Physics at the Large Hadron Collider (LHC) and the International e + e − Linear Collider (ILC) will be complementary in many respects, as has been demonstrated at previous generations of hadron and lepton colliders. This report addresses the possible interplay between the LHC and ILC in testing the Standard Model and in discovering and determining the origin of new physics. Mutual benefits for the physics programme at both machines can occur both at the level of a combined interpretation of Hadron Collider and Linear Collider data and at the level of combined analyses of the data, where results obtained at one machine can directly influence the way analyses are carried out at the other machine. Topics under study comprise the physics of weak and strong electroweak symmetry breaking, supersymmetric models, new gauge theories, models with extra dimensions, and electroweak and QCD precision physics. The status of the work that has been carried out within the LHC / LC Study Group so far is summarised in this report. Possible topics for future studies are outlined.4

The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.2

Contrary to commonly held belief, we show that one can obtain a low value for M#, the SU(2)H breaking scale, in grand unification theories based on SO(10). This possibility emerges in the supersymmetric version of SO(10) with a judicious choice of Higgs content. The unification scale is found to be consistent with the constraint from proton decay. This result is first explicitly demonstrated using the one-loop renormalization group equations, and then a full two-loop analysis is carried out.It is commonly believed [1,2] that the group SU(2).R has to be broken at a large energy scale MR ~ 10 10 GeV if it is to emerge from a grand unified symmetry such as SO(10). This is also assumed to be true for the supersymmetric (SUSY) version of SO( 10) [1,2]. Consequently, additional gauge bosons that could possibly be produced at supercollider energies are thought to originate only from additional U(l) factors which lead to Z' bosons [3]. The phenomenology of new charged W bosons at supercolliders is therefore less frequently investigated [4], We will show in this Letter that although the above result is true for the simplest Higgs structure, if this sector is suitably enlarged, the scale for the right-handed gauge bosons, MR, could be made arbitrarily low. We will consider only the supersymmetric version in detail, with some brief remarks on the nonsupersymmetric case given at the end of our discussion.We investigate the break chainwhere, as an example of our notation, 2^ represents SU(2)i,. Here, we have set the "effective" super symmetry breaking scale to be Mz, and will comment on this later. In Ref.[5], it was shown that if both 2JJ2R\B-L^C singlets of the 210 representation, together with the ^L^BXB-L&C singlet of the 45 representation, acquire vacuum expectation values (VEVs) then this is sufficient to break supersymmetric SO(10) down to supersymmetric 2L2RIB-L%C without D parity. The breaking at MR can be performed either by the Higgs fields in the 1260126 representation or in the 16 © 16 representation and we consider both these possibilities in our discussion below. We further assume that ordinary electroweak breaking at the Z scale is achieved as usual by a complex 10 representation. For the purpose of generating fermion masses, we assume that the entire bi-doublet of the 10 representation has a mass at the scale of Mz> [We remind the reader that a bi-doublet corresponds to the (2,2,0,1) representation of 2L2R1B-L^C] Also, we assume that the SU(2)# triplets of the 126 and 126 representations and the SU^)^ doublets of 16 and 16 representations have masses at the scale MR. All other Higgs multiplets are given masses of order MJJ as follows from the survival hypothesis. We make the important observation that in this symmetry breaking pattern pseudo Goldstone bosons do not appear [5].First let us examine the one-loop equations:The 6j's are the one-loop beta functions, which for the supersymmetric case are given byfor n g generations, the gauge group SU(iV), and the complex Higgs fields contribution which is parametri...

We examine the ability of the detector of the Solenoidal Detector Collaboration (SDC) to identify the origin of a new neutral gauge boson Z 2 in the TeV mass range at the Superconducting Super Collider. Specifically, given the measurements of the Z 2 production cross section, width, and leptonic forwardbackward asymmetry, together with their associated statistical and systematic errors, we address two related questions: (i) For two different extended electroweak models, up to what mass can their corresponding Z 2 bosons be distinguished, and (ii) how well can the Z 2 couplings be determined? Our calculations include O ( a f ) QCD, as well as oblique electroweak radiative corrections to the above quantities, and allow for uncertainties due to structure functions, detector efficiencies, lepton identification, luminosity measurement errors, and finite lepton-pair mass resolution, using the specifications of the SDC detector. Nine distinct classes of extended electroweak models are investigated and results are obtained for integrated luminosities of lo4 and lo5 pb-'.PACS number(s): 13.85. Rm, 12.15.Cc, 14.80.Er