Polarisation and beam energy measurement at a linear e⁺e⁻collider

Abstract

The International Linear Collider (ILC) is a future electron/positron collider at the energy frontier. Its physics goals are clearly focused on precision measurements at the electroweak scale and beyond. Beam energy and beam polarisation are two important beam parameters, which need to be measured and monitored to any possible precision. We discuss in this publication the foreseen concepts of beam energy and beam polarisation measurement at the ILC: Two Compton polarimeters per beam line will determine the beam polarisation. The anticipated precision of this measurement amounts to ∆P/P = 2.5 × 10 −3 , which is a challenging goal putting highest demands on detector alignment and linearity. Recent detector developments as well as a detector calibration technique are described, which allow for meeting these requirements. The beam energy is measured before and after the interaction point to a targeted precision of ∆E/E = 10 −4 . Thereby, the two foreseen concepts are introduced: A noninvasive energy spectrometer based on beam position monitors is planned to be operated before the interaction region. Behind, a synchrotron radiation imaging detector will allow not only for measuring the beam energy, but also gives access to the beam energy spread of the (disrupted) beam.

Direct searches of Type-III seesaw triplet fermions at high energy $$e^+e^-$$ e + e - collider

“…This third scenario leaves both charged as well as neutral heavy fermions in the spectrum. It is possible that such additional fermions have masses in the range of TeV, and thus could possibly be searched for at the LHC and at the proposed high energy leptonic colliders like the International Linear Collider (ILC) [17][18][19][20][21][22][23][24][25][26] or the Compact Linear Collider (CLIC) [27][28][29][30]. Generically, we shall refer to these high energy leptonic collider facilities as the Future Leptonic Colliders (FLCs).…”