TOTEM Physics s tot TOTEM Collaboration elastic scattering diffraction (together with CMS) Politecnico di Bari and Sezione INFN Bari, Italy Case Western Reserve University Cleveland, Ohio,USA Institut für Luft- und Kältetechnik, Dresden, Germany CERN, Geneva, Switzerland Università di Genova and Sezione INFN Genova, Italy University of Helsinki and HIP, Helsinki, Finland Academy of Sciences, Praha, Czech Republic Penn State University University Park, USA Brunel University, Uxbridge, UK Karsten Eggert CERN, PH Department on behalf of the TOTEM Collaboration http://totem.web.cern.ch/Totem/ TOTEM TDR is fully approved by the LHCC and the Research Board

TOTEM Physics Total cross-section with a precision of 1% Elastic pp scattering in the range 10 -3 < t = (p  )2 < 10 GeV2 Particle and energy flow in the forward direction Measurement of leading particles Diffractive phenomena with high cross-sections Different running scenarios (b* = 1540, 170, 18, 0.5 m)

TOTEM Experiment

Total p-p Cross-Section Current models predictions: 90-130 mb Aim of TOTEM: ~1% accuracy COMPETE Collaboration fits all available hadronic data and predicts: LHC: [PRL 89 201801 (2002)]

Experimental apparatus T1: 3.1 < h < 4.7 T2: 5.3 < h < 6.5 Optical Theorem

Elastic Scattering Cross-Section Photon - Pomeron interference  r Multigluon (“Pomeron”) exchange  e– B |t| 104 per bin of 10-3 GeV2 ds/dt [mb / GeV2]  t  p2 q2 diffractive structure pQCD wide range of predictions pp 14 TeV BSW model -t [GeV2] b* = 1540 m L = 1.6 x 1028 cm-2 s-1 (1) b*=18 m L = 3.6 x 1032 cm-2 s-1 (2) ~1 day (1) (2)

Elastic Scattering at low-t Coulomb scattering (1/L) dNel/dt = ds/dt = [4pa2(c)2G4(t)]/|t|2 + {[a(r-af)stotG2(t)]/|t|}exp(-B|t|/2) + [stot2 (1 + r2)/16p(c)2] exp(-B’|t|) Nuclear scattering Coulomb-Nuclear interference - how to calculate? (Kundrat et al.) L = integrated luminosity dNel/dt = observed elastic events a = fine structure constant = relative Coulomb-nuclear phase: = ln(0.08|t|-1 – 0.577) (see: West & Yennie, PR172(1968)1413. G(t) = nucleon em form factor: = (1 + |t|/0.71)-2

Extrapolation uncertainty due to Coulomb interference Extrapolation to t=0 model dependent Error < 0.5 % ds/dt ~ exp( -Bt) Coulomb interference Coulomb scattering Nuclear scattering Coulomb- Nuclear interference Change of the slope B r = Re/Im f(pp)

Elastic Scattering:  = Re f(s,0)/Im f(s,0) TOTEM  Ref+(s,0)/Imf+(s,0) (analyticity of the scattering amplitude via dispersion relations) constant/lns with s

Elastic Scattering- From ISR to Tevatron ~1.5 GeV2

Elastic Scattering- Models (e.g. Islam et al.) large impact parameters- defines the region where inelastic diffraction occurs ”Reggeon” & ”soft Pomeron” single gluon exchange between valence quarks  1/t8 Observations: fwd diffraction cross section increases, diffractive peak shrinks interference dip moves to smaller t at –t  1 GeV2 ds/dt  1/t8 , little s dependence (Donnachie & Landshoff)  1/t8

Elastic Scattering-large t Possible effect of a hard Pomeron Elastic Scattering-large t 1-gluon exchange between the three valence quarks: each with a contribution 1/t2  1/t8!

Elastic Scattering- el/tot Rel = sel(s)/stot(s) Rdiff = [sel(s) + sSD(s) + sDD(s)]/stot(s) 0.30 0.375 sel  30% of stot at the LHC ? sSD + sDD  10% of stot (= 100-150mb) at the LHC ?

