Tests of the Standard Model at the International Linear Collider
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yaunning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roma… 展开作者
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yaunning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roman Poeschl, Juergen Reuter, Frank Simon, Tomohiko Tanabe, James D. Wells, Jaehoon Yu, Junping Tian, Taikan Suehara, Marcel Vos, Graham Wilson, James Brau, Hitoshi Murayama
备注：
58 pages, 8 figures, 13 tables; v2: minor corrections to Table 11; v3: typo corrections; v4: additions to the W boson section
We present an overview of the capabilities that the International Linear Collider (ILC) offers for precision measurements that probe the Standard Model. First, we discuss the improvements that the ILC will make in precision electroweak observables, both from W boson production and radiative return to the Z at 250 GeV in the center of mass and from a dedicated GigaZ stage of running at the Z pole. We then present new results on precision measurements of fermion pair production, including the production of b and t quarks. We update the ILC projections for the determination of Higgs boson couplings through a Standard Model Effective Field Theory fit taking into account the new information on precision electroweak constraints. Finally, we review the capabilities of the ILC to measure the Higgs boson self-coupling.
The talk summarises the case for Higgs physics in $e^+e^-$ collisions and explains how Higgs parameters can be extracted in a model-independent way at the International Linear Collider (ILC). The expected precision will be discussed in the context of projections for the experiments at the Large Hadron Collider (LHC).
The pair productions of leptons and quarks at $e^+e^-$ Higgs factory are an important probe for new physics via precise measurements. The discovery and exclusion limits of $Z^\prime$ models at the International Linear Collider with $\sqrt{s} = 250$, 500 and 1000 GeV are calculated with selection efficiencies estimated in the existing full simulation studies. It shows a large potential of BSM searches with precise measurements at future energy-frontier $e^+e^-$ colliders.
The next-generation high-energy facilities, the CERN Large Hadron Collider (LHC) and the prospective $e^+e^-$ International Linear Collider (ILC), are expected to unravel new structures of matter and forces from the electroweak scale to the TeV scale. In this report we review 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, and the unification of forces in the frame of supersymmetry.
In the minimal Universal Extra Dimension model, single production of n = 2 gauge bosons provides a unique discriminating feature from supersymmetry. We discuss how the proposed International Linear Collider can act as a n = 2 factory, much in the same vein as LEP. We also touch upon the potential of the gamma-gamma mode of the collider to study the production and the decay of an intermediate mass Higgs boson and its KK excitations.
This presentation gives the prospects of measuring the general Lorentz structures of $VVH$ ($V=Z$, $γ$ and $W$) couplings at the International Linear Collider (ILC). Sensitivities to Higgs CP-even and CP-odd structures are evaluated by using various Higgs production channels and employing measurements of kinematical distributions. The evaluation is performed based on full detector simulation of the International Large Detector (ILD) at center-of-mass energies $\sqrt{s}=$ 250 and 500 GeV. Combined sensitivities on the anomalous $ZZH$ couplings are provided for a realistic operating scenario of …
A Higgs factory like the International Linear Collider (ILC) can play a significant role in searching for exotic decays of Higgs bosons. As an illustration, we investigate the ILC sensitivity for the decay topology $h\to a_1 a_1 \to τ\bar ττ\bar τ$ in the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM). Here $h$ can be either Standard-Model-like or non-standard, and $a_{1}$ is the lightest CP-odd Higgs boson. We also compare results to expectations for this channel at the LHC.
Weakly Interacting Massive Particles (WIMPs, $χ$) are candidates for Dark Matter. WIMP searches at lepton colliders are complementary to searches at hadron colliders and direct and indirect detection, since they directly probe the coupling to electrons which a priori is independent of the coupling to hadrons. Like at hadron colliders, WIMP pair production can be observed via an additional tag particle, in particular a photon from initial state radiation ($e^+e^-\rightarrowχχγ$). With this technique WIMP masses to nearly half the centre-of-mass energy can be probed. Polarised beams are essentia…
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…
Measurement of the Higgs coupling to W-bosons is an important test of our understanding of the electroweak symmetry breaking mechanism. We study the sensitivity of the International Linear Collider (ILC) to the presence of anomalous HW+W- couplings using ZH -> nu nu WW* -> nu nu 4j events. Using an effective Lagrangian approach, we calculate the differential decay rates of the Higgs boson including the effects of new dimension-5 operators. We present a Monte Carlo simulation of events at the ILC, using a full detector simulation based on geant4 and a real event reconstruction chain. Expected c…
The document is prepared for the LCWS2016 conference proceedings. The expected status of Higgs physics at the end of Run-3 is presented. The current Run-2 status is briefly reviewed, and the expected Higgs reach after the HL-LHC period is also summarized for some channels.
