Future Accelerators at the energy frontier

Peter Hansenfebruary 2010

University of Copenhagen

What physicists would like

2010: Start LHC@7TeV, cautiously increase energy and find the Higgs and first signs of new physics

2011: Approve the International Linear Collider. Operate it by about 2018.

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: 1.1 10¹¹ 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: 1034 cm-²s-¹

Possible luminosity upgrade

Around 2015-16 LHC will have exhausted its potential. However by a 10-fold luminosity upgrade, the discovery reach could be moved about 0.5-1 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 2010. Price would be about 6 B$.

ILC technology: Superconducting RF cavities , 31MV/m gradient. Beam-height of 6 nm. Luminosity of 21034 cm-2 s-1.

CLICCLIC is CERNs design for a future linear e + e- collider.It is more ambitous than the ILC and requires longer development time.The perspective is to make a machine with up to 3 TeV collisions.Instead of cavities, it uses the RF power stored in 30 GHz buckets of anelectron “drive beam” for acceleration by up to 100 MV/m in the main beam.

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 tobe in a position to define the optimal neutrino programmebased on the information available in around 2012; Council will play an active role in promoting a coordinated Europeanparticipation in a global neutrino programme.

Low energy options

Super beam (nu_mu's)

Beta beam (nu_e's)

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

Other planned experiments

Nu-factory best. But costs 2B$

Proton Driver

Super Conducting Linacaround 10 GeVaround 4MW carried in beam!Feasible at CERN >2016R&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 coolingMICE@RAL to demonstrate one sectorFirst 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.