Complementarity of the CERN Large Hadron Collider and the $e^+e^-$ International Linear Collider
S. Y. Choi
备注：
14 pages, 17 figures, to be published in "Supersymmetry on the Eve of the LHC", a special volume of European Physical Journal C, Particles and Fields (EPJC) in memory of Julius Wess
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.
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…
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…
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…
We study the complementarity between the Large Hadron Collider (LHC) and future lepton colliders in probing electroweak baryogenesis induced by an additional bottom Yukawa coupling $ρ_{bb}$. The context is general two Higgs doublet model (g2HDM) where such additional bottom Yukawa coupling can account for the observed baryon asymmetry of the Universe if $\mbox{Im}(ρ_{bb}) \gtrsim 0.058$. We find that LHC would probe the nominal $\mbox{Im}(ρ_{bb})$ required for baryogenesis to some extent via $bg \to bA \to bZh$ process if $300~\mbox{GeV}\lesssim m_A \lesssim 450$ GeV, where $A$ is the CP-odd s…
We address the complementarity of the CERN Large Hadron Collider and an $e^+ e^-$ Linear Collider in determining SUSY model parameters for a particular SO(10) SUSY GUT case study.
The Physics Beyond Colliders initiative is an exploratory study aimed at exploiting the full scientific potential of the CERN's accelerator complex and scientific infrastructures through projects complementary to the LHC and other possible future colliders. These projects will target fundamental physics questions in modern particle physics. This document presents the status of the proposals presented in the framework of the Beyond the Standard Model physics working group, and explore their physics reach and the impact that CERN could have in the next 10-20 years on the international landscape.
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…
The International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are the two options for a future high-energy, high-luminosity linear electron-positron collider. Both are expected to be built in stages, optimised for their physics potential. The main goals are the precision measurements of Higgs-boson and top-quark properties as well as direct and indirect searches for new physics Beyond Standard Model. In my talk I will review some of the latest results from both ILC and CLIC demonstrating their physics potential, pointing to similarities and complementarity of both projects.
We review the present seach for scalar leptoquarks and the potential of the CERN Large Hadron Collider (LHC) to unravel the existence of first generation leptoquarks. Talk given by O. J. P. Eboli at the International Workshop on "Physics Beyond the Standard Model: from Theory to Experiment", Valencia, 1997.
We study the production and signatures of doubly charged Higgs bosons in the process γγH^{- -} H^{++} at the e^-e^+ International Linear Collider and CERN Linear Collider, where the intermediate photons are given by the Weizs[a\ddot]cker-Willians and laser backscattering distributions.
A 100 TeV pp collider is under consideration, by the high-energy physics community, as an important step for the future development of our field, following the completion of the LHC and High-luminosity LHC physics programmes. In particular, CERN is considering 100 TeV pp collisions as the key target of a Future Circular Collider facility, built around a 100 km tunnel and designed to deliver pp, e+e- and ep collisions, in addition to a programme with heavy ion beams and with the injector complex. CERN is coordinating an international study tasked with the completion, by the end of 2018, of a Co…
The SU(3)$_L\otimesU(1)_N$ electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of doubly charged Higgs bosons in the $e^-e^+$ International Linear Collider and in the CERN Linear Collider. We compute the branching ratios for the doubly charged gauge bosons of the model.
Heavy neutral gauge bosons, Z's, are predicted by many theoretical schemes of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future high energy colliders. It is quite possible that Z's are heavy enough to lie beyond the discovery reach expected at the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z' exchanges may occur at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We here discuss in this context the foreseeable sensitivity to Z's of fermion-…
In this work we present an analysis of production and signature of neutral Higgs bosons $H_2^0$ in the version of the 3-3-1 model containing heavy leptons at the ILC (International Linear Collider) and CLIC (Cern Linear Collider). The production rate is found to be significant for the direct production of $e^{+} e^{-} \rightarrow H_{2}^{0} Z$. We also studied the possibility to identify it using their respective branching ratios.