The International Linear Collider is now proposed with a staged machine design, with the first stage at $\sqrt{s}=$~250 GeV and an integrated luminosity goal of 2~ab$^{-1}$. One of the questions for the machine design is the importance of positron polarization. In this report, we review the impact of positron polarization on the physics goals of the $250$ GeV stage of the ILC and demonstrate that positron polarization has distinct advantages.
In this study, the sensitivity of future lepton colliders to WIMP dark matter is evaluated assuming WIMP pair production accompanied by a photon from initial state radiation, through which the process can be identified. A full detector simulation for the International Large Detector (ILD) concept at the International Linear Collider (ILC) is performed for a \com energy of 500\,GeV. Energy scales of up to $3$\,TeV can be tested for different effective operators for WIMP masses almost up to half the \com energy. The sensitivity benefits from the polarised beams, which can reduce the main SM back…
We study collider signatures for extra scalar bosons in the inert doublet model at the international linear collider (ILC). The inert doublet model is a simple extension of the standard model by introducing an additional isospin-doublet scalar field which is odd under an unbroken Z_2 symmetry. The model predicts four kinds of Z_2-odd scalar bosons, and the lightest of them becomes stable and a candidate of the dark matter as long as it is electrically neutral. Taking into account the constraints from various theoretical and phenomenological conditions, we perform a simulation study for the dis…
Top quark production in the process $e^+e^- \rightarrow t\bar{t}$ at a future linear electron positron collider with polarized beams is a powerful tool to determine the scale of new physics. Studies at the $\ttbar$ threshold will allow for precise determination of the top quark mass in a well defined theoretical framework. At higher energies vector, axial vector and tensorial CP conserving couplings can be separately determined for the photon and the $Z^0$ component in the electro-weak production process. The sensitivity to new physics would be dramatically improved w.r.t. to what expected fro…
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.
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.
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 International Linear Collider is now proposed with a staged machine design, with the first stage at 250 GeV with a luminosity goal of 2 ab-1. In this paper, we review the physics expectations for this machine. These include precision measurements of Higgs boson couplings, searches for exotic Higgs decays, other searches for particles that decay with zero or small visible energy, and measurements of e+e- annihilation to W+W- and 2-fermion states with improved sensitivity. A summary table gives projections for the achievable levels of precision based on the latest full simulation studies.
We study the capability of the international linear collider (ILC) to probe extra dimensions via the seesaw mechanism. In the scenario we study, heavy Kaluza-Klein neutrinos generate tiny neutrino masses and, at the same time, have sizable couplings to the standard-model particles. Consequently, a Kaluza-Klein tower of heavy neutrinos (N) can be produced and studied at the ILC through the process: e+e- -> vN followed by N -> Wl decay. We show that the single lepton plus two-jets final states with large missing energy from this signal process will provide a good opportunity to measure the masse…
We study direct searches of additional Higgs bosons in multi-top-quarks events at the LHC Run-II, its luminosity upgraded version with 3000 fb$^{-1}$, and the International Linear Collider (ILC) with the collision energy of 1 TeV. Additional Higgs bosons are predicted in all kinds of extended Higgs sectors, and their detection at collider experiments is a clear signature of the physics beyond the standard model. We consider two Higgs doublet models with the discrete symmetry as benchmark models. If these additional Higgs bosons are heavy enough, the decay modes including top quarks can be domi…
This document is prepared for the LCWS2016 conference proceedings. It reviews the current results on the Higgs CP property measurements from both ATLAS and CMS experiments in the Higgs to diboson decays, and in the Vector Boson Fusion production of Higgs via the ditau decay channel. The projected sensitivity of the ditau signal in HL-LHC is briefly discussed. Finally, it gives the prospects for the CP measurement in the Higgs to ditau decay with the tau substructure developments at both collaborations.
