7. schematically skewed unintegrated structure functions (suPDF) (x’~Qt/√s) <<(x~ M/√s) <<1 (Rg=1.2 at LHC) T(Qt,μ)is the probability that a gluon Qt remains untouched in the evolution up to the hard scale M/2 T + anom .dim. → IR filter ( theapparent divergency in the Qt integration nullifies) <Qt>SP~M/2exp(-1/αs),αs =Nc/παsCγ SM Higgs, <Qt>SP ≈ 2 GeV>> ΛQCD

8. MAIN FEATURES • An important role of subleading terms in fg(x,x’,Qt²,μ²), • (SL –accuracy). • Cross sectionsσ~(fg )(PDF-democracy) • S²KMR=0.026 (± 50%)SM Higgs at LHC • (detailed two-channel eikonal analysis of soft pp data) • surprisingly good agreement with other ‘unitarizer’s approaches andMCs. • S²/b² - quite stable (within 10-15%) • S²~ s(Tevatron-LHC range) • dL/d(logM² ) ~ 1/ (16+ M) • a drastic role of Sudakov suppression(~ 1/M³) • σH ~ 1/M³ , (σB) ch ~ Δ M/ M 4 ^ ^ ^ ^ -016 3.3 6 • Jz=0 ,even P-selection rule forσis justified • only if <pt>² /<Qt>² « 1

9. pp pp->p +M +p (S²)γγ =0.86 α² αs²/8 we should not underestimate photon fusion !

10. The advantages of CED Higgs production • Prospects for high accuracy mass measurements • (ΓHand even lineshape in some MSSM scenarios) • mass windowM = 3 ~ 1 GeV (the wishlist) • ~4 GeV(currently feasible) • Helsinki Group • Valuable quantum number filter/analyzer. • ( 0++dominance ;C , P-even) • difficult or even impossible to explore the light HiggsCPat the LHC conventionally. • (an important ingredient of pQCD approach, • otherwise, large|Jz|=2 …effects, ~(pt/Qt)2!) • H ->bb ‘readily’ available • (gg)CED bbLO (NLO,NNLO)BG’s -> studied • SM HiggsS/B~3(1GeV/M) • complimentary information to the • conventional studies( also ՇՇ) • H →WW*/WW - an added value • especially for SM Higgs with M≥ 135GeV,MSSMat lowtanβ • New leverage –proton momentum correlations • (probes of QCD dynamics, pseudoscalar ID, • CP violation effects)KMR-02; A.Kupco et al 04; V.Petrov et al -04; J.Ellis et al -05

11. ☻Experimental Advantages Measure the Higgs mass via the missing mass technique Mass measurements do not involve Higgs decay products Experimental Challenges Tagging the leading protons Selection of exclusive events & backgrounds Triggering at L1 in the LHC experiments Model dependence of predictions: (soft hadronic physics is involved after all) resolve some/many of the issues with Tevatron data There is a lot to learn from present and future Tevatron diffractive data

12. Current consensus on the LHC Higgs • search prospects • (e.g, A.Djouadi, Vienna-04; G.Weiglein, CMS, 04; A.Nikitenko,UK F-m,04)) • SM Higgs : detection is in principle guaranteed ☺ • for any mass. • In the MSSMh-boson most probably cannot ☺ • escape detection ,and in large areas • of parameter space other Higgses can be found. • But there are still troublesome areas of the  • parameter space: • intense coupling regime, • MSSM with CP-violation….. • More surprises may arise in other SUSY • non-minimal extensions • After discovery stage(Higgs identification): • The ambitious program of precise measurements of the mass, width, couplings, • and, especially of the quantum numbers and • CP properties would require an interplay • with a ILC

13. SM Higgs Cross Section * BR • Cross sections~O(fb) • Diffractive Higgs mainly studied for Hbb -K(KMR)97-04 • -DKMOR-02 • Boonekamp et al. ,01-04 • Petrov et al. ,04 •  Recently study extended • for the decay into WW*,WW • can reach higher masses • ‘Leptonic trigger cocktail’ • (WW,bb,ZZ,) • work in progress, FT420UKteam Note Hbb (120 GeV) at Tevatron  0.13 fb

14. SM Higgs, CEDP LHC, L=30fb-1 KMR-00,KKMR-03,DKMOR-02 M(GeV) 120 140comments accuracy could be improved σ 3fb 1.9fb(theory +experim., CEDP dijets ) (1 -5.5fb)(0.6-3.5fb) Sbb11 3.5cuts + efficiences. (S/B)bb3(1GeV/M) 2.4(1GeV/ M)cuts +effic. LO,NLO,NLLO BG ϭH (M=120GeV)= 3fb for reference purposes. natural low limit 0.1fb (photon fusion) H->WW (with full CMS detector simulation) B.Cox, A. De Roeck, VAK ,M.Ryskin, T.Pierzchala,W.J.Stirling et al M(GeV) 140 150 160 SWW(LH)6.3 9 12.6 work in progress with leptonic ‘trigger cocktail ‘ we can go up in mass with adetectable signal up to 200 GeV

