The potential of the process $γγ\rightarrow τ\barτγ$ is examined in a model-independent way using the effective Lagrangian approach for the ILC which is designed with standard configurations of 0.25 TeV/2000 fb$^{-1}$, 0.35 TeV/200 fb$^{-1}$ and 0.5 TeV/4000 fb$^{-1}$. The limits obtained for $\tilde{a}_τ$ and $\tilde{{d}_τ}$ parameters defining the anomalous $τ\barτγ$ couplings at $95\%$ confidence level and systematic uncertainties of $δ_{sys}=0,5,10 \%$ are compared with the experimental results. The best limits obtained without systematic error on the anomalous couplings are $-0.00082<\tilde{a}_τ<0.00050$ and $|\tilde{{d}_τ}|<3.5969 \times 10^{-18}$ $e\,cm$, respectively. Thus, our results show that $γγ$ collisions at the ILC lead to a remarkable improvement in the existing experimental limits on the anomalous magnetic and electric dipole moments of the tau lepton.
We present a detailed study of the anomalous single fourth generation $t'$ quark production within the dominant Standard Model(SM) decay modes at future $e^+e^-$ colliders. We calculate the signal and background cross sections in the mass range 300-800 GeV. We also discuss the limits of $t'qγ$ and $t'qZ$ ($q=u,c$) anomalous couplings as well as values of attainable integrated luminosity for 3$σ$ observation limit.
We investigate the anomalous $W^+W^-γ$ couplings through the process $e^-e^+\,\rightarrow\,ν_e\barν_eγ$ for unpolarized and polarized electron (positron) beams at the International Linear Collider. We give the 95$\%$ Confidence Level limits on the anomalous couplings with and without the systematic uncertainties for various values of center-of-mass energies and the integrated luminosities. We show that the obtained limits on the anomalous couplings through the process $e^-e^+\,\rightarrow\,ν_e\barν_eγ$ can highly improve the current experimental limits.
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…
The recent discovery of a Higgs boson at LHC, while establishing the Higgs mechanism as the way of electroweak symmetry breaking, started an era of precision measurements involving the Higgs boson. In an effective Lagrangian framework, we consider the e+e- --> ZHH process, at an ILC running at a centre of mass energy of 800 GeV to investigate the effect of the ZZH and ZZHH couplings on the sensitivity of HHH coupling on this process. Our results show that the sensitivity of the trilinear Higgs self couplings on this process has somewhat strong dependence on the Higgs-gauge boson couplings. Sin…
In this work, Higgs couplings with gauge bosons is probed through $e^-e^+ \rightarrow W^-W^+H$ in an effective Lagrangian framework. An ILC of 500 $GeV$ center of mass energy with possible beam polarization is considered for this purpose. The reach of ILC with integrated luminosity of 300 $fb^{-1}$ in the determination of both the CP-conserving and CP-violating parameters are obtained. Sensitivity of the probe of each of these couplings on the presence of other couplings is investigated. The most influential couplings parameters are $\bar c_W=-\bar c_B$. Other parameters of significant effect …
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.