We consider supergravity with a gravitino lightest supersymmetric particle. The next-to-lightest supersymmetric particle (NLSP) decays to the gravitino with lifetime naturally in the range 10^4 - 10^8 s. However, cosmological constraints exclude lifetimes at the upper end of this range and disfavor neutralinos as NLSPs, leaving charged sleptons with lifetimes below a year as the natural NLSP candidates. Decays to gravitinos may therefore be observed by trapping slepton NLSPs in water tanks placed outside Large Hadron Collider (LHC) and International Linear Collider (ILC) detectors and draining…
The International Linear Collider (ILC) is the next large project in accelerator based particle physics. It is complementary to the LHC in many aspects. Measurements from both machines together will finally shed light onto the known deficiencies of the Standard Model of particle physics and allow to unveil a possible underlying more fundamental theory. Here, the possibilities of the ILC will be discussed with special emphasis on the Higgs sector and on topics with a strong connection to cosmological questions like extra dimensions or dark matter candidates.
This paper presents the status of Monte Carlo simulation of one of the luminosity detectors considered for the future e+e- International Linear Collider (ILC). The detector consists of a tungsten/silicon sandwich calorimeter with pad readout. The study was performed for Bhabha scattering events assuming a zero crossing angle for the beams.
The International Linear Collider (ILC) is the next large scale project in accelerator particle physics. Colliding electrons with positrons at energies from 0.3 TeV up to about 1 TeV, the ILC is expected to provide the accuracy needed to complement the LHC data and extend the sensitivity to new phenomena at the high energy frontier and answer some of the fundamental questions in particle physics and in its relation to Cosmology. This paper reviews some highlights of the ILC physics program and some of the major challenges for the accelerator and detector design.
The 4th Concept detector presently being designed for the International Linear Collider introduces several innovations in order to achieve the necessary experimental goal of a detecter that is 2-to-10 times better than the already excellent SLC and LEP detectors. We introduce a dual-readout calorimeter system, a cluster counting drift chamber, and a second solenoid to return the magnetic flux without iron. We discuss particle identification, momentum and energy resolutions, and the machine-detector interface that together offer the possibility of a very high-performance detector for e^+e^-phys…
We investigate a possibility of precision measurements for parameters of the Littlest Higgs model with T-parity at the International Linear Collider (ILC). The model predicts new gauge bosons (AH, ZH, and WH), among which the heavy photon (AH) is a candidate for dark matter. The masses of these new gauge bosons strongly depend on the vacuum expectation value that breaks a global symmetry of the model. Through Monte Carlo simulations of the processes: e+ e- ->AH ZH and e+ e- -> WH+ WH-, we show how precisely the masses can be determined at the ILC for a representative parameter point of the mod…
With the discovery of a Higgs boson at LHC, all particles of the Standard Model seem to have been observed experimentally, yet many questions are left unanswered. The discovery has intensified the planning for future high-energy colliders, which aim to probe the Standard Model and the mechanism of electroweak symmetry breaking with higher precision and to extend and complement the search for new particles currently under way at the LHC. The most mature option for such a future facility is the International Linear Collider ILC, an electron-positron collider with a centre-of-mass energy of 500 G…
The prospects for measuring the branching fraction of $H \to μ^+ μ^-$ at the International Linear Collider (ILC) have been evaluated based on a full detector simulation of the International Large Detector (ILD) concept, considering centre-of-mass energies ($\sqrt{s}$) of 250 GeV and 500 GeV. For both $\sqrt{s}$ cases, the two final states $e^+ e^- \to q\overline{q}H$ and $e^+ e^- \to ν\overlineνH$ have been analyzed. For integrated luminosities of 2 ab$^{-1}$ at $\sqrt{s} = 250$ GeV and 4 ab$^{-1}$ at $\sqrt{s} = 500$ GeV, the combined precision on the branching fraction of $H \to μ^+ μ^-$ is …
We present a brief summary of the International Linear Collider as documented in the 2013 Technical Design Report. The Technical Design Report has detailed descriptions of the accelerator baseline design for a 500 GeV e+e- linear collider, the R&D program that has demonstrated its feasibility, the physics goals and expected sensitivities, and the description of the ILD and SiD detectors and their capabilities.