15. Exclusive SM Higgs production b jets : MH = 120 GeV s = 2 fb (uncertainty factor ~2.5) MH = 140 GeV s = 0.7 fb MH = 120 GeV :11 signal / O(10) background in 30 fb-1 (with detector cuts) H WW* : MH = 120 GeV s = 0.4 fb MH = 140 GeV s = 1 fb MH = 140 GeV :8 signal / O(3) background in 30 fb-1 (with detector cuts) • The b jet channel is possible, with a good understanding of detectors and clever level 1 trigger (needs trigger from the central detector at Level-1) • The WW* (, ZZ*…) channel is extremely promising : no trigger problems, better mass resolution at higher masses (even in leptonic / semi-leptonic channel), weaker dependence on jet finding algorithms • If we see SM-like Higgs + p- tags the quantum numbers are 0++ H

16. ☺An added value of the WW channel 1. ‘less demanding’ experimentally (trigger and mass resolution requirements..) allows to avoid the potentially difficult issue of triggering on the b-jets 2. higher acceptances and efficiencies 3. an extension of well elaborated conventional program, (existing experience, MC’s…) 4. the decrease in the cross section is compensated for by the increasing Br and increased detection efficiency 5. missing mass resolution improves as MH increases 6. the mass measurement is independent of the decay products of the central system 7. Better quantitative understanding of backgrounds. Very low backgrounds at high mass. 8.0+ assignment and spin-parity analyzing power - still hold ☻we should not ignore MSSM with low tan β

17. The yield of WW/ bb for CED production of the SM Higgs H→WW H→bb

18. MSSM with low tan β LEP low tan β exclusion boundsweaken if the top mass goes up (Karlsruhe group- 99)  with new Mtwe should pay more attention to the low tan β scenarios M(GeV) Mind the mass gap

19. γγ-backgrounds Calculated using CalcHEP(T.Pierzchala -05) with centrality cuts (|h| < 2.5 leptons and jets) and DM = 0.05 MH ,MH = 120 GeV (140 GeV)s(WW*) = 0.06 fb (0.12 fb) Note : these can be reduced, if/when necessary, by pT > 100 MeV cut on protons. Mass resolution is conservative here)

20. gg backgrounds VAK, M.Ryskin & W.J.Stirling 05 s(MH = 140 GeV) = 0.8 fb Estimate reduction of BGs by factor of ~ 10 from jet / proton pT cuts above WW threshold - more work needed below threshold.

21. WW / WW* Summary • Trigger is no problem • S/B ~ 1 (much better above WW threshold) • expect to see double tagged SM Higgs up to ~180 GeV with increasing precision on mass • MSSM low tan bresults are encouraging • The advantages of forwardproton tagging are still explicit ~200

22. The MSSM and more exotic scenarios If the coupling of the Higgs-like object to gluons is large, double proton tagging becomes very attractive • The intense coupling regime of the MSSM (E.Boos et al, 02-03) • CP-violating MSSM Higgs physics(A.Pilaftsis,98; M.Carena et al.,00-03, B.Cox et al 03, KMR-03, J. Ellis et al -05) Potentially of great importance for electroweak baryogenesis • an ‘Invisible’ Higgs(BKMR-04)

23. Higgs couplings (G.Weiglein)

24. (a )The intense coupling regime • MA≤ 120-150GeV, tanβ>>1( E.Boos et al,02-03) • h,H,A- light, practically degenerate • largeΓ, must be accounted for • the ‘standard’ modes WW*,ZZ*, γγ…-strongly suppressed v.s. SM • the best bet – μμ -channel, • in the same time – especially advantageous for CEDP: ☺ • (KKMR 03-04) • σ(Higgs->gg)Br(Higgs->bb) - significantly exceeds SM. • thus ,much larger rates. • Γh/H~ ΔM, • 0- is filtered out, and the h/H separation may • be possible • (b) The intermediate regime: MA ≤ 500 GeV, • tan β< 5-10 • (the LHC wedge, windows) • (c) The decoupling regime • MA>> 2MZ(in reality, MA>140 GeV, tan β>10) • h is SM-like, H/A -heavy and approximately degenerate, • CEDP may allow to filterAout ~

