Total Cross Section Elastic Scattering and Diffraction Dissociation

Total Cross Section, Elastic Scattering and Diffraction Dissociation at the LHC Prime misure di TOTEM & stato dell’esperimento Stefano Lami INFN Pisa INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 1

Principali attivita` tecniche 2010 u u u u Presa dati in IP 5 : RP (220 m) + T 2 Produzione RP (147 m) + Test in H 8 T 1 Preparazione installazione in IP 5 (+/- side) (Tools, EDR, ESR, LHCC rev. ) T 1 Lavori d’installazione in IP 5 (7. 12. 2010) RP Installazione a 147 m (7. 12. 2010) T 2 Lavori di manutenzione (7. 12. 2010) INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 2

Presa dati 2010 Installato ora 3. 1 4. 7 Operativo nel 2010 Installate ora Operative nel 2010 5. 3 6. 5 L’ottima performance di DAQ & Trigger ha permesso: • Periodi di presa dati con RP a ~18 dai fasci, grandi t~3. 5 Ge. V 2 RP at 20 sigma • Special TOTEM Runs: • 21. 9. 2010 • RP “alignment” at 3. 5 Te. V to define a safe running condition with the pots as close as possible to the circulating beams • Short data taking (one pilot bunch) with RP to 7 • 30. 10. 2010 • Special run with 1 bunch (1 e 10 p/b) + 4 bunches x 7 e 10 p/b int. L 184 nb-1 18 sigma 3. 5 pb-1 7 sigma 9. 5 nb-1 (1 y( x) = 0. 42 (0. 19) mm @ β* = 3. 5 m) • 5 hours data taking for TOTEM • data with T 2 at reduced pile-up on mini-bunch crossing (~ 10 -2) INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 3

Prime misure di Scattering Elastico: il sistema delle Roman Pot scattering angle q Horizontal Pot Vertical Pot BPM INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 4

Tracce ricostruite (RP 220 raw distribution) Hit map (side 4, 5) - Coincidenze Left - Right |t|~p 2 *2 x = Dp/p * = at IP Lx~0 , vx, y small at 220 m for x 0 Reconstructed tracks in “left (45) AND right (56)” Elastic scattering in the vertical plane visible from raw data INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 5

Collinearity in x Low x, i. e. |x| < 0. 4 mm and 2 cut in Dqy* Compatible with the beam divergence (17 rad, for nominal = 3. 75 m rad) INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 6

Collinearity in y Low x, i. e. |x| < 0. 4 mm and 2 cut in Dqx* Compatible with the beam divergence INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 7

Preliminary t distribution ~ 84 K elastic scattering candidate events in ~ 9 nb -1 s = 7 Te. V * = 3. 5 m RPs @ 7 (V) and 16 (H) “Raw” distribution: 0. 7 Ge. V 2 - No smearing corrections - No acceptance corrections - No background subtraction Syst. error sources under study: alignment, beam position and divergence, background, optical functions, efficiency, … INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 8

Elastic Scattering - from ISR to Tevatron ISR ~ 1. 7 Ge. V 2 ~ 0. 7 Ge. V 2 ~1. 5 Ge. V 2 Diffractive minimum: analogous to Fraunhofer diffraction: |t|~p 2 q 2 • exponential slope B at low |t| increases • minimum moves to lower |t| with increasing s interaction region grows (as also seen from tot) • depth of minimum changes shape of proton profile changes • depth of minimum differs between pp, pˉp different mix of processes INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 9

Telescopio T 2 GEM telescopes for tracks and vertex reconstruction 5. 3<|h|<6. 5 Df=2 p T 2 trigger in “special run” • min-bias only on minibunch INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 10

Alcuni eventi ricostruiti da T 2 4 tks 5 tks 6 tks 8 tks 39 tks 46 tks INFN CSN 1 24. 01. 2011 4 tks 9 tks Stefano Lami, INFN Pisa - p. 11

Min. bias events and elastics in T 2 INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 12

Single diffraction low x INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 13

T 2 - Preliminary Data from 30/10/2010 TOTEM special run - trigger: min bias on mini-bunch only (~400 K inelastic events) Raw distribution including secondaries pointing to IP and no efficiency correction Work ongoing on unfolding corrections INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 14

Towards the Unfolding Corrections Preliminary study with PYTHIA + full GEANT detector simulation Work in progress on: - Understanding secondary contribution and smearing effects - Proper tuning of detector performance simulation - Optimization of track algorithm and selection cuts for improved rejection of secondary charged tracks HF HF - Estimate of systematic uncertainties INFN CSN 1 24. 01. 2011 IP 5 Beam Pipe cone at ~ 5. 54 (>100 radiation lengths) Stefano Lami, INFN Pisa - p. 15

Lavori durante lo Shutdown General installation schedule u T 1 – Installation of both arms n n n u T 2 – Service n n u Installation started on 7. 12. 2010 Minus side fully installed by 10. 01. 2011, Plus side by 14. 01. 2011 First tests OK, Commissioning with first data Work packages were integrated in T 1 installation schedule Priority given to T 1 installation RP (147 m) at 4/5 and 5/6 n n RP installation started on 7. 12. 2010, installed by end 2010 Calibration: main activity in 2011 INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 16

