International Linear Collider (ILC) is an electron-positron collider with the initial center-of-mass energy of 500 GeV which is upgradable to about 1 TeV later on. Its goal is to study the physics at TeV scale with unprecedented high sensitivities. The main topics include precision measurements of the Higgs particle properties, studies of supersymmtric particles and the underlying theoretical structure if supersymmetry turns out to be realized in nature, probing alternative possibilities for the origin of mass, and the cosmological connections thereof. In many channels, Higgs and leptonic sector in particular, ILC is substantially more sensitive than LHC, and is complementary to LHC overall. In this short article, we will have a quick look at the capabilities of ILC.
This article reviews the physics case for the ILC. Baseline running at 500 GeV as well as possible upgrades and options are discussed. The opportunities on Standard Model physics, Higgs physics, Supersymmetry and alternative theories beyond the Standard Model are described.
In the Randall-Sundrum model there can be a rich new phenomenology associated with Higgs-radion mixing. A photon-photon collider would provide a crucial complement to the LHC and a future ILC collider for fully determining the parameters of the model and definitively testing it.
The measurement of the Higgs coupling to W bosons is an important program at the international linear collider (ILC) to search for the anomaly in the coupling to the gauge bosons. We study the sensitivity of ILC to the Higgs anomalous coupling to W bosons by using ZH->vvWW* events. In this article, we report the status of the study.
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~ slepton in the coannihilation region relevant to dark matter, as well as other SUSY signatures. he studies are based on the ILD concept at the ILC.
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~ slepton in the coannihilation region relevant to dark matter, as well as other BSM signatures. The studies are based on the ILD concept at the ILC.
The prospects for the discovery and exploration of low-energy Supersymmetry at future colliders, the Large Hadron Collider (LHC) and the future international linear electron positron collider (ILC) are summarized. The focus is on the experimental techniques that will be used to discover superpartners and to measure their properties. Special attention is given to the question how the results from both machines could influence each other, in particular when they have overlapping running time.
The synergy between the Large Hadron Collider and the International Linear Collider during concurrent running of the two machines has the potential to maximise the physics gain from both facilities. Some examples of detailed case studies of the interplay between the LHC and ILC are given, with a particular emphasis on new results that have been obtained after the first LHC / ILC Study Group report was released.
Combined analyses at the Large Hadron Collider and at the International Linear Collider are important to reveal precisely the new physics model as, for instance, supersymmetry. Examples are presented where ILC results as input for LHC analyses could be crucial for the identification of signals as well as of the underlying model. The synergy of both colliders leads also to rather accurate SUSY parameter determination and powerful mass constraints even if the scalar particles have masses in the multi-TeV range.
A dark Z is a massive Abelian gauge boson which is coupled to the Standard Model through both kinetic and mass mixing with the electroweak sector. We study the phenomenology of the dark Z at an energy-frontier electron-positron collider, such as the proposed International Linear Collider (ILC). We show that precision electroweak constraints and the current bounds from the hadron colliders allow a dark Z that is kinematically accessible at the ILC with 250 GeV or 500 GeV center-of-mass energy. Further, the reach of the ILC searches for a dark Z significantly exceeds the expected reach of the hi…
We present the full O(alpha) electroweak radiative corrections to 9 Higgs boson production with the beam polarization at the International Linear Collider(ILC). The computation is performed with the help of GRACE-Loop. We compared the full O(alpha) electroweak radiative corrections with the factorized initial state radiation(ISR) effects to estimate the pure weak corrections. This reveals the pure weak corrections are not negligible and should be taken into account for the precision measurements of the Higgs boson property at the ILC experiments.
The large hadron collider (LHC) is anticipated to provide signals of new physics at the TeV scale, which are likely to involve production of a WIMP dark matter candidate. The international linear collider (ILC) is to sort out these signals and lead us to some viable model of the new physics at the TeV scale. In this article, we discuss how the ILC can discriminate new physics models, taking the following three examples: the inert Higgs model, the supersymmetric model, and the littlest Higgs model with T-parity. These models predict dark matter particles with different spins, 0, 1/2, and 1, res…
The measurement of hadronic Higgs Boson branching ratios H -> bb, H -> gg for a light Standard Model-like Higgs boson produced at 250 GeV centre of mass energy at the International Linear Collider (ILC) is presented. The tools and techniques used for the analysis are briefly discussed.
