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Potential Precision on Higgs Couplings and Total Width at the ILC
http://ilcdoc.linearcollider.org/record/47261
We outline a systematic approach to the determination of the Standard Model-like Higgs boson total width and measurable coupling parameters in a model-independent manner at the International Linear Collider (ILC) and illustrate the complementarity for operating the ILC at $250$ GeV near the $Zh$ threshold and at $500$ GeV utilizing the $WW, ZZ$ fusion processes. We perform detailed simulations for an important contributing channel to the coupling determination and for invisible decays. Without model assumptions, and combining the information for the coupling ratios from the LHC, the total width can be determined to an accuracy of about $6\%$, and the couplings for the observable channels can be measured to the $(3-5)\%$ level at 250 GeV, reaching $(1-3)\%$ level including the 500 GeV results. The best precision for the branching fraction measurement of the Higgs to invisible modes can be reached at $0.5-0.7\%$ around the $Zh$ threshold. Further studies from $ZZ$ fusion at higher energies may provide significant improvement for the measurements. With modest theory assumptions, the width and coupling determinations can be further improved to the percent or sub-percent level.Han, TaoMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472612013A New Method for the Spin Determination of Dark Matter
http://ilcdoc.linearcollider.org/record/47260
We construct a new kinematical variable that is able to fully reconstruct the absolute value, and partially reconstruct the sign, of the angular distribution in the center of momentum system of a decaying particle in certain cases where the center of momentum system is only known up to a two-fold ambiguity. We apply this method to the pair-production of dark matter in association with two charged leptons at the International Linear Collider and show that for a small intermediate width, perfect agreement is found with the true angular distribution in the absence of initial state radiation. In the presence of initial state radiation, we find that the modification to the angular distributions is small for most angles and that the different spin combinations should still be distinguishable. This enables us to determine the spin of the mother particle and the dark matter particle in many cases.Christensen, Neil DMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472602013Future Electron-Positron Colliders and the 4-Dimensional Composite Higgs Model
http://ilcdoc.linearcollider.org/record/47259
In this note we analyse the prospects of a future electron-positron collider in testing a particular realisation of a composite Higgs model encompassing partial compositeness, namely, the 4-Dimensional Composite Higgs Model. We study the main Higgs production channels for three possible energy stages and different luminosity options of such a machine and confront our results to the expected experimental accuracies in the various Higgs decay channels accessible herein and, for comparison, also at the Large Hadron Collider.Barducci, DanieleMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472592013Parallel Universe, Dark Matter and Invisible Higgs Decays
http://ilcdoc.linearcollider.org/record/47258
The existence of the dark matter with amount about five times the ordinary matter is now well established experimentally. There are now many candidates for this dark matter. However, dark matter could be just like the ordinary matter in a parallel universe. If both universes are described by a non-abelian gauge symmetries, then there will be no kinetic mixing between the ordinary photon and the dark photon, and the dark proton, dark electron and the corresponding dark nuclei, belonging to the parallel universe, will be stable. If the strong coupling constant, $(\alpha_s)_{dark}$ in the parallel universe is five times that of $\alpha_s$, then the dark proton will be about five time heavier, explaining why the dark matter is five times the ordinary matter. However, the two sectors will still interact via the Higgs boson of the two sectors. This will lead to the existence of a second light Higss boson, just like the Standard Model Higgs boson. This gives rise to the invisible decay modes of the Higgs boson which can be tested at the LHC, and the proposed ILC.Chakdar, ShreyashiMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472582013A practical GMSB model for explaining the muon (g-2) with gauge coupling unification
http://ilcdoc.linearcollider.org/record/47257
