1 / 37

The CMS/TOTEM Forward Physics Study

The CMS/TOTEM Forward Physics Study. Albert De Roeck (CERN) Physics with Forward Proton Taggers at the Tevatron and LHC. Introduction: CMS/TOTEM Study Physics Detectors. The Large Hadron Collider (LHC). PP collisions at  s = 14 TeV 5 experiments 25 ns bunch spacing

eryk
Download Presentation

The CMS/TOTEM Forward Physics Study

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The CMS/TOTEM Forward Physics Study Albert De Roeck (CERN) Physics with Forward Proton Taggers at the Tevatron and LHC Introduction: CMS/TOTEM Study Physics Detectors

  2. The Large Hadron Collider (LHC) • PP collisions at • s = 14 TeV • 5 experiments • 25 ns bunch spacing •  2835 bunches • 1011 p/bunch • Design Luminosity: • 1033cm-2s-1 -1034cm-2s-1 • 100 fb-1/year 23 inelastic events per bunch crossing In LEP tunnel (circonf. 26.7 km) TOTEM Planned Startup: April 2007

  3. 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 < || < 3 • Calorimetry • 0 < || < 5 A Hugeenterprise ! Main program: EWSB, Beyond SM physics…

  4. -t=10-2 -t=10-1 The TOTEM Experiment TOTEM physics program: total pp, elastic & diffractive cross sections Apparatus: Inelastic Detectors & Roman Pots (2 stations) CMS IP 150 m 215 m High * (1540m): Lumi 1028-1030cm-2s-1(few days or weeks) >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 215m: 0.02 <  < 0.2 300/400m: 0.002 <  < 0.2 (RPs in the cold region) More on TOTEM & acceptance by R. Orava/K. Osterberg

  5. TOTEM inelastic detectors T1/T2 inelastic event taggers T1 CSC/RPC tracker (99 LOI)  T2 GEM or Silicon tracker (TOTEM/New)  CASTOR Calorimeter (CMS/New) TOTEM T2 T2 T2 T1 T1 3<  <5 T2 5< <6.7 CASTOR 9,71 λI

  6. Forward Physics Program • Soft & Hard diffraction • Total cross section and elastic scattering • Gap survival dynamics, multi-gap events, proton light cone (pp3jets+p) • 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?) • 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)

  7. 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

  8. DPE:  from Di-jet events • Et> 100 GeV/2 figs Pt>100 GeV/c for different structure functions d (pb) events H1 fit 6 (1-x)5 H1 fit 5 x(1-x) H1 fit 6 H1 fit 4 (x 100)   =jets ET e-/(s) ; from Roman Pots; ET and  from CMS High  region probed/ clear differences between different SFs

  9. pp  p + jet + jet + p Petrov et al. ET > 100 GeV ET > 10 GeV |t| (GeV) |t| dependence  information on shape & size of the interaction region Evolution in the presence of a short-time perturbation?

  10. Diffractive Higgs Production Exclusive diffractive Higgs production pp p H p : 3-10 fb Inclusive diffractive Higgs production pp  p+X+H+Y+p : 50-200 fb -jet E.g. V. Khoze et al M. Boonekamp et al. B. Cox et al. … gap gap H h p p Advantages Exclusive:  Jz=0 suppression of ggbb background  Mass measurement via missing mass -jet beam dipole dipole p’ ~New: Under study by many groups p’ roman pots roman pots

  11. MSSM Higgs Kaidalov et al., hep-ph/0307064 100 fb Cross section factor ~ 10 larger in MSSM (high tan) 1fb Also: Study correlations between the outgoing protons to analyse the spin-parity structure of the produced boson 120 140  See talk of A. Martin

  12. 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. (see AD Martin talk) 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.

