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K.Eggert/CERN TOTEM Physics tot elastic scattering diffraction (together with CMS) Karsten Eggert CERN, PH Department on behalf of the TOTEM Collaboration / Politecnico di Bari and Sezione INFN Bari, Italy Case Western Reserve University Cleveland, Ohio,USA Institut für Luft- und Kältetechnik, Institut für Luft- und Kältetechnik, Dresden, Germany CERN,CERN, Geneva, Switzerland Università di Genova and Sezione INFN 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 XI th Int. Conf. on Elastic and Diffractive Scattering, Blois, France, May 2005 TOTEM TDR is fully approved by the LHCC and the Research Board

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

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K.Eggert/CERN Current models predict for 14 TeV: 90 – 130 mb Aim of TOTEM: ~ 1% accuracy Luminosity independent method: Total p-p Cross-Section COMPETE Collaboration : Optical Theorem COMPETE Collaboration fits all available hadronic data and predicts at LHC: [PRL (2002)]

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K.Eggert/CERN T1: 3.1 < < 4.7 T2: 5.3 < < 6.5 T1 T2 CASTOR (CMS) RP1 (147 m) RP2 (180 m) RP3 (220 m) Experimental apparatus

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K.Eggert/CERN T1 and T2 Telescopes ~3 m T1: Cathode Strip Chambers Compass APV hybrids 400 mm Castor Calorimeter (CMS) Vacuum Chamber T2: GEMs 2004 Test Beam in X5

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K.Eggert/CERN Roman Pot station with two units 4 m apart Roman Pot unit -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

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

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K.Eggert/CERN Running Scenarios ScenarioPhysics:1 low |t| elastic, tot, min. bias, soft diffraction 2 large |t| elastic 3diffraction4 hard diffraction (under study) * [m] N of bunches N of part. per bunch 0.3 x x ( ) x x Half crossing angle [ rad] Transv. norm. emitt. [ m rad] RMS beam size at IP [ m] RMS beam diverg. [ rad] Peak luminosity [cm -2 s -1 ] 1.6 x x x ~

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K.Eggert/CERN TOTEM Optics Conditions High- optics for precise measurement of the scattering angle * ) = / * ~ 0.3 rad As a consequence large beam size * = * ~ 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 L TOTEM ~ cm -2 s –1 * 1540m and low TOTEM needs special/independent short runs at high- * 1540m and low Scattering angles of a few rad y = L y y * + v y y * L = ( ) 1/2 sin (s) x = L x x * +v x x * + D x v = ( ) 1/2 cos (s) Maximize L and minimize v

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K.Eggert/CERN v= ( ) 1/2 cos (s) L = ( ) 1/2 sin (s) High optics ( 1540 m ): lattice functions L (m) v Parallel to point focusing in both projections

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K.Eggert/CERN Elastic Scattering * = 1540 m acceptance

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

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K.Eggert/CERN Elastic Cross section (t=0) Uncertainty Fit error Beam divergence 10% -0.05% Energy offset 0.1% -0.25% 0.05% -0.1% Beam/ detector offset 100 m -0.32/-0.41 % 20 m -0.06/-0.08 % Crossing angle 0.2 rad -0.08/-0.1% Theoretical uncertainty (model dependent) ~ 0.5% Beam offset (20 m) Energy offset (0.1%) Beam offset (100 m) Statistical error L dt= cm -2 t max = 0.1 GeV 2

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K.Eggert/CERN Extrapolation uncertainty due to Coulomb interference Change of the slope B Coulomb interference Extrapolation to t=0 model dependent Error < 0.5 % d /dt ~ exp( -Bt)

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K.Eggert/CERN Accuracy of tot ( inel.~80mb, el.~30mb) (mb) Double arm Single arm After Extrapolation Minimum bias Single diffractive Double diffractive Double Pomeron Elastic Scattering Trigger Losses (mb ) Acceptance Vertex extrapolation simulated extrapolated detected Inelastic error t=0 extrapol. error

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K.Eggert/CERN Try to reach the Coulomb region and measure interference: move the detectors closer to the beam than 10 mm run at lower energy √s < 14 TeV Possibilities of measurement

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K.Eggert/CERN Elastic Scattering Cross-Section diffractive structure Photon - Pomeron interference pQCD * = 1540 m L = 1.6 x cm -2 s -1 (1) * =18 m L = 3.6 x cm -2 s -1 (2) pp 14 TeV BSW model Multigluon (“Pomeron”) exchange e – B |t| -t [GeV 2 ] t p 2 2 d /dt [mb / GeV 2 ] ~1 day (1) (2) wide range of predictions 10 4 per bin of GeV 2

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K.Eggert/CERN > 90 % of all diffractive protons are detected 10 million min. bias events, including all diffractive processes, in a 1 day run with * = 1540 m CMS+TOTEM: largest acceptance detector ever built at a hadron collider Roman Pots TOTEM+CMS T1,T2 Roman Pots Charged particles Energy flux CMS + TOTEM: Acceptance dN ch /d dE/d Total TOTEM/CMS acceptance ( * =1540m) RPs =172m (prelim.)