Experimental apparatus T1: 3.1 < h < 4.7 T2: 5.3 < h < 6.5 T1 T2 CASTOR (CMS) RP1 (147 m) RP2 (180 m) RP3 (220 m)

T1 telescope Support 1 arm 5 planes with measurement of three coordinates per plane. 3 degrees rotation and overlap between adjacent planes Primary vertex reconstruction Trigger with CSC wires 1 arm Support

Castor Calorimeter(CMS) GEM Telescope: 8 planes 13500 mm from IP T2 Telescope 5.3< lhl < 6.5 Vacuum Chamber 1800 mm 400 mm Bellow Castor Calorimeter(CMS) T2 GEM Telescope: 8 planes 13500 mm from IP

T2: telescope 8 triple-GEM planes, to cope with high particle fluxes 5.3<||<6.6 54(j) x 22(h) = 1536 pads Pads: Dh x Dj = 0.06 x 0.018p ~2x2 mm2 __ ~7x7 mm2 Strips: 256 (width: 80 mm,pitch: 400 mm) Digital r/o pads Technology used in COMPASS pads strips Analog r/o circular strips

GEM for the T2 Telescope Totem GEM Final Design 2005 TOTEM GEM Prototype 2004 Full Telescope Mock up pads strips

Prototypes of all three detectors tested in X5 test beam in 2004 CSC RP GEM

Planar with 3D edges TRADITIONAL PLANAR DETECTOR + DEEP ETCHED EDGE FILLED WITH POLYSILICON p + Al E-field 13keV 6 mm X-ray beam Insensitive edge = 5 + 2 mm Leakage current = 6 nA at 200V n + Al n + Al

Edgeless Silicon Detectors for the RPs Add here photo of RP Active edges: X-ray measurement 150 mm Signal [a.u.] 5mm dead area Strip 1 Strip 2 Planar technology: Testbeam 40 m dead area 66 mm pitch Detector 1 Detector 2 10 mm dead area 50 mm dead area active edges (“planar/3D”) planar technology CTS (Curr. Termin. Struct.)

TOTEM ROMAN POT IN CERN SPS BEAM

Roman Pot Assembly of Silicon Detectors for the SPS test beam BPM reconstructed track Tracks Roman Pot unit (Final Design) : -Vertical and horizontal pots mounted as close as possible -BPM fixed to the structure gives precise position of the beam -Final prototype at the end of 2005 BPM

 functions at the LHC for *=0.5 m

TOTEM Optics Conditions LTOTEM ~ 1028 cm-2 s –1 TOTEM needs special/independent short runs at high-b* (1540m) and low e Scattering angles of a few mrad High-b optics for precise measurement of the scattering angle s(q*) = e / b* ~ 0.3 mrad As a consequence large beam size s* =  e b* ~ 0.4 mm Reduced number of bunches ( 43 and 156 ) to avoid interactions further downstream Parallel-to-point focusing ( v=0) : Trajectories of proton scattered at the same angle but at different vertex locations y = Ly qy*+ vy y* L = (bb*)1/2 sin m(s) x = Lx qx *+vx x*+x Dx v = (b/b*)1/2 cos m(s) Maximize L and minimize v

L (m) v High b optics ( 1540 m ): lattice functions v= (b/b*)1/2 cos m(s) L = (bb*)1/2 sin m(s) L (m) Parallel to point focusing in both projections v

Elastic Scattering b* = 1540 m acceptance

Elastic Scattering: Resolution t-resolution (2-arm measurement) f-resolution (1-arm measurement) Test collinearity of particles in the 2 arms  Background reduction. f correlation in DPE

Elastic Cross section (t=0) Beam offset (20 mm) Energy offset (0.1%) Beam offset (100 mm) Statistical error L dt=4 1032 cm-2 tmax = 0.1 GeV2 Uncertainty Fit error Beam divergence 10% -0.05% Energy offset 0.1% -0.25% 0.05% -0.1% Beam/ detector offset 100mm -0.32/-0.41 % 20mm -0.06/-0.08 % Crossing angle 0.2mrad -0.08/-0.1% Theoretical uncertainty (model dependent) ~ 0.5%

1% Accuracy of s tot Trigger Losses (mb) (sinel.~80mb, sel.~30mb) Double arm Single arm After Extrapolation Minimum bias 58 0.3 0.06 Single diffractive 14 - 2.5 0.6 Double diffractive 7 2.8 0.1 Double Pomeron 1 0.02 Elastic Scattering 30 Inelastic error t=0 extrapol. error Vertex extrapolation simulated extrapolated Acceptance detected