RP installation at 147 m during shutdown TOTEM has installed the last 12 detectors in the LHC tunnel (“ 147 m”) completing in this way the detectors installation u u u 12 detector packages have been produced, completely assembled by Nov 2010; final checks with particles were completed in H 8 All services for the RPs at 147 m were already installed. Installation in the tunnel completed by end 2010. Under test TIF INFN CSN 1 24. 01. 2011 H 8 Stefano Lami, INFN Pisa - p. 17

T 1 installation • Update on mechanical components (EDR with CMS held on June 2010) • Update on electrical components (ESR with CMS held on September 2010) • 30 Nov 2010: Final Installation Review with CMS • Installation at IP 5 (7. 12. 2010 – 21. 01. 2011) All issues have been monitored by TOTEM and CMS and followed up in close collaboration Detailed installation planning, required the presence of the T 1 /CMS team during Christmas break Schedule finalized with manpower from CERN & INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 18

Summary of main Review issues u TRUSS installation tool (Cantilever): new tool built, stress calculations, certificate (DGS-SEE) u u Transfer of T 1: from cage Survey: truss, successful for all 4 telescopes measurement of deformation during & after transfer, shimming u u u Leak test of cooling system Sensors (B, position) mounted Alignment system of CMS traversing T 1: checked all cables for possible interference u T 1 supported by cage Mock up simulating CMS-YE: measurement of clearance during/after transfer u Mock up simulates CMS-YE Electrical consolidation: Transfer rails IP side Al Truss shielding, grounding, low voltage connectors INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 19

Installazione T 1 lato ‘–’ 21/12/2010 Installazione del traliccio di supporto 22/12/2010 Posizionamento in piattaforma del rivelatore nelle gabbie di installazione 22 - 30/12/2010 Connessione temporanea ai servizi e test in piattaforma INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 20

Installazione T 1 lato ‘–’ 7/1/2011 10/1/2011 13/1/2011 INFN CSN 1 24. 01. 2011 Prova di inserimento dei due semibracci Inserimento del rivelatore, connessione finale servizi lato rivelatore Innalzamento piattaforma Stefano Lami, INFN Pisa - p. 21

Installazione T 1 lato ‘+’ 20 -30/12/2010 10/1/2011 11 - 12/1/2011 INFN CSN 1 24. 01. 2011 Installazione servizi (gas, raffreddamento, fibre ottiche) su YE 3+ Installazione traliccio di supporto Posizionamento in piattaforma del rivelatore nelle gabbie di installazione Connessione temporanea ai servizi e test in piattaforma Stefano Lami, INFN Pisa - p. 22

Installazione T 1 lato ‘+’ 13/1/2011 14/1/2011 20/1/2011 INFN CSN 1 24. 01. 2011 Prova di inserimento dei due semibracci (1 giorno di anticipo) Inserimento del rivelatore, connessione finale servizi lato rivelatore (1 giorno di anticipo) Innalzamento piattaforma Stefano Lami, INFN Pisa - p. 23

Test completo 21/1/2011 INFN CSN 1 24. 01. 2011 Connessione finale servizi e test completo sull’intero rivelatore (accensione e lettura di tutte le camere in run di rumore) Stefano Lami, INFN Pisa - p. 24

Test sul rivelatore - Ad ogni passo dell’installazione di ciascun braccio (T 1 in piattaforma, T 1 inserito, T 1 inserito e piattaforma sollevata) sono stati ripetuti i test sul rivelatore: Soglie per rumore < 5% (tutti i VFAT) • tenuta alta tensione; misure in H 8 (Nov 2010) misure dopo l’installazione • corretta lettura dei sensori; • presenza di tutti i canali di lettura e scan di soglia per il livello di noise - La corretta mappatura dei canali di DCS e DSS è stata verificata • • soglia (canali ADC) - A rivelatore inserito, un test congiunto con le CSC di CMS è stato effettuato da entrambi i lati: nessun contributo di rumore aggiuntivo riscontrato dai due rivelatori quando l’altro è acceso. INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 25

Detector Control System Durante i test, il controllo dello stato e delle operazioni del rivelatore è stato effettuato interamente utilizzando i pannelli del DCS di TOTEM INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 26

Posizione del rivelatore Le misure effettuate durante i test di inserzione hanno permesso di verificare il corretto posizionamento delle camere rispetto al tubo a vuoto di LHC e all’end-cap di CMS La posizione delle camere è costantemente mantenuta sotto controllo dai sensori di posizione INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 27

TOTEM Running Strategy for 2011 Understand the new optics and improve statistics at large t-values Repeat RP alignment at nominal conditions: approach the RP detectors to the sharp beam edges produced by the LHC collimators For regular running at closer approaches to the beams (~15 ) Low proton density bunches (~1 1010 p/b) Special runs with such bunches: Approach RP to ~ 5 to reach a minimum t of ~ 0. 2 Ge. V 2 Addition of one small bunch during normal low runs (if possible) Take data with T 1, T 2 at reduced pile-up (< 10 -2 ) Prepare the * = 90 m optics Measure the total cross-section and luminosity at 7 Te. V (small difference if running at 8 Te. V) Targets: • With *=90 m optics and RP close to the beams measure tot and el • Correlations between the forward proton and topologies in T 1 and T 2 with a rich programme on Single Diffraction and Double Pomeron exchange INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 28

