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The FP420 Project: Introduction and Physics Potential

This project focuses on the use of 1.2mm gas on slimmed silicon pixels in the replacement of Si trackers for improved physics measurements. Two types of Cerenkov detectors, GASTOF and QUARTIC, are explored for their timing capabilities. The goal is to achieve a time resolution of 20 ps or better for the full detector system.

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The FP420 Project: Introduction and Physics Potential

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  1. The FP420 Project:Introduction and Physics Potential Albert De Roeck CERN and University of Antwerp

  2. 1.2 mm Gas On Slimmed SIlicon Pixels Gossip: replacement of Si tracker Essential: thin gas layer (1.2 mm)

  3. FP420 Baseline Plan 1 GASTOF 2 QUARTICs Lots of 3D silicon • Two types of Cerenkov detector are employed: • GASTOF – a gas Cerenkov detector that makes a single measurement • QUARTIC – two QUARTIC detectors each with 4 rows of 8 fused silica bar allowing up to a 4-fold improvement over the single bar resolution • Both detectors use Micro Channel Plate PMTs (MCP-PMTs)

  4. The Detectors : 1) GASTOF (Louvain) Full Cerenkov cone is captured. Simulations show yield of about 10 pe accepted within few ps! 1 measurement of ~10 ps See K.P. Gastof talk for details

  5. The Detectors : 2) QUARTIC proton 4x8 array of 6 mm2 fused silica bars UTA, Alberta, FNAL Only need 40 ps measurement if you can do it 16 times (2 detectors with 8 bars each)! Has x-segmentation for multi-proton timing photons

  6. Fast Timing Is Hard! 3 mm =10 ps Detector Phototube or equivalent Electronics Reference timing Rad Hardness of detector, phototube and electronics, where to put electronics in tunnel Lifetime and recovery time of tube, grounding Background in detector and MCP Multiple proton timing ISSUES Time resolution for the full detector system: 1. Intrinsec detector time resolution 2. Jitter in PMT's 3. Electronics (AMP/CFD/TDC) 4. Reference Timing

  7. Latest QUARTIC Prototype Note: prior to June 2008 test beam, results marginal for QUARTIC 15mm bar: 80 ps/bar 80% efficient; allows you to reach close to 20 ps, but not 10 ps HC HH HE Testing long bars 90 mm (HE to HH) and mini bars 15 mm (HA to HD) Long bars more light from total internal reflection vs. losses from reflection in air light guide, but more time dispersion due to n()

  8. FP420 Timing Setup veto G2 G1 Q1 Amplifiers

  9. Detectors for 20 ps System Primary focus has been on designing detectors that are capable of 20 ps or better timing measurement at low to moderate luminosity (several 1033) with high efficiency. (Lurkingradiation issues , MCPPMT issues discussed later) For GASTOF ~15 ps with 90-99% efficiency depending on position (see K.P. talk) has been achieved for detector/PMT part of path with GASTOF/Hamamatsu (6 um pore), working on improvements, but don’t obviously need them for Phase I. Main issue: there has been no test of CFD/TDC (single photon counter?) and there is no clear readout integration plan For QUARTIC ~40 ps/bar has been achieved with 90+% efficiency including LCFD, separate tests of HPTDC promising (Pinfold talk) Main issue: Still need to demonstrate definitively lack of correlation between measurements allowing Sqrt(n)~4 reduction, MCPMT issues Reference timing of <10 ps does not appear to be a problem, but has not yet been demonstrated R&D funding needed for this

  10. Cathode (drift) plane Si depletion layer Cluster1 Cluster2 1mm, 100V Vbias Cluster3 Integrated Grid (InGrid) CMOS chip 50um, 400V Slimmed Silicon Readout chip Input pixel 50um Si (vertex) track detector GOSSIP Gas: 1 mm as detection medium 99 % chance to have at least 1 e- Gas amplification ~ 1000: Single electron sensitive All signals arrive within 16 ns • Si strip detectors • Si pixel detectors • MAPs