The International Linear Collider (ILC) is a proposed electron-positron collider for the centre-of-mass energy range of 200 to 500 GeV and with upgrade options towards 1 TeV. The ILC would be the ideal tool to explore with high precision the properties of the new Higgs-like particle that has recently been discovered at the LHC with a mass of around 125 GeV. The ILC accelerator design is based on the mature superconducting technology that has been developed in the TESLA collaboration and that is currently being used for the European XFEL. The exploitation of the huge physics potential of the IL…
We discuss complementarity of discovery reaches of heavier neutral Higgs bosons and charged Higgs bosons at the LHC and the International Linear Collider (ILC) in two Higgs doublet models (2HDMs). We perform a comprehensive analysis on their production and decay processes for all types of Yukawa interaction under the softly-broken discrete symmetry which is introduced to avoid flavour changing neutral currents, and we investigate parameter spaces of discovering additional Higgs bosons at the ILC beyond the LHC reach. We find that the 500 GeV run of the ILC with the integrated luminosity of 500…
If the gamma-gamma resonance at 750 GeV suggested by 2015 LHC data turns out to be a real effect, what are the implications for the physics case and upgrade path of the International Linear Collider? Whether or not the resonance is confirmed, this question provides an interesting case study testing the robustness of the ILC physics case. In this note, we address this question with two points: (1) Almost all models proposed for the new 750 GeV particle require additional new particles with electroweak couplings. The key elements of the 500 GeV ILC physics program---precision measurements of the…
We investigate the potential of the International Linear Collider (ILC) to probe the mechanisms of neutrino mass generation and leptogenesis within the minimal seesaw model. Our results can also be used as an estimate for the potential of a Compact Linear Collider (CLIC). We find that heavy sterile neutrinos that simultaneously explain both, the observed light neutrino oscillations and the baryon asymmetry of the universe, can be found in displaced vertex searches at ILC. We further study the precision at which the flavour-dependent active-sterile mixing angles can be measured. The measurement…
The Circular Electron Positron Collider (CEPC) is a large-scale future collider facility that can serve as a factory of the Higgs boson, the W boson and the Z boson. This document provides a brief summary of the CEPC physics potential and the detector design concepts, both of which are laid out in detail in the Conceptual Design Report (CDR) released in November 2018. We also outline future directions and challenges. In the Addendum, we briefly describe the planning and the international organization of the CEPC. The next step for the CEPC team is to perform detailed technical design studies. …
The SiD Detector is one of two validated detector designs for the future International Linear Collider. SiD features a compact, cost-constrained design for precision Higgs couplings determination, and other measurements, and sensitivity to a wide range of possible new phenomena. A robust silicon vertex and tracking system, combined with a 5 Tesla central solenoidal field, provides excellent momentum resolution. The highly granular calorimeter system is optimized for Particle Flow application to achieve very good jet energy resolution over a wide range of energies. Details of the proposed imple…
We present a study of the experimental determination of the forward-backward asymmetry in the process $e^+e^-\to t\bar t$ and in the subsequent $t\to Wb$ decay, studied in the context of the International Linear Collider. This process probes the elementary couplings of the top quark to the photon, the $Z$ and the $W$ bosons at a level of precision that is difficult to achieve at hadron colliders. Measurement of the forward-backward asymmetry requires excellent $b$ quark identification and determination of the quark charge. The study reported here is performed in the most challenging all-hadron…
Many supersymmetric models predict new particles within the reach of the next generation of colliders. For an understanding of the model structure and the mechanism(s) of symmetry breaking, it is important to know the masses of the new particles precisely. In this article the measurement of the mass of the scalar partner of the top quark (stop) at an e+e- collider is studied. A relatively light stop is motivated by attempts to explain electroweak baryogenesis and can play an important role in dark matter relic density. A method is presented which makes use of cross-section measurements near th…
The Technical Design Report (TDR) of the ILC mainly concentrates on a baseline machine of 500 GeV centre-of-mass with detailed cost and manpower estimates consistent with this option. However, the discovery of a Higgs Boson with a mass of 125 GeV opens up the possibility of reducing cost by starting at a centre-of-mass energy of 250 GeV with the possibility of future upgrades to 500 GeV or even 1 TeV should the physics case for such an upgrade be compelling. The rest of this paper outlines the options for the design of a 250 GeV "Higgs factory".
