The TOTEM experiment Status and upgrade project Nicola Turini

 CHALLENGE TOTEM has interface to CMS and LHC  T1 & T2 integrated in CMS  Roman Pot integrated in LHC T1 5 planes of CSC Chambers (wire & cathode strips T2 10 planes of GEM Chambers (pads&strips) Roman Pot: detector enters inside the LHC beam tube Protons are transported in LHC beam-pipe from IP 5 to the Roman Pot stations 2 ρ parameter from Compete fit

Aprile 2012: Engineering Run (Allineamento RPs) - Trigger CMS<>TOTEM - Sincronizzazione Dati OK Maggio 2012: Run basso pile-up, 8M eventi (RPs non inserite), scambio di triggers: TOTEM -> CMS: trigger menu -> TOTEM, entrambi gli esperimenti hanno registrato gli stessi eventi. Analisi in corso. CMS trigger con RPs ora possibile grazie a nuovo trigger elettrico (entro latency L1 CMS) + grande copertura CMS+T1+T2 (- 6.5 <  < +6.5) – dN ch /d  su completo range con stesso min. bias trigger – sezione d’urto inelastica – rapidity gap – jets – underlying event – energy flow nella regione in avanti – central, single diffraction: trigger – CMS jets + TOTEM RPs: 1 o 2 protoni 3

Run speciali nel 2012 Run  *=0.6m, low pileup ottenuto separando i due fasci con CMS: Rp non inserite solo studio del dN/d  Run  *=0.6m, alta intensità ~1400 bunches, standard injection + CMS: Solo RP orizzontali inserite e rivelatori inelastici off:  >2/3 %, ogni t accessibile Alta luminosità, masse relativamente alte accessibili Run  *=90m, 112 bunches, pileup~0.05 Totem + CMS Accettanza per i protoni per ogni , |t|>0.02 GeV2 Soft, medium, hard diffraction elastic and total cross section Run  *=1000m, 2/3 bunches: Low t elastic scattering Determinazione del parametro  Run Pa, RP lato protoni inserite e rivelatori inelastici + CMS: Scattering protoni Ultra Periferic interactions.

TOTEM ha pubblicato a √s = 7 TeV : 1) scattering elastico (dati 2010) EPL 95 (2011) 41001, 2) sezione d’urto totale p-p (dati 6/2011) EPL 96 (2011) 21002, 3) forward charged particle pseudorapidity density (dati 5/2011) EPL 98 (2012)  Dal run speciale a  *=90m di Ottobre 2011 (RPs a 4.8  beam ) sono in preparazione 3 pubblicazioni: Analisi dati 2010/2011

P1. Measurement of proton-proton elastic scattering and total cross-section New elastic differential cross-section measurement down to t-values of GeV 2 Compared to our previous publication EPL96: – 15 x higher statistics – |t| min ~ GeV 2 91% of cross-section observed (only 67% before)

7 P2. Measurement of the inelastic pp cross-section Tracks in both arms: Non-diffractive minimum bias & double diffraction Tracks in one arm: Mainly single diffraction w ith M X >3.4 GeV/c 2 After corrections for trigger efficiency (2.3%), track reconstruction efficiency (1%), beam-gas bkgd (0.5%), pile-up (1.5%): After corrections for non visible events (Tracks in T1 & T2 empty), Rapidity gap covering T2: Several models studied, correction for low mass diffraction based on QGSJET-II-4 ~ 3.7% ± 2% (syst), imposing observed 2hemisphere/1hemisphere event ratio & taking into account seen “secondaries”  inelastic, T2 visible = 69.7 ± 0.1 (stat) ± 0.7 (syst) ± 2.8 (lumi) mb  inelastic, T2 visible  inelastic, |  |<6.5  inelastic,|  |<6.5 = 71.0 ± 0.1 (stat) ± 0.7 (syst) ± 2.8 (lumi) mb  inelastic,  <6.5  inelastic  inelastic = 73.7 ± 0.1 (stat) ± 1.7 (syst) ± 2.9 (lumi) mb