25. suppressed enhanced The MSSM can be very proton tagging friendly The intense coupling regime is where the masses of the 3 neutral Higgs bosons are close to each other and tan  is large 0++ selection rule suppresses A production: CEDP ‘filters out’ pseudoscalar production, leaving pure H sample for study MA = 130 GeV, tan b = 50 Mh = 124 GeV :71 signal / 3background/GeV in 30 fb-1 MH = 135 GeV :124 signal / 2 background/GeV in 30 fb-1 MA = 130 GeV :3 signal / 2 background/GeV in 30 fb-1 for 5 ϭ BR(bb) > 0.7fb (2.7fb) for 300 (30fb-1) Well known difficult region for conventional channels, tagged proton channel may well be the discovery channel, and is certainly a powerful spin/parity filter

26. SM Higgs: (30fb-1) 11 signal events (after cuts) O(10) background events Cross section factor ~ 10-20 larger in MSSM (high tan) 100 fb KKMR-03 Study correlations between the outgoing protons to analyse the spin-parity structure of the produced boson 1fb A way to get information on the spin of the Higgs  ADDED VALUE tothe LHC 120 140

27. decoupling regime: mA ~ mH large h = SM intense coupl: mh ~ mA ~ mH ,WW.. coupl suppressed • with CEDP: • h,Hmay be • clearlydistinguishable • outside130+-5 • GeV range, • h,Hwidths are quite different

28. SMpp  p + (Hbb) + p S/B~11/4(M) with M (GeV) at LHC with 30 fb-1 e.g. mA = 130 GeV, tan  = 50 (difficult for conventional detection, but CEDP favourable) S B mh = 124.4 GeV 71 3 mH = 135.5 GeV 124 2 mA = 130 GeV 1 2 x M/ 1GeV incredible significance (10 σ) for Higgs signal even at 30 fb -1

29. Helping to cover the LHC gap? needs update With CEDP the mass range up to 160-170 GeV can be covered at medium tan and up to 250 GeV for very high tan , with 300 fb-1 Needs ,however, still full simulation

30. Spin Parity Analysis Azimuthal angle between the leading protons depends on spin of H • Azimuthal angle between the leaprotons depends on spin of H • Measure the azimuthal angle of the proton on the proton taggers  angle between protons with rescattering effects included  angle between protons KKMR -03

31. Probing CP violation in the Higgs Sector Azimuthal asymmetry in tagged protons provides direct evidence for CP violation in Higgs sector ‘CPX’ scenario (s in fb) KMR-04 A is practically uPDF - independent CP odd active at non-zero t CP even Ongoing studies - are there regions of MSSM parameter space where there are large CP violating couplings AND enhanced gluon couplings?

32. Recent development

33. CP- violating MSSM with large tri-mixing J.Ellis et al 05 tanβ=50, MH+=150 GeV In thetri-mixing scenario we expect ϭbb ~ 1fb and proton asymmetries A ~0.1-03

34. X M 1 GeV Summary of CEDP • The missing mass method may provide unrivalled Higgs mass resolution • Real discovery potential in some scenarios • Very clean environment in which to identify the Higgs,for example, in the CPX scenario • Azimuthal asymmetries may allow direct measurement of CP violation in Higgs sector • Assuming CP conservation, any object seen with 2 tagged protons has positive C parity, is (most probably) 0+, and is a colour singlet e.g. mA = 130 GeV, tan b = 50 (difficult for conventional detection, but exclusive diffractive favourable) L = 30 fb-1 S B mh = 124.4 GeV 71 3 events mH = 135.5 GeV 124 2 mA = 130 GeV 1 2 ► WW*/WW modes are looking extremely attractive. Detailed studies are underway (UK FT420 team)

35. ExoticsGluinoniumsAn ‘Invisible’ Higgs ~ ~  Gluinonium (gluinoball) : G=gg scenarios where gluino g is the the LSP (or next- to-LSP) currentntlyhit of the day -split -SUSY the lowest-lying bound state 0++(³ P ) the energies of P-wave states En= -9/4 mg αs²/n² (n ≥2) G – a ‘Bohr atom’ of the g g- system ΓG= (MG/100 GeV) 0.33 MeV, σG=30 fb (MG/100 GeV) ~ 0 ~ ~ ~ 5 -2 (S/B)gg= 0.25 !0 (1/ΔM) (MG/ 100 GeV) visualization is challenging even with angular cuts

36. ►an ‘Invisible ‘ HiggsKMR-04 M.Albrow & A .Rostovtsev -00 • several extensions of the SM: a fourth generation, • some SUSY scenarios, • large extra dimensions • (one of the ‘LHC headaches’ ) • the advantages of the CEDP – a sharp peak in the MM spectrum, mass determination, quantum numbers • strong requirements : • triggering directlyon L1 on the proton taggers • low luminosity : L= 10³² -10³³cm-2 sec-1 (pile-up problem) , • forward calorimeter(…ZDC) (QED radiation , soft DDD), • veto from the T1, T2- type detectors (background reduction, improving the trigger budget) various potential problems of the FPT approach reveals themselves however there is a (good) chance to observe such an invisible object, which otherwise may have to await a ILC