The International Linear Collider (ILC) is now under consideration as the next global project in particle physics. In this report, we review of all aspects of the ILC program: the physics motivation, the accelerator design, the run plan, the proposed detectors, the experimental measurements on the Higgs boson, the top quark, the couplings of the W and Z bosons, and searches for new particles. We review the important role that polarized beams play in the ILC program. The first stage of the ILC is planned to be a Higgs factory at 250 GeV in the centre of mass. Energy upgrades can naturally be im…
We describe another detectora designed for the International Linear Collider based on several tested instrumentation innovations in order to achieve the necessary experi- mental goal of a detecter that is 2-to-10 times better than the already excellent SLC and LEP detectors, in particular, (1) dual-readout calorimeter system based on the RD52/DREAM measurements at CERN, (2) a cluster-counting drift chamber based on the successful kloe chamber at Frascati, and (3) a second solenoid to return the magnetic flux without iron. A high-performance pixel vertex chamber is presently undefined. We discu…
In this work, we consider the process $e^{+}+e^{-}\rightarrow b\bar{b}+\slashed{E}_{T}$, at the future electron-positron colliders such as the International Linear Collider and Compact Linear Collider, to look for the dark matter (DM) effect and identify its nature at two different center-of-mass energies $E_{c.m.}=500~\mathrm{GeV}~and~1~\mathrm{TeV}$. For this purpose, we take two extensions of the standard model, in which the DM could be a real scalar or a heavy right-handed neutrino (RHN) similar to many models motivated by neutrino mass. In the latter extension, the charged leptons are cou…
The International Linear Collider (ILC) is a proposed electron-positron collider with a center-of-mass energy of 500~GeV, and a peak luminosity of $2 \cdot 10^{34}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$. The ILC will complement the Large Hadron Collider, a proton-proton accelerator, and provide precision measurements, which may help in solving some of the fundamental questions at the frontier of scientific research, such as the origin of mass and the possible existence of new principles of nature. The linear collider community has set a goal to achieve a precision of $10^{-4}$ on the luminosity meas…
Precise measurement of Higgs boson couplings is an important task for International Linear Collider (ILC) experiments and will facilitate the understanding of the particle mass generation mechanism. In this study, the measurement accuracies of the Higgs boson branching fractions to the $b$ and $c$ quarks and gluons, $ΔBr(H\to b\bar{b},\sim c\bar{c},\sim gg)/Br$, were evaluated with the full International Large Detector model (\texttt{ILD\_00}) for the Higgs mass of 120 GeV at the center-of-mass (CM) energies of 250 and 350 GeV using neutrino, hadronic and leptonic channels and assuming an inte…
We present new results on charmonium-like states from the BaBar experiment located at the PEP-II asymmetric energy $e^+e^-$ collider at the SLAC National Accelerator Laboratory.
