The TOTEM Experiment at the LHC  Physics program  Detector overview Giuseppe Latino (University of Siena & Pisa INFN) (on behalf of the TOTEM Collaboration) Rencontres de Moriond – QCD & HEI La Thuile – March 20, /16

CERN Large Hadron Collider (LHC) 2/16 TOTEM - Total Cross Section - Elastic Scattering - Diffractive Dissociation LHC - p-p collisions at  s =14 TeV - L inst up to ~ cm -2 s -1 - start up ~ Fall experiments Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC TOTEM Collaboration: Bari, Budapest, Case Western Reserve, CERN, Genova, Helsinki, Penn State, Pisa/Siena, Prague, Tallin (~ 80 physicists) Total and Elastic Measurement CMS TOTEM

T1 T2 Castor (CMS) T2 Castor (CMS) Leading protons: RPs at  147m and  220m Rap gaps & Fwd particle flows: T1 & T2 telescopes Fwd energy flows: Castor & ZDC (CMS) CMS T1 Leading Protons measured at +147m & +220m from IP Leading Protons measured at -147m & -220m from IP TOTEM Experiment TOTEM & IP5 3/16 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

TOTEM Physics Program Overview Stand-Alone -  TOT pp with a precision ~ 1-2%, simultaneously measuring: N el down to -t ~10 -3 GeV 2 and N inel with losses < 3% - Elastic pp scattering in the range < |t| ~ (p  ) 2 < 10 GeV 2 - Soft diffraction (SD and DPE) - Particle flow in the forward region (cosmic ray MC validation/tuning) 4/16 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC CMS-TOTEM (CMS/TOTEM Physics TDR, CERN/LHCC /G-124) - Soft and hard diffraction in SD and DPE (production of jets, bosons, h.f.) - Central exclusive particle production - Low-x physics - Particle and energy flow in the forward region

5/16 Total Cross Section  PP  Current models predict at  s = 14 TeV:  PP = mb  TOTEM goal: absolute error ~ 1mb ( L inst ~ cm -2 s -1 )  possibility to distinguish among different models  Luminosity independent method: - elastic scattering (down to |t| ~ GeV 2 ) - inelastic scattering  proper tracking acceptance in forward region required  COMPETE Coll. [PRL 89, (2002)] (~ ln 2 s ) Optical Theorem : Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

 t  p 2  2 Predicted at LHC:  el pp ~ mb Elastic Scattering Cross Section d  PP el /dt 6/16 (1)  * = 1540 m (typical L inst = 1.0 x cm -2 s -1 ): |t| min = GeV 2 (2)  * = 90 m (typical L inst = 1.0 x cm -2 s -1 ): |t| min = 0.04 GeV 2 Allowed |t| range depends on beam optics Wide range of predictions; big uncertainties at large |t|; whole |t| range measured with good statistics. Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC N Events/GeV 2 (BSW) Diffractive structure pQCD Photon - Pomeron interference   Multigluon (“Pomeron”) exchange  e – B |t| ~ 1 day (1) (2) Coulomb int.: CKL formula Dedicated short runs at high-  * (and reduced  ) are required for precise measurement of the scattering angles of a few  rad

Scenario Physics: 1 low |t| elastic,  tot ~1%), MB, soft diffr. 2 low/large |t| elastic,  tot ~5%), MB, soft/semi-h. diffr. 3 large |t| elastic, hard diffraction  * [m]  0.5 N of bunches 43   2808 Bunch spacing [ns] 2025  N of part. per bunch (0.6  1.15) x x Half crossing angle [  rad] 0092 Transv. norm. emitt.  n [  m rad] RMS beam size at IP [  m] RMS beam diverg. at IP [  rad] Peak Luminosity [cm -2 s -1 ]  2 x x Running Scenarios 7/16 Accessible physics depends on luminosity &  *  Optimal  * = 1540m optics requires special injection optics: probably NOT available at the beginning of LHC  ‘Early’  * = 90m optics achievable using the standard LHC injection optics  * ( m) L (cm -2 s -1 ) TOTEM runs Standard runs Cross section Luminosity beam ang. spread at IP:   * =  /  * ) beam size at IP:  * =  (  *) Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Combined Uncertainty in  tot 8/16  * = 90 m 1540 m  Extrapolation of elastic cross-section to t = 0: ± 4 % ± 0.2 %  Total elastic rate (strongly correlated with extrapolation): ± 2 % ± 0.1 %  Total inelastic rate: ± 1 % ± 0.8 % (error dominated by Single Diffractive trigger losses)  Error contribution from (1+  2 ): ± 1.2 % (using full COMPETE error band d  /  = 33 %) Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC  Total uncertainty in  tot including correlations in the error propagation :  * = 90 m : ± 5%  * = 1540 m : ± (1 ÷ 2) % Slightly worse in L (~ total rate squared) : ± 7 % (± 2 %) Precise Measurement with  * = 1540 m requires: improved knowledge of optical functions; alignment precision < 50  m  * = 90 m required for early  tot measurement during the first year of LHC running at  s = 10 TeV

