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Large Hadron electron Collider LHeC …. … indisputably the next step. Deep-Inelastic Lepton Scattering at the LHC. John Dainton * Cockcroft Institute , Daresbury Science and Innovation Centre, GB. http://www.lancs.ac.uk/cockcroft-institute/. Introduction
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Large Hadron electron Collider LHeC … … indisputably the next step Deep-Inelastic Lepton Scattering at the LHC John Dainton* Cockcroft Institute, Daresbury Science and Innovation Centre, GB http://www.lancs.ac.uk/cockcroft-institute/ • Introduction • LHeC: “energy, precision and luminosity” • 3. The Physics Horizon • 4. Experiment • 5. Onwards ? *with M Klein (DESY Zeuthen) P Newman (Univ Birmingham), E Perez (CE Saclay) F Willeke (DESY Hamburg) hep-ex/0603016 DESY 06-006 Cockcroft-06-05
2007: a vintage year for Physics ●July 2007: final HERA data sample e± p chiral probe @ 0.001 fm ●July 2007: first collisions @ LHC pp @ 14000 GeV @ 1033 cm-2 s-1 ●July 2007: hitherto unique p and A beam 7 TeV per nucleon, high intensity new opportunities ? LR ? 20??: 70 GeV e± in LHC tunnel e± p chiral probe @ 0.00014 fm LR
Kinematic Reach ●70 7000 GeV e±p cm energy 1400 GeV space-like >TeV e ? RL Z W 3×10-7 ? quark structure @ ≥ 0.0001 fm eq>TeV
Structure of Matter ●unique chiral probe @ 0.0001 fm ? dstructure nucleus nucleon q = 2/ electron point-like “source” Z0 W quark ● gluons EW NC+CC+gluon LHeC ? ●precision
Progress … ? (fm) -0.0001 -0.0003 -0.001 -0.003 -0.01 -0.03 -0.1 beyond? ep eA ? leptons + quarks hadronic mass in Universe Higgs mass CKM LQ l* q* SUSY? LHeC ? ep HERA SM EW QCD .. ? .p p A QCD+EW unification QCD+EW e+e-. ep eA ep eA HERA .ep pSLAC+CERN CERN+FNAL ? QCD spin gluon HF+EW QPM quarks in proton NC P 1960 1970 1980 1990 2000 2010 ….?
2. LHeC: “energy, precision 2. LHeC: “energy, precision and luminosity” 2. LHeC: “energy,
Proton beam ●”standard” LHC protons … with electrons? antiprotons protons protons electrons? protons Np εpN
ep Luminosity ●few 10s GeV electrons (LEP = 70 GeV!) ●RF power = 50 MW = 0.86 LEP = 28% CERN site ●RF power = synchrotron radiation Ie= 74 mA luminosity 74×10-3×1.67×1011×7000/.938 = “perfect” bunch x-ing 4π×1.6×10-19×3.75×10-6× (m2) cm-2 s-1 L = 1.15×1033/ L ~ 1033 cm-2s-1 for reasonable p-beam β ~ 1 m
e±p Luminosity ●astounding ! ●×102LNMC @ 0.01 fm ●LeRHIC @ 0.007 fm ●×102LHERA @ 0.001 fm ●LLHeCe±p @ 0.00014 fm indisputably the next step … is it feasible ?
Feasible Luminosity ? ●bunch matching βeεe= βpεp= βpγp ●electron βeconstrained by depth of focus for p-bunches σp ~ 7 cm σp ●electron emittance εe constrained by - dynamic aperture - geometric aperture - beam-beam tune shifts feasible match with tolerable “hour-glass” loss
Lepton Ring ●in LEP tunnel so like LEP - FODO in eight arcs β-tron phase advance φH=108oφV=90o - bending radius 3005.3 m - (δE/Ebeam)rms = 1.1×10-3 - SR 26 W/cm (Ec=254 KeV) - scRF @ 1GHz resonators @ 12 MV/m 100 m structure = 670 cells sync. Phase 31o bucket takes 10× (δE/Ebeam)rms - unlikely e-beam instability single bunch current modest impedance << LEP 8 7 1 6 2 5 3 4 LEP=9 W/cm HERA=13.5 W/cm scRF proven @ 6 MV/m
Lepton Ring LHeC
ep Collisions ●afterB physics @ LHC e p civil engineering tunnel 2×250m×2m Ø @IP LHeC duringpp pA AA data-taking @ LHC
Interaction Region ●highest lumi - low βe close sc quads - low x-ing angle “hard” bend SR fan sc p-beam « HERA - “crab” RF cavity p-bunch rotation top elevation “crabbed” (rotated) p-bunch V-displaced 3.4 kW 3.2 kW 11.4 kW 3.5 mrad 0.5 mrad ●1o beam access = low-lumi/low-x option (cf HERA)
Interaction Region ●high luminosity operation
Operational Luminosity ●beam-beam - “hour-glass” - dynamic β: < HERA - long range beam-beam (parasitic interactions): marginal ! operational luminosity
IR and Experiment ●IR ±many m ●IR ≥9.4o around beam
LHeC ●tunnel exists (LEP, LHC) ●injection once existed (LEP) ●operating p-beam (from 2007) ●operating A-beam (from 2007) ●ep operating alongside pppAAA ●LHC upgrade ●cost ?