Backup INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 29

Apparato Sperimentale Telescopi per Inelastico: T 1: 3. 1 < | | < 4. 7 T 2: 5. 3 < | | < 6. 5 CMS CSC Trackers GEM Trackers HF T 1 10. 5 m ~14 m T 2 RP 1 Roman Pots: RP 2 147 220 INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 30

T 1 Telescope with Cathode Strip Chambers (CSCs) 3 m CMS muon end-caps IP 3. 1 < |η| < 4. 7 • • INFN CSN 1 24. 01. 2011 T 1 7. 5 10 m. 5 m 5 planes with measurement of 3 coordinates per plane 3 deg rotation and overlap between adjacent planes Primary vertex reconstruction allows background rejection Trigger with anode wires Stefano Lami, INFN Pisa - p. 31

T 1 Telescope Both arms assembled and successfully tested with pion and muon beams in the test line H 8 Efficiency rec. hits (transverse plane) Pions on Cu target to get many-trk events CSC efficiencies with muons (triple coincidences) Longitudinal vertex reconstruction Vtx-X (z<1 m) Vtx-Y (z<1 m) Cu target x ~ 3 -4 cm z ~ 80 -90 cm y ~ 3 -4 cm Beam monitor frame INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 32

Hit profile in T 2 INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 33

T 2 Global Alignment and Vertex Reconstruction Before Align. rms=1. 4 cm rms=1. 7 cm rms=0. 8 cm rms=1. 0 cm rms=3. 1 m After Align. INFN CSN 1 24. 01. 2011 rms=2. 3 m Stefano Lami, INFN Pisa - p. 34

RP Alignment w. r. t. the Beam: Beam-Based Method Test done at 450 Ge. V and at 3. 5 Te. V using BLM (beam loss monitor) signal during special collimator/RP setup runs Collimator cuts a sharp beam edge symmetrically to the centre RP approaches this edge until it scrapes … … producing spike in BLM downstream The second RP approaches When both top and bottom pots “feel” the edge: they are at the same number of sigmas from the beam centre as the collimator and the beam centre is exactly in the middle between top and bottom pot Procedure repeated in different configurations, allowing safe insertion down to 18 (V) in standard runs and down to 7 (V) in special runs. (1 x ( y) = 0. 19 (0. 42) mm @ β* = 3. 5 m) INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 35

Prime misure di Scattering Elastico exponential region 7 Te. V Range della presa dati del 2010 * = 3. 5 m * = 1540 m * = 90 m squared 4 -momentum transfer t - p 2 2 INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 36

Hit map (side 5, 6) for left - right coincidences INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 37

Single diffraction large x INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 38

Double Pomeron Exchange INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 39

Stato dell’ Elettronica § For INSTALLATION & COMMISSIONING T 1 § Reviewed grounding and shielding by the TOTEM/CMS task force. § CABLING RP 147: quite a bit of work done § ELECTRICAL TRIGGER: on hold for the moment, would like to install sufficient amount to test correctly. § SPARE PARTS: § 5 new HOST boards received for TOTEM, 14 still in production in Israel. § Purchased from CMS 60 transmitters (GOH), (already had damage in a few Roman Pot due to special reset condition, and needed to carry out replacement) § Hybrids for Gas VFATs needed. INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 40

Total p-p cross-section • Current models predict for 14 Te. V: 90 – 130 mb Status of the art • Aim of TOTEM: ~ 1% accuracy Luminosity independent method Optical Theorem el • Misura concettualmente semplice ma…: ottica speciale ( * alto) + sistematica INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 41

Totem menu ~ 60 mb Elastic Scattering 18 - 35 mb 10 - 16 mb Single Diffraction M 4 - 14 mb Double Diffraction Double Pomeron Exchange M 0. 2 - 1. 5 mb << 1 mb INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 42

TOTEM Physics goals u TOTEM n TOTpp with a precision ~ 1%, simultaneously measuring: n Nel down to -t ~10 -3 Ge. V 2 l Ninel with losses < 3% Elastic pp scattering in the range 10 -3 < |t| ~ (p )2 < 10 Ge. V 2 Soft diffraction (SD and DPE) Particle flow in the forward region (cosmic ray MC validation/tuning) l n n u TOTEM & CMS n n 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 INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 43

Acceptance for Inelastic Events 5 Large uncertainties in inelastic cross sections: 4 • non-diffractive minimum bias (MB) 40 60 mb 3 • single diffraction (SD) 10 15 mb 2 • double diffraction (DD) 4 11 mb 1 Low multiplicities in diffraction PHOJET s = 7 Te. V T 2 T 1 T 2 h Accepted event fraction: Efficiency increases INFN CSN 1 24. 01. 2011 Stefano Lami, INFN Pisa - p. 44