37. The physics case for proton tagging • If you have a sample of Higgs candidates, triggered by any means, accompanied by proton tags, it is a 0++ state. • The mass resolution will be better than central detectors (e.g. H -> WW -> nl jj … no need to measure missing ET) • With a mass resolution of ~O(1 GeV )the standard model Higgs b decay mode opens up, with S/B > 1 • In certain regions of MSSM parameter space, S/B > 20, and double tagging is THE discovery channel • In other regions of MSSM parameter space, explicit CP violation in the Higgs sector shows up as an azimuthal asymmetry in the tagged protons -> direct probe of CP structure of Higgs sector at LHC • Any 0++ state, which couples strongly to glue, is a real possibility (radions? gluinoballs? etc. etc.)

38. EXPERIMENTAL CHECKS • Up to now the diffractive production data are consistent with K(KMR)S results • Still more work to be done to constrain • the uncertainties • Very low rate of CED high-Et dijets ,observed yield • of Central Inelastic dijets. • (CDF, Run I, Run II) data up to (Et)min>50 GeV • ‘Factorization breaking’ between the effective diffractive structure functions measured • at the Tevatron and HERA. • (KKMR-01 ,a quantitative description of the results, • both in normalization and the shapeof the • distribution) • The ratio of high Et dijets in production with one • and two rapidity gaps • The HERA data on diffractive high Et dijets in • Photoproduction. • (Klasen& Kramer-04 NLO analysis) • Preliminary CDF results on exclusive charmonium • CEDP. Higher statistics is underway. • Energy dependence of the RG survival (D0, CDF) • CDP of γγ, data are underway • KKMR .….. has still survived theexclusion limits • set by the Tevatron data….(M.Gallinaro, hep-ph/01410232)

39. CONCLUSION Forward Proton Taggingwouldsignificantlyextend the physics reachof the ATLAS and CMS detectors by giving access to a wide range of exciting new physics channels. For certain BSM scenarios the FPT may be the Higgs discovery channel within the first three years of low luminosity running  FPT may provide a sensitive window into CP-violation and new physics Nothing would happen unless theexperimentalists come FORWARDand do theREAL WORK We must work hard here – there is no easy solution

40. Proposed UK project to launch activity Forward proton tagging at the LHC as a means to discover new physics • Proposal for a project submitted to PPARC (UK) R. Barlow1,7, P. Bussey2, C. Buttar2, B. Cox1, C. DaVia3, A. DeRoeck4, J. R. Forshaw1, G. Heath5, B. W. Kennedy6, V.A. Khoze4, D. Newbold5, V. O’Shea2, D. H. Saxon2, W. J. Stirling4, S. J. Watts3 1. The University of Manchester, 2. The University of Glasgow, 3. Brunel University, 4. IPPP Durham, 5. Bristol University, 6. Rutherford Appleton Laboratory, 7. TheCockroft Institute • Request for funds for • R&D for cryostat development • R&D for detectors (3D silicon so far) • Studies for trigger/acceptance/resolution • Total of order 2.106 pounds been asked for 2005-2008 period. Covers 2 cryostats, manpower (engineers), detector design study  Has received go ahead (with some boundary conditions)  If launched, other (non-UK) groups in CMS could kick in!! Opportunities for present/new collaborators to join Forward Physics . Start international collaboration now

41. New Forward Detector Proposal (in prep.) Cold region 420 m region: connecting (empty cryostat) Acceptance of 200m is not sufficient fot Higgs detection Proposal to study a modification of the cryostat and to operate compact detectors in the region of 400m (for ATLAS & CMS) R&D collaboration building: UK groups, Belgian & Finish institutes, CERN… US420(consortium of US groups who are on CMS & ATLAS)

42. of Forward Proton Tagging 1. Thoushalt not worship any other god but the First Principles, and even if thoulikest it not, go by thyBook. 2. Thou slalt not make untotheeanygraven image, thou shalt not bow down thyself to them . (non-perturbative Pomeron) 3.Thou shalttreat the existing diffractive experimental data in ways that show great consideration and respect. 4.Thou shalt drawthy daily guidance from the standard candleprocesses for testing thy theoretical models. 5. Thou shalt remember the speed of light to keep it holy. (trigger latency) 6.Thou shalt notdishonour backgrounds and shaltstudy them with great care. 7.Thou shalt notforget about the pile-up (an invention ofSatan). 8.Though shalt notexceed the trigger threshold and the L1 saturation limit. Otherwise thy god shall surely punish thee for thy arrogance.

43. 9.Thou shalt not annoy machine people. 10. Thou shalt not delay, the LHC start-up is approaching