  13. SM Higgs Studies Needs Roman Pots at new positions 320 and/or 420 m Technical challenge: “cold” region of the machine, Trigger signals… Curves: Helsinki Group Dots FAMOS simulation Mass of Higgs

  14. Detectors at 300m/400m Detectors in this region requires changes in the machine • Physics Case • Can we expect to see a good signal over background?  Signal understood (cross section)  Needs good understanding of the background (inclusive!)  Needs more complete simulations (resolutions, etc.) • Trigger • 300m/400m signals of RPs arrive too late for the trigger  Can we trigger with the central detector only for L1? Note: L1 2-jet thresholds ET > ~150 GeV • Machine • Can detectors (RPs or microstations) be integrated with the machine? Technically there is place available at 330 and 420 m Some Major Concerns: Of interest for both ATLAS and CMS

  15. Detectors at 300/400m • Initial discussions with the machine group (early 2002; see talk of D Marcina in the May CMS/TOTEM meeting) • Cold section: Detectors have to be integrated with cryostat No bypass option considered. TOTEM presently not interested to follow this up further with the machine. Common CMS+ATLAS effort needed?

  16. Action is needed soon. Any change now means paperwork!

  17. Low-x at the LHC LHC: due to the high energy can reach small values of Bjorken-x in structure of the proton F(x,Q2) Processes:  Drell-Yan  Prompt photon production  Jet production  W production If rapidities below 5 and masses below 10 GeV can be covered  x down to 10-6-10-7 Possible with T2 upgrade in TOTEM (calorimeter, tracker) 5<< 6.7 ! Proton structure at low-x !! Parton saturation effects?

  18. Low-x at the LHC Rapidity ranges of jets or leptons vs x range ||<5 5<||<7 Log10(x) Log10(x) 7<||<9 5.5<||<7.8 Kimber Martin Ryskin Log10(x) Log10(x)

  19. High Energy Cosmic Rays Cosmic ray showers: Dynamics of the high energy particle spectrum is crucial Interpreting cosmic ray data depends on hadronic simulation programs Forward region poorly know/constrained Models differ by factor 2 or more Need forward particle/energy measurements e.g. dE/d…

  20. Model Predictions: proton-proton at the LHC Predictions in the forward region within the CMS/TOTEM acceptance

  21. CMS Totem p p Two-photon interactions at the LHC Process K. Piotrzkowski WWA spectrum Reach high W values!! Relative luminosity S = L/Lpp:: ~ 0.1% for W> 200 GeV Must tag protons at small |t| with good resolution: TOTEM Roman Pots!

  22. p p Two-photon interactions at the LHC Sensitivity to Large Extra Dimensions total  cross section W~1000 GeV? New studies: p interactions with 10-100x  Luminosity

  23. SM HIGGS case Number of Higgs events for single tags and assuming integrated lumi-nosity of 30, 0.3 and 0.03 fb-1 for pp, pAr and ArAr collisions, respectively. SUSY K. Piotrzkowski Significant production rates and very clean signatures available - both transverse and longitudinal missing energy Exclusive production! Range up to 200-250 GeV for single tags

  24. p interactions at the LHC K Piotrzkowski • 0.01 < x < 0.1, g tagging range • 0.005 < x < 0.3, Bjorken-x range ggluminosityspectra • • anomalous W and Z production at Wgq  1 TeV • top pair production - top charge + threshold scanning? • single top production and anomalous Wtb vertex • SM BEH - for example,g b  H b, g q H W q • SUSY studies (complementary to the nominal ones) - • H+ t production (and H++), b and t spairs, t~c pair, ... • Exotics: compositness, excited quarks, ... • pPhysics Menu:

  25. Luminosity: Example of a QED process for luminosity monitoring D. Bocian pp  pp e+e- Electrons are in forward range 5<  < 8 Cross section ~barns Tracking important! EM calorimetry essential Can get the luminosity to 1-2%? So far > 5% from W,Z production

  26. Status of the Project • Common working group to study diffraction and forward physics at full LHC luminosity approved by CMS and TOTEM (spring 2002) (ADR/ K. Eggert organizing) Use synergy for e.g. simulation, physics studies & forward detector option studies. Some of this happened e.g. RP & T2 simulation, detector options • Detector options being explored • Roman Pot/microstations for beampipe detectors at 150, 215 , add 310 & 420 m ? (cold section!) • Inelastic detectors T1 CSC trackers of TOTEM (not usable at CMS lumi) Replace T2 with a compact silicon tracker (~ CMS technology) or GEMs Add EM/HAD calorimeter (CASTOR) behind T2 Add Zero degree calorimeter (ZDC) at 140 m • Common DAQ/Trigger for CMS & TOTEM • Common simulation etc…