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K.Eggert/CERN CMS/TOTEM Physics CMS/TOTEM Physics CMS / TOTEM detector ideal for study of diffractive and forward physics Soft and hard diffraction in Single and Double Pomeron Exchange production of jets, W, J/ , heavy flavours, hard photons Excellent proton measurement: gap survival Double Pomeron exchange as a gluon factory Production of low mass systems (SUSY, ,D-Y,jet-jet, …) Glue balls, … Higgs production ??? Structure functions (parton saturation) with and without detected protons Forward physics: DCC, particle and energy flow physics

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

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K.Eggert/CERN Running Scenarios ScenarioPhysics:1 low |t| elastic, tot, min. bias, soft diffraction 2 large |t| elastic 3diffraction4 hard diffraction (under study) * [m] N of bunches N of part. per bunch 0.3 x x ( ) x x Half crossing angle [ rad] Transv. norm. emitt. [ m rad] RMS beam size at IP [ m] RMS beam diverg. [ rad] Peak luminosity [cm -2 s -1 ] 1.6 x x x ~

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K.Eggert/CERN TOTEM log( ) log(-t) Diffractive protons are observed in a large -t range > 90% are detected -t > GeV < < 0.1 resolution ~ few ‰ Diffractive protons at *=1540 m

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K.Eggert/CERN Diffractive proton detection at 0.5 m > 2.5 % mm log log -t 420 (mm) log -t log

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K.Eggert/CERN New optics m L y large (~270 m) t min =2 x GeV 2 L x ~ 0 independent Vertex measured by CMS determination with a precision of few To optimize diffractive proton detection at L=10 32 in the “warm” region at 220m LyyLyy L x x +v x x + D = m (CMS) 30mm ~ 65% of all diffractive protons are seen 10 beam

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K.Eggert/CERN Diffractive protons at =172 m Log( ) vs Log(-t) TOTEM Preliminary Log( ) vs Log(-t) TOTEM Preliminary 420

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K.Eggert/CERN Conclusion on new optics ( *=172 m) - preliminary Luminosity of 0.5 x cm -2 s -1 About 65% of diffractive protons are seen in the RP at 220 m resolution of resolution of few rad Future: more detailed studies on resolution further optimization towards higher luminosities

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K.Eggert/CERN Example Processes P p1p1 p2p2 p2’p2’ X d /d proton:p 2 ’ diffractive system X rapidity gap = – ln min 0 ln(2p L /p T ) max Measure leading proton ( and rapidity gap ( test gap survival). Single Diffraction: 2 =– ln 1 =– ln p1p1 p2p2 p2’p2’ p1’p1’ P M X 2 = s P X diffractive system X proton:p 2 ’ proton:p 1 ’ rapidity gap min max Double Pomeron Exchange: Measure leading protons ( 1, 2 ) and compare with M X, 1, 2 M X 2 = s

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K.Eggert/CERN Exclusive Central Diffraction The Pomeron has the internal quantum numbers of vacuum. PP : C = +, I=0,... P : J P = 0 +, 2 +, 4 +,... PP : J PC = 0 ++ Gap Jet+Jet p1p1 p2p2 p2’p2’ p1’p1’ P P diffractive system proton:p 2 ’ proton:p 1 ’ rapidity gap min max min max Signature: 2 Leading Protons & 2 Rapidity Gaps Exclusive physics Gluon factory Threshold scan for New Physics Large mass objects O(1TeV) c : events before decay b : events before decay - a precursor to DPE Higgs, SUSY

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K.Eggert/CERN Exclusive Production by DPE: Examples Advantage: Selection rules: J P = 0 +, 2 +, 4 + ; C = +1 reduced background, determination of quantum numbers. Good resolution in TOTEM: determine parity: P = (-1) J+1 d /d ~ 1 +– cos 2 Particle excl Decay channel BR Rate at 2x10 29 cm -2 s -1 Rate at cm -2 s -1 (no acceptance / analysis cuts) c0 (3.4 GeV) 3 b [KMRS] J/ + – + – K + K – 6 x / h 46 / h 62 / h 1900 / h b0 (9.9 GeV) 4 nb [KMRS] + – < / d 3 / d H (120 GeV) 0.1 100 fb assume 3 fb bb / y 1 / y Higgs needs L ~ cm -2 s -1, i.e. a running scenario for = 0.5 m: try to modify optics locally, try to move detectors closer to the beam, install additional Roman Pots in cold LHC region at a later stage.

