Write-Up: `Beam Polarisation at a LC'

Changes for chapter 2, 3, 4 included

I. Introduction:

         Theory: chirality<->helicity, definitions, conventions,history
         Beam polarisation as an analyzer for the coupling structure
         Expected degree of polarisation at a future LC

II. Physics with Polarisation:

II.1 The Physics Case for polarised Electrons:

         Electron polarisation only: quite short, good summary and list of references
                                                      SM -> New Physic,
Conventions,
   well-known background processes for New Physics

'Editor': probably myself and perhaps Herb Steiner?

II.2 The Physics Case for longitudinally polarised Beams:

II.2.1 Both Beams polarised required

Susy: selectrons, enhancement of rates in 'critical' scenarios, etc.

II.2.2 Polarisation Measurement: GigaZ

Need for the Blondel Scheme
Inclusion of the new LC note of Gideon

II.2.3 Improved Precision : Measurement of eff. Polarisation

Introduction and use of eff. polarisation, kind of relevant processes
Error propagation
Physics examples: precise knowledge of polarisation needed?
(SM, Susy: Parameter determination, Z', ED, CP Asymmetries)
Radiative corrections

II.2.4 Suppression of Background Channels

Systematic introduction of s-, t-channel characteristics
General formulae a la Renard
Tables with scaling factors (S/B and S/sqrt{B})

Examples: Higgs production in Higgsstrahlung and Fusion
t-channel suppression in TGC studies in e+e- -> W+W-
Bhabha process, Moeller process
ZZ production

II.2.5 Improved Statistics

Examples why statistics get improved
E.g. e+e- -> gamma/Z -> ff

Editors: Uriel Nauenberg, Achim Stahl, Gudi

II.3 Physics Case for transversely polarised Beams

Effects in e+e- -> W+W-, CP violation
New Physics Searches: Susy, ED,

Editors: Tom Rizzo, Achim

II.4 Implementation of Spin Effects in Monte Carlo Generators

Contribution of S. Moretti and P. Richardson

III. Machine issues:

General remarks about machine operation of polarised sources: e.g. Loss of luminosity?
Increased energy spread? (small impact -> Klaus?)

III.1 Electron polarisation:

History,
Results,
Description of the hardware
New developements in gradient doping
Spin rotators (design and operation characteristics)

Editors: John Sheppard + Jim?

III.2 Positron polarisation:

Description of the hardware,
Possible schemes (undulator based, laser based)
                                                Helical undulator from the very beginning
                                                  Expected polarisation degree
Length of undulators ( P(e+)--length useful? )
Impact on lumi and energy spread (-> remarks in the beginning of III.)

                                                  Description of E166: short summary of proposal
                                                                                      physics potential
                                                                                      relevance for LC
   undulator design
time schedule

Undulator design at Daresbury

Editors: Klaus Floettmann, Rainer Pitthan, John Sheppard

III.3 Transverse polarisation:

   short description of hardware
                                                       which R&D needed?
                                             determination of azimuthal angle?
measuring the polarisation -> Chapter 4

Editors: Klaus Floettmann, John Sheppard

IV. Polarisation Measurement:

          History
Results
Remark on Moeller+Bhabha option
            Details for Compton: description of hardware, polarimeter (Peter?)
technical potential (Peter?)
upstream
downstream (Ken?)
option for transverse?
difference with/out crossing angle (no, but remark)
achievable precision: now and later
   polarisation transport and depolarisation in the IP
            Polarimetry for transverse beam polarisations

Editors: Ken Moffeit, Peter Schueler, Mike Woods

Editorial Board: 'Polarisation dream team

       Physics:         Tachishige Hirose, Uriel Nauenberg, Thomas Rizzo, Achim Stahl,
                                Herb Steiner and myself
       Machine:      Klaus Floettmann, Tsutomu Nakanishi, Tsunehiko Omori,
                                Rainer Pitthan, John Sheppard
       Polarimetry: Peter Schueler, Mike Woods

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Last update of this page: 19-September-03

by Gudi