One of the most-studied signals for physics beyond the standard model in the production of gauge bosons in electron-positron collisions is that due to the anomalous triple gauge boson couplings in the $Z γ$ final state. In this work, we study the implications of this at the ILC with polarized beams for signals that go beyond traditional anomalous triple neutral gauge boson couplings. Here we report a dimension-8 CP-conserving $Z γZ$ vertex that has not found mention in the literature. We carry out a systematic study of the anomalous couplings in general terms and arrive at a classification. We…
We study the possibility to determine the supersymmetric (SUSY) contribution to the muon anomalous magnetic dipole moment by using ILC measurements of the properties of superparticles. Assuming that the contribution is as large as the current discrepancy between the result of the Brookhaven E821 experiment and the standard-model prediction, we discuss how and how accurately the SUSY contribution can be reconstructed. We will show that, in a sample point, the reconstruction can be performed with the accuracy of ~ 13 % with the center-of-mass energy 500 GeV and the integrated luminosity ~ 500-10…
New physics effect on the top-Yukawa coupling at ILC
测量top-Yukawa耦合对于理解费米子质量产生机制和电弱对称性破缺动力学具有重要意义。我们讨论了可以用高维算符描述的顶夸克反常耦合。我们研究了过程$e^-e^+ \to W^-W^+ν\barν\to t \bar t ν\barν$，研究了反常的top-Higgs耦合对截面的贡献。在截面上，六维的顶-希格斯相互作用的影响可能比SM预测的大几百个百分点。这种巨大的效应可以在国际直线对撞机上测量到。
In the framework of the minimal $U(1)_{B-L}$ extension of the Standard Model, we investigate the Higgs boson production processes $e^{+}e^{-}\rightarrow ZH$, $e^{+}e^{-}\rightarrow ν_{e}\bar{ν_{e}}H$, $e^{+}e^{-}\rightarrow t\bar{t}H$, $e^{+}e^{-}\rightarrow ZHH$ and $e^{+}e^{-}\rightarrow ν_{e}\bar{ν_{e}}HH$ at the International Linear Collider (ILC). We present the production cross sections, the relative corrections and compare our results with the expected experimental accuracies for Higgs decay channel $H\rightarrow b\bar{b}$. In the allowed parameter space, we find that the effects of the…
In topcolor-assisted technicolor models (TC2) the hitherto unconstrained lepton flavor mixing induced by the new gauge boson $Z'$ will lead to the lepton flavor violating productions of $τ\bar μ$, $τ\bar e$ and $μ\bar e$ in photon-photon collision at the proposed International Linear Collider (ILC). Through a comparative analysis of these processes, we find that the better channels to probe the TC2 is the production of $τ\bar μ$ or $τ\bar e$ which occurs at a much higher rate than $μ\bar e$ production due to the large mixing angle and the large flavor changing coupling, and may reach the detec…
The full $\mathcal{O}(α)$ electroweak radiative corrections to $t \bar{t} γ$ and $e^-e^+γ$ productions at the International Linear Collider (ILC) are presented in this paper. The computation is performed with the help of GRACE-Loop system. In the physical results, we discuss on the cross section, electroweak corrections, and the top quark forward-backward asymmetry ($A_{FB}$) which are the function of the center-of-mass energy.
Study of V_LV_L\to t\bar{t} at the ILC Including O(alpha_s) QCD Corrections
如果希格斯粒子的质量很大，或者电弱相互作用在高能量下有很强的相互作用，那么顶夸克与弱规范玻色子的纵向分量的耦合可以为潜在的动力学提供重要的线索。提出了W_L W_L \to t \bar{t}和Z_L Z_L \to t \bar{t}的精确测量可能提供新物理的线索。本文给出了在ILC下O（alpha_s）QCD对V_LV_L \to t \bar{t}散射的修正结果.我们发现，横截面的修正可以高达30%，必须占在VV \to t \bar{t}的任何精度测量。
The 1-loop effects of the MSSM at the ILC are investigated through numerical analysis. We studied the higgs production processes $e^-e^+\rightarrow Zh$ and $e^-e^+\rightarrow ν\barνh$ at the ILC. It is found that the magnitude of the MSSM contribution through the 1-loop effects is sizable enough to be detected. In the study, three sets of the MSSM parameters are proposed, which are consistent with the observed higgs mass, the muon $g$-$2$, the dark matter abundance and the decay branching ratios of $B$ mesons. In the $e^-e^+\rightarrow Zh$ process, the 1-loop effects of the MSSM are visible an…
Higgs boson couplings with gauge bosons are probed through $e^-e^+ \rightarrow Z γh$ in an effective Lagrangian framework. For this study the beam polarization facility at the ILC along with the typical center-of-mass energy of 500 GeV is considered. The reach of the ILC with an integrated luminosity of 300 fb$^{-1}$ in the determination of $CP$-conserving parameters is obtained. Sensitivity of the probe of each of these couplings in the presence of other couplings is investigated. The most influential coupling parameters are $\bar c_W=-\bar c_B$. Other parameters of significant effect are $\b…
We discuss phenomenology in a new TeV scale model which would explain neutrino oscillation, dark matter, and baryon asymmetry of the Universe simultaneously by the dynamics of the extended Higgs sector and TeV-scale right-handed neutrinos. Tiny neutrino masses are generated at the three-loop level due to the exact $Z_2$ symmetry, by which the stability of the dark matter candidate is guaranteed. The model provides various discriminative predictions in Higgs phenomenology, which can be tested at the Large Hadron Collider and the International Linear Collider.