In this paper we study double vector meson production in $γγ$ interactions at high energies and, using the color dipole picture, estimate the main observables which can be probed at the International Linear Collider (ILC). The total $γ(Q_1^2) + γ(Q_2^2) \rightarrow V_1 + V_2$ cross-sections for $V_i = ρ$, $ϕ$, $J/ψ$ and $Υ$ are computed and the energy and virtuality dependencies are studied in detail. Our results demonstrate that the experimental analysis of this process is feasible at the ILC and it can be useful to constrain the QCD dynamics at high energies.
Lepton flavor violating (LFV) process $e^+ e^- \to e^+ τ^-$ induced by the four-Fermi contact interactions at the International Linear Collider (ILC) is studied. Taking account of the event selection conditions, it is shown that the ILC is sensitive to smaller LFV couplings as compared to the measurement of $τ\to 3e$ process at the B-factory experiment. The upper bounds on some of the LFV couplings are improved by several factors using polarized $e^-/e^+$ beams at $\sqrt{s}=250~\mathrm{GeV}$ and by an order of magnitude at $\sqrt{s}=1~\mathrm{TeV}$.
I estimate the accuracies on Higgs boson coupling constants that experiments at the Large Hadron Collider and the International Linear Collider are capable of reaching over the long term.
We present an analysis for the measurement of the Higgs boson branching ratio H-> cc-bar for a light Standard Model-like Higgs boson produced at 250 GeV centre of mass energy at the International Linear Collider (ILC). The tools and technique used for the analysis are described and relative uncertainties are determined.
The International Linear Collider has a rich physics programme, whatever lies beyond the standard model. Accurate measurement of the top quark mass is needed to constrain the model or its extensions. If there is a light Higgs boson the LHC should see it, but the ILC will pin down its characteristics and test them against model predictions. If Supersymmetric particles appear the ILC will measure a complementary set of them to those seen at the LHC, and may allow extrapolation to the Grand Unified scale. And if a strong electroweak sector is indicated the ILC will be sensitive to the presence of…
A study is presented illustrating the excellent potential of future International Linear Collider (ILC) experiments to detect metastable staus $\stau$, measure precisely their mass and lifetime, and to determine the mass of the gravitino $\sG$ from the decay $\stau\toτ\sG$, thus providing direct access to the gravitational coupling, respectively Planck scale.
We study the neutral Higgs boson production at the CERN Large Hadron Collider (LHC) and the future $e^- e^+$ linear collider (ILC) in the two Higgs doublet model with CP violation. The CP-even and CP-odd scalars are mixed in this model, which affects the production processes of neutral Higgs boson. We examine the correlation of the Higgs production at LHC and ILC and provide a strategy to distinguish the model from the CP conserving model and to determine the parameters of the Higgs sector.
In this paper we study the effect of new physics contributions to the top quark pair production ($t\bar{t}$) in a possible future linear collider, such as the International Linear Collider (ILC). The use of a dimension-six gauge invariant effective operator approach allows to compare the prospected results at the ILC with the current ones obtained at the Large Hadron Collider (LHC), both in neutral and charged current processes. We also prove that the use of specific observables, together with a combination of measurements in different polarized beam scenarios and with different center-of-mass…
The physics case for studying top-quark physics at the International Linear Collider is well established. This summary places in context the top-quark physics goals, examines the current state-of-the art in understanding of the top-quark mass, and identifies some areas in which the study of the top-quark mass enhances our understanding of new techniques.
We investigate the sensitivity to long-lived dark photons produced in Higgstrahlung events via the Higgs portal, $H \rightarrow γ_{D} γ_{D}$, with the Silicon Detector (SiD) at the International Linear Collider (ILC). These events provide a useful benchmark for tracking and vertex detector performance with long-lived particle decays at displaced vertices. The ILC is one of several Higgs factories proposed by the international community to study the properties of the Higgs boson at high precision.
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 parameters is discussed.
The International Linear Collider (ILC) will be able to precisely measure the electroweak couplings of the top in e+e- -> tt~. We compare the limits which can be achieved at the ILC with those which can be obtained in tt~gamma$ and tt~Z production at the Large Hadron Collider (LHC).
We consider possible production of heavy leptons via anomalous interactions at future $ep$ colliders (THERA and LHeC), $e^+e^-$ colliders (ILC and CLIC) and $pp$ collider CERN LHC. The production, backgrounds and signatures of heavy leptons are analyzed. We obtain the upper mass limits of 800 GeV at LHeC, 450 GeV at ILC and 650 GeV at LHC for optimal choices of relevant parameters.