  11. GOSSIP-Brico: PSI-46 (CMS Pixel FE chip) First prototype of GOSSIP on a PSI46 is working: • 1.2 mm drift gap • Grid signal used as trigger • 30 µm layer of SiProt

  12. track sample contains several BXs • position resolution: ~ 20 electrons participate • time resolution: ~ 2 ns for each electron • (thinned) detector mass: 50 µm Si equiv. GridPix in FPA beam CMOS pixel chip Gas Volume & Field Cage

  13. Forward detectors at LHC TOTEM -T2 CASTOR ZDC/FwdCal TOTEM-RP FP420? I P 5 14 m 16 m 14 0 m 1 4 7 m - 2 2 0 m 4 2 0 m I P 1 LUCID ZDC ALFA/RP220 FP420?

  14. FP420 History • Higgs prod. with RapGaps: Dokshitzer, Troyan and Khoze ‘87 • End of the 90’s: interest growing in “diffractive Higgs production” • Expected to be cleaner than incl. production. High cross section predicted by Bialas&Landhoff, and Nachtmann et al. • Many groups get interested. Durham group (Khoze et al) make QCD calculations of the central exclusive production process. K. Piotrzkowski on exclusive Higgs production in  • R. Orava, ADR, Khoze,… write in 2002 a paper on the Higgs measurement and experimental issues proposing detectors at 420 m. Cross sections are still used to date. • December 2003: Forward physics meeting in Manchester • June 2004; Formation of the FP420 R&D collaboration • June 2005: LOI to LHCC CERN-LHCC-2005-025 ; LHCC-I-015 • April 2008: R&D report of FP420 ready

  15. Exclusive Central Production • Selection rules mean that central system is 0++ pinning down the quantum numbers • CP violation in the Higgs sector shows up directly as azimuthal asymmetries • Tagging the protons means excellent mass resolution (~ GeV) irrespective of the decay products of the central system. LO QCD backgrounds suppressed • Proton tagging may be the discovery channel in certain regions of the MSSM. • Unique access to a host of interesting QCD processes Very schematically: exclusive central production is a glue – glue collider where you know the beam energy of the gluons - source of pure gluon jets - and central production of any 0++ state which couples strongly to glue is a possibility …

  16. FP420: Detectors at 420m TOTEM (ATLAS/RP220) FP420 Low *: (0.5m): Lumi 1033-1034cm-2s-1 215m: 0.02 <  < 0.2 300/400m: 0.002 <  < 0.02 Detectors in the cold region are needed to access the low  values FP420 R&D Study

  17. R&D Report 2005 2008 Last (?) updates received last night  Release imminent

  18. Schematic of Extremely High Precision Proton Spectrometer CMS High precision (~ 5 m) BPM High precision (~ 5m) BPM 420m of vacuum pipe 120m of 8T dipoles Precision ~ 5 m on track displacement and ~ 1 rad on angle w.r.t. beam. Layout schematic ... Still being optimized

  19. FP420 Detectors at 420 m from the IP to detect forward protons Replace empty cryostat with ATMs and “FP420” beampipe described in the document Workshop on 2-photon @ CERN last week: Interest from ALICE/(LHCb?)

  20. Detectors: Tracking/Timing Tracking: Proposed solution 3D dectors Timing Detectors Quartic and GASTOF

  21. October Testbeam at CERN + testbeam campaign at FNAL in 2006/2007 for timing detectors

  22. TOTEM d(epeXp)/dxL [nb] det@420 xL=P’/Pbeam= 1-x FP420 R&D Study • Feasibility study and R&D for the development of detectors to measure protons at 420 m from the IP, during low  optics at the LHC • Main physics aim pp  p+ X + p • Higgs, New physics • QCD/diffractive studies • Photon induced interactions • Study aims • Mechanics/stability for detectors at 420 meter (cryostat region) • Detectors to operate close to the beam • Fast timing detectors (10-20 picosecond resolution) • RF issues, integration, precision alignment, radiation, resolution,… • Trigger/selection issues/pile-up for highest luminosity To become pat of the ATLAS and/or CMS program, when successful • Collaboration web page: http://www.fp420.com Excellent collaboration with machine/cryo groups; Keith Potter mediator