We present a gauge mediated supersymmetry breaking model having weak SU(2) triplet, color SU(3) octet and SU(5) 5-plet messengers, that can simultaneously explain the muon $(g-2)$ data within 1$\sigma$ and the observed Higgs boson mass of 125 GeV. Gauge coupling unification is nontrivially maintained. Most of the parameter space satisfying both is accessible to the 14 TeV LHC. The lighter of the two staus weighs around (100-200) GeV, which can be a potential target of the ILC.Bhattacharyya, GautamMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472572013Higgs Pair Production at the LHC and ILC from general potential
http://ilcdoc.linearcollider.org/record/47256
Higgs cubic coupling plays a crucial role to probe an origin of electroweak symmetry breaking. It is expected that the cubic coupling is measured by Higgs pair production at the LHC and ILC, and the deviations from the standard model can be extracted from the Higgs pair production process, and those can give us a hint of new physics beyond the standard model. We consider a general potential that achieves the suitable electroweak symmetry breaking. As one of the interesting models, we suggest a non-perturbative Higgs model in which a run-away type of potential is used. In the model, the cross sections of pair production at the LHC is enlarged compared to the standard model. We also study the Higgs pair production induced by a non-canonical kinetic term of Higgs fields which will be important to search the pair-production at the ILC.Haba, NaoyukiMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472562013Charged Higgs Pair Production in a General Two Higgs Doublet Model at $e^+e^-$ and $\mu^+\mu^-$ Linear Colliders
http://ilcdoc.linearcollider.org/record/47255
In this paper, charged Higgs pair production through $\ell^+ \ell^- \rightarrow H^+ H^-$ where $\ell = e$ or $\mu$, is studied within the framework of a general Two Higgs Doublet Model (2HDM). The analysis is relevant to a future $e^+e^-$ or $\mu^+\mu^-$ collider operating at center of mass energy of $\sqrt{s}=500$ GeV. Two different scenarios of small and large $\alpha$ values is studied. Here $\alpha$ is the parameter which diagonalizes the neutral CP-even Higgs boson mass matrix. Within the Minimal Supersymmetric Standard Model (MSSM), cross section of this process is almost the same at $e^+e^-$ and $\mu^+\mu^-$ colliders. It is shown that at $e^+e^-$ colliders within a general 2HDM, cross section is not sensitive to the mass of neutral Higgs bosons, however, it can acquire large values up to several picobarn at $\mu^+\mu^-$ colliders with the presence of heavy neutral Higgs bosons. A scan over Higgs boson mass parameter space is performed to analyze the effect of large masses of neutral Higgs bosons involved in the s-channel propagator and thus in the total cross section of this process.Hashemi, MajidMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472552013Testing Higgs Physics at the Photon Collider
http://ilcdoc.linearcollider.org/record/47254
Here we review potential of the Photon Collider for study of Higgs physics after discovery of the SM-like Higgs boson at the LHC. In general, the Photon Collider will fill in the LHC and ILC results, giving in some cases unique information which cannot be obtained at other machines.Ginzburg, IlyaMon, 02 Dec 2013 17:07:54 GMThttp://ilcdoc.linearcollider.org/record/472542013Radiatively-driven natural supersymmetry at the LHC
http://ilcdoc.linearcollider.org/record/47253
Radiatively-driven natural supersymmetry (RNS) potentially reconciles the Z and Higgs boson masses close to 100 GeV with gluinos and squarks lying beyond the TeV scale. Requiring no large cancellations at the electroweak scale in constructing M_Z=91.2 GeV while maintaining a light Higgs scalar with m_h 125 GeV implies a sparticle mass spectrum including light higgsinos with mass 100-300 GeV, electroweak gauginos in the 300-1200 GeV range, gluinos at 1-4 TeV and top/bottom squarks in the 1-4 TeV range (probably beyond LHC reach), while first/second generation matter scalars can exist in the 5-30 TeV range (far beyond LHC reach). We investigate several characteristic signals for RNS at LHC14. Gluino pair production yields a reach up to m_{\tg} 1.7 TeV for 300 fb^{-1}. Wino pair production -- pp\to\tw_2\tz_4 and \tw_2\tw_2 -- leads to a unique same-sign diboson (SSdB) signature accompanied by modest jet activity from daughter higgsino decays; this signature provides the best reach up to m_{\tg} 2.1 TeV within this framework. Wino pair production also leads to final states with (WZ\to 3\ell)+\eslt as well as 4\ell+\eslt which give confirmatory signals up to m_{\tg} 1.4 TeV. Directly produced light higgsinos yield a clean, soft trilepton signature (due to very low visible energy release) which can be visible, but only for a not-too-small a \tz_2-\tz_1 mass gap. The clean SSdB signal -- as well as the distinctive mass shape of the dilepton mass distribution from \tz_{2,3}\to\tz_1\ell\ell decays if this is accessible -- will mark the presence of light higgsinos which are necessary for natural SUSY. While an e^+e^- collider operating with \sqrt{s} 600 GeV should unequivocally reveal the predicted light higgsinos, the RNS model with m_{1/2}> 1 TeV may elude all LHC14 search strategies even while maintaining a high degree of electroweak naturalness.Baer, HowardMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472532013Neutrino Physics, Lepton Flavour Violation and the LHC