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K.Eggert/CERN y = – ln y max = 6.5 Trigger via Roman Pots > 2.5 x Trigger via rapidity gap < 2.5 x * = 1540 m: ~ 0.5% L 2.4 x cm -2 s -1 * = 172 m: ~ L ~ cm -2 s -1 * = 0.5 m: ~ ‰ L ~ cm -2 s -1 Detection Prospects for Double Pomeron Events dN/dy – ln – ln y pp CMS CMS + TOTEM p1p1 p2p2 p2’p2’ p1’p1’ P M 2 = s P * = 0.5 m

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K.Eggert/CERN ExHume Phojet log -t log input and t distributions for 120 GeV Higgs Proton acceptance 68% Proton acceptance 63% Detected protons at 220 m

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K.Eggert/CERN ExHume Phojet Mass Acceptance in DPE (preliminary) =172 m =0.5 m 220 m 420 m m ExHume Phojet Totem Preliminary

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K.Eggert/CERN 420m PHOJET Asym m 420m EXHUME Mass resolution at 420 m and m Note: beam position accuracy 10 m

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K.Eggert/CERN p1p1 p2p2 p2’p2’ p1’p1’ P M X 2 = s P X DPE cross-sections =1540 m ∫ L dt = 40 nb -1 3days =172 m ∫ L dt = 10 pb -1 3days c0 3 b x BR(10 -3 ) ~ 3 nb b0 4nb x BR(10 -3 ) ~ 4 pb pp pXp ~ mb pp p j 1 j 2 p pt jet >10 GeV inclusive ~ 1 b exclusive ~ 7 nb jet-jet background to the Higgs: pp p j 1 j 2 p M(j 1 j 2 ) = 120 GeV exclusive ~ 18 pb / M= 10 GeV (Eur. Phys. J.C25,391)

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K.Eggert/CERN

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Conclusions Measure total cross-section tot with a precision of 1 % L = ~10 28 cm -2 s -1 with * = 1540 m Measure elastic scattering in the range < t < 8 GeV 2 With the same data study of soft diffraction and forward physics: ~ 10 7 single diffractive events ~ 10 6 double Pomeron events With * = 1540 m optics at L = 2 cm -2 s -1 : semi-hard diffraction (p T > 10 GeV) With * = 170 m optics (under study) at L ~ cm -2 s -1 : hard diffraction and DPE Study of rare events (Higgs, Supersymmetry,…) with * = 0.5 m using eventually detectors in the cold region (420m) TOTEM and CMS will write a common physics LOI in 2005

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K.Eggert/CERN

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Diffraction Exchange of colour singlets (“Pomerons”) rapidity gaps Most cases: leading proton(s) with momentum loss p / p P( ) = e - , = dn/d p p g, q Exchange of colour triplets or octets: Gaps filled by colour exchange in hadronisation Exponential suppression of rapidity gaps: p p p p P P Unlike minimum bias events: Example:

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K.Eggert/CERN Optical Theorem T1: 3.1 < < 4.7 T2: 5.3 < < 6.5

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K.Eggert/CERN Determination of the emission angle via the measurement at RP-147 m x (147 m) precision ~ few rad

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K.Eggert/CERN Measurement of tot Measurement of the total cross section with the luminosity independent method using the Optical Theorem. Measurement of the elastic and inelastic rate with a precision better than 1%.

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K.Eggert/CERN Particle elongation (x) for L x =0 and different -values Lx = 0 x(m) s(m) Example at =0.007 and different emission angles L x =0 LxLx

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K.Eggert/CERN X 220 -x 216 ( m) (x 220 +x 216 )/2 (mm) 22 22 =172 m: resolution ~ (preliminary) TOTEM Preliminary =

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K.Eggert/CERN Detector Layout y(mm) x(mm) Leading diffractive protons seen at different detector locations ( * = 0.5m) 215m300m 420m Dispersion D = 0.08 m D=0.7m D=1.5m

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