CMS/TOTEM Common Physics Program CMS + TOTEM  largest acceptance detector ever built at a hadron collider: the large  coverage and p detection on both sides allow the study of a wide range of physics processes in diffractive interactions Charged particles Energy flux TOTEM+CMS dE/d  dN ch /d  Roman Pots T1,T2 Roman Pots LHC, inelastic collisions CMS 9/16 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC M M Double Pomeron Exchange Double Diffraction Single Diffraction Elastic Scattering ~ 60 mb mb mb mb mb << 1 mb

10/16 Early TOTEM Measurents ( p = 5 TeV,  * = 3m ) T1/T2 Charged multiplicity studies (min. bias and cosmic ray MC generators tuning/val.) Rapidity gap studies (topologies of diffr. events) NDSD DPE Roman Pots Sing. Diff. (horizontal RPs): d  SD /dM at high masses, 1.4 < M < 4.2 TeV,  (M)/M < 10 % DPE (horizontal RPs): d  DPE /dM at high masses, 0.2 < M < 1.8 TeV,  (M)/M < 10 % El. Scatt. (vertical RPs): d  ES /dt for 2 < |t| < 10 GeV 2,  (t)/t ~ 0.2/  |t| Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC Acceptance: 0.02 <  =  p/p < 0.18 Resolution:  (  ) ~ 1  6 · 10 -3,  (  ) ~ 15  rad

TOTEM Detectors: Setup in CMS CMS HF T1:  3.1 <  < 4.7 T2: 5.3 <  < 6.5 Inelastic Telescopes: reconstruction of tracks and interaction vertex; trigger capability with acceptance > 95 %  T1: mrad T2: mrad  = - log(tg(  /2))  ~14 m 10.5 mT1T2 Detectors on both sides of IP5 11/16 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC RP220 RP147 ZDC Elastic Detectors (Roman Pots): Elastic Detectors (Roman Pots): position of p scattered elastically at small angles Active area up mm from beam: 5-10  rad HF

Horizontal Pot: extend acceptance; overlap for relative alignment using common track. Absolute (w.r.t. beam) alignment from beam position monitor (BPM) Beampipes Roman Pots Each RP station has 2 units, 4m apart. Each unit has 2 vertical insertions (‘pots’) and 1 horizontal Units installed into the beam vacuum chamber allowing to put proton detectors as close as possible to the beam Protons at few  rad angles detected at 10  + d from beam (  beam ~ 80  m at RP)  ‘Edgeless’ detectors to minimize d Horizontal Pot Vertical Pot BPM 12/16 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

200  m thick beam Roman Pots Each Pot:  10 planes of Si detectors  512 strips at 45 o orthogonal  Pitch: 66  m  Total ~ 5.1K channels  Digital readout (VFAT): trigger/tracking  Resolution:  ~ 20  m Readout chip VFAT Edgeless Si detector: 50 μm of dead area Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC Integration of traditional Voltage Terminating Structure with the Current Terminating Structure 13/16 Detectors expected to work up to L int ~ 1 fb -1 Installation ongoing: RP220 (147) m fully (partially) equipped by June

Each arm:  5 planes with 3 coordinates/plane, each formed by 6 trapezoidal CSC detectors  3 degrees rotation and overlap between adjacent planes  Trigger with anode wires  Digital readout (VFAT) for ~ 13.5K ch.  Resolution:  ~ 1 mm T1 Telescope 3m Moriond QCD & HEI – March 20, /4 of T1 Ageing studies at CERN GIF: no loss of performance during 12-month test, with ~ 0.07 C/cm accumulated charge on wires, a dose equivalent to ~ 5 years at L inst =10 30 cm -2 s -1 Installation foreseen for May/June (if necessary also in September) G. Latino – The TOTEM Experiment at the LHC 14/16

