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Forward Physics From 2008 onwards at the LHC

Diffraction and Central Exclusive Production From 2008 Onwards at the LHC. Forward Physics From 2008 onwards at the LHC. Albert De Roeck (CERN) Manchester 2004. Introduction Physics Detector upgrades. The CMS experiment. Tracking Silicon pixels Silicon strips Calorimeters

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Forward Physics From 2008 onwards at the LHC

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  1. Diffraction and Central Exclusive Production From 2008 Onwards at the LHC Forward Physics From 2008 onwards at the LHC Albert De Roeck (CERN) Manchester 2004 Introduction Physics Detector upgrades

  2. The CMS experiment • Tracking • Silicon pixels • Silicon strips • Calorimeters • PbW04 crystals • for Electro-magn. • Scintillator/steel • for hadronic part • 4T solenoid • Instrumented iron • for muon detection • Coverage • Tracking • 0 < || < 2.5-3 • Calorimetry • 0 < || < 5 Example: CMS Main program: EWSB, Beyond SM physics…

  3. Diffraction at LHC: • PP scattering at highest energy • Soft & Hard Diffraction  < 0.1  O(1) TeV “Pomeron beams“ E.g. Structure of the Pomeron F(,Q2)  down to ~ 10-3 & Q2 ~104 GeV2 Diffraction dynamics? Exclusive final states ? • Gap dynamics in pp presently not fully understood!  = proton momentum loss Reconstruct  with roman pots

  4. Diffraction and Forward Physics at LHC TOTEM: • Approved July 2004 (TDR of TOTEM web page http://totem.web.cern.ch/Totem/) • TOTEM stand alone • Elastic scattering, Total pp cross section and soft diffraction. Totem has no central detector CMS: • EOI submitted in January 2004: /afs/cern.ch/user/d/deroeck/public/eoi_cms_diff.pdf • Diffraction with TOTEM Roman Pots and/or rapidity gaps • Technical Proposal in preparation for new forward detectors (CASTOR, ZDC,+…) • Diffractive and low-x physics part of CMS physics program (low + high ) CMS+TOTEM: • LOI due in April 2005 (K. Eggert/ADR organizing) • Full diffractive program with central activity. TOTEM will be included as a subdetector in CMS (trigger/data stream) ATLAS:( P. Grafstrom, J. Pinfold) • LOI submitted (March 04) for RP detectors to measure elastic scattering/ total cross sections/luminosity. Diffraction will be looked at later ALICE, LHCb: no direct forward projects plans but keeping eyes open.

  5. Forward Physics Program (CMS-TOTEM LOI) • Soft & Hard diffraction • Total cross section and elastic scattering (TOTEM, precision of O(1)%) • Gap survival dynamics, multi-gap events, proton light cone (pp3jets+p), odderon • Diffractive structure: Production of jets, W, J/, b, t, hard photons • Double Pomeron exchange events as a gluon factory (anomalous W,Z production?) • Diffractive Higgs production, (diffractive Radion production?), exclusive SPE?? • SUSY & other (low mass) exotics & exclusive processes • Low-x Dynamics • Parton saturation, BFKL/CCFM dynamics, proton structure, multi-parton scattering… • New Forward Physics phenomena • New phenomena such as DCCs, incoherent pion emission, Centauro’s • Strong interest from cosmic rays community • Forward energy and particle flows/minimum bias event structure • Two-photon interactions and peripheral collisions • Forward physics in pA and AA collisions • Use QED processes to determine the luminosity to 1% (ppppee, pppp) Many of these studies can be done best with L ~1033 (or lower)

  6. Diffraction at LHC Plan to use both rapidity gap and proton tagging techniques • Rapidity gaps based on the central detector • Used extensively at HERA and the Tevatron • Uses correlation between the max and , the momentum loss of the proton • Once detector/readout stable, can be lead first results quickly. Most significant HERA papers, like F2D, are still with rapgaps • Only usable if pile up small and can be controled • Cannot distinguish between outgoing proton or low mass system • Need Monte Carlo based corrections • Tagging protons based on detectors along the beamline • Clean measurement for non-dissociative final protons, kinematics! • Need to understand positioning, alignment, acceptance corrections… This can take some time (HERA & Tevatron experience) • May have reduced luminosity: can insert RPs only when beams/background low and stable Experience from both HERA and Tevatron vital

  7. The HERA/LHC and TeV4LHC Workshops Both workshops have diffractive subgroups Next meetings Feb 3-5 @ BNL Next meetings Jan 17-21 @CERN M. Albrow/ADR diff convenors R. Orava/K. Piotrzkowski diff convenors