8 P3. Luminosity-independent measurements of total, elastic and inelastic cross-sections C omplementary measurements: to control and reduce systematic effects to remove dependence on luminosity to remove dependence on the  parameter Proton-Proton 4 Methods 1.Low_L(CMS) + Elastic + Optical T. depends on CMS luminosity for low-L bunches & elastic efficiencies &  2.High_L(CMS) + Elastic + Optical T. checks the CMS luminosity for high-L vs low-L bunches 3.High_L(CMS) + Elastic + Inelastic minimizes dependence on elastic efficiencies and no dependence on  4.(L-independent) + Elastic + Inelastic + Optical T. eliminates dependence on luminosity    =  EL +  INEL

   = 98.3 mb ± mb    = 98.6 mb ± mb    = 99.1 mb ± 4.3 mb    = 98.1 mb ± mb pp Total √s=7TeV

Diffractive forward RPs Dispersion shifts diffractive protons in the horizontal direction Low  * : 0.5 – 2 m  * = 90 m For low-  * optics L x, L y are low v x, v y are not critical because of small IP beam size L x =0, L y is large beam  = 212 µm → v x, v y important (deterioration of rec. resolution)

Upgrade Program during LS1 (High beta special runs) The baseline Upgrade program is a consolidation of the present hardware towards the repetition of the present measurements at higher energies. – RP overhauling + spare production (no radiation damage seen till now) – T1 overhauling (some VFAT replacement) – T2 some electronics development to ensure a better functionality. – DAQ some electronics development to have a simpler and efficient system.

T1 The detector have to be removed and put on surface in a controlled area. We need the gas flow in the detector. Some VFAT has been damaged and have to be replaced Some power problem seen at higher track multiplicity have to be investigated and solved

T2 The front-end card, named 11 th card, have to be redone. The present one (4 in total) is very complicated and in a technology (multiwire) that is giving troubles (lines that disconnect with time) The actual signal cables have to be removed (8% of broken lines) and a simpler and closer to the detector data transmission card have to be produced A new HV divider have to be produced. – Faster electron collection with different voltage gaps between and on the GEM foils – Some gain limitation at higher track multiplicity have to be solved

DAQ Currently the DAQ is performed in four different VME crates to ensure enough bandwidth. We foresee a simpler system with one crate (SRS) directly connected via Ethernet to the central DAQ computer. For common CMS-Totem runs a complete integration in their system is under development (Slink -> FRL).

OptoRX + SRS Inteface DAQ Upgrade

High luminosity program Low Beta runs The major problem is the large pileup that is mixing up different elastic and inelastic processes in one event The possibility to get the primary vertex tag in the forward region is possible only trough TOF measurements. We are starting an R&D program to find out the best hardware to ensure enough time resolution in the Horizontal Pots to disentangle the primary vertexes (10 ps resolution). – Cherenkov – APD – SiPm Fast TDCs and/or Sampler under investigation.

High luminosity program Low Beta runs Multiple track reconstruction due to the pileup – Si Pixel – 3D – More planes Radiation damage – 3D – P over N silicon strips

Totem + CMS The present upgrade proposal is a major project that requires the collaboration of CMS and TOTEM groups. The joint effort between the two collaborations is under discussion. Some step has already been done towards a common project.

TOTEM Roman Pots installed at LHC Separation of high LHC vacuum from detector vacuum RP mother board Secondary vacuum ~ 20mbar Temp : C Roman Pot unit with motor system (step size: 5 µm) Roman Pot parking position Roman Pot data taking position LHC beam-pipe Typical beam size: 540 µm / 850 µm RP mother board: interface Si- detectors to outside world: Signal, Trigger,HV,LV Hosts Radmon sensor and PT

220m Pots New Horizontal Pots stations are under evaluation

220m Pots New Collimator in front of Q6

Inelastic detector with ToF We are investigating the possibility to insert ToF planes in the T2 region. We can disentangle primary vertexes from ToF measurement of primary particle (selected with the present algorithm and spatial resolution) The same hardware used in the Pots stations can be assembled in front of T2 Possible to recover double arm vertex position combining Pots and T2 ToF information.

Backup

Towards a CMS – TOTEM Upgrade synergy

Event display N=20 (assuming independent Vtx-reco and the current T2-track resolution) - Tracking capability at high luminosity is assumed. - Reconstruction performed assuming no track overlap from different vertexes and using the default T2 reconstruction. -Only double arm events displayed -Primary event selection efficiency ~85%.

Single vertex spatial resolution (averaged peak-signal used)  Single vertex can be tagged with a good spatial resolution (~ 0.1 cm).