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TOTEM Physics Scenarios at the LHC; Elastic Scattering, Total Cross section, Diffraction,

TOTEM Physics Scenarios at the LHC; Elastic Scattering, Total Cross section, Diffraction, and beyond. Risto Orava HIP & UH.

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TOTEM Physics Scenarios at the LHC; Elastic Scattering, Total Cross section, Diffraction,

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  1. TOTEM Physics Scenarios at the LHC; Elastic Scattering, Total Cross section, Diffraction, and beyond ... Risto Orava HIP & UH XXXV ISMD 2005 KROMĚŘÍŽ , CZECH 9.-15.8.2005

  2. CMS is TOTEMized... Leading Protons measured at -220m & -147m from the CMS CMS Experimental Area (IP5) (Also CMS is here...) TOTEM Experiment • Leading protons are detected at 147m & 220m from the IP. • CMS coverage is extended by Totem T1 and T2 spectrometers. • Additional forward calorimetry & veto counters are under planning. Leading Protons measured at +147m & +220m from the CMS XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  3. Configuration of the Experiment Aim at detecting colour singlet exchange processes with the leading protons scattered at small angles with respect to the beam. b-jet Roman Pot Station at 147 / 220m Roman Pot Station at 147/220m CMS T1 CASTOR CASTOR T2 T1 T2 - b-jet Aim at measuring the: • Leading protons on both sides down to D  1‰ • - Rapidity gaps on both sides – forward activity – for |h| > 5 • Central activity in CMS XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  4. Base Line LHC Experiments: pT-h coverage LHC TOTEMized 1000 CMS ATLAS 100 T1 T1 pT (GeV) ALICE LHCb 10 T2 T2 1 microstation microstation RP RP 0.1 veto veto pTmax~ s exp(-h) -12 -10 -8 -6 -4 -2 0 +2 +4 +6 +8 +10 +12 h The base line LHC experiments will cover the central rapidity region - TOTEMCMS will complement the coverage in the forward region. XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  5. Base Line LHC Experiments • ATLAS & CMS: • Energy flow in |h| 5 • Minimum bias event structure • need to sort out the pile-up events at L › 1033 • present MC models differ by large factors • ALICE: • Charged multiplicities in -5  h 3 • Zero Degree Calorimetry (neutral & charged) • TOTEM: • Charged multiplicities: 3  h 7 • Leading particle measurement: • Totem sees ~ all diffractively scattered protons • TOTEM/CMS inelastic coverage is unique: • Holes only at h~ 5 & 7-9 (could be covered with ms & veto counters) XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  6. Diffractive scattering is a unique laboratory of confinement & QCD: A hard scale + hadrons which remain intact in the scattering process. Transversal view Elastic soft SDE hard SDE soft CD hard CD Longitudinal view - Lorentz contracted – not to scale! ‘wee’ parton cloud - grows logarithmically p jet lnMX2 Baryonic charge distribution-r  0.5fm jet + b b lns h Valence quarks in a bag with r  0.1fm rapidity • Soft diffractive scattering: • large b Hard diffractive scattering - small b p Rapidity gap survival & ”underlying” event structures are intimately connected with a geometrical view of the scattering - eikonal approach! 25mb? 10mb? 1mb? • Soft processes: • Coherent • interactions • impact parameter • picture. Hard processes: Jet momenta correlated with the initial parton momenta. Cross sections are large. Totem sees SDE MX  20 GeV XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  7. With the leading protons and additional forward coverage a new physics realm opens up at the LHC: Elastic scattering, stot and soft diffraction – surely... But also: • Hard diffraction with multi- rapidity gap events (see: Hera, Tevatron, RHIC...)  Problems intimately related to confinement. • Gluon density at small xBj (10-6 – 10-7) – “hot spots” of glue in vacuum? • Gap survival dynamics, proton parton configurations (pp3jets+p) – underlying event structures • Diffractive structure: Production of jets, W, J/, b, t, hard photons, • Parton saturation, BFKL dynamics, proton structure, multi-parton scattering • Studies with pure gluon jets: gg/qq… LHC as a gluon factory! (see: KMR EPJC19(2001)477) • Signals of new physics based on forward protons + rapidity gaps Threshold scan for JPC = 0++ states in: pp  p+X+p – Spin-parity of X ! (LHC as the pre -e+e- linear collider in the gg-mode.) • Extend ‘standard’ physics reach of the CMS experiment into the forward region:  Full Monty! • Measure the Luminosity with the precision of DL/L 5 % (KMRO EPJC19(2001)313) XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  8. As a Gluon Factory LHC could deliver... • High purity (q/g ~ 1/3000) gluon jets with ET >50 GeV; • gg-events as “Pomeron-Pomeron” luminosity monitor • Possible new resonant states in a background free environment (bb, W+W- & • t+t- decays); (see: KMR EPJC23(2002)311) • Higgs • glueballs • quarkonia 0++ (b ) • gluinoballs • invisible decay modes of Higgs (and SUSY)!? • CP-odd Higgs • Squark & gluinothresholds are well separated • practically background free signature: multi-jets & ET • model independence (missing mass!) [expect O(10) events for gluino/squark masses of 250 GeV] • an interesting scenario: gluino as the LSP with mass window 25-35 GeV(S.Raby) • Events with isolated high mass ggpairs • Moreover: Mini-Black Holes, Extra Dimensions –The Brane World !!!... • (see: Albrow and Rostovtsev) - XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  9. Probing Very Small-x Gluons • Consider a high momentum proton: • Measure gluon distribution G(x,Q2) at fixed Q2 • and small x with x››Q •  probe gluons with the transverse size = |Db|~1/Q and • longitudinal size = |Dz|~1/px. • gluon saturation, colour-glass condensates, colour-dipoles,.... In SD: If a pair of high ET jets are produced, then: If the interacting partons have fractional momenta b of P, then b=xBj/, then (if all hadrons i in the event are measured): Instrument region with tracking, calorimetry (em+had), muons, jets, photons ... XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  10. Central Diffraction produces two leading protons, two rapidity gaps and a central hadronic system. In the exclusive process, the background is suppressed and the central system has selected quantum numbers. JPC = 0++ (2++, 4++,...) MX212s Measure the parity P = (-1)J: ds/d 1 + cos2 2p  Gap Jet+Jet Gap 0 hmin h hmax Mass resolution  S/B-ratio Survival of the rapidity gaps?1 see: DKMOR EPJC25(2002)391 Also: Jet energy scale calibration? – M. Albrow XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  11. Signatures • Proton (Roman Pots): • elastic proton (b*=1540m: 5  10-4  -t  1 GeV2, b*=18m: 310-1  -t  10 GeV2) • diffractive proton (b*=1540m: 90% of all diffractive protons:   10-2 & -t  10-3 GeV2) • hard diffractive proton (b* = 0.5m: excellent coverage in -t space) • Rapidity Gap (T1 & T2, Castor & ZDC): • rapidity gaps (up to L~ 1033cm-2 s-1: 3  |h| 7, +veto counters?) • Very Fwd Objects (T1 & T2, Castor & ZDC): • Jets (up to L~ 1033cm-2 s-1: 3  |h| 7, +veto counters?) • g, e, m (fwd em calorimetry & muons: 3 |h| 7) • tracks (vx constraints & pattern recognition: 3  |h| 7) • particle ID? • Correlation with CMS Signatures (central jets, b-tags,...) XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  12. Correlation with the CMS Signatures • e, g, m, t, and b-jets: • tracking: |h| < 2.5 • calorimetry with fine granularity: |h| < 2.5 • muon: |h| < 2.5 • Jets, ETmiss • calorimetry extension: |h| < 5 • High pT Objects • Higgs, SUSY,... • Precision physics (cross sections...) • energy scale: e & m 0.1%, jets 1% • absolute luminosity vs. parton-parton luminosity via • ”well known” processes such as W/Z production? XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  13. To Reach the Forward Physics Goals Need: • Leading Protons • Extended Coverage of Inelastic Activity • CMS XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  14. Leading Protons - Measurement The small-angle protons are detected within the LHC beam pipe at large distances from the IP. To facilitate detection of elastically and diffractively scattered protons, special machine optics are needed b* = 1540m (-t down to  10-3 GeV2), 18m (-t up to 10 GeV2) For hard diffraction and low-x physics, nominal – high luminosity – conditions are required  b* = 0.5m RP2 RP1 RP3 CMS 147 m 180 m 220 m RPi: Special insertion devices needed for placing the proton detectors within the beam pipe  Roman Pots IP5 CMS Interaction Point TAS Beam Absorber for secondaries between the IP and Q1 Qi Quadrupole Magnets TASA Beam Absorber for secondaries between Q1 and Q2 TASB Beam Absorber for secondaries between Q2 and Q3 DFBx Cryogenic Electrical Feed-Boxfor Arc Di Dipole Magnet i TAN Beam Absorber for neutral secondaries before Q1-Q3 BSR Synchrotron Radiation Observation System TCL Long Collimator for protecting Quadrupole Magnets XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  15. Leading Proton Detection-An Example 0m 147m 180m 220m 308m 338m 420 430m D2 Q4 Q5 Q6 Q7 B8 Q8 B9 Q9 B10 Q10 B11 IP    D1    Q1-3      x = 0.02   Note the magnification x vs. z! Helsinki group: Jerry Lamsa & RO XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  16. Photon - Pomeron interferencer Pomeron exchange ~ e–B|t| diffractive structure pQCD ~ |t|–8 Ldt = 1033 and 1037 cm-2 Elastic Scattering: ds/dt extrapolate to – t = 0! ds/dt (mb/GeV2) -tmin~ 2 · 10-3 GeV2 -tmax~ 10 GeV2 -t (GeV2) XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  17. Elastic Scattering: Acceptance in -t Region |t| [GeV]2Running Scenario Coulomb region 510-4 [lower s, RP closer to