  8. Gap moves farther from outgoing proton for smaller xPOM xPomeron < 0.03 xPomeron < 0.02 xPomeron < 0.0075 POMWIG Hard Single diffraction  of minimum- particle per event Rapidity gap trigger study

  9. -t=10-2 -t=10-1 Roman pot acceptances High * (1540m): Lumi 1028-1031cm-2s-1 >90% of all diffractive protons are seen in the Roman Pots. Proton momentum measured with a resolution ~10-3 Low *: (0.5m): Lumi 1033-1034cm-2s-1 220m: 0.02 <  < 0.2 300/400m: 0.002 <  < 0.2 (RPs in the cold region/ under discussion in CMS/ATLAS)

  10. Central Exclusive Production One of the exciting possibilities: Central exclusive production of new massive states (Higgs, Radion,…) Generates a large interest in the CMS/ATLAS communities • 7 UK groups submitted a proposal to PPARC for R&D for the 400m option Extending the reach of the central detectors Cryo-engineer, detectors, trigger hardware, of order 2106£ • Has received go ahead and now a PPRP bid is called for (early 2005)

  11. Higgs Studies 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 Kaidalov et al., hep-ph/0307064 1fb Study correlations between the outgoing protons to analyse the spin-parity structure of the produced boson A way to get information on the spin of the Higgs ADDED VALUE TO LHC 120 140

  12. LHC Reach for a Higgs Discovery Different channels Total sensitivity 30 fb-1 2-3 years LHC can cover the whole region of interest with 10 fb-1 (SM) However… troublesome regions when beyond SM (V. Khoze) Higgs + tag as a spin/parity analyser

  13. Beyond Standard Model Diffractive production of new heavy states pp p + M + p Particularly if produced in gluon gluon (or ) fusion processes Examples: Light CP violating Higgs Boson MH < 70 GeV B. Cox et al. Light MSSM Higgs hbb at large tan  Light H,A (M<150 GeV) in MSSM with large tan  (~ 30)  S/B > 10 Medium H,A (M=150-200 GeV) medium tan ? V. Khoze et al. Radion production - couples strongly to gluons Ryutin, Petrov Exclusive gluino-gluino production? Only possible if gluino is light (< 200-250 GeV) V. Khoze et al.

  14. Problems with bb channel • Trigger • 420 m signals are too late for the L1 trigger • The L1 trigger threshold in CMS for the jets is ~180 GeV • Even with topological tricks still a factor of ~10 is missing in rate (see studies from Helsinki, Wisconsin, Bristol) • Not final, but certainly not going to be easy • Note: rate determination contains a safety factor of 3-6 • Probably ok for asymmetric events, ie. 1 proton tagged in the 220m Roman Pot + dijet trigger: needs testing. • However these events have a bad mass resolution measured in the pp system (1% 6%) • Background • QCD process ggbb(g), even when bb production suppressed at LO, ggqq(g) with misidentification… • S/B~1 at best, likely <1 (detector simulation) • Detection efficiency of the bb • Need to identify b-quarks/loose typically factor of 2  check other channels (HWW*, ADR)

  15. Detectors at 300/400m • Initial discussions with the machine group (early 2002; D. Marcina) • Cold section: Detectors have to be integrated with cryostat Is a bypass an option? 15m cold-warm transition… SC services…  Many machine components already ordered, some already delivered  Machine wants “easy” start-up/no perturbation  Change means an “LHC upgrade” (phase II)

  16. Cryostat upgrades Very positive discussions with the machine group Possible to modify the cryostat in future! Option:Two sections in cold but the detectors warm Could be exchanged during a shutdown earliest autumn 2008 Discussions with the machine ongoing/see D. Macina

  17. 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. The Cockroft 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!!

  18. CMS support for the Study

  19. Detecting an off-momentum proton At 420 m an off-momentum proton lies between the two beam pipes D ≈ 2 mΔp/p = 0.5 %Δx = 10 mm i.e. still inside the beampipe But 10 beamσ≈ 3mm K. Potter Detectors to measure the protons? Mechanics, access etc.? Alignment, calibration issues…

  20. Detectors: micro stations? -station concept (Helsinki proposal) Silicon pixel or strip detectors in vacuum (shielded), 3D silicon… Very compact! Movable detector How close to mass shell are these detectors? They have not been in any testbeam/real environment yet. Which groups are interested to contribute to the developments? It is the time for decisive R&D, test beam etc.

