Future in Particle Physics! ECFA: Future of Accelerator-Based Particle Physics in Europe HEPAP: Long Range Planning for U.S. High-Energy Physics ACFA: coming up soon? F. Linde, 14-December-2001, Amsterdam

Input to ECFA report Laboratories: L. Maiani: “CERN: views for the future” A. Wagner: “Views on the future of DESY” J. Bagger: “HEPAP sub-panel on long range planning for U.S. High energy physics” F. Gilman: “The U.S. high energy physics advisory panel white paper” A. Skrinsky: “Russian HEP activity: status and perspectives” S. Komamiya: “Report on ACFA activities” Projects: F. Gianotti: “Physics perspectives with the LHC within Standard Model” P. Sphicas: “Physics perspectives with the LHC: SuSy and other physics beyond SM” K. Hubner: “New acceleration methods and plans for high intensity proton machines” R. Klanner: “Future perspectives for e  p physics” D. Miller: “Physics potential and concrete perspectives for <1 TeV linear colliders” P. Zerwas: “Muti-TeV lepton colliders: the physics potential” J.P. Delahaye: “CLIC, a two beam multi-TeV e  linear collider” A. de Roeck: “CLIC, a compact linear collider: experimentation and physics potential” M. Tigner: “Perspectives and experimental environment of a muon collider” P. Janot: “What physics at muon colliders” K. Peach: “Neutrino factories”

Physics challenges many questions, e.g.: matter  anti-matter? dark matter? three families? generation of mass? proton decay? charge quantization? unification? “recent” discoveries: three families (LEP) t-quark discovered (Tevatron) indirect Higgs mass (LEP/Tevatron) -oscillations (Kamiokande) CP violation in B system (BaBar/Belle)

Progress within the Standard Model Outstanding issues: Higgs mechanism quark-gluon plasma CP violation quark sector neutrino sector Improvements: masses: m W, m t, … couplings:  s, G , … other: sin 2  w, CKM, g-2,...

Approaches: Rare/forbidden decays New particles New interactions Unification Unknown: look into the sky! Progress beyond the Standard Model

Experimental opportunities

Hadron-hadron (CERN & Fermilab) –LHC upgrades: Luminosity upgrade  cm -2 s -1 “easy” (you want it?) Energy upgrade difficult (we might want it!) –Very large hadron colliders: VLHC Lepton-lepton (CERN, DESY, US, Japan) –e  e  linear colliders: TESLA, NLC, JLC, CLIC –     collider Intense neutrino beams (CERN, FermiLab, Japan) –  ,  ,  e,  e Future “G$” projects

Very large hadron collider Fermilab VLHC phased project (240 km circumference tunnel) Issue: cost, cost and cost Lumi (cm -2 s -1 ) B-field (T)  s (TeV) VLHC-2VLHC-1 dipole magnets interesting (transmission line) Physics The unknown, new, exciting! The unknown, new, exciting! Continuation of LHC Continuation of LHC But also clear you only embark on this well after the LHC has cleared the TeV energy range

p      e  e     e  e  Intense neutrino beams (      collider?) 1.SPL:E p  2-15 GeV, p/s 2.target: p     -decay:       -cooling:reduce  E , E   50 GeV  -decay:   decay in “ring”  -collider:future music neutrino beam neutrino beam Physics “Near” (<1 km, high rate) structure functions CKM matrix new physics “Far” ( km, low rate) oscillations CP Japan, CERN & FermiLab

    collider Everything e  e  linear collider offers with as advantages: –Far less Beamstrahlung (negligible) –Far better calibration (  E  5 keV, energy spread & polarization) –Much larger couplings to Higgs bosons (   /  ee  4  10 4 )  Higgs lineshape!

Linear e  e  collider: cartoons DESY Japan SLAC

Linear e  e  collider: real work

Lepton colliders: e  e  40  1200    1000  x  y (nm 2 ) Length (km) NLC/JLC TESLA ? (10?) 0.1 SLC 10Lumi (10 34 cm -2 s -1 ) 30-40Beamstrahlung (%) Gradient (MV/m)  s (TeV) CLIC e  e  Higgs Supersymmetry lots more (QCD, …) X-ray FEL option: biology material  e  and   e  and  options

Making choices! $$$$$$$$$$$$$$$$$$$$$$ HEP creativity exceeds available finances  must be selective allow orginal, excellent, new,... proposals  be flexible limit (expensive) duplications  operate globally sufficient R&D before technology decision  be economical realistic time schedules! accelerator  non-accelerator links to astro-physics, cosmology and nuclear physics “plan” for the unexpected fill “no-physics” between large accelerator projects Fairly well covered already B-physics: HeraB/Tevatron - BaBar/Belle - LHCb Heavy-ion physics: RHIC - ALICE

ECFA recommendations Make the LHC a success i.e. get it running timely! Exploit ongoing facilities optimally in pre-LHC era Stimulate accelerator home institutes Next project: a sub-TeV (  s  400 GeV) e  e  linear collider (irrespective of the findings of the LHC i.e. justification exists today) Coordinated R&D effort to study  -storage ring (SPL  intense -beam) VLHC, CLIC &  -collider: far future i.e. beyond 2020 (coordinate R&D efforts) HEPAP addition Importance of non-accelerator based experiments

Linear e  e  colliders pp  e  e  colliders: complementary (SppS  LEP  Tevatron) Z, W discovery  Z factory m t prediction  top discovery m H prediction  Higgs discovery? pp: discovery physics (  Nobel exp.) e  e  : precision physics (  Nobel th.) c.m. energy  s: facts: “Giga Z”:  s  m Z  90 GeV “top factory”:  s  2m t  350 GeV speculation: “SM Higgs factory”:  s  m H +m Z  350 GeV new physics: super-symmetry, extra dimensions, …..   s  400 GeV

e  e  linear collider: physics Precision Higgs study (m H, spin,  H, HHH,  H  ff, …) Super-symmetry spectroscopy (threshold scans) Precision measurements thereby probing higher energies Anything new and unexpected (unlikely to escape LHC though)

e  e  linear collider: Higgs ZH  l + l - bb ZH  qqbb Higgs signals Higgs selfcoupling  HHZ (fb) mHmH e + e -  HHZ Higgs spin ss  HZ (fb) e + e -  HZ Higgs decay width

Exciting non-accelerator program –proton decay, neutrino, satellite-based & gravitational wave experiments Develop -superbeam/factory facility –SPL: intense p source –  -cooling R&D –? Get the e + e - linear collider on track –sort out technology (cold  warm) –agree upon one site (FermiLab?) & get it funded! –do the experiment(s):  2013 –better insight into …. (Higgs, supersymmetry, higher energy scales) Prospects (limit duplications: BTeV, … !) Resolve CERN/LHC situation –management & finances –realise machine & experiments –do the experiments: –find Higgs, supersymmetry, quark-gluon plasma, CKM & CP ? ? NIKHEF