beam] Interference, r meas. 510-4510-3 [as above], standard b* = 1540 m Pomeron exchange 510-3  0.1 b* = 1540 m Diffractive structure 0.1  1b* = 1540 m, 18 m Large |t| – perturb. QCD 1  10 b* = 18 m XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  18. Extrapolation of Elastic Cross-Section to t = 0 Non-exponential ds/dt fitted to Slope parameter according to BSW Model see: KMRO EPJ(2001)313 XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  19. Soft Diffractive Protons (highb*) b* = 1540 m A > 95 % 85 - 95 % A < 5 % ~ 90 % of all diffractive protons are seen in the Roman Pots -assuming x = Dp/p can be measured with a resolution of ~ 5 x 10-3 . XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  20. Hard Diffraction (highb*): Acceptance XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  21. Luminosity-independent measurement of the total cross-section by using the Optical Theorem: Measurement of tot • Measure the elastic and inelastic rate with a precision better than 1%. • Extrapolate the elastic cross-section to t = 0. • Or conversely: • Extract luminosity: XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  22. Need Extension to Inelastic Coverage To measure the colour singlet exchange, need to extend central detector coverage in the forward direction: h > 5. T1: 3.1 <h< 4.7 T2: 5.3 <h< 6.5 10.5 m T1 10.5 m T2 CASTOR ~14 m XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  23. simulated extrapolated Acceptance single diffraction Loss at low masses detected Measurement of the Total Rate Nel + Ninel Total: 0.8 % Extrapolation of diffractive cross-section to large 1/M2 using ds/dM2 ~ 1/M2 . • 50% acceptance down to 3.5 (1.5) GeV Model uncertainties are large! XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  24. Accuracy of stot Total rate Nel + Ninel r = 0.12 ± 0.02 Extrapolation to t = 0 XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  25. Total Cross Section - TOTEM TOTEM stot (lns)e as s   e = 0, 1, 2, or - 0.08 ?? XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  26. Elastic Scattering- TOTEM TOTEM XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  27. Diffractive Mass Acceptance +veto counters TOTEM ’base line’ XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  28. Towards Hard Diffraction - Tevatron results jets, heavy quarks, heavy bosons produced at ~ 1% of the inclusive rate XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  29. Running Scenarios + Runs atb* = 0.5 m, L = (1033  1034) cm-2 s-1 foreseen as an extension to the TOTEM program. XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  30. Exciting new physics potential in the process: pp  p  (JPC=0++)  p • Colour singlet exchange process with exclusive priviledges • - JPC selection rule •  e+e- ILC type threshold scan for new physics! h p 10 p p Dh 5 jet P jet 0 jet P p jet p -5 Dh -10 p • Need to solve the L1 trigger issue at high luminosity (pile-up) • conditions. see: KMR EPJ(2002) XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  31. Exclusive Production by CED: Examples Advantage: Selection rules: JP = 0+, 2+, 4+; C = +1  reduced background, determination of quantum numbers. Good f resolution in TOTEM: determine parity: P = (-1)J+1 ds/df ~ 1  cos 2f • Need L ~ 1033 cm-2 s-1 for Higgs, i.e. a running scenario for b* = 0.5 m: • try to modify optics for enhanced dispersion, • try to move detectors closer to the beam, • install additional Roman Pots in cold LHC region at a later stage. XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  32. Hard Diffractive Protons (Low b*) horizontal offset = Dx ( = momentum loss) For a 2.5 mm offset of a   0.5 % proton, need dispersion  0.5 m.  Proton taggers to be located at > 250 m from the IP (i.e. in a ”cryogenic section” of the LHC). Dx y Optical function  in x and y (m) Dispersion in horizontal plane (m) x CMS XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  33. Potential locations for measuring the leading protons in pp  p  X  p with MX~ O(100 GeV). Cryogenic (”cold”) region (with main dipole magnets) locations of currently planned TOTEM pots!! 420 m (308/338m) 220 m CMS Dispersion suppressor Matching section Separation dipoles Final focus XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  34. Leading protons: Hard Central Diffraction • pp  p + X + p simulated using PHOJET1.12& ExHuME • Protons tracked through LHC6.2& 6.5 optics using MAD • Uncertainties included in the study: • Initial conditions at the interaction point • Conditions at detector location • Transverse vertex position (x,y = 11 m) • Beam energy spread (E = 10-4) • Beam divergence ( = 30 rad) • Position resolution of detector (x,y = 10 m) • Resolution of beam position determination (x,y = 5 m) • Off-sets at detector locations J.Lamsa, T. Maki, R.Orava, K.Osterberg...