New Kinematic Reach in Lepton-Hadron space-like >TeV ●Q2LHEC 102Q2HERA ●xLHEC 10-2xHERA ●sLHEC 20sHERA eq eq 3×10-7 ●extrapolation … …or interpolation? eq>TeV
Lepton-Parton and Parton-Parton ●sLHC 102×sLHeC 70 GeV ●for target parton xprobe/proton = = 0.01 @ LHC sLHeC sLHC ●LHC probe - confused LHC>LHeC - complementary for LHC~LHeC gluon @ low-x
Energy Frontier ●leptoquarks e e Z 10 fb-1 (1 year @ LHeC) q e e + LQ q e 2 q … + 100 fb-1 LQ q
Energy Frontier e ●leptoquarks -formation and decay -e±qNC,CC -fermion number -branching ratios -spin-parity -chirality ? -flavourcoupling e Z q e e + LQ q e 2 q … + LQ ●if LQ spectroscopy discovered precision tools to understand it q
Dense Chromodynamics ●relentless low-xrise of F2 for x ≥ 10-4 -saturation?partons must someday recombine -LHeC: precision for x > 3×10-7: extreme nuclei ? (∂F2/∂ lnx)Q2
Precision Chromodynamics ●short distance structure of QCD -2006 @ 10-9 -2006 GF@ 10-5 -2006 G@ 0.1% -2006 S @ 1-2% -LHeC precisionS few/mil ●discovery + precision probe new chromodynamic physics ?
Comprehensive Physics Horizon ●energy for eq discovery extreme chromodynamics ●precision for eq discovery eq understanding extreme chromodynamics ●luminosity for eq discovery LHeC and LHC LHeC and ILC LHeC and LHC
Acceptance and Measurement ●70 7000 GeV ●high lumi quads (±10o bp) Q2 > 100 GeV2x > 3×10-5 ●few GeV ≤ Eh,e≤ few TeV ●low lumi for low x (no quads) 1 < Q2< 100 GeV2 x < 3×10-5 “forward” hadrons: “forward rapgap” instrumentation precision e/had-measurement 170 < θe< 179o170 < θh< 179o e jet e !
Rate ●100/10 fb-1 = 100/LHeC y-1 @ Q2 = 1 TeV2
Now ●LHeC 70e 7000p GeV - can be built - has startlingly good luminosity 1033 cm-2s-1 grows with LHC pp luminosity - adds substantially, uniquely and with synergy to LHCTeVenergy physics - probes chromodynamics @ new density frontier in uniquely comprehensive manner with unchallengable precision synergetically with LHC pppAAA
Now ●CERN: Engelen “work it out!” Fall 2005 ●hep-ex/0603016 toCERN Strategy group Jan 2006 - emphasised by speakers - encouraging individual response ●hep-ex/0603016 noted in the US DoE strategy: meeting now on lepton-hadron ●strong interest in LHeC @ DIS2006 … to be carried to CERN Strategy group by its members @ DIS2006 - implies global support - confirms importance of breadth in future HEP Strategy Group “interesting to work it out” ? ?
Next ●begin preparation of detailed evaluation - establish global working group (CERN pivotal) 1. machine e±injection e± ring LHC impact and modifications 2. experiment 3. physics ●look for any remaining “showstoppers” ●prepare CERN “white book” ●LoI to LHCC ●cost 2009 ? other LHC upgrades?
Coordinating Group ●organisation ? ●coordinator(s) ? ●first meeting where ? ●first meeting when ? ●first meeting to organise work + schedule
In case you were wondering … ? Sir John Cockcroft … doing accelerator physics ca 1950 … … with 1950 DAQ – pencil and paper! … with 1950 graphics – ammeter! voltmeter!