Questions on accelerator-detector interplay for CLIC at different energies:
A. Detector/Physics part
Introduction
List of questions to be studied in the near future. Some could have first answers at CLIC09, for others persons interested to address the question might be found at CLIC09.
General issues (CLIC @ 500 GeV or @ 3 TeV)
• Correlation between luminosity & beamstrahlung & hadronic background:
Trade-off between luminosity in 1% peak and background ?
Trade-off between luminosity in a large energy window and background ? Revisit conclusions from 2004 report.
• Correlation between longer bunch-spacing, luminosity and background:
E.g. for absolute calibration runs (once a year?) one may not want to accumulate the background from many bunch-crossings.
• Requests for regular alignment runs at the Z (91 GeV c.m.)
• What is loss in forward physics due to a 20 mrad crossing angle
• What are consequences of a longer detector (e.g. + 1m)? Space considerations and luminosity loss at 0.5 TeV and 3 TeV.
CLIC @ 500 GeV
• Comparison of CLIC – ILC parameters relevant for physics, e.g. luminosity spectrum and backgrounds
CLIC @ 3 TeV
• A possible run-plan for the first XYZ years of CLIC: Strategy for SUSY threshold scans for a given total integrated luminosity (several ab-1). This would require efficient change of energy (steps of several 100 GeV).
Update Snowmass 2001 results on threshold scans to high energy.
• What is realistic long term integrated luminosity at high energy in a pull-push scenario and with extra calibration runs? Give physics cases for 1, 3 and 5 ab-1
• Physics cases which need positron polarisation. How much polarisation is needed?
• Depolarisation due to beam-beam effect ? What is uncertainty in the e- polarisation at the IP ?
• Reduction of backscattering may require modifications in the very forward region (<50mrad) such as a different beam pipe profile or extra compensation magnets etc. What is possible?
• Bhabha events deflection due to beam-beam – what is this effect at 3 TeV, and how does it degrade the accuracy of the luminosity measurement ?