Future Accelerators at the energy frontier Peter Hansen february 2010 University of Copenhagen

What physicists would like  2010: Start cautiously increase energy and find the Higgs and first signs of new physics  2011: Approve the International Linear Collider. Operate it by about  2012: Approve a potent neutrino factory and a B-factory to reach 100 ab.  2014: LHC upgrade to increase statistics  2020: Start genuine “discovery machines” (CLIC and/or a muon collider)  But the realistic timescale is rather longer!

CERNS accelerator complex

Large Hadron Collider

LHC in numbers  Circumference: 27km  Energy: 2x7 TeV  Peak dipole field: 8.3 Tesla  Injection: 450 GeV protons or A  Protons per bunch: ¹¹  Bunch spacing: 25 ns  Stored energy/beam: 362 MJ

LHC in numbers  Normalised emittance: 3.75 mm mrad  beta function at IP (at inject): 10m  beta function at IP (at coll.): 0.55m  Beam size at IP: 16.6 mu  Bunch length: 3.75cm  Events per bunch crossing: 19  Peak luminosity: cm-²s-¹

Possible luminosity upgrade Around LHC will have exhausted its potential. However by a 10-fold luminosity upgrade, the discovery reach could be moved about TeV further out and precision measurements could be significantly improved. That would require a major machine and detector upgrade to withstand the radiation and deal with many thousands of particles per event.

International Linear Collider  By 2000 a world-wide consensus developed that the next step would be a linear e+e- collider at 500 GeV, upgradable to 1 TeV, in order to do precision measurements in the Higgs sector and any new physics that were discovered at the LHC.  Engineering design and go-ahead planned for in Price would be about 6 B$.

CLIC

Neutrino factory

Motivation  Ideas from GUTs on mass hierarchy  and on the mass mixing matrix  Is the mass hierarchy “natural”?  Is theta_13 really very small?  Is theta_12 really close to pi/4?  Very clean CP violation laboratory!

NEUFAC “An emerging facility” (European priority placed after LHC and also after ILC/CLIC) CERN-SG: 4.[…] it is vital to strengthen the advanced accelerator R&D programme; a coordinated programme should be intensified, to develop the CLIC technology and high performance magnets for future accelerators, and to play a significant role in the study and development of a high-intensity neutrino facility. 6.Studies of the scientific case for future neutrino facilities and the R&D into associated technologies are required to be in a position to define the optimal neutrino programme based on the information available in around 2012 ; Council will play an active role in promoting a coordinated European participation in a global neutrino programme.

Low energy options

High Energy option (5-20 GeV) Nu factory does it all..

Other planned experiments Nu-factory best. But costs 2B$

Proton Driver Super Conducting Linac around 10 GeV around 4MW carried in beam! Feasible at CERN >2016 R&D at RAL: H- source, beam chopper

Target Optimization of Ep (HARP exp – CERN) Moving Tantalum wire (RAL R&D) High power LHg jet (MERIT exp - CERN)

Fast dE/dx cooling to demonstrate one sector First beam Jan 2008 – total cost 23M£

Other Ideas

Outlook  It would be super to have it all - and fast!  However, the sponsors are inclined to long lead-times for the post-LHC accelerators at the energy frontier.  This could of course change if something really exiting were discovered at the LHC!  So a good way to speed up future accelerators is to work hard on the LHC physics.