The International Linear e+e- Collider (ILC) could go into operation in the second half of the upcoming decade. Experimental analyses and theory calculations for the physics at the ILC are currently performed. We review recent progress, as presented at the LCWS06 in Bangalore, India, in the fields of Higgs boson physics and top/QCD. Also the area of loop calculations, necessary to achieve the required theory precision, is included.
Neutralino pair production via photon-photon collisions is analyzed in the context of Minimal Supersymmetric Standard Model at future linear collider. Since photon does not have self coupling, this process is only possible at Next-to-Leading order and all the possible terms are calculated for the photon-photon interaction, including box, triangles and quartic coupling diagrams. Numerical analysis of the production rates for $ \tildeχ^0_1 \tildeχ^0_1$, $ \tildeχ^0_1 \tildeχ^0_2$ and $ \tildeχ^0_2 \tildeχ^0_2$ are presented for four new distinct benchmark models which are presented in the light …
The future of high-precision electroweak physics lies in e+e- collider measurements of properties of the Z boson, the W boson, the Higgs boson, and the top quark. We estimate the expected performance of three possible future colliders: the ILC, FCC-ee (formerly known as TLEP), and CEPC. In particular, we present the first estimates of the possible reach of CEPC, China's proposed Circular Electron-Positron Collider, for the oblique parameters S and T and for seven-parameter fits of Higgs couplings. These results allow the physics potential for CEPC to be compared with that of the ILC and FCC-ee…
Two next-generation high-energy experiments, the Large Hadron Collider (LHC) and the $e^+e^-$ International Linear Collider (ILC), are highly expected to unravel the new structure of matter and forces from the electroweak scale to the TeV scale. In this talk we give a compelling but rather descriptive review of the complementary role of LHC and ILC in drawing a comprehensive and high precision picture of the mechanism breaking the electroweak symmetries and generating mass, the unification of forces and the structure of spacetime. Supersymmetry is exploited in this description as a prototype s…
I will begin by making a few general comments on the synergy between the Large Hadron Collider (LHC) which will go in action in 2007 and the International Linear Collider (ILC) which is under planning. I will then focus on the synergy between the LHC and the PLC option at the ILC, which is expected to be realised in the later stages of the ILC program. In this I will cover the possible synergy in the Higgs sector (with and without CP violation), in the determination of the anomalous vector boson couplings and last but not the least, in the search for extra dimensions and radions.
We summarize the physics case for the International Linear Collider (ILC). We review the key motivations for the ILC presented in the literature, updating the projected measurement uncertainties for the ILC experiments in accord with the expected schedule of operation of the accelerator and the results of the most recent simulation studies.
Some aspects of electroweak physics at the International Linear Collider (ILC) are reviewed. The importance of precision measurements in the Higgs sector and in top-quark physics is emphasized, and the physics potential of the GigaZ option of the ILC is discussed. It is shown in particular that even in a scenario where the states of new physics are so heavy that they would be outside of the reach of the LHC and the first phase of the ILC, the GigaZ precision on the effective weak mixing angle may nevertheless allow the detection of quantum effects of new physics.
During the preparatory phase of the International Linear Collider (ILC) project, all technical development and engineering design needed for the start of ILC construction must be completed, in parallel with intergovernmental discussion of governance and sharing of responsibilities and cost. The ILC Preparatory Laboratory (Pre-lab) is conceived to execute the technical and engineering work and to assist the intergovernmental discussion by providing relevant information upon request. It will be based on a worldwide partnership among laboratories with a headquarters hosted in Japan. This proposal…
The WIMP (weakly interacting massive particle) paradigm for dark matter is currently being probed via many different experiments. Direct detection, indirect detection and collider searches are all hoping to catch a glimpse of these elusive particles. Here, we examine the potential of the ILC (International Linear Collider) to shed light on the origin of dark matter. By using an effective field theory approach we are also able to compare the reach of the ILC with that of the other searches. We find that for low mass dark matter (< 10 GeV), the ILC offers a unique opportunity to search for WIMPS…
Weakly interacting massive particles (WIMPs) form a promising solution to the dark matter problem and many experiments are now searching for these particles. Using effective field theories to describe the interaction of the WIMP with the Standard Model has proven successful in providing an easy way to compare the different experimental results. In this work, we show how effective operators can be formally derived from a UV-complete underlying theory, and we analyse these operators in different experimental contexts. We put our main focus on the expected sensitivity of the International Linear …
