Run Scenarios for the Linear Collider

The physics program of the linear e+e- collider LC is potentially very extensive, particularly in the case that a Higgs boson with mass below 300 GeV is found and relatively low energy scale supersymmetry (SUSY) exists. For such a case, they have examined a possible run plan for the LC to explore the new states and their masses, and estimated the precision on measured parameters that can be attained in a reasonable time span. For this study, they have examined a scenario with a light SM-like Higgs boson of mass 120 GeV and two minimal supergravity (mSUGRA) models with many low mass sparticles. This scenario is conservative; with many particles to study there are many desired operational conditions for the collider (different energies and beam polarizations). They have not assumed that positron polarization is available, again a conservative assumption from the point of view of the running time required. We have taken the total time for the runs to be that required to accumulate 1 ab-1 (1000 fb -1) at 500 GeV. Based on estimates [1] of the luminosity that could be delivered by the LC summarized in Table I, we estimate that this represents a program for the first 6-7 years of LC operation. Such an estimate is only qualitative and depends more upon the ultimate luminosity of the accelerator than upon the details of early low luminosity during commissioning. We have chosen two SUSY benchmarks shown in Table II: the TESLA TDR RR1 [2] and the Snowmass E3 working group [3] point, also known as benchmark SPS1. They provide a rich spectrum of sparticles at relatively low masses. The TESLA RR1 scenario has been used for a variety of previous studies, but is now ruled out by LEP data. The SPS1 point gives low sparticle masses, but emphasizes decays via τ's and thus provides additional experimental challenges. For both scenarios, LHC should have discovered SUSY and explored some of its aspects prior to the LC operation. However, the precision measurements available at the LC, and its access to states unobservable at the LHC, will be needed for the full exploration of the new physics. In devising a proposed run plan, one should keep in mind that it is entirely possible, even likely, that there is new physics to be explored that depends on operation of the LC near its highest energy. Thus a run plan that devotes excessive operation at lower energies may be counterproductive. Scenarios are developed for runs at a Linear Collider, in the case that there is a rich program of new physics