http://ilcdoc.linearcollider.org/record/47252
We briefly review flavour violation in the lepton sector: starting from neutrino oscillations and their implications, we consider several charged lepton flavour violating observables at high and low energies. We present new physics models and discuss the r\^ole of the latter in disentangling them. In particular, we show how the interplay of different observables allows to derive important information on the underlying mechanism of lepton flavour violation. As an example, we discuss the impact of a type-I SUSY seesaw concerning lepton flavour violation at low energies and at colliders (LHC and a future Linear Collider).Abada, AsmaaMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472522013Supersymmetry and Dark Matter post LHC8: why we may expect both axion and WIMP detection
http://ilcdoc.linearcollider.org/record/47251
In the post-LHC8 era, it is perceived that what is left of SUSY model parameter space is highly finetuned in the EW sector (EWFT). We discuss how conventional measures overestimate EWFT in SUSY theory. Radiatively-driven natural SUSY (RNS) models maintain the SUSY GUT paradigm with low EWFT at 10% level, but are characterized by light higgsinos ~100-300 GeV and a thermal underabundance of WIMP dark matter. Implementing the SUSY DFSZ solution to the strong CP problem explains the small \mu parameter but indicates dark matter should be comprised mainly of axions with a small admixture of higgsino-like WIMPs. While RNS might escape LHC14 searches, we would expect ultimately direct detection of both WIMPs and axions. An e^+e^- collider with \sqrt{s} ~ 500-600 GeV should provide a thorough search for the predicted light higgsinos.Baer, HowardMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472512013Unitarity Constraints on Higgs Portals
http://ilcdoc.linearcollider.org/record/47250
Dark matter that was once in thermal equilibrium with the Standard Model is generally prohibited from obtaining all of its mass from the electroweak phase transition. This implies a new scale of physics and mediator particles to facilitate dark matter annihilation. In this work, we focus on dark matter that annihilates through a generic Higgs portal. We show how partial wave unitarity places an upper bound on the mass of the mediator (or dark) Higgs when its mass is increased to be the largest scale in the effective theory. For models where the dark matter annihilates via fermion exchange, an upper bound is generated when unitarity breaks down around 8.5 TeV. Models where the dark matter annihilates via fermion and higgs boson exchange push the bound to 45.5 TeV. We also show that if dark matter obtains all of its mass from a new symmetry breaking scale that scale is also constrained. We improve these constraints by requiring perturbativity in the Higgs sector up to each unitarity bound. In this limit, the bounds on the dark symmetry breaking vev and the dark Higgs mass are now 2.4 and 3 TeV, respectively, when the dark matter annihilates via fermion exchange. When dark matter annihilates via fermion and higgs boson exchange, the bounds are now 12 and 14.2 TeV, respectively. The available parameter space for Higgs portal dark matter annihilation is outlined. We also show how the bounds are improved if Higgs portal dark matter is only a fraction of the observed relic abundance. Finally, we discuss how to apply these arguments to other dark matter scenarios and discuss prospects for direct detection and future collider searches. If the Higgs portal is responsible for dark matter annihilation, planned direct detection experiments will cover almost all the parameter space. The ILC and/or VLHC, however, is needed to establish the Higgs portal mechanism.Walker, Devin G EMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472502013ILC Higgs White Paper
http://ilcdoc.linearcollider.org/record/47249
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 on the ILC TDR machine design are used throughout. The gamma-gamma collider option at the ILC is also discussed.Asner, D MMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472492013Pair Production of New Heavy Leptons with $U(1)'$ Charge at Linear Colliders
http://ilcdoc.linearcollider.org/record/47248
