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Forward Physics at the LHC. James L. Pinfold University of Alberta. The LHC Collider. The LHC Experiments. LHC ring ~26km in circ. 368 SC quads (B/L=223T/m L=3.1m). 1232 SC dipoles (B=8.33T, L=14.2m). C ryogenic system (1.8 K, sup er fluid He ) 27 km of 8T magnets 100 m below surface.
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Forward Physics at the LHC James L. Pinfold University of Alberta
The LHC Collider The LHC Experiments LHC ring ~26km in circ. 368 SC quads (B/L=223T/m L=3.1m) 1232 SC dipoles (B=8.33T, L=14.2m) Cryogenic system(1.8 K,super fluid He) 27 km of 8T magnets100 m below surface • SCHEDULE • March 2007: Last magnet installed & machine closed March 2007 • Nov. 2007: LHC commissioning run – 1st collisions at Eb =450 GeV) • 2008: First physics (starting in April) run 10 fb-1 L~ 1033 cm-2s-1 • 2009-10: Low luminosity run 20-70 fb-1 L ~10331034cm-2s-1 • 2011-17: High luminosity run at 100 fb-1/year L ~1034 cm-2s-1 James L. Pinfold TAHOE 2007 1
The LHC Experiments ATLAS • ATLAS & CMS Higgs physics, SUSY, EDs… QCD, Top Physics, Heavy-ions • LHCb CP Violation • ALICE Quark-Gluon Plasma • TOTEM Total pp x-section, forward physics • MoEDAL (LoI) Monopole search* • LHCF (LoI) Forward physics, prod. x-sect measurement # ALICE CMS LHCb James L. Pinfold TAHOE 2007 2
The ATLAS Detector Mass –7000 tons Length – 46 m Diameter – 25m Cost ~ 500 MCHF X-sec thru the barrel reveals the typical onion structure of A collider detector Inner Tracker – pixel, silicon strip, TRT 2T solenoidal field, good e/g ID, e/p sep, t/b tag Coverage in |h| - tracker < 2.5, cal < 4.9 LAr EM Calorimeter -- good e/g ID, energy & ETmiss resolution Muon spectrometer – air core toroids B.dl = 2-6Tm (4-8 Tm) James L. Pinfold TAHOE 2007 3
SUPERCONDUCTING COIL Total weight : 12,500 t Overall diameter : 15 m Overall length : 21.6 m Magnetic field : 4 Tesla Silicon Microstrips Pixels The CMS Detector CALORIMETERS ECAL HCAL Scintillating PbWO4 crystals Plastic scintillator/brass sandwich IRON YOKE TRACKER MUON ENDCAPS MUON BARREL Drift Tube ResistivePlate Cathode Strip Chambers (CSC) Chambers ( ) Resistive Plate Chambers (RPC) DTChambers( ) RPC James L. Pinfold TAHOE 2007 4
Status: ATLAS & CMS Detectors • Surface infrastructure in place. • Both detectors on track for first data taking in 2007 • Mostly complete detectors deployed for start. ATLAS Detector Contruction WebCam February 16th 2007 CMS gantry crane tested to 2500T James L. Pinfold TAHOE 2007 5
The LHC Collaborations CMS • ALICE: 30 countries, ~1000 physicists • LHCb: 15 countries, ~600 physicists • LHCf: 3 countries, 3 countries, ~22 physicists • TOTEM Collaboration: 8 countries, 12 Institutions, ~80 physicists 35 nations, ~160 institutions, ~1800 scientists 38 nations, ~174 institutions, ~2030 scientists James L. Pinfold TAHOE 2006 6 James L. Pinfold IVECHRI 2006 6
Astro-Collider Physics– the Synergies Direct Detection of Cosmic Rays in Collider Detectors (CosmoLEPCosmoLHC – so far ACORDE) Forward Collider Physics Few particles with low pT but very high energy (90% of eventrelevant to the understanding of HECR, etc. High PT Collider Physics Involving ETmiss, jet production, lepton ID, etc Relevant to Dark Matter, Extra Dimensions, etc. Astroparticle Physics & Cosmology James L. Pinfold TAHOE 2007 7
Collider & Cosmics Energy Spectrum • Proton-(anti)Proton cross-sections – important for measuring extended air shower development (EAS), every primary particle produces an EAS Knee (~1015eV) I particle/ (m2 year) Ankle(~1018 eV 1 particle/ (km2 century) James L. Pinfold TAHOE 2006 8
Forward Physics Program • Soft & Hard diffraction • Total cross section and elastic scattering (TOTEM, precision of O(1)%) • Gap survival dynamics, multi-gap events, odderon, etc. • Diffractive structure: Production of jets, W, J/, b, t, hard photons • Double Pomeron Exchange events as a gluon factory (anomalous W,Z production?) • Diffractive Higgs production, SUSY & other exotics & exclusive processes • Low-x Dynamics • Parton saturation, proton structure, multi-parton scattering… • New Forward Physics phenomena • New phenomena such as DCCs, incoherent pion emission, Centauro’s • Strong interest from cosmic rays community • Forward energy and particle flows/minimum bias event structure • LHC as a photon collider - two-photon interactions & peripheral collisions • Use QED processes to determine the luminosity to ~1% (ppppee/) • Forward physics in pA and AA collisions James L. Pinfold TAHOE 2007 9