  27. New T2 Tracker Proposal (TOTEM) Silicon tracker or GEM tracker Distance from IP: 13570 mm T2 inner radius: 25 mm + 8 mm = 33mm  Vacuum chamber inner radius: 25 mm Outer radius: 135mm  Length: 400 mm CMS TRACKER Silicon Strip detectors : Single side p+ strips on n-type substrate, thickness=320 mm, AC-coupled, pitch 80~205 mm, Radiation hardness up to 1.6x1014 1MeV equ./cm2, Cold enviroment –20oC. Or an 8 plan GEM detector? T2 h range : 5.3 < h < 6.5 Under study by TOTEM… GEMs usable for CMS pp and HI runs?

  28. A Forward Calorimeter A calorimeter in the range 5.3 << 6.8 (CASTOR) Position of T2 and Castor (7/2/03) 13570 T2 CASTOR Tungsten and quartz fibres Length 152 cm~ 9I Electromagnetic section 8 sectors/ needs extension

  29. CASTOR PROTO BEAM TEST

  30. Installation of T2 tracker/CASTOR CASTOR shielding T2 HF

  31. “Spectators” ZDC: zero degree calorimeter ZDC ZDC Beam pipe splits 140m from IR ZDC LOCATION M. Murray Tungsten/ quartz fibre or PPAC calorimeter EM and HAD section Funding pending in DOE BEAMS

  32. Opportunities for present/new Collaborators • CMS central detector • Diffractive Gap Trigger (possible in CMS trigger but needs to be studied) • T2 region • Calorimeter (CASTOR) • Add  granularity (silicon, PPAC,…) • Castor trigger • So far only one side of CMS equipped (500 kCHF) • T2 tracker (part of TOTEM, but still in flux…) • May need participation from CMS (if silicon option) • May need new tracker by CMS (if GEM option)… watch TOTEM TDR • Detectors at 300/400m • Completely new project • Needs new resources (there are interested parties in CMS & ATLAS) • ZDC small project but funding not yet garanteed • New detectors in the range 7< <9??? (20 m from IP)  Certainly help welcome on simulation tools, detailed physics studies…

  33. Rapidity Gaps at LHC Number of overlap events versus LHC luminosity distribution of number of interactions 1.1033 2.1033` 1032 1033 1034 1 int. 22% 4% Doable at startup lumnosity without Roman Pots!

  34. 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  G. Snow rapidity gap trigger study

  35. Groups that expressed interest (my interpretation) • Athens : Proposes to built one CASTOR • Annecy : Physics and Roman Pot studies/ Hardware participation in T2 • Belgium : Interest in Roman Pots Hardware (detectors: RD39) Detector layout/radiation hardness/occupancy/trigger/integration Gamma-gamma /gamma-p studies/Low-x studies/Fast simulation. • CERN : Radiation studies Physics studies on diffraction and low-x • Nebraska: Trigger with gaps including CASTOR, Luminosity • Texas Univ: ZDC Hardware • UCLA : DAQ (CMS/TOTEM connection), Physics studies in future • North-Eastern: APD’s for CASTOR readout • Helsinki: Micro stations hardware R&D and Beamline simulation studies • Brazil: Diffractive studies & RPs in cold section • Saclay: Roman pots in cold section? • Protvino : Background calculations for RPs • ITEP: Participation in CASTOR via INTAS project • Moskou Physics Studies/ CASTOR hardware • Karlsruhe: Cosmic ray interest. • Buenos Areas: QCD/diffractive studies/ Hardware interest to be defined Preliminary

  36. Summary • A study group has been formed to explore the common use of CMS and TOTEM detectors and study the forward region. • Physics Interest - 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…) • Probably initial run at high * (few days/weeks  0.1-1 pb-1 ) • Runs at low * (10-100 fb-1 ) • NEW: CMS officially supports forward physics as a project! • Expression of interest for the LHCC • Opportunities for present/new collaborators to join  complete forward detectors for initial LHC lumi

More Related