Linear Colliders: ILC and CLIC

Experiments at future accelerators

Future accelerator experiments are being developed in a global collaboration – projects which allow a precise investigation of the Higgs boson and the top quark, the heaviest particles in the Standard Model of particle physics. In addition, they should offer discovery potential for “new physics”, complementing the possibilities afforded by the LHC.

The “Future Detectors” Group at the MPP investigates the physics potential of future linear accelerators. It develops detector technologies for the next generation of experiments in particle physics. The Group is an active partner in various research collaborations:


•    in CALICE to develop highly granular calorimeters,
•    in CLIC Detectors und Physics (CLICdp),
•    in the International Large Detector (ILD) concept for the ILC.

Furthermore, the detector technologies developed in CALICE are being used in the commissioning of the SuperKEKB accelerator in Japan.

The ILC and CLIC linear colliders

In contrast to what happens in the Large Hadron Collider (LHC), it is electrons and their antiparticles, the positrons, that are made to collide at high energy in these accelerators. These experiment are intended to allow researchers to study tera-scale physics: The work here focuses on questions relating to the origin of mass, the nature of the dark matter in the universe, possible new symmetries and new spatial dimensions.

Unlike the protons used in the LHC, electrons and positrons are elementary particles without a substructure. Their collisions therefore provide cleaner events, have a much lower background, and thus a higher measurement precision. This allows detailed investigations of the physics within and beyond the Standard Model.

Electrons and positrons must be on linear trajectories in order to be accelerated to the highest energies; on a circular trajectory, their low mass means that they lose too much energy through synchrotron radiation.

A linear accelerator therefore comprises two long tubes which accelerate the particles to high energies before bringing them to collision. Two technologies are currently being developed for this: The International Linear Collider (ILC), with a maximum energy of 500 gigaelectronvolts up to 1 teraelectronvolt, and the Compact Linear Collider (CLIC), with energies up to 3 teraelectronvolts. At the same time, complex detector systems are being developed in order to achieve the best possible precision. Several hundred scientists around the world are involved in the development of these new accelerators.

Further information on the group "ILC & CLIC"

Group members

name function extension office www

Caldwell, Allen, Prof. Dr.

Director 529 212

Emberger, Lorenz

PhD-Student 393 116C

Humair, Thibaud

Postdoc 307 118C

Hummer, Fabian

Student 393 116C

Krätzschmar, Thomas

PhD-Student 557 117C

Popov, Ivan

Student 393 116C

Sasikumar, Kollassery Swathi

Postdoc 307 119C

Simon, Frank, Dr.

Scientist 535 121C

Wacker, Ina

Secretary 207 213

Wagner, Malte

Student 556 120c

Windel, Hendrik

PhD-Student 556 120C

Key publications

Physics Case for the International Linear Collider
ILC Physics Working Group
arXiv:1506.05992 [hep-ex]

The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers
CALICE Collaboration
JINST 9, P07022  (2014)
arXiv:1404.6454 [hep-ex]

Top quark mass measurements at and above threshold at CLIC
Eur. Phys. J. C73, 2530 (2013)

Hadronic energy resolution of a highly granular scintillator- steel hadron calorimeter using software compensation techniques
CALICE Collaboration
JINST 7, P09017 (2012)
arxiv:1207.4210 [physics.ins-det]

The CLIC Programme: Towards a Staged e+e- Linear Collider Exploring the Terascale: CLIC Conceptual Design Report
P. Lebrun, L. Linssen, A. Lucaci-Timoce, D. Schulte, F. Simon, S. Stapnes, N. Toge and H. Weerts et al.
arXiv:1209.2543 [physics.ins-det]