Precision Physics Program at International Linear Collider (ILD & SiD) Conference

News from LCC Conference Working Group ICHEP 2014 Submitted abstracts: - 6 Physics, 2 Concepts (ILD & SiD), 4 detector R&D Response from organizers - 2 Higgs abstracts 1 talk + 1 poster ? - Others ? Speaker voluntaries, nominations, suggestions ?

Measurement of Higgs Boson Couplings at the International Linear Collider One of the key topics in the physics program of the ILC is the precision measurement of the couplings of the Higgs boson. At linear colliders, Higgs bosons are produced singly in association with Z bosons and by W boson fusion. In both processes, the backgrounds to Higgs production are relatively small, and all major Higgs boson decay modes can be observed. The Zh process gives tagged Higgs bosons, allowing measurement of absolute branching ratios and the observation of invisible and other exotic decays. The W fusion process gives high rates for precision measurement and allows the model-independent determination of the Higgs boson width and the individual Higgs couplings. This contribution will report the current status of this program, with results from full-simulation studies of Higgs processes in the detectors proposed for the ILC. Measurement of the Higgs Boson Coupling to the Top Quark and the Higgs Boson Self-Coupling at ILC At center of mass energies of 500 GeV and above, e+e- collisions lead to processes in which the Higgs boson is radiated from top quarks and antiquarks and events in which two Higgs bosons are produced. The first of these processes leads to a precision measurement of the Higgs boson coupling to top quarks, the second to a measurement of the Higgs boson self-coupling. The rates of these processes are small, but linear colliders offer many tools to extract the signal processes from background, including highly efficient flavor tagging, the full reconstruction of top-antitop systems, precise control of (3-dimensional) missing energy, control of initial beam polarization, and measurement of final-state polarization. This contribution will report the current status of this program, with results from full-simulation studies of these processes in the detectors proposed for the ILC. Measurement of the Top Quark Mass at Linear Colliders The future precision studies of the Standard Model require excellent knowledge of the top quark mass, to an accuracy of 100 MeV or better. This mass can be measured in a way that is free of any ambiguities from soft QCD by locating the threshold position for e+e- annihilation to top quarks, or, more precisely, the mass of the unstable 1S resonance. The measurement requires a combination of precise QCD calculations, excellent detection efficiency and recognition of top quark events, and excellent control of the initial beam energy and profile. This contribution will report the current status of this program, with results from full-simulation studies of measurements of the top quark threshold in the detectors proposed for ILC and CLIC.

Measurement of Top Quark Couplings at Linear Colliders Models in which the Higgs boson is composite or strongly interacting typically predict modifications of the coupling of the top quark to vector bosons and, in particular, to the Z boson. The production of the top quarks at e+e- colliders goes through the top quark couplings to the photon and the Z. Thus, precision studies of this pair production process, including its full dependence on electron and top quark polarization, has the potential to extract the form factors for the top quark couplings with high precision and in a model-independent way. This contribution will report the current status of this program, with results from full-simulation studies of top quark pair production in the detectors proposed for ILC and CLIC. Discovering Supersymmetry and Dark Matter at the International Linear Collider Although the LHC experiments have put strong limits on coloured supersymmetric states, it is still possible that electroweakly interacting supersymmetric particles have masses in the range 100-200 GeV. Even outside of supersymmetry, candidates for the particle of dark matter may have masses in this range unconstrained by LHC data. In e+e- annihilation, the low backgrounds, precise knowledge of the initial-state beams, and sensitivity to small energy depositions provides discovery potential complementary to the LHC, for instance in cases with small mass differences. This contribution will report the current status of studies for the prospects of measurements of WIMPs, Higgsinos and other light electroweak states at the International Linear Collider, with results based on simulation of the detectors proposed for the ILC. Precision measurement of SUSY at the ILC While the current 7/8 TeV results form the LHC excludes highly constrained SUSY models with a light sparticle spectrum, less constrained models are still viable. Certain such models promise both discovery of coloured sparticles during the 14 TeV run of the LHC, and a rich spectrum of non-coloured states, accessible at the ILC. LHC might or might not give a hint to the existence of these electro-weak states, but only at the ILC can measurements with sufficient precision be done to elucidate the details of the model. This contribution reports on studies of such models at the ILC based on simulation of the current detector proposals. It also discusses how the combined observations from LHC and ILC can be used to determine MSSM parameters in models with large numbers of free parameters.

Other conferences PANIC at the end of August in Hamburg, Germany (http://panic14.desy.de) - Abstract Deadline May 15 (!) - If no abstracts submitted yet, LCC could consider submit abstracts on Higgs, BSM, Top. International Conference on New Frontiers in Physics (ICNFP 2014) at the end of July / early August in Crete (http://indico.cern.ch/event/icnfp2014) - Abstract Deadline May 31 - any interests ?