We study the pair production of new heavy leptons within a new $U(1)'$ symmetry extension of the Standard Model. Because of the new symmetry, the production and decay modes of the new heavy leptons would be different from those of three families of the standard model. The pair production cross sections depending on the mixing parameter and the mass of heavy leptons have been calculated for the center of mass energies of $0.5$ TeV, $1$ TeV and $3$ TeV. The accessible ranges of the parameters have been obtained for different luminosity projections at linear colliders. We find the sensitivity to the range of mixing parameter $-1<x<1$ for the mass range $M_{l'}<800$ GeV at $\sqrt{s}=3$ TeV and $L_{int}=100$ fb$^{-1}$Ari, VMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472482013Strong Higgs Interactions at a Linear Collider
http://ilcdoc.linearcollider.org/record/47247
We study the impact of Higgs precision measurements at a high-energy and high-luminosity linear electron positron collider, such as CLIC or the ILC, on the parameter space of a strongly interacting Higgs boson. Some combination of anomalous couplings are already tightly constrained by current fits to electroweak observables. However, even small deviations in the cross sections of single and double Higgs production, or the mere detection of a triple Higgs final state, can help establish whether it is a composite state and whether or not it emerges as a pseudo-Nambu-Goldstone boson from an underlying broken symmetry. We obtain an estimate of the ILC and CLIC sensitivities on the anomalous Higgs couplings from a study of WW scattering and hh production which can be translated into a sensitivity on the compositeness scale 4\pi f, or equivalently on the degree of compositeness \xi=v^2/f^2. We summarize the current experimental constraints, from electroweak data and direct resonance searches, and the expected reach of the LHC and CLIC on \xi and on the scale of the new resonances.Contino, RobertoMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472472013Higgs Phenomenology in the Two-Singlet Model
http://ilcdoc.linearcollider.org/record/47246
We study the phenomenology of the Standard Model (SM) Higgs sector extended by two singlet scalars. The model predicts two CP-even scalars $h_{1,2}$ which are a mixture of doublet and singlet components as well as a pure singlet scalar $S_{0}$ which is a dark matter candidate. We show that the model can satisfy the relic density and direct detection constraints as well as all the recent ATLAS and CMS measurements. We also discuss the effect of the extra Higgs bosons on the different Higgs triple couplings $h_{i}h_{j}h_{k}$, $i,j,k=1,2$. A particular attention is given to the triple self-coupling of the SM-like Higgs where we found that the one loop corrections can exceed 50% is some cases. We also discuss some production mechanisms for $h_{1}$ and $h_{2}$ at the LHC as well as at the future International Linear Collider. It is found that the production cross section of a pair of SM-like Higgs bosons could be much larger than the corresponding one in the SM and would reveal physics beyond the SM if observable. We also show that in this model the branching ratio of the SM-like Higgs decaying to two singlet scalars could be of the order of 20%, therefore the production of the SM Higgs followed by its decay to a pair of singlets would be an important source of production of singlet scalars.Ahriche, AmineMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472462013The lepton flavor violating signal of the charged scalar \phi^\pm and \phi^{\pm\pm} in photon-photon collision at the ILC
http://ilcdoc.linearcollider.org/record/47245
The hitherto unconstrained lepton flavor mixing, induced by the new charged scalar \phi^\pm and \phi^{\pm\pm} predicted by many new physics models such as higgs triplet models, may lead to the lepton flavor violating productions of \tau\bar \mu, \tau\bar e and \mu\bar e in photon-photon collision at the proposed international linear collider. In this paper, we consider the contributions of the \phi^\pm and \phi^{\pm\pm} in the context of the higgs triplet models to the processes \gamma\gamma\to l_i\bar l_j (i, j= e, \mu, \tau, i\neq j) and find that they can be good channels to probe these new physics models. The lepton flavor violating processes \gamma\gamma\to l_i\bar l_j (i, j= e, \mu,\tau,i\neq j) occur at a high rate due to the large mixing angle and the large flavor changing coupling, so, in view of the low standard model backgrounds, they may reach the detectable level of the ILC for a large part of the parameter space. Since the rates predicted by the standard model are far below the detectable level, these processes may serve as a sensitive probe for such new physics models.Liu, Guo-LiMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472452013A supersimple analysis of $e^-e^+\to W^- W^+$ at high energy
http://ilcdoc.linearcollider.org/record/47244