  35. Acceptance: ExHuME vs. PHOJET 50% 33% 24% 12% see Marek Tasevsky’s talk on Monday "420+220" calculation: either both protons are detected at 420m, or both protons are detectedat 220m, or one proton is detected at 420 [220]m with the other one detected at 220 [420]m. XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  36. Resolution: ExHuME vs. PHOJET 420m+220m ExHuME 420m ExHuME 420m+220m PHOJET 420m PHOJET PHOJET 420+220m 3.7% ExHuME 420+220m 2.8% PHOJET 420m ExHuME 420m 0.9% Helsinki group: Jerry Lamsa et. al. Helsinki group: J.Lamsa (parametrisations of the MAD simulation results of T. Mäki by RO) XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

  37. TOTEM Physics Scenarios Proton b* (m) rapidity gap L(cm-2s-1) inelastic activity jet g,e,m,t L, D++,... TOTEM & CMS TOTEM & CMS TOTEM & CMS elastic scattering ’1540’ ’18’ beam halo? 1028 -1032 total cross section inelastic acceptance ’1540’ 1028 -1033 soft diffraction ’1540’ ’170’ gap survival L, K±, ,... 1029 -1031 mini-jets? ’170’ ’ 0.5’ jet acceptance central & fwd W, Z, J/,... hard diffraction 1031 -1033 ’170’ ’0.5’ di-jet backgr central pair b-tag, g, J/,... CED Higgs, SUSY,... 1031 -1033 trigger ’170’ ’0.5’ mini-jets resolved? central & fwd jets di-leptons jet-g,... low-x physics 1031 -1033 exotics (DCC,...) p± vs. po multiplicity jet anomalies? leptons g’s,...? ’0.5’ 1031 -1033 XXXV ISMD 2005, KROMĚŘÍŽ , CZECH Risto Orava 12.8.2005

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