One of the detector benchmark processes investigated for the SiD Detailed Baseline Design (DBD) is given by: e+e- -> ttH, where H is the Standard Model Higgs boson of mass 125 GeV. The study is carried out at a centre-of-mass energy of 1 TeV and assuming an integrated luminosity of 1 ab-1. The physics aim is a direct measurement of the top Yukawa coupling at the ILC. Higgs boson decays to beauty quark-antiquark pairs are reconstructed. The investigated final states contain eight jets or six jets, one charged lepton and missing energy. Additionally, four of the jets in signal events are caused …
The International Linear Collider (ILC) will collide polarised electrons and positrons at beam energies of 45.6 GeV to 250 GeV and optionally up to 500 GeV. To fully exploit the physics potential of this machine, not only the luminosity and beam energy have to be known precisely, but also the polarisation of the particles has to be measured with an unprecedented precision of dP/P ~ 0.25% for both beams. An overall concept of high precision polarisation measurements at high beam energies will be presented. The focus will be on the polarimeters (up- and downstream of the e+e- interaction point) …
Polarised electron and positron beams are key ingredients to the physics programme of future linear colliders. Due to the chiral nature of weak interactions in the Standard Model - and possibly beyond - the knowledge of the luminosity-weighted average beam polarisation at the $e^+e^-$ interaction point is of similar importance as the knowledge of the luminosity and has to be controlled to permille-level precision in order to fully exploit the physics potential. The current concept to reach this challenging goal combines measurements from Laser-Compton polarimeters before and after the interact…
The International Large Detector (ILD) is a concept for a detector at the International Linear Collider, ILC. The ILC will collide electrons and positrons at energies of initially 500 GeV, upgradeable to 1 TeV. The ILC has an ambitious physics program, which will extend and complement that of the Large Hadron Collider (LHC). A hallmark of physics at the ILC is precision. The clean initial state and the comparatively benign environment of a lepton collider are ideally suited to high precision measurements. To take full advantage of the physics potential of ILC places great demands on the detect…
CMOS sensors were successfully implemented in the STAR tracker [1]. LHC experiments have shown that efficient b tagging, reconstruction of displaced vertices and identification of disappearing tracks are necessary. An improved vertex detector is justified for the ILC. To achieve a point(spatial single layer) resolution below the one-μm range while improving other characteristics (radiation tolerance and eventually time resolution) we will need the use of 1-micron pitch pixels. Therefore, we propose a single MOS transistor that acts as an amplifying device and a detector with a buried charge-co…
One of the potential problems of a Micro-Pattern Gaseous Detector (MPGD)-based Time Projection Chamber (TPC) is the Ion back Flow (IBF): ions generated through the avalanche amplification process flow back to the drift volume of the TPC and disarrange an electric field inside it. Consequently non-negligible degradation of azimuthal spatial resolution is caused due to this IBF. Meanwhile, it is necessary to collect primary ionized electrons to maintain intrinsic performance of the MPGDs. The MPGD based TPC is currently planned to be used as a central tracking detector of the International Large…
A large, world-wide community of physicists is working to realise an exceptional physics program of energy-frontier, electron-positron collisions with the International Linear Collider (ILC). This program will begin with a central focus on high-precision and model-independent measurements of the Higgs boson couplings. This method of searching for new physics beyond the Standard Model is orthogonal to and complements the LHC physics program. The ILC at 250 GeV will also search for direct new physics in exotic Higgs decays and in pair-production of weakly interacting particles. Polarised electro…
The International Linear Collider (ILC) being proposed in Japan is an electron-positron linear collider with an initial energy of 250 GeV. The ILC accelerator is based on the technology of superconducting radio-frequency cavities. This technology has reached a mature stage in the European XFEL project and is now widely used. The ILC will start by measuring the Higgs properties, providing high-precision and model-independent determinations of its parameters. The ILC at 250 GeV will also search for direct new physics in exotic Higgs decays and in pair-production of weakly interacting particles. …
Although the existence of Dark Matter (DM) has been suggested by various astrophysical observations, it has not yet been discovered today. We can assume a scenario in which the particles that account for the DM can interact with the Standard Model particles only through their couplings with the Higgs sector, the so-called Higgs-portal model. This model can be investigated by collider experiment using the invisible decay of Higgs boson. In this study, we evaluate the search ability of International Linear Collider (ILC) for invisible decay of the Higgs using International Large Detector (ILD) f…
This paper presents the latest development at CERN, concentrating on the status of the LHC and the strategy for future linear colliders. The immediate plans include the exploitation of the LHC at its design luminosity and energy as well as upgrades to the LHC (luminosity and energy) and to its injectors. This may be complemented by a linear electron-positron collider, based on the technology being developed by the Compact Linear Collider and by the International Linear Collider and/or by a high-energy electron-proton collider. This contribution describes the various future directions, all of w…
