Physics at the International Linear Collider

I discuss the motivation and physics potential of an electron-positron linear collider with a center-of-mass energy at the 1 TeV scale, in light of what we may expect to learn with the LHC. The comparison is illustrated with examples drawn from Higgs physics, top quark physics, and the search for large extra spacetime dimensions.

The ILC physics working group is a mixture of experimentalists and theorists mainly working in Japan. It has its origin in the previous LC physics study group and has been reformed with the initiative of a JSPS Creative Scientific Research project: "Research and Development of a Novel Detector System for the International Linear Collider". The working group is, however, formally independent of the JSPS project and is open to everybody who is interested in ILC physics. The pri...

Although the LHC experiments have searched for and excluded many proposed new particles up to masses close to 1 TeV, there are many scenarios that are difficult to address at a hadron collider. This talk will review a number of these scenarios and present the expectations for searches at an electron-positron collider such as the International Linear Collider. The cases discussed include the light Higgsino, the stau lepton in the coannihilation region relevant to dark matter, ...

Though there is strong evidence that dark matter is a major component of the universe, most aspects of dark matter are completely mysterious. We do not know what dark matter is, and we do not know how it is distributed in our galaxy. To resolve these and related questions, we will need information both from particle physics and from astrophysics. In this article, we will describe a path toward the solution of the problems of dark matter, and we will highlight the important ro...

I summarize the prospects for discovering and studying the properties of Higgs particles at future high-energy and high-luminosity $e^+e^-$ linear colliders. I will focus on the Higgs particle of the Standard Model and the Higgs bosons predicted by Supersymmetric theories.

The LHC experiments have searched for and excluded many proposed Beyond the Standard Model (BSM) theories. However, there are many scenarios where LHC has little or no sensitivity. Electron-positron colliders offers a different avenue for searches for such phenomena.In this talk, we will review the expectations for searches for number of BSM models at the International Linear Collider (ILC). We will discuss new Higgs-like scalars, indirect BSM via Standard Model Effective Fie...

The search for physics beyond the Standard Model motivates new high-energy accelerators, which will require high luminosities in order to produce interesting new heavy particles. Using the Higgs boson and supersymmetry as examples, we discuss the capabilities of the LHC and $e^+ e^-$ linear colliders in the TeV and multi-TeV energy ranges to discover and study new particles.

This presentation intends to illustrate the specific capabilities of an e$^+$e$^-$ sub-TeV collider to provide answers on the basic issues in physics: origin of mass, hierarchy of masses, cosmological problems. Some foreseeable scenarios are discussed with a possible synergy with LHC.

Recent progress in Higgs boson studies for the International e+e- Linear Collider (ILC) is reported. These studies include extended simulations of the measurement of the Higgs mass, measurements of the Higgs boson branching ratios at higher center-of-mass energies, and methods for extracting the Higgs boson self-coupling. Also, the interplay between the LHC and the ILC in the measurement of the top Yukawa coupling and in the extraction of the supersymmetric Higgs sector param...

The discovery of the Higgs boson at the LHC has opened the door to clarify the mechanism of electroweak symmetry breaking and the origin of masses of particles. The Higgs sector in the SM is the simplest but has no theoretical principle, so that there is a possibility of non-minimal Higgs sectors. While the standard model is not contradict with the current data at the LHC within the error, most of extended Higgs sectors can also reproduce the data. An extended Higgs sector of...