Possibilities of r measurement Try to reach the Coulomb region and measure interference: move the detectors closer to the beam than 10  + 0.5 mm run at lower energy √s < 14 TeV

CMS + TOTEM: Acceptance largest acceptance detector ever built at a hadron collider 90% (65%) of all diffractive protons are detected for b* = 1540 (90) m Total TOTEM/CMS acceptance CMS central T1 HCal T2 CASTOR b*=90m RPs b*=1540m ZDC Roman Pots TOTEM+CMS T1,T2 Charged particles dNch/dh dE/dh Energy flux Pseudorapidity:  = ln tg /2

min. bias, soft diffraction Semi-hard diffraction Running Scenarios Scenario Physics: 1 low |t| elastic, stot , min. bias, soft diffraction 2 Semi-hard diffraction 3 hard diffraction large |t| elastic (under study) b* [m] 1540 90 N of bunches 43 156 936 N of part. per bunch 0.3 x 1011 1.15 x 1011 Half crossing angle [mrad] 100 Transv. norm. emitt. [mm rad] 3.75 RMS beam size at IP [mm] 450 880 200 RMS beam divergence 0.29 0.57 2.4 Peak luminosity [cm-2 s-1] 1.6 x 1028 2 x 1029 ~ 2 x 1031

TOTEM Diffractive protons at *=1540 m Diffractive protons are log() log(-t) Diffractive protons are observed in a large -t range > 90% are detected -t > 2.5 10 -3 GeV2 10-8 <  < 0.1  resolution ~ few ‰

Diffractive proton detection at b* = 0.5 m > 2.5 % (mm) (mm) mm 420 (mm) (mm) mm Diffractive proton detection at b* = 0.5 m > 2.5 % (mm) (mm) log  log  log -t log -t

New optics b*= m Ly large (~270 m) To optimize diffractive proton detection at L=1031 in the “warm” region at 220m Lyy Lxx+vxx*+D =0 -2 10m (CMS) 30mm Ly large (~270 m) tmin = 3 x 10-2 GeV2 Lx ~ 0 q independent 10 beam Vertex measured by CMS ~ 65% of all diffractive protons are seen x determination with a precision of few 10 -4

Particle elongation (x) for Lx=0 and different x-values x(m) s(m)   Lx=0 Example at x=0.007 and different emission angles

TOTEM Preliminary =172 m:  resolution ~ 4 10-4 (preliminary) = 10-3 2 10-3 X220-x216 (mm) 2 2 TOTEM Preliminary (x220+x216)/2 (mm)

TOTEM Preliminary TOTEM Preliminary Diffractive protons at b*=172 m 420 Log(x) vs Log(-t (GeV2)) TOTEM Preliminary Log(x) vs Log(-t) TOTEM Preliminary

CMS/TOTEM Physics CMS / TOTEM detector ideal for study of diffractive and forward physics: almost complete rapidity coverage combined with excellent proton measurement Hard diffractive structure in Single and Double Pomeron Exchange Production of jets, W, J/y, heavy flavours, hard photons Double Pomeron exchange as a gluon factory Production of low mass systems (SUSY, c ,D-Y,jet-jet, …) Glue balls, … Higgs production ??? (Susy Higgs) Low - x dynamics Proton structure and multi-parton scattering Color transparency Parton saturation Forward physics particle and energy flow (relevant for cosmic ray interpretation) New forward phenomena: Centauros, DCC, gg physics

TOTEM+CMS Physics: Diffractive Events Measure > 90% of leading protons with RPs and diffractive system ‘X’ with T1, T2 and CMS. X Double Pomeron Exchange -Triggered by leading proton and seen in CMS -Central production of states X: X = cc, cb, Higgs, dijets, SUSY particles, ...