Diffraction & Forward Physics at LHC TOTEM: Approved July ‘04 • TOTEM stand alone • Elastic scattering, total pp cross section and soft diffraction. CMS: • EOI submitted in Jan. 2004 • Diffraction with TOTEM Roman Pots and/or rapidity gaps • TP in preparation for new forward detectors (CASTOR, ZDC,+…) • Diffractive and low-x physics part of CMS physics program (low + high ) CMS+TOTEM: • Prepared common LOI due in Summer 2006 • Full diffractive program with central activity with TOTEM as a CMS subdetector ATLAS: • LOI submitted (March 04). • RP detectors to measure elastic scattering/ total cross sections/luminosity. Diffraction will be looked at later • LUCID and the ATLAS ZDC approved for installation in 2007 LHCf: Approved by LHCC in 2006 FP420: Collaboration for R&D and feasibility study for detectors at 420 m James L. Pinfold TAHOE 2007 10
LHC Experiments: pT- coverage • The base line LHC experiments will cover the central rapidity region. • TOTEM+ CMS will complement the coverage in the forward region • ALICE & LHCb have restricted eta coverage wrt to ATLAS & CMS James L. Pinfold TAHOE 2007 11
ATLAS Coverage in Forward Direction Breaking news: LUCID and the ZDC recently approved for installation in 2007 ZDC Proposed James L. Pinfold TAHOE 2007 12
CMS Coverage in Forward Direction ZDC CASTOR 5.25<<6.5 Tungsten/quartz plates 1 TeV n shower in ZDC Tungsten/quartz fibres CASTOR Calorimeter ZDC Calorimeter (at 140 m) Common runs planned with TOTEM: Roman Pots and T1/T2 James L. Pinfold TAHOE 2007 13
CMS+TOTEM: a “Full” Coverage Detector CMS/TOTEM will be the largest acceptance detector ever built at a hadron collider +ZDC James L. Pinfold TAHOE 2007 14
The FP420 Project TOTEM / ATLAS RPs FP420 CMS/ATLAS • Extend the acceptance for leading proton tagging • Combine information from central detector and RP @ 220m • Exclusive central Higgs prod. pp p H p: 3-10fb • Inclusive central Higgs prod. pp p+X+H+Y+p: 50-200 fb • Reconstruction of the central mass: FP420: R&D fully funded • TDR to ATLAS/CMS by 1st -half of ‘07 then to the LHCC. Installation ~’08-’09? M = O(1.0 - 2.0) GeV James L. Pinfold TAHOE 2007 15
LHCf Experiment • LHCf: measurement of photons and neutral pions in the very forward region of LHC • Add an EM calorimeter at 140 m from the Interaction Point (of ATLAS) (Scintillating fiber /Tungsten calorimeter + Silicon strip det. Calorimeter) • At the LHC the 14 TeV Ecm translates to a 1017 eV Lab. Energy - by comparing experimental results with MC predictions one can tune MC used in cosmic ray EAS simulation. 400 GeV photon I TeV neutron James L. Pinfold TAHOE 2007 16
LHC Forward Physics & Cosmic Rays • Measurement of forward hadronic particle production at the LHC will play a key role in understanding UHECR EAS where major in uncertainties in our understanding still exist • The NEEDS workshop (Karlsruhre 2002) listed the hadronic interaction data (pp/pA/ AA) required from collider measurements: • Precise measurement of stot& sinel. p-p x-sec • Energy distribution of leading FS nucleon • Measurement of sdiff/sinel • Inclusive p-spectra in the frag. region xF >0.1 • The phenomenological models describing non-perturbative QCD hadronic multi-particle production in HECR simulation,are: • Low/medium energy: GHEISHA, FLUKA, UrQMD, TARGET, HADRIN, etc • High energy: DPMJETII.5 &III, neXus 3.0, QGSjet 01, SIBYLL 2.1, etc • The models describe the Tevatron well - but LHC model predictions reveal large discrepancies in extrapolation ET (LHC) E(LHC) James L. Pinfold TAHOE 2007 17
1st ATLAS/CMS Data–Cosmic Rays! Cosmic muons observed byCMSat IP5 (recorded by hadron barrel calorimeter) Cosmic ray muons observed in the ATLAS Tile Calorimeter James L. Pinfold TAHOE 2007 18
LOW X AT THE LHC LHC: due to the high energy can reach small values of Bjorken-x in structure of the proton F(x,Q2) Processes: Drell-Yan Prompt photon production Jet production W production If rapidities below 5 and masses below 10 GeV can be Covered--> x down to 10-6-10-7 Possible with T2 upgrade in TOTEM (calorimeter, tracker) 5<< 6.7 ! Proton structure at low-x !! Parton saturation effects?
