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Karsten Eggert CERN, PH Department on behalf of the TOTEM/CMS Collaboration Startup running of a combined CMS-TOTEM trigger LHC/HERA workshop, WG 4 (17.

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Presentation on theme: "Karsten Eggert CERN, PH Department on behalf of the TOTEM/CMS Collaboration Startup running of a combined CMS-TOTEM trigger LHC/HERA workshop, WG 4 (17."— Presentation transcript:

1 Karsten Eggert CERN, PH Department on behalf of the TOTEM/CMS Collaboration Startup running of a combined CMS-TOTEM trigger LHC/HERA workshop, WG 4 (17. Jan. 2005)

2 Optical Theorem T1:  3.1 <  < 4.7 T2: 5.3 <  < 6.5

3 > 90 % of all diffractive protons are detected 10 million min. bias events, including all diffractive processes, in a 1 day run with  * = 1540 m microstation at 19m ? RPs Total TOTEM/CMS acceptance (  * =1540m) 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 

4 Elastic Scattering  * = 1540 m acceptance

5 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

6 A > 95 % % Diffraction at high    Acceptance Resolution in  :  * = 1540 m:  (  ) = 5 x ( L  2.4 x cm -2 s -1 ) ~ 90 % of all diffractive protons are seen in the Roman Pots (assuming ).  * = 1540 m, RP at 220 m: Leading protons in diffraction characterized by t =  p 2  2 and  =  p / p

7 CMS / TOTEM : ideal detector to study diffractive and forward physics with proton measurements CMS / TOTEM : ideal detector to study diffractive and forward physics with proton measurements   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 Different running scenarios (  * = 1540, 172, 18, 0.5 m)

8 Running Scenarios ScenarioPhysics:1 low |t| elastic,  tot, min. bias, soft diffraction 2diffraction3 large |t| elastic 4 hard diffraction  * [m] N of bunches N of part. per bunch 0.3 x ( ) x x Half crossing angle [  rad] Transv. norm. emitt. [  m rad] RMS beam size at IP [  m] RMS beam diverg. [  rad] t 220 m [GeV 2 ] 2 x x t 220 m [GeV 2 ] Peak luminosity [cm -2 s -1 ] 1.6 x x x (1 -4) x 10 31

9 New optics    m L y large (~270 m) t min =2 x GeV 2 ~90% of all diffractive protons are seen L x ~ 0  independent Vertex measured by CMS   determination with a precision of few 10 -4

10 t min ~ 2 x GeV 2 10  beam

11 Conclusion on new optics (  *=172 m) - preliminary Luminosity of 4 x cm -2 s -1 About 90% of diffractive protons are seen in the RP at 220 m  resolution of few to  resolution of few  rad Future: more detailed studies on acceptance and resolution further optimization towards higher luminosity

12 Level-1 Trigger Schemes for min. bias physics p p p p p T1/T2 RP CMS Elastic Trigger: Signal: 500 Hz Background: 20 Hz Single Diffractive Trigger: Signal: 200 Hz Background: < 1 Hz ? (using vertex reconstruction in T1/T2) Double Diffractive Trigger: Signal: 100 Hz Central Diffractive Trigger: Signal: 10 Hz Background: 2 Hz Minimum Bias Trigger: Signal: 1 kHz Backgrounds under study! (L = 1.6 x cm -2 s -1 )

13 Runs with ~90% detection of diffractive protons  Initial several one day runs with  * = 1540 m and 43 bunches L = 1.6 x cm -2 s min. bias events / day 1000 events /  barn per day Trigger combinations:CMS min bias, Trigger combinations:CMS min bias, T1, T2, forward protons   * = 1540 m and 156 bunches   * = 1540 m and 156 bunches L = 2.4 x cm -2 s events / nbarn per day central diffraction: p left x p right x central activity single diffraction:(T1, T2, CMS forward cal.) left x p right heavy flavours, jets :low pt leptons, min jets   * = 172 m and 2808 bunches   * = 172 m and 2808 bunches L = 4 x cm -2 s events / nbarn per day Trigger combinations: low pt leptons, jets, diffr. protons

14 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.

15 High luminosity runs (  *=0.5m) with  >2.5% L = 0.5 x cm -2 s -1 Trigger condition 1: jets and leptons x p left x p right Trigger condition 2 : jets and leptons x p left x gap right define the trigger thresholds: 2 jets with pt > 40 GeV for the Higgs 2 large pt jets for high mass central diffraction

16 Totem acceptance Higgs event Characteristics: d  /dt &  min  min  for one side trigger with  max > 2.5% dN/dt  N/dt dN/d  min  N/d  min -t (GeV 2 )  min DPE PHOJET (M H = 120 GeV)  dN/dt  exp(6t)  should detect p’s down to   t < 1 GeV 2  acceptance?

17 dN/d  b max  N/d  b max dN/d  b max  N/d  b max  b max DPE PHOJET (M H = 120 GeV)  p max  0.02  p min   All the b-jets are confined within  5. Event Characteristics: Where do the decay b-jets go? Asymmetric pair of protons Symmetric pairs dominate Asymmetric pair of protons A typical – symmetric - pair of protons

18  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:   ~ few L ~ cm -2 s -1  * = 0.5 m:   ~ 1 ‰ L ~ cm -2 s -1 Detection Prospects for Double Pomeron Events In collaboration with CMS dN/dy – ln   – ln   y pp CMS CMS + TOTEM p1p1 p2p2 p2’p2’ p1’p1’ P M 2 =     s P  * = 0.5 m

19 Double Pomeron Exchange: Cross-Section [  from Pomeron trajectory  (t) = 1 +  +  ’ t ] x x x ~ 1 day (3), (4) L = 2x10 29, cm -2 s  DPE = 0.5 – 1 mb  (1–2) x 10 7 events per day at  * = 1540 m, L = 2 x cm -2 s -1 Events / GeV

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