Diffraction M clean case to study gluon-gluon interactions Dh1 Example: Exchange of colour singlets (“Pomerons”)  rapidity gaps Dh Most cases: leading proton(s) with momentum loss Dp / p  x clean case to study gluon-gluon interactions gluon - gluon collider Dh1 M Dh2 Unlike minimum bias events: p Exchange of colour triplets or octets: Gaps filled by colour exchange in hadronisation  Exponential suppression of rapidity gaps: g, q g, q p P(Dh) = e-r Dh, r = dn/dh

Diffractive Deep Inelastic Scattering “Pomeron structure function” Q2 e xIP = fraction of proton’s momentum taken by Pomeron = x in Fermilab jargon b = Bjorken’s variable for the Pomeron = fraction of Pomeron’s momentum carried by struck quark = x/xIP g* xIP IP p p’ t F2D(4)  fIP (xIP,t) F2IP (b,Q2) Naively, if IP were particle: [Ingelman, Schlein] Flux of Pomerons “Pomeron structure function”

Test factorisation in pp events Factorisation of diffractive PDFs not expected to hold for pp, pp scattering – indeed it does not: jet b Normalisation discrepancy (x10) (depends on s [CDF, D0]) Hard scattering factorisation violated in pp (lots more evidence available) FDJJ (= F2D) ? (x =xIP) hard scattering LRG IP

Double Pomeron Exchange: Example Processes Single Diffraction: X p1 ds/dh proton:p2’ MX2 = x s diffractive system X rapidity gap P Dh =–ln p2’ hmin hmax p2 ln(2pL/pT) Measure leading proton ( x) and rapidity gap ( test gap survival). Double Pomeron Exchange: p1 p2 p2’ p1’ P diffractive system X proton:p2’ proton:p1’ rapidity gap hmin hmax X MX2 = x1 x2 s P Dh2=– ln x2 Dh1=– ln x1 Measure leading protons ( x1, x2) and compare with MX, Dh1, Dh2

Hard Diffractive Events Diffractive events with high pT particles produced M hard Double Pomeron Exchange Probing the hard structure of the Pomeron ET > 10 GeV Rates at L = 2 1029 cm-2 s-1 sincl ~1 mb 720/h sexcl ~ 7 nb 5/h M ( j1,j2) = 120 GeV Rates at L = 2 1031 cm-2 s-1 sexcl ~ 18 pb / M=10 GeV 30/day

Particle production in Double Pomeron Exchange Use the LHC as a clean gluon-gluon collider Quantum numbers are defined for exclusive particle production Gluonic states c , b , Higgs, supersymmetric Higgs,….. Clean gluon-gluon interactions

Exclusive Production by DPE: 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 Particle sexcl Decay channel BR Rate at 2x1029 cm-2 s-1 1031 cm-2 s-1 (no acceptance / analysis cuts) c0 (3.4 GeV) 3 mb [KMRS] g J/y  g m+m– p+ p– K+ K– 6 x 10-4 0.018 1.5 / h 46 / h 62 / h 1900 / h b0 (9.9 GeV) 4 nb [KMRS] g U  g m+m– < 10-3 0.07 / d 3 / d H (120 GeV) 0.1  100 fb assume 3 fb bb 0.68 0.02 / y 1 / y Higgs needs L ~ 1033 cm-2 s-1, i.e. a running scenario for b* = 0.5 m: trigger problems in the presence of overlapping events install additional Roman Pots in cold LHC region at a later stage

Exclusive Higgs production Standard Model Higgs 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 for m=3 GeV 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 H The b jet channel is possible, with a good understanding of detectors and clever level 1 trigger (need 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) If we see SM Higgs + tags - the quantum numbers are 0++ Phenomenology moving on fast See e.g. J. Forshaw HERA/LHC workshop

 and t distributions for 120 GeV Higgs (=90 m) input ExHume Proton acceptance 68% Detected protons at 220 m Uncertain predictions ! log  log -t Phojet Proton acceptance 63% log  log -t

Preliminary Totem Mass Acceptance in DPE (preliminary) 220 m 420 m ExHume Phojet =0.5 m ExHume Phojet Preliminary Totem = 90 m

Detection Prospects for Double Pomeron Events b* = 1540 m:  ~ 0.5% L  2.4 x 1029 cm-2 s-1 b* = 90 m:  ~ 4 10 -4 L ~ 0.2 1032 cm-2 s-1 b* = 0.5 m  ~ 0.2-0.6 ‰ L < 1033 cm-2 s-1 p1’ p1 P M2 = x1 x2 s Trigger via Roman Pots x > 2.5 x 10-2 Trigger via rapidity gap x < 2.5 x 10-2 P p2 p2’ Dy = – ln x ymax = 6.5 b* = 0.5 m dN/dy – ln x2 – ln x1 y p CMS CMS + TOTEM