Moriond QCD & HEI – March 20, 2009 Each arm:  10 planes formed by 20 triple-GEM semi-circular modules, with “back-to-back assembly and overlap between modules 15/16 Test Beam T2 Telescope pads strips Castor Calorimeter (CMS) ~ 0.4 m T2: “GEM” Technology GEM Technology:   Gas Detector   Rad-hard   High rate   Good spatial and timing resolution T2 Triple GEM technology adequate to work at least 1 yr at L =10 33 cm -2 s -1   Double readout layer: Strips for radial position (R); Pads for R,   Trigger from Pads (1560/chamber)  Digital readout (VFAT) for ~ 41.4K ch.  Resolution:  R ~ 100  m,   ~ 1 o Installation ongoing: fully done by May G. Latino – The TOTEM Experiment at the LHC

16  TOTEM will be ready for data taking at the LHC restart and will run under all beam conditions. and will run under all beam conditions.  Measurement of total pp cross-section (and L ) with a precision of 1-2% (2%) with  * = 1540 m (dedicated runs). of 1-2% (2%) with  * = 1540 m (dedicated runs).  Measurement of elastic scattering in the range < |t| < 10 GeV 2  Early measurements  low  *: - study of SD and DPE at high masses - study of SD and DPE at high masses - elastic scattering at high |t| - elastic scattering at high |t| - measurement of forward charged multiplicity - measurement of forward charged multiplicity   * = 90 m: - first measurement of  tot (and L ) with a precision of ~ 5% (~ 7%) - first measurement of  tot (and L ) with a precision of ~ 5% (~ 7%) - elastic scattering in a wide |t| range - elastic scattering in a wide |t| range - inclusive studies of diffractive processes - inclusive studies of diffractive processes - measurement of forward charged multiplicity - measurement of forward charged multiplicity  Later: common CMS/TOTEM Physics Programme Summary & Conclusions 16/16 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Backup Slides Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

 = fine structure constant  = relative Coulomb-nuclear phase G(t) = nucleon em form factor = (1 + |t|/0.71) -2  = Re/Im f(p  p) Measurement of the exponential slope B in the t-range GeV 2 needs beams with tiny angular spread  large  * Model dependent uncertainty due to Coulomb interferences Determination of d  /dt at t=0 B1 Coulomb scattering Nuclear scattering Coulomb- Nuclear interference BSW Very approximate formula: West and Yenneie model for Coulomb-Nuclear interference (  (t) = const) Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Try to reach the Coulomb region and measure interference: move the detectors closer to the beam than 10  mm run at lower √s < 14 TeV asymptotic behaviour:  1 / ln s for s    pred. ~ 0.13 at LHC Possibilities of  measurement La Thuile – March 1, 2008 G. Latino – The TOTEM Experiment at LHC B2

Details on Optics Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC B3  =  p/p ; t = t x + t y ; t i ~ -(p  i *) 2 (x *, y * ): vertex position at IP (  x *,  y * ): emission angle at IP Proton transport equation: x = L x  x * + v x x * + D  y = L y  y * + v y y * Optical functions: - L (effective length); - v (magnification); - D (machine dispersion) Describe the explicit path of particles through the magnetic elements as a function of the particle parameters at IP.  Define t and  range (acceptance) Example same sample of diffractive protons at different  * - low  *: p detected by momentum loss (  ) - high  *: p detected by trans. momentum (t y )

21 L = (  *) 1/2 sin(  (s))  Idea: L y large L x =0 v y = 0  y (220) =  /2  x (220) =  (parallel-to-point focussing on y)  (m)‏ hit distribution (elastic) x = L x  x * + v x x * +D  y = L y  y * + v y y * Optical Functions (  * = 90 m) v = (  /  *) 1/2 cos(  (s)) Optical functions: - L (effective length) - v (magnification) defined by  (betatron function) and  (phase advance); - D (machine dispersion)  describe the explicit path of particles through the magnetic elements as a function of the particle parameters at IP B4  =  p/p (x *, y * ): vertex position at IP (  x *,  y * ): emission angle at IP t = t x + t y t i ~ -(p  i * ) 2 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Detector distance to the beam: 10  +0.5mm -t = 0.01 GeV 2 -t = GeV 2 Beam  * = 1540 m  *=2 m  *=90 m log(-t / GeV 2 ) Acceptanc e Roman Pots Acceptances B5 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC Det. dist. 1.3 mm 6 mm   = 1540 m L = – 2 x % of all p seen; all    = 90 m L = – 3 x % of all p seen; all    = 0.5 – 2 m L = – p with  seen; all t  = 0.5m - 2m  resolved RP 220m Elastic Scattering (RP220)

