PERFORMANCE GOALS AND DESIGN CONSIDERATIONS FOR A LINEAR COLLIDER CALORIMETER

Abstract

We demonstrate that the physics potential at a future linear electron positron collider (LC) demands a detector with excellent performance, in particular with unprecedented jet energy resolution. This can be achieved within the so-called particle flow approach which puts high emphasis on the imaging capabilities of the calorimeters. We discuss some principal design considerations for the electromagnetic and hadronic calorimeters which follow from this approach, and point to the most relevant technological challenges in the LC calorimeter R&D program. In the past years, a consensus has emerged in the international particle physics community that an electron positron linear collider (LC) with an initial centre-of-mass energy of 500 GeV, upgradeable to 1 TeV, should be the next big accelerator facility, and it should have significant running concurrent with the large hadron collider LHC. The presently envisaged time line with a start of commissioning in 2015 implies that conceptual detector design choices need to be made well before the end of this decade. A vigorous R&D program has therefore been started with the goal to advance the candidate technologies and to provide an experimental basis for these choices. 2. Physics performance goals The excellent physics potential of the linear collider [1] stems from the possibilities for discoveries as well as for precision measurements which provide sensitivity to physics far beyond its nominal energy reach. The detector has to match this precision with unprecedented resolution and minimized systematic effects. Some key measurements involve final states with heavy bosons (W, Z, H) which must be reconstructed in their hadronic decay mode in order to optimally exploit the available statistics. In general, in these multi-jet events no kinematic fits (as often applied in LEP physics) are possible.