The p-p Total Cross-section • The ATLAS approach is to measure elastic scattering down to such small t-values that the cross section becomes sensitive to the EM amp. via the Coulomb interference term. • In this case an additional valuable constraint is available from the well-known EM amplitude, as can be seen from: that describes elastic scattering at small t • sT, L and the slope parameter b can be determined by a fit to the above expression • At 7 TeV the strong amplitude is equal to the EM amplitude for |t| = 0.00065 GeV2. This corresponds to a scattering angle of 3.5 µrad – thus we need special beam optics • LHC measurement of sTOT expected to be at the 1% level – useful in the extrapolation up to HECR energies 10% difference in measurements of Tevatron Expts: (log s) James L. Pinfold IVECHRI 2006 14
LHC Operation in a Normal Year LHC OPERATION • 140-180 days of running per year • 100-120 days of p-p collisions per year • 4 x 106s of proton luminosity running per year. • Around 40 days of heavy-ion (30 days) and TOTEM running per year HEAVY ION PROGRAM (at present) • LHC Phase I: Collisions with Pb ions “baseline programme” • LHC Phase II: Collisions with lighter ions (A-A collisions –Cand’s: He, O, Ar, Kr, In) • LHC Upgrade Programme: so-called hybrid collisions (e.g. p-A collisions - Pb, Ar, 0) James L. Pinfold IVECHRI 2006 3
The Experimental Challenge • High interaction rate • pp interaction rate 109 interactions/s • Only ~100 events chosen out of 40 MHz event rate • Level-1 trigger decision will take 2-3 ms Electronics needs to store data locally (pipelining) • Large particle multiplicity • <23> superposed events in each crossing • ~100 tracks stream into the detector each 25 ns Need highly granular detectors with good time resolution for low occupancy • Very good muon ID and momentum measurement trigger efficiently and measure the sign of a few TeV muons • Good energy resolution in the EM calorimetry (eg for Hgg) ~0.5% @ ET~50 GeV • Precise inner tracking for good mom. resolution & vertexing (b-decays ~10 better momentum resolution than at LEP • Hermetic calorimeter Good ETmiss resolution • High Radiation levels (10MRads/yr & 1014 n’s/cm2/yr in the Forward reg) Need radiation hard detectors and electronics James L. Pinfold TAHOE 2007 7
ATLAS Coverage in Forward Direction ) ZDC FP420 Inst-TAS Inst-TAS
CMS Coverage in Forward Direction CASTOR 1 TeV shower in CASTOR ZDC
LHCb & ALICE Coverage in Forward Direction ALICE: || < 0.9: charged & neutral E,p measurement and ID 2.4 < < 4: muon measurement -5.4< < 3: charged multiplicity 2.3 < < 3.5: photon multiplicity Zero Degree Calorimeters at ~ 100 m LHCb: 1.9 < < 4.9: charged & neutral E, p measure & ID to ~ 200 GeV James Pinfold ATLAS Physics tutorial June 2003 16
ZDC Tungsten/ quartz fibres
The Triggering & Data Challenge Trigger system - Real time multi-level trigger to filter out background and reduce data volume 40 MHz (40 TB/s) Level 1 – special hardware processors 75 KHz (75 GB/s) Level 2 – embedded processors + PC farms 1-KHz (1-GB/s) Level 3 – PC farms 100 Hz (100 MB/s) Data recording and offline analysis Data recording rate for ATLAS ~0.1 GB/s ~1 PetaByte / LHCyear James L. Pinfold TAHOE 2007 9