Elastic Scattering Double Pomeron Double diffractive Single diffractive Minimum bias Uncertainty after Extrapolation (mb) Single arm T1/T2 Double arm T1/T2  (mb) Trigger Losses (mb): Acceptance simulated extrapolated detected Pythia generator Loss at low masses Total 0.8% Error on  B6 Measurement of  TOT at 1%  T /  T ~  [(0.006) 2 + (0.002) 2 + (0.012) 2 ] ~ Moriond QCD & HEI – March 20, 2009 Inelastic + Elastic Error Extrapolation t=0 Error

Forward Physics: VHE Cosmic Ray Connection B7 Interpreting cosmic ray data depends on hadronic simulation programs. Forward region poorly known/constr. Models differ by factor 2 or more. Need forward particle/energy measurements e.g. dN/d , dE/d  … Total multiplicity in T2 (5<  <7) p-p LHC as predicted by generators tipically used to model hadronic showers generated by VHE CR Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Expected Radiation Dose in CMS/TOTEM Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC B8 In 1 L inst = cm -2 s -1 At RPs locations =>

Planar technology with CTS (Current Terminating Structure ) 50 µm I2I2 I1I1 + - biasing ring Al p+p+ n+n+ cut edge current terminating ring Al SiO 2 n-type bulk p+p+ 50 µm AC coupled microstrips made in planar technology with novel guard-ring design and biasing scheme 50 μm of dead area B9 Si CTS Edgeless Detectors for Roman Pots bias gard/clean-up ring (CR) Integration of traditional Voltage Terminating Structure with the Current Terminating Structure Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

T1 Cathode Strip Chamber (CSC) B10 Cathode strips – 5mm pitch  Detector design similar to CMS CSC muon chamber  Gas Mixture Ar/CO 2 /CF 4  Max size: ~ 1m x 0.68 m  Gas gap: 10 mm  Anode wires:  30  m, 3mm pitch  Cathode strips: 4.5 mm width, 5mm pitch  Digital readout (VFAT) Ageing studies at CERN Gamma Irradiation Facility: no loss of performance during 12-month test, with ~0.07 C/cm accumulated charge on wires corresponding to a dose equivalent to ~ 5 years at L=10 30 cm -2 s -1 Anode wires – 3mm pitch Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Gas Electron Multiplier (GEM) 5 µm Cu 70 µm 55 µm 50 µm Kapton 70 µm 140 µm B11 Electrons Ions T2 GEM:  Developed at CERN (F. Sauli ~ 1997)  Used in COMPASS, LHCb, …  Gas Detector  “Rad-hard”, high rate, good spatial and timing resolution and timing resolution  Electrodes: 50  m kapton + 2x5  m Cu  Density: holes/mm 2  Electric field (channel) ~ 100 KV/cm (V gem = 500 V)  electron cascade (V gem = 500 V)  electron cascade  Gain: GEM Technology Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

T2 Triple-GEM Detectors HV Divider Gas in/out Cooling Digital R/O pads VFAT for Trigger 17 VFAT / module  pads strips 65(  ) x 24(  = 1560 pads Pads:  x  = 0.06 x   ~2x2 mm 2 - ~7x7 mm 2 Strips: 256x2 (width 80  m, pitch 400  m)  Ar/CO 2 70/30 gas mixture  Operating gas gain M = 8000  Digital readout (VFAT)  T2 Triple GEM technology adequate to work at least 1 yr at L=10 33 cm -2 s -1 B12 Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC

Totem Electronics VFAT Chip  Developed at CERN by the Micro- Electronics group  128 channels of tracking front- end with digital storage and data transmission  8 programmable trigger outputs  Designed for radiation tolerance B13 Standardization for all detectors: identical front-end electronics (VFAT chips); identical DAQ and trigger cards Moriond QCD & HEI – March 20, 2009 G. Latino – The TOTEM Experiment at the LHC