In this work, we analyze three dominant single SM-like Higgs boson production processes in the left-right twin Higgs model (LRTHM): the Higgs-strahlung (HS) process $e^{+}e^{-}\rightarrow Zh$, the vector boson fusion (VBF) process $e^{+}e^{-}\to ν\barνh$ and the associate production with top pair process $e^{+}e^{-}\to t\bar{t}h$ for three possible energy stages of the International Linear Collider (ILC), and compared our results with the expected experimental accuracies for various accessible Higgs decay channels. The following observations have been obtained: (i) In the reasonable parameter …
In the present paper, we make a detailed study on the doubly heavy baryon photoproduction in the future $e^+e^-$ International Linear Collider (ILC). The baryons $Ξ_{cc}$, $Ξ_{bc}$, and $Ξ_{bb}$ are produced via the channel $γγ\to Ξ_{QQ'} +\bar{Q'} +\bar{Q}$, where $Q$ and $Q'$ stand for heavy $c$ or $b$ quark, respectively. As for the $Ξ_{QQ'}$-baryon production, it shall first generate a $(QQ')[n]$-diquark and then form the final baryon via fragmentation, where $[n]$ stands for the color- and spin- configurations for the $(QQ')$-diquark states. According to the non-relativistic QCD theory, f…
We studied the dimension-6 leptonic anomalous gauge couplings in the formulation of linearly realized gauge symmetry effective Lagrangian and investigated the constraints on these anomalous couplings from the existed experimental data including LEP2 and $W$/$Z$ boson decay. Some bounds of $O(0.1-10){\rm TeV}^{-2}$ on four relevant anomalous couplings are given by the Z factories. We studied the sensitivity of testing the leptonic anomalous couplings via the process $e^+e^-\rightarrow W^+W^-$ at future $e^+e^-$ linear colliders. We discussed different sensitivities to anomalous couplings at pol…
We have studied the associated production processes of a neutral top-Higgs in the topcolor assisted technicolor model with a pair of heavy quarks in γγcollisions at the International Linear Collider (ILC). We find that the cross section for t\bar{t}h_t in γγcollisions is at the level of a few fb with the c.m. energy \sqrt{s}=1000 GeV, which is consistent with the results of the cross section of t\bar{t}H in the standard model and the cross section of t\bar{t}h in the minimal supersymmetric standard modeland the little Higgs models. It should be distinct that hundreds of to thousands of h_t per…
We study the photoproduction of the heavy quarkonium at the future International Linear Collider (ILC) within the nonrelativistic QCD theory. We focus on the production channel via the subprocess $γγ\to |[Q\bar{Q'}]_{\bf 1}(n)>+Q'+\bar{Q}$, where $Q$ and $Q'$ stand for heavy $c$- or $b$-quark, respectively. $|[Q\bar{Q'}]_{\bf 1}(n)>$ stands for color-singlet $S$-wave quarkonium, i.e., $η_{c}(|[c\bar{c}]_{\bf 1}(^1S_0)>)$, $J/ψ(|[c\bar{c}]_{\bf 1}(^3S_1)>)$, $B_{c}(|[c\bar{b}]_{\bf 1}(^1S_0)>)$, $B^*_{c}(|[c\bar{b}]_{\bf 1}(^3S_1)>)$, $η_{b}(|[b\bar{b}]_{\bf 1}(^1S_0)>)$, and $Υ(|[b\bar{b}]_{\b…
In the present work the $Z^\prime tc$ coupling is bounded by using the current experimental data on the $D^{0}-\bar{D^{0}}$ meson-mixing system. It is found that the strength associated to this coupling is less than $5.75\times 10^{-2}$. The single top production through the $e^+e^-\to Z^\prime\to tc$ process at the $Z^\prime$ boson resonance is studied and we found that around $10^7$ $tc$ events will be expected at the International Linear Collider. For the $Z^\prime\to tc$ decay, we predict a branching ratio of $10^{-2}$.