  21. Detectors with Silicon: e.g. see: C. Da Via

  22. TOTEM/CMS Forward Detectors • T1/T2 inelastic event taggers • T1 CSC/RPC tracker (‘99 LOI) •  T2 GEM or Silicon tracker (TOTEM/New) • CASTOR Calorimeter (CMS/New) • ZDC Calorimeter (CMS/New) TOTEM T2 T2 T2 T1 T1 3.1<  <4.7 T2 5.3< <6.7 Castor 5.25< <6.5 CASTOR 10.63 λI Extend the reach in  from ||<5 to || <6.7 Opportunities to contribute to the LOI !!

  23. CMS/TOTEM: a “complete” LHC detector CMS/TOTEM will be the largest acceptance detector ever built at a hadron collider +ZDC K. Eggert Still studying other regions (19m, 25m, 50m…)

  24. “Spectators” ZDC: zero degree calorimeter (CMS) ZDC ZDC Beam pipe splits 140m from IR ZDC LOCATION Tungsten/ quartz fiber EM and HAD section Career grand awarded for the project! Full funding still pending in DOE BEAMS

  25. CASTOR PROTOTYPE II 5mm W + 2mm Q 3mm W 1.5mm Q

  26. H CASTOR A L Energy resolusion in tst beam (APDs) E(GeV) Octant Geometry Electron

  27. Run Scenarios • High  runs (low luminosity runs) • Large acceptance • 10 pb-1? Control of systematics (short runs)? • Example: di-jets in Double Pomeron Exchange ( < 0.1, H1 structure function) LHC pt> 10 GeV pt> 100 GeV pt > 500 GeV 1.2 106 pb 0.9 pb 5 10-4 pb Tevatron 1.3 105 pb • Gain in energy w.r.t. Tevatron and detector acceptance/quality • Low  runs (high luminosity runs) • Lower acceptance for the roman pots • Rapidity gaps (till 1033cm-2s-1) • Calibrate understanding with the roman pot acceptance at high  • For processes/selections below 1 pb (exclusive Higgs etc.) • Low  runs (lower luminosity runs)?

  28. Dedicated Running for SM Diffraction? Note: Heavy Ions to get ~ 1 month/year dedicated. This is a much more modest suggestion for discussion by us. Much SM physics but especially much diffraction can best (even only) be done without pile-up … mostly rap gaps. Optimal luminosity (all bunches) is 3-5.10^32 Will get some in 2007, but want also later (eg with v.fwd. pots) Suppose had ~ 2 weeks (per year?): 15d x 20h x 3600s x 5e32 = 5e38 = 500 pb^-1 (more than TeV Run 2 so far) e.g. SDpp  p+WWX p+llvvX~ 30 events(but only 12 single) DPE pp  p+(bj,bj)X+p(M(bj,bj) > 50 GeV) ~ X events Other SM physics should benefit, e.g. precision top measurements. Interesting? Strategy? Get it part of the scenario already soon? M. Albrow Note: Maybe we can live on the ‘end of run’ data, triggers for lower lumi See also proposals by K. Eggert on different optics

  29. Summary • Diffractive and forward physics is on the physics program of LHC experiments. CMS+TOTEM developing, working towards a LOI.  Diffractive and forward physics will be done from the start at the LHC • Upgrades for the experiments are being proposed • In particular large momentum for 400m region is developingUK bid. Should capitalize on that and establish a full R&D program, with the aim to deploy in the 2008 autumn shutdown and start using these detectors for the 2009 physics run. Start international collaboration now? • Large field of Physics Topics - Hard (& soft) diffraction, QCD and EWSB (Higgs), New Physics - Low-x dynamics and proton structure - Two-photon physics: QCD and New Physics - Special exotics (centauro’s, DCC’s in the forward region) - Cosmic Rays, Luminosity measurement, pA, AA… • We should keep thinking on favourable run scenarios, even beyond 2008-9 • Opportunities for present/new collaborators to join forward physics  complete forward detectors for initial LHC lumi

  30. SCHEMATICS OF NEW CASTOR + Si MICROSTRIP IN SEMI-OCTANT GEOMETRY η = 5.0 η = 5.3 H Si EM EM

  31. 5mm W + 2mm Q H Octant 3mm W + 1.5mm Q EM Semi-Octant CASTOR PROTO II

  32. Diffraction & Forward physics in CMS/TOTEM • Common working group to study diffraction and forward physics at full LHC luminosity. Use synergy for e.g. simulation, physics studies & forward detector studies. • Common DAQ/Trigger for CMS & TOTEM • Common simulation etc… • Share physics studies a diffractive physics program/group, using CMS+TOTEM detectors.  Common CMS+TOTEM LOI on diffractive physics by spring of ‘05 (ADR/ K. Eggert organizing)  Chapter in the CMS physics TDR (due end of ’05)

  33. Electrons 100 GeV: PMTs (FEU-187+R7899) μ

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