  23. Physics Program • General: the physics program starts when TWO arms are avaialble (discussion in the breakout) • QCD and Diffraction  Accessible from 1032 onwards • Diffractive structure: Production of jets, W, J/, b, t, hard photons; GPDs (1 fb-1) • Double Pomeron exchange events as a gluon factory (anomalous W,Z production?) (1 fb-1) • Exclusive production of new mass states  accessible from 1033 onwards • Exclusive Higgs production in bb, WW and  final states (~ 10-30 fb-1) • Exclusive nMSSM higgs  aa (~ 100 fb-1) • CP properties of the MSSM Higgs (~ 30 fb-1) • CP violation in the Higgs sector ( > 100 fb-1) • Radion production (~ 30 fb-1), split supersymmetry (> 100 fb-1) • Two-photon photon-proton interactions  accessible from 1033 onwards • SUSY slepton and chargino (~ 100 fb-1) • Anomalous couplings (~ 10 fb-1)

  24. Acceptance and Resolution 420m+220m Hector simulation included in CMSSW

  25. Central Exclusive Higgs Production Central Exclusive Higgs production pp p H p : 2-10 fb (SM) ~10-100 fb (MSSM) -jet E.g. V. Khoze et al ADR et al. M. Boonekamp et al. B. Cox et al. V. Petrov et al… Brodsky et al. gap gap H h p p -jet M = O(1.0 - 2.0) GeV beam dipole A way to get information on the spin of the Higgs ADDED VALUE TO LHC dipole p’ FP420 R&D Project http://www.fp420.com p’ roman pots roman pots

  26. ppp+H+p cross section • Checkered history: range of possible numbers existed until 1-2 years ago • Durham numbers were checked by J. Forshaw et al, and by a Protvino group • More importantly the Tevatron predictions for dijets and diphotons are • confirmed within a factor of ~ 2 • Main uncertainties • Proton survival probability (Tevatron  LHC) • Could be pinned down with early LHC data • pp  diffractive W production • (PAS-DIF 2007/002) • Background calculation confirmation with FSC? • -PDF uncertainty • Take pessimistic approach in most • cases: MRST PDFs More suggestions for first measurements in arXiv:0802.0177

  27. CDF +exclusive 2 photon and di-lepton events in CDF: See Mike Albrow’s talk

  28. Higgs Studies 100 fb • Cross section factor • > 10 larger in MSSM • (high tan) • Few 100 events with ~ 10 background events for 30 fb-1 1fb Kaidalov et al., hep-ph/0307064 120 140

  29. Hbb Mhmax MSSM scenario: Hbb (mA=120 GeV, tan = 40, 60 fb-1) = 20 fb Invariant mass calculated with the two protons Events / 1 GeV New trigger strategy: L1 jet thresholds 40 GeV and accept 10-25 KHz Clean at HLT with FP420 protons to few Hz Trigger acceptance > 50% * proton acceptance Pile-up taken into account Walk-through this channel in breakout session Taking into account acceptance, trigger efficiencies etc. Presently:SM Hbb will be marginal

  30. Hbb 20 ps timing 10 ps timing

  31. MSSM Scenario Studies MA = 130 GeV Hbb No-mixing scenario Contours of ratio of signal events in the MSSM over the SM

  32. H b, W, τ b, W, τ Discovery potential CEP may be the discovery channel for MSSM Higgs: Heavy Higgs states decouple from gauge bosons, hence preferred search channels at LHC not available But large enhancement of couplings to bb,  at high tan Detailed mapping of discovery potential for pp→p + H,h + p

  33. Measuring the Azimuthal Asymmetry Khoze et al., hep-ph/0307064 Azimuthal correlation between the tagged protons Allows to eg to differentiate O+ from O- A way to get information on the spin of the Higgs ADDED VALUE TO LHC