In the littlest Higgs model with T-parity, the new interactions between the mirror leptons and the Standard Model leptons can induce some lepton flavor violation (LFV) processes at loop level. We study the possibility of the ILC to probe the LFV production processes $e^+e^-(γγ)\rightarrow l_{i}\bar{l}_{j}$. Our results show that the rates of $γγ\rightarrow l_{i}\bar{l}_{j}$ can reach 1 fb in optimal cases after reasonable kinematical cuts, which implies that these processes may be observed at the ILC.
Neutral Higgs Boson Pair-Production and Trilinear Self-Couplings in the MSSM at ILC and CLIC Energies
我们在未来国际线性$e^{+}e^{-}$对撞机（ILC）和紧凑型线性对撞机（CLIC）上研究了最小超对称标准模型（MSSM）中性希格斯玻色子的成对产生和三重自耦合。该分析基于$e^{+}e^{-}\to b \bar b h_ih_i, t \bar t h_ih_i$与$h_i=h, H, A$的反应。我们评估了$b\bar bh_ih_i$，$t\bar th_ih_i$的总截面，并计算了事件的总数，考虑在树级的费曼图的完整集合。我们在$κ=-1$和+2范围内改变三重耦合$κλ_{hhh}$、$κλ_{Hhh}$、$κλ_{hAA}$、$κλ_{HAA}$、$κλ_{hHH}$和$κλ_{HHH}$。数值计算完成的预期在ILC与质心能量500，1000，1600 $GeV$和光度1000 $fb^{-1}$的能量。通道$e^{+}e^{-}\to b \bar b h_ih_i$和$e^{+}e^{-}\to t \bar t h_ih_i$也被讨论到质心能量为3 $TeV$和亮度为1000 $fb^{-1}$和5000 $fb^{-1}$。
We present a study of the Higgs boson decay branching ratios to $b\bar{b}$, $c\bar{c}$ and gluons, one of the cornerstones of the physics program at the International Linear Collider (ILC). A standard model Higgs boson of 120\,GeV mass, produced in the Higgs-strahlung process at $\sqrt{s} = 250$\,GeV was investigated using the full detector simulation and reconstruction procedures. The analysis was performed in the framework of the Silicon Detector (SiD) concept with full account of inclusive standard model backgrounds. The selected decay modes contained two heavy flavour jets in the final sta…
We explore discrimination of two types of leptonic Yukawa interactions associated with Higgs triplet, $\bar L^c_L ΔL_L$, and with $SU(2)$ singlet doubly charged scalar, $\bar e_R^c k^{++} e_R$. These interactions can be distinguished by measuring the effects of doubly charged scalar boson exchange in the $e^+ e^- \to \ell^+ ell^-$ processes at polarized electron-positron colliders. We study a forward-backward asymmetry of scattering angular distribution to estimate the sensitivity for these effects at the ILC. In addition, we investigate prospects of upper bounds on the Yukawa couplings by com…
We discuss top-quark physics at the ILC with a focus on the full off-shell processes for $t\bar{t}$ and $t\bar{t}H$ production, including top-quark decays and also leptonic $W$ decays. A special focus is on the matching of the resummed vNRQCD threshold calculation and the fixed-order NLO QCD continuum calculation, where we present an update on the validation of the matching. All of the calculations have been performed in the \wz event generator framework.