Studying $e^-e^+\to W^- W^+$ at the 1loop electroweak (EW) order, we derive very accurate and simple expressions for the four Helicity Conserving (HC) amplitudes, which dominate this process at high energies. The calculations are done in both, the SM and MSSM frameworks. Such expressions, called supersimple (sim), nicely emphasize the dynamical contents of each framework. Numerical illustrations are presented, which show the accuracy of this description, and how it can be used for identifying possible additional new physics contributions; like e.g. Anomalous Gauge Couplings (AGC) or a new $Z'$ vector boson exchange. The procedure is useful even if only SM is visible at the future Linear Collider energies.Gounaris, G JMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472442013Beam polarization effects in the radiative production of lightest neutralinos in $e^+ e^-$ collisions in supersymmetric grand unified models
http://ilcdoc.linearcollider.org/record/47242
We study the production of the lightest neutralinos in the process $e^+ e^- \rightarrow \chi_1^0 \chi_1^0 \gamma$ in supersymmetric grand unified models for the International Linear Collider Energies with longitudinally polarized beams. We consider cases where the standard model gauge group is unified into the grand unified gauge groups SU(5), or SO(10). We have carried out a comprehensive study of this process in the SU(5) and SO(10) grand unified theories which includes the QED radiative corrections. We compare and contrast the dependence of the signal cross section on the grand unified gauge group, and on the different representations of the grand unified gauge group, when the the electron and positron beams are longitudinally polarized. To assess the feasibility of experimentally observing the radiative production process, we have also considered in detail the background to this process coming from the radiative neutrino production process $e^+ e^- \rightarrow \nu \bar\nu \gamma$ with longitudinally polarized electron and positron beams. In addition we have also considered the supersymmetric background coming from the radiative production of scalar neutrinos in the process $e^+ e^- \rightarrow \tilde \nu \tilde\nu^* \gamma$ with longitudinally polarized beams. The process can be a major background to the radiative production of neutralinos when the scalar neutrinos decay invisibly.Pandita, P NMon, 02 Dec 2013 17:07:53 GMThttp://ilcdoc.linearcollider.org/record/472422013The Higgs Particle and Higher-Dimensional Theories
http://ilcdoc.linearcollider.org/record/47241
In spite of the great success of LHC experiments, we do not know whether the discovered "standard model-like" Higgs particle is really what the standard model predicts or a particle some new physics has in its low energy effective theory. Also the long-standing problems concerning the property of Higgs and its interactions are still there, and we still do not have any conclusive argument of the origin of the Higgs itself. In this article we focus on higher-dimensional theories as new physics. First we give a brief review of their representative scenarios and closely related 4-dimensional scenarios. Among them, we mainly discuss two interesting possibilities of the origin of the Higgs: Higgs as a gauge boson and Higgs as a (pseudo) Nambu-Goldstone boson. Next, we argue that theories of new physics are divided into two categories, i.e. theories with normal Higgs interactions and those with anomalous Higgs interactions. Interestingly both of two candidates concerning the origin of the Higgs mentioned above predict characteristic "anomalous" Higgs interactions, such as the deviation of the Yukawa couplings from the standard model predictions. Such deviations can be hopefully investigated by the precision tests of Higgs interactions at the planned ILC experiment. Also discussed is the main decay mode of the Higgs, $H \to \gamma \gamma$. Again, theories belonging different categories are known to predict remarkably different new physics contributions to this important process.Lim, C SMon, 02 Dec 2013 17:07:51 GMThttp://ilcdoc.linearcollider.org/record/472412013Optimal one-parameter observables for Z' searches in e^+e^- \to \mu^+\mu^- process
http://ilcdoc.linearcollider.org/record/47240
To detect the off-shell Abelian Z' boson signal in e^+e^- \to \mu^+\mu^-, we propose one-parameter observables with the best value-to-uncertainty ratio. The observables are constructed by angular integration of the differential cross-section with smooth weight functions. The value-to-uncertainty ratio is used as a criterion to select the unique weight function leading to the observable with the best statistical power for data analysis. The observables allow to select either vector or axial-vector Z' couplings to leptons. We also take into account model-independent relations between the Z' couplings to the standard model particles. Due to the relations the observable to select the axial-vector couplings appears to be sign-definite allowing to accept or reject the hypothesis about Z' existence. The obtained observable can be useful in future experiments at lepton colliders such as the ILC.Gulov, AlexeyMon, 02 Dec 2013 17:07:51 GMThttp://ilcdoc.linearcollider.org/record/472402013Lorentz-violating effects on pair production of W bosons in photon collisions