Rate (kHz) at L= 10 32 Integrated QCD rate for events with at least two jets Integrated QCD rate for events with at least two jets and which satisfy the ‘loose’ RP condition R. Croft Luminosity Events / bx 25 nsec Rate at 40GeV (kHz) Reduction at 40 GeV 1x10^32 2.6 | 7e-3 371 1x10^33 3.5 26 | 4 6.5 2x10^33 7 52 | 14.5 3.6 5x10^33 17.6 130 | 73 1.8 Roman Pot trigger Effect of adding the ‘loosest’ RP condition in either 220m pot, on the total QCD dijet rate. Reduction in rate of around 370 at 40GeV. Caveat: 75 nsec bunch spacing at the LHC start

Mass resolution at 420 m and 420+220m Note: beam position accuracy 10 m 420m PHOJET Asym. 420+215 m 420m EXHUME

MSSM Higgs is the hope Examples: 1. mA = 130 GeV 2. mA = 100 GeV tan b = 30 tan b = 50 mA s x BR (A bb) 130 GeV 0.07 fb 0.2 fb mh s x BR (h bb) 122.7 GeV 5.6 fb 124.4 GeV 13 fb mH s x BR (H bb) 134.2 GeV 8.7 fb 133.5 GeV 23 fb 2. mA = 100 GeV tan b = 30 tan b = 50 mA s x BR (A bb) 100 GeV 0.4 fb 1.1 fb mh s x BR (h bb) 98 GeV 70 fb 99 GeV 200 fb mH s x BR (H bb) 133 GeV 8 fb 131 GeV 15 fb [from A. Martin] Comparison: SM with mH = 120 GeV: s x BR (H bb) = 2 fb

Proton structure at low x For rapidities above 5 and masses below 10 GeV  x down to 10-6 ÷ 10-7 Possible with T2 in TOTEM (calorimeter, tracker): 5 <  < 6.7 Proton structure at low-x: Parton saturation effects? Saturation or growing proton?

Colour Transparency Parton localisation? pT plane: Single diffraction: pp  p + 3j 10 GeV j1 j2 j3 p jet 1 (pT 1) jet 2 (pT 2) jet 3 (pT 3) g u d Example: 3 jets at 10 GeV polar jet angle ~ 4.3 mrad  h ~ 6.1 jet separation ~ 7 mrad  10 cm in T2 jet width ~ 0.3  3 mrad  0.4  4 cm in T2 Estimated cross-section , where one of the jets has pT > pT min 1 day at L = 2 x 1031 cm-2 s-1 with pT min = 10 GeV: 80  800 events

Integral flux of high energy cosmic rays Measurements of the very forward energy flux (including diffraction) and of the total cross section are essential for the understanding of cosmic ray events At LHC pp energy: 104 cosmic events km-2 year-1 > 107 events at the LHC in one day

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…

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

Photon - photon physics

Conclusions Measure total cross-section stot with a precision of 1 % L = ~1028 cm-2 s-1 with b* = 1540 m Measure elastic scattering in the range 10 -3 < t < 8 GeV 2 With the same data study of soft diffraction and forward physics: ~ 107 single diffractive events ~ 106 double Pomeron events With b* = 1540 m optics at L = 2  1029 cm-2 s-1 : semi-hard diffraction (pT > 10 GeV) With b* = 90 m optics (under study) at L ~ 0.2 1032 cm-2 s-1: hard diffraction and DPE Study of rare events (Higgs, Supersymmetry,…) with b* = 0.5 m using eventually detectors in the cold region (420m)  Detailed study of the structure of the proton and the parton interactions

Exclusive Central Diffraction The Pomeron has the internal quantum numbers of vacuum. Signature: 2 Leading Protons & 2 Rapidity Gaps p1’ p1 PP: C = +, I=0,... P: JP = 0+, 2+, 4+,... PP: JPC = 0++ P P Large mass objects O(1TeV) c: 10 6-7 events before decay b: 10 3-4 events before decay - a precursor to DPE Higgs, SUSY p2’ p2 2p  Gap Jet+Jet Gap diffractive system proton:p1’ hmin h hmax proton:p2’ rapidity gap rapidity gap hmin hmax Exclusive physics  Gluon factory  Threshold scan for New Physics