Physics opportunities with polarized e? and e+ beams at TESLA

Abstract

Beam polarization at e + -e − linear colliders will be a powerful tool for high precision analyses. Often it is assumed that the full information from polarization effects is provided by polarization of the electron beam and no further information can be obtained by the simultaneous polarization of the positrons. In this paper we point out the advantages of polarizing both beams, and summarize the polarization-related results of the Higgs, Electroweak, QCD, SUSY and Alternative Theories working groups of the ECFA/DESY workshop for a planned linear collider operating in the energy range √ s = 500 − 800 GeV. 1

CLIC CDR - physics and detectors: CLIC conceptual design report.

“…The contribution from e + e − → γZ → γνν can easily be eliminated by cutting out the E γ region around the corresponding Z-peak, but there remains a significant, continuous distribution in E γ from e + e − → γνν that has similar behaviour as the signal. Since the neutrino couples only left-handed, the background has nearly maximal polarisation asymmetry and can be effectively suppressed via beam polarisation: with (P e − , P e + ) = (+80%, 0) the ratio S/ √ B is enhanced by about a factor 2.2 and with (+80%, −60%) by about a factor 5 [76].…”

Polarized Positrons at a Future Linear Collider and the Final Focus Test Beam

“…2 However, if polarized positrons are available, a separation of the different combinations might be possible.…”

New physics searches at a linear collider with polarized beams

“…The process gives a significant signal over the background. Since it requires both lefthanded e − and e + beams, it can be easily analysed and identified by the use of beam polarization ( [2] and references therein): here simultaneously polarized beams enhance the signal by about a factor of 10. Introducing in the MSSM an additional Higgs singlet leads to the (M+1)SSM with one additional neutralino.…”

“…The LC has large potential for the discovery of new particles and is unique concerning the precision analysis of new physics (NP) as well as of the Standard Model (SM) [1]. An important tool of a LC is the use of polarized beams [2]. Already in the base line design it is foreseen to use the electron beams polarized to around 80% via a strained photocathode technology.…”