The International Linear Collider (ILC) is a proposed electron -- positron collider with a collision energy of $\sqrt{s}$ = 500 GeV in the baseline configuration. The ILC physics program takes full advantage of the fact that the machine can be operated at arbitrary energy from the maximum down to the peak of the ZH production cross section near $\sqrt{s}$ = 250 GeV or below. It will advance our understanding of nature through precision measurements of Standard Model parameters, detailed study of the Higgs sector, and a comprehensive search for new phenomena that extends beyond the purely kinem…
The signature of heavy fermionic triplets belonging to Type III seesaw at the International Linear Collider (ILC) is probed. Presence of charged fermionic triplets upto a mass of about $ 750$ GeV could be established through single production at a 1 TeV ILC with moderate luminosity of 300 fb$^{-1}$, assuming a fermion triplet-electron mixing of about 0.05. Unlike the case of LHC, the production process is highly sensitive to the mixing, making the process interesting. The single production of neutral triplet is found to be somewhat harder, considering the large SM background present. Pair prod…
The physics prospect at future linear $e^{+}e^{-}$ colliders for the study of the Higgs triple self-coupling via the process of $e^{+}e^{-}\to ZHH$ is investigated. In this paper, we calculate the contribution of the new particles predicted by the littlest Higgs model to the cross sections of this process in the future high energy $e^{+}e^{-}$ collider($ILC$). The results show that, in the favorable parameter spaces preferred by the electroweak precision, the deviation of the total cross sections from its $SM$ value varies from a few percent to tens percent, which may be detected at the future…
We study the feasibility of the Type-X two Higgs doublet model (THDM-X) at collider experiments. In the THDM-X, new Higgs bosons mostly decay into tau leptons in the wide range of the parameter space. Such scalar bosons are less constrained by current experimental data, because of the suppressed quark Yukawa interactions. We discuss a search strategy of the THDM-X with multi-tau lepton final states at International linear collider and Large Hadron Collider. By using the collinear approximation, we show that a four tau lepton signature (e^+e^- -> HA -> 4τ) can be a clean signal.
We calculate the cross-section of the near-threshold off-shell $ZZZ$ and $ZW^+W^-$ production at the International Linear Collider taking into account their instability and the principal part of NLO corrections. The calculations are performed in the framework of the model of unstable particles with smeared mass-shell. We show that the contribution of the finite $Z/W$ and $H$ widths (their instability) is large in the Higgs resonance range and should be taken into account in the Higgs boson searches at future colliders.
The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unravelling the structure of the underlying physics. The physics return of the ILC can be maximized by the use of polarized beams, in particular the simultaneous polarization of the e- and the e+ beam. Ongoing physics studies are accompanied by active R&D on the machine part for generating polarized beams and for measuring the polarization with high precision at the ILC. Some new results on the physics case and on the technical aspects of the polarization of both …
The T-odd leptons are the typical particles predicted by the littlest Higgs model with T-parity (LHT model) and the observation of these particles might be regarded as the direct evidence of the LHT model. In this paper, we investigate the production of a pair of T-odd leptons associated with a gauge boson $V$($γ$ or $Z$) at the international linear $e^{+}e^{-}$ collider (ILC). The numerical results show that the possible signals of the T-odd leptons may be detected in the future ILC experiments.
We study direct searches of additional Higgs bosons in multi-top-quarks events at the LHC with the collision energy of 14 TeV as well as the International Linear Collider (ILC) with the collision energy of 1 TeV. As a benchmark model, we consider two Higgs doublet models with a softly-broken discrete $Z_2$ symmetry, where the $t\bar t$ decay mode of additional neutral Higgs bosons can be dominant if their masses are heavy enough. Thus, the multi-top-quarks events become an important probe of the extended Higgs sector at future colliders. We estimate the discovery reach at the LHC and the ILC, …
In the littlest Higgs model with T-parity, we studied the contributions of the new particles to the top-quark pair production via $e^{+}e^{-}$ collision at the International Linear Collider. We calculated the top-quark pair production cross section and found this process can generate significantly relative correction. The result may be a sensitive probe of the littlest Higgs model with T-parity.
An attempt is made to present the contribution of the scalar unparticle on some scattering processes in the Randall - Sundum (RS) model. We have evaluated the contribution of the scalar unparticle on the W - pair production cross-sections at International Linear Colliders (ILC). The results indicate that at the low values of the scaling dimension and the bounds on scale $Λ_{U}$ are around few TeV, the cross-sections are much enhanced, which is quite comparable with the W-production in the standard model and hence it is worthwhile to explore in future colliders.