  34. HWW Standard Model Higgs WW* : MH = 120 GeV s = 0.4 fb MH = 140 GeV s = 1 fb MH = 140 GeV :3-4 signal / O(3) background in 30 fb-1 MH = 140 GeV :17 signal / O(15) background in 300 fb-1 MH = 120 GeV :5 signal in 300 fb-1 H with fast detector simulation • In certain MSSM space the signal rate goes up by a factor 4 • The WW* (ZZ*) channel has no: no trigger problems, better mass resolution at higher masses (even in leptonic / semi-leptonic channel)

  35. haa Low mass higgs in NMSSM: If ma < mB difficult (impossible) at standard LHC J. Gunion: FP420 may be the only way to see it at the LHC 150 fb-1 Result above for ATLAS treshold. Slightly better result for CMS/internal note in preparation unique

  36. “lineshape analysis” This scenario needs a mass resolution of about 1 GeV and 100 fb-1 J. Ellis et al. hep-ph/0502251 Scenario with CP violation in the Higgs sector and tri-mixing Unique

  37. Long Lived gluinos at the LHC P. Bussey et al hep-ph/0607264 Gluino mass resolution with 300 fb-1 using forward detectors and muon system The event numbers includes acceptance in the FP420 detectors and central detector, trigger… Added value Measure the gluino mass with a precision (much) better than 1%

  38. Exotics Anomalous WW Production? Alan White: theory of supercritical pomeron reggeized gluon+many (infinite) wee gluons • color sextet quarks required by asymptotic freedom, have strong colour charge, (at least) few 100 GeV constituent mass • Sextet mesons  EWSB • UDD neutron dark matter candidate • Explain high energy cosmic rays, Knee? • Color sextet quarks couple strongly to W and Z and to the pomeron • Phenomenology: Anomalous production of WW when above threshold ie. At the LHC (with possibly some onset already detectable at the Tevatron color color triplets sextets u c t U d s b D Unique for CEP • Measure exclusive WW,ZZ cross sections in DPE at the LHC Expected cross section to be orders of magnitude larger than in SM

  39. CMS Near beam Detectors p p Photon-photon and photon-proton @ LHC Process WWA spectrum • Extensive Program •   , ee QED processes •   QCD (jets..) •   ZZ/WW anomalous couplings •   top pairs •   Higgs •   Charginos • … …and p

  40. Two photon processes Q2<2 GeV2 Relative elastic luminosity for 20 GeV <E < 900 GeV Initial study: K. Piotrzkowsk, Phys.Rev.D63:071502,2001

  41. WW Quartic Anomalous Couplings Added value! 10000 better than the best established LEP limits Two-photon workshop@ CERN last week: WW at LHC sensitive to two new couplings

  42. Supersymmetric Particles Added value for the mass measurements

  43. Photon-Proton Processes Associated WH production Anomalous top production

  44. QED Processes for Alignment PAS-DIF 2007/001

  45. Summary • Near beam detectors at 420m will extend the physics potential of the central detector CMS. • Main physics aim pp  p+ X + p • Higgs, in particular in the MSSM, New physics, Exotic physics • SM Higgs in bb decay mode at the limit • QCD/diffractive studies • not much explored but dijets, W,Z ,WW, 2 photon, heavy flavour production measurements can be made • Photon induced interactions • Significant sensitivity to new physics • Data taking at 1034 cm-2s-1 seems feasible • FP420 is an excellent ‘extension’ of the CMS baseline detector

  46. Backup

  47. Machine induced backgrounds • Low number of expected hadrons per bunch due to local beam-gas events • Low beam-halo backgrounds (momentum cleaning, distant beam-gas) • necessary condition to work at 5 mm: keep IR3 collimators at 15σ as presently foreseen ONGOING STUDIES: • Charged and neutral secondary particles fluxes , mainly generated by diffractive proton losses • FP420 detector models integration in the simulations and background rejection techniques undergoing Beam Halo Diffractive protons LOSS MAPs

  48. Radions Petrov Ryutin Radions like to couple to gluons Large production rates in DPE Large rate of bb fb fb

  49. FP420 Allignment

  50. Silicon tracker mechanical design

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