This paper addresses the question of whether the International Linear Collider has the capability of discovering new particles that have not already been discovered at the CERN Large Hadron Collider. We summarize the various paths to discovery offered by the ILC, and discuss them in the context of three different scenarios: 1. LHC does not discover any new particles, 2. LHC discovers some new low mass states and 3. LHC discovers new heavy particles. We will show that in each case, ILC plays a critical role in discovery of new phenomena and in pushing forward the frontiers of high-energy physic…
We review our recent global analysis for probing the electroweak symmetry breaking (EWSB) mechanism by the universal effective Lagrangian description. After summarizing and commenting upon the current bounds for the EWSB parameters, we focus on testing them at the forthcoming high energy colliders such as the CERN LHC and the future linear colliders. We develop a precise electroweak power counting method (a la Weinberg) and formulate the longitudinal-Goldstone boson equivalence as a necessary criterion for sensitively probing the EWSB sector. Armed with these, we systematically estimate and cl…
Fermion dark matter (DM) as an admixture of additional singlet and doublet vector like fermions provides an attractive and allowed framework by relic density and direct search constraints within TeV scale, although limited by its discovery potential at the Large Hadron Collider (LHC). An extension of the model with scalar triplet can yield neutrino masses and provide some cushion to the direct search constraint of the DM through pseudo-Dirac mass splitting. This in turn, allow the model to live in a larger region of the parameter space and open the door for detection at LHC, even if slightly. …
The Compact Linear Collider (CLIC) is a proposed high-luminosity collider that would collide electrons with their antiparticles, positrons, at energies ranging from a few hundred Giga-electronvolts (GeV) to a few Tera-electronvolts (TeV). By covering a large energy range and by ultimately reaching multi-TeV $e^+e^-$ collisions, scientists at CLIC aim to improve the understanding of nature's fundamental building blocks and to discover new particles or other physics phenomena. CLIC is an international project with institutes world-wide participating in the accelerator, detector and physics studi…
In the framework of the left-right twin Higgs model, we study pair production of the neutral Higgs bosons at the International Linear Collider ($ILC$) and the $CERN$ $LHC$. We find that the production cross section of the process $e^{+}e^{-}\to ϕ^{0}h$ are at the level of several tens $fb$ at the $ILC$, the production cross section of the $ϕ^{0}ϕ^{0}$ pair and $ϕ^{0}h$ pair are at the level of several hundreds $fb$ at the $LHC$. As long as the neutral Higgs boson $ϕ^{0}$ is not too heavy, we conclude that its pair production might be used to test for the left-right twin Higgs model at the $LHC…
We investigate the effect induced by the Kaluza-Klein (KK) graviton in the $W^+W^-γ/Z$ production in the framework of the large extra dimensions (LED) model at both the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). The integrated cross sections and various kinematic distributions in the LED model are presented and compared with those in the standard model. The results show that the contributions from KK-graviton exchange remarkably affect the observables of the triple gauge boson ($W^+W^-γ/Z$) production processes at both the ILC and the LHC, particularly either…
String compactification with fluxes yields MSSM soft SUSY breaking terms that receive comparable contributions from modulus and anomaly mediation whose relative strength is governed by a phenomenological parameter $α$. Gaugino and first/second generation (and sometimes also Higgs and third generation) scalar mass parameters unify at a mirage unification scale $Q \not= M_{\rm GUT}$, determined by the value of $α$. The ratio of scalar to gaugino masses at this mirage unification scale depends directly on the scalar field modular weights, which are fixed in turn by the brane or brane intersection…
In the attempt to fully profile a $Z'$ boson accessible at the Large Hadron Collider (LHC), we study the sensitivity of di-lepton (for the electron, muon and tauon cases) and di-quark (for the case of the heavy flavours, $t$ and, possibly, $b$) samples to the nature of the new gauge state, for a one-dimensional class of non-exotic $Z'$ bosons. Assuming realistic final state reconstruction efficiencies and error estimates, we find that, depending on the CERN collider energy and luminosity, the best chances of extracting the $Z'$ quantum numbers occur when two or more of these channels are simul…
For the foreseeable future, the exploration of the high-energy frontier will be the domain of the Large Hadron Collider (LHC). Of particular significance will be its high-luminosity upgrade (HL-LHC), which will operate until the mid-2030s. In this endeavour, for the full exploitation of the HL-LHC physics potential an improved understanding of the parton distribution functions (PDFs) of the proton is critical. The HL-LHC program would be uniquely complemented by the proposed Large Hadron electron Collider (LHeC), a high-energy lepton-proton and lepton-nucleus collider based at CERN. In this wo…