The ILC Higgs White Paper is a review of Higgs Boson theory and experiment at the International Linear Collider (ILC). Theory topics include the Standard Model Higgs, the two-Higgs doublet model, alternative approaches to electroweak symmetry breaking, and precision goals for Higgs boson experiments. Experimental topics include the measurement of the Higgs cross section times branching ratio for various Higgs decay modes at ILC center of mass energies of 250, 500, and 1000 GeV, and the extraction of Higgs couplings and the total Higgs width from these measurements. Luminosity scenarios based o…
A collider probe of the radiative seesaw models are considered. Two key ingredients of these models, the extended Higgs sector and the source of the Majorana mass, although these details differ model by model, would be studied at the TeV-scale electron-positron and electron-electron colliders. The searches and mass determinations in the inert doublet model, which is the extended Higgs sector of the Ma model, are summarized as an example.
The construction of the ILC tangential to Tevatron ring will give opportunity to investigate electron-proton, positron-proton, electron-antiproton, positron-antiproton interactions at 1 TeV center of mass energy. The analysis of the lepton-hadron collisions in these energy region is very important both for understanding of strong interaction dynamics and for adequate interpretation of future LHC and VLHC data. In addition, ILC-Tevatron collider will provide a possibility to realize photon-hadron collisions in the same energy region using Compton backscattered laser photon off ILC electron beam…
The Littlest Higgs Model with T-parity is one of the attractive candidates of physics beyond the Standard Model. One of the important predictions of the model is the existence of new heavy gauge bosons, where they acquire mass terms through the breaking of global symmetry necessarily imposed on the model. The determination of the masses are, hence, quite important to test the model. In this paper, the measurement accuracy of the heavy gauge bosons at the international linear collider (ILC) is reported.
The physics potential of the Large Hadron Collider in combination with the planned International Linear Collider is discussed for a difficult region of supersymmetry that is characterized by scalar SUSY particles with masses around 2 TeV. Precision measurements of masses, cross sections and forward-backward asymmetries allow to determine the fundamental supersymmetric parameters even if only a small part of the spectrum is accessible. No assumptions on a specific SUSY-breaking mechanism are imposed. Mass contraints for the kinematically inaccessible particles can be derived.
We discuss ILC measurements for a specific MSSM scenario with CP phases, where the lightest neutralino is a good candidate for dark matter, annihilating efficiently through t-channel exchange of light staus. These prospective (CP-even) ILC measurements are then used to fit the underlying model parameters. A collider prediction of the relic density of the neutralino from this fit gives 0.116<Omega h^2<0.19 at 95% CL. CP-odd observables, while being a direct signal of CP violation, do not help in further constraining Omega h^2. The interplay with (in)direct detection of dark matter and with meas…
This paper is the second part of my overview on photon colliders given at the conference ``The photon: its first hundred years and the future'' (PHOTON2005 + PLC2005). The first paper describes the first 25 years of the history and evolution of photon colliders. The present paper considers the photon collider at the ILC: possible parameters, technical problems and present status.
The top-color assisted technicolor (TC2) mode predicts the existence of a pair of charged top-pions $π^{\pm}_t$. In this paper, we study the production of the charged top-pions pair $π^{\pm}_t$ at next generation $γγ$ colliders. The results show that the production rates can reach the level of $10^2$ fb with reasonable parameter space. With a large number of events and the clean background, the charged top-pion should be observable at the $γγ$ colliders. Therefore, our studies can help us to search for charged top-pion, and furthermore, to test the TC2 model.
We study the effects of dimension six effective operators on the flavour violating production and decay of leptons at the International Linear Collider. Analytic expressions for the cross sections, decay widths and asymmetries of all flavour changing processes will be presented, as well as an analysis of the feasibility of their observation at the ILC.
Based on the non-relativistic quantum chromodynamics factorization framework, we study the inclusive $J/ψ$ photoproduction at the future high energy $e^+e^-$ collider, International Linear Collider(ILC), where the initial photons come from the back-scattering of laser and electron (positron). The intermediate states, $c\bar{c}$$({}^3\!S_1^{[\textbf{1}]}$,${}^1\!S_0^{[\textbf{8}]}$,${}^3\!S_1^{[\textbf{8}]}$,${}^3\!P_{0,1,2}^{[\textbf{8}]})$, and resolved photoproduction processes are considered. Numerical results show that the cross section of $J/ψ$ photoproduction at the ILC could be very lar…
Combined analyses at the Large Hadron Collider and at the International Linear Collider are important to unravel a difficult region of supersymmetry that is characterized by scalar SUSY particles with masses around 2 TeV. Precision measurements of masses, cross sections and forward-backward asymmetries allow to determine the fundamental supersymmetric parameters even if only a small part of the spectrum is accessible. Mass constraints for the heavy particles can be derived.