http://ilcdoc.linearcollider.org/record/47239
We examine Lorentz-violating effects that could appear through deviations of the Standard Model gauge couplings WWgamma and WWgammagamma. These new physics effects are explored on the gamma gamma -> WW reaction at the International Linear Collider. In particular, the associated helicity amplitudes are computed in the context of the Standard Model Extension (which is a model-independent approach to CPT and Lorentz violation) and the Effective Lagrangian Model (which incorporates new physics effects that respect CPT and Lorentz violation). We perform an exhaustive study of the polarized differential cross sections to stand out effects related to Lorentz symmetry violation, where it is evidenced that the effects of Lorentz symmetry violation are more sensitive to the presence of the b constant background field. We found that for the $(\pm,\pm,(L,T+T,L))$ polarization state, only Standard Model Extension and Effective Lagrangian Model contribute at the lowest order, however, both types of new physics effects are clearly distinguished, being dominant the convoluted cross section of the Standard Model Extension in around 4 orders of magnitude. For this polarization state, at the last stage of operation of International Linear Collider, it is expected an integrated luminosity of 10^3 fb^{-1}, finding around of 2 events for a Lorentz-violating energy scale of 32 TeV.Aranda, J IMon, 02 Dec 2013 17:07:51 GMThttp://ilcdoc.linearcollider.org/record/472392013Dark Sector spectroscopy at the ILC
http://ilcdoc.linearcollider.org/record/47238
Recent studies have shown that searches in the mono-photon and missing energy final state can be used to discover dark matter candidates at the ILC. While an excess in this final state over the Standard Model background would indicate the existence of a dark sector, no detailed information about the internal structure of this sector can be inferred. Here, we demonstrate how just a few observables can discriminate between various realizations of dark sectors, including e.g. the spin of mediators.Andersen, Jeppe RMon, 02 Dec 2013 17:07:51 GMThttp://ilcdoc.linearcollider.org/record/472382013Top quark anomalous tensor couplings in the two-Higgs-doublet models
http://ilcdoc.linearcollider.org/record/47236
We compute the one loop right and left anomalous tensor couplings ($g_R$ and $g_L$, respectively) for the top quark, in the aligned two-Higgs-doublet model. They are the magnetic-like couplings in the most general parameterization of the $tbW$ vertex. We find that the aligned two-Higgs doublet model, that includes as particular cases some of the most studied extensions of the Higgs sector, introduces new electroweak contributions and provides theoretical predictions that are very sensitive to both new scalar masses and the neutral scalar mixing angle. For a large area in the parameters space we obtain significant deviations in both the real and the imaginary parts of the couplings $g_R$ and $g_L$, compared to the predictions given by the electroweak sector of the Standard Model. The most important ones are those involving the imaginary part of the left coupling $g_{L}$ and the real part of the right coupling $g_R$. The real part of $g_L$ and the imaginary part of $g_R$ also show an important sensitivity to new physics scenarios. The model can also account for new CP violation effects via the introduction of complex alignment parameters that have important consequences on the values for the imaginary parts of the couplings. The top anomalous tensor couplings will be measured at the LHC and at future colliders providing a complementary insight on new physics, independent from the bounds in top decays coming from B physics and $b \rightarrow s \gamma$.Duarte, LucĂaMon, 02 Dec 2013 17:07:51 GMThttp://ilcdoc.linearcollider.org/record/472362013Projections for Two Higgs Doublet Models at the LHC and ILC: A Snowmass White Paper
http://ilcdoc.linearcollider.org/record/47235
The discovery of the 125 GeV Higgs boson and the measurement of its branching ratios has initiated the exploration of the electroweak symmetry breaking sector. There have been numerous studies exploring the restrictions these results place on the parameter space of two Higgs doublet models. We extend these results to include the full data set and study the expected sensitivity that can be obtained with 300 and 3000 inverse femtobarn of integrated luminosity. In addition, searches for a heavy Standard Model Higgs boson are also considered. It is shown that the nonobservation of such a Higgs boson can substantially narrow the allowed regions of parameter space in two Higgs doublet models. Finally, projections for the ILC at the center of mass energy 250, 500, and 1000 GeV are investigated.Chen, Chien-YiMon, 02 Dec 2013 17:07:51 GMThttp://ilcdoc.linearcollider.org/record/472352013