To illustrate the complementarity of the linear collider and astrophysics bounds on the light (MeV-scale mass) dark matter (DM), we study the constraints on the magnetic dipole DM from the DM-electron interactions at the proposed International Linear Collider (ILC) and in supernova (SN) 1987A. We in particular focus on the $e^+ e^-$ annihilation which is the common process for producing DM pairs both at the ILC and in the SN. We estimate the bounds on the DM magnetic dipole moment from the mono-photon signals at the ILC and also from the energy loss rate due to the freely streaming DM produced…
Left-Right twin Higgs(LRTH) model predicts the existence of a pair of charged Higgs $ϕ^{\pm}$. In this paper, we study the production of the charged Higgs bosons pair $ϕ^{\pm}$ via the process $e^{+}e^{-}\to ϕ^{+}ϕ^{-}$ at the International Linear Collider(ILC). The numerical results show that the production rates are at the level of several tens fb, this process can produce the adequate distinct multi-jet final states and the SM background can be efficiently reduced. We also discuss the charged Higgs boson pair production via the process $q\bar{q}\to ϕ^{+}ϕ^{-}$ at the $CERN$ Large Hadron Col…
Data from the Large Electron Positron collider (LEP) at CERN on hadron production in gamma-gamma interactions exceed the predictions of the standard model by an order of magnitude at the highest observed transverse momenta in three channels. The amplitude for the process is asymptotically proportional to the sum of the squares of the charges of quarks. The data are suggestive of models where quarks have unit charges, or larger, and where partons have substructure. A previously proposed model of electro-strong interactions includes both these features. Definitive measurements could be made with…
We study the neutral Higgs sector of the minimal supersymmetric standard model (MSSM) with explicit CP violation at the one-loop level. We take into account the one-loop contributions by the top quark, the stop quarks, the bottom quark, the sbottom quarks, the tau lepton, the stau leptons, the $W$ boson, the charged Higgs boson, the charginos, the $Z$ boson, the neutral Higgs bosons, and the neutralinos. The production cross sections of the neutral Higgs boson are calculated to the leading order. The processes in our consideration are divided in two groups: the Higgs-strahlung and gluon fusion…
The measure of the triple Higgs coupling is one of the major goals of the high-luminosity run of the CERN Large Hadron Collider (HL-LHC) as well as the future colliders, either leptonic such as the International Linear Collider (ILC) or hadronic such as the 100 TeV Future Circular Collider in hadron-hadron mode (FCC-hh). We have recently proposed this observable as a test of neutrino mass generating mechanisms in a regime where heavy sterile neutrino masses are hard to be probed otherwise. We present in this article a study of the one-loop corrected triple Higgs coupling in the inverse seesaw …
We explore the phenomenology of an $SU(2)$-singlet doubly charged scalar at the high and low energy frontier. Such a particle is predicted in different new physics models, like left-right symmetric models or the Zee-Babu model. Nonetheless, since its interactions with Standard Model (SM) leptons are gauge invariant, it can be consistently studied as a UV complete SM extension. Its signatures range from same-sign di-lepton pairs to flavour changing decays of charged leptons to muonium-antimuonium oscillations. In this article, we use a systematic effective-field-theory approach for studying the…
We investigate the possibility of detecting dark matter at TeV scale linear colliders in the scenario where the dark matter is a massive particle weakly interacting only with the Higgs boson $h$ in the low energy effective theory (the Higgs portal dark matter scenario). The dark matter in this scenario would be difficult to be tested at the CERN Large Hadron Collider when the decay of the Higgs boson into a dark matter pair is not kinematically allowed. We study whether even in such a case the dark matter $D$ can be explored or not via the $Z$ boson fusion process at the International Linear C…
In split supersymmetry the gauginos and higgsinos are the only supersymmetric particles possibly accessible at foreseeable colliders like the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). In order to account for the cosmic dark matter measured by WMAP, these gauginos and higgsinos are stringently constrained and could be explored at the colliders through their direct productions and/or virtual effects in some processes. The clean environment and high luminosity of the ILC render the virtual effects of percent level meaningful in unraveling the new physics effect…
New heavy neutral gauge bosons Z' are predicted by many models of physics beyond the Standard Model. It is quite possible that Z's are heavy enough to lie beyond the discovery reach of the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z' exchanges may emerge at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We discuss in this context the foreseeable sensitivity to Z's of W^\pm-pair production cross sections at the e^+e^- International Linear Collider (ILC), especially as regards the potential of distinguishin…