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…
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.
Taking into account the constraints on the free parameters of the littlest Higgs model with T-parity (called $LHT$ model) from some rare decay processes, such as $μ\rightarrow eγ$ and $μ\rightarrow 3e$, we consider the contributions of the $LHT$ model to the lepton flavor violating ($LFV$) processes $e^{+}e^{-}\rightarrow l_{i}\bar{l}_{j}$ and $γγ\rightarrow l_{i}\bar{l}_{j}$ ($i\neq j$). We find that the $LHT$ model can indeed produce significant contributions to these $LFV$ processes and its $LFV$ signal might has a chance of being observed in the future $ILC$ experiments.
In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the special flavor structures and some new flavor-changing (FC) couplings which could greatly enhance the production rates of the FC processes. We in this paper study some bottom and anti-strange production processes in the LHT model at the International Linear Collider (ILC), i.e., $e^+e^-\to b\bar{s}$ and $γγ\to b\bar{s}$. The results show that the production rates of these processes are sizeable for the favorable values of the parameters. Therefore, it is quite possible to test the LHT model or make some constrains on …
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 …
The hitherto unconstrained lepton flavor mixing, induced by the new charged scalar ϕ^\pm and ϕ^{\pm\pm} predicted by many new physics models such as higgs triplet models, may lead to the lepton flavor violating productions of τ\bar μ, τ\bar e and μ\bar e in photon-photon collision at the proposed international linear collider. In this paper, we consider the contributions of the ϕ^\pm and ϕ^{\pm\pm} in the context of the higgs triplet models to the processes γγ\to l_i\bar l_j (i, j= e, μ, τ, i\neq j) and find that they can be good channels to probe these new physics models. The lepton flavor vi…
The anomalous $WWγ$ coupling is probed through $eγ\rightarrow νW$ at the ILC. With a spectacular single lepton final state, this process is well suited to study the above coupling. Cross section measurements can probe $δκ_γ$ to about $\pm 0.004$ for a luminosity of 100 fb$^{-1}$ at $500$ GeV center-of-mass energy with unpolarized electron beam. The limits derivable on $λ_γ$ from the total cross section are comparatively more relaxed. Exploiting the energy-angle double distribution of the secondary muons, kinematic regions sensitive to these couplings are identified. The derivable limit on $λ_γ…
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 $e^+e^- \to γγb\bar b$ is an irreducible background process in measuring the $H^0 \to γγ$ decay width, if Higgs boson is produced in association with a $Z^0$-boson which subsequently decays via $Z^0 \to b\bar b$ at the ILC. In this paper we study the impact of the ${\cal O}(α_s)$ QCD corrections to the observables of the $e^+e^- \to γγb\bar b$ process in the standard model. We investigate the dependence of the leading-order and ${\cal O}(α_s)$ QCD corrected cross sections on colliding energy and the additional jet veto schemes. We also present the results of the LO and ${\cal O}(α_s)$ QCD …
The Triple Higgs Boson Self-Coupling at Future Linear e+e- Colliders Energies: ILC and CLIC
我们分析了三重希格斯玻色子自耦合在未来的$e^{+}e^{-}$对撞机的能量，与反应$e^{+}e^{-}\to b \bar b HH, t \bar t HH$。我们计算了$b\bar bHH$和$t\bar tHH$的总截面，并在树级上计算了费曼图的完整集合。我们在$κ=-1$和+2范围内改变三重耦合$κλ_{3H}$。数值计算的能量预计可在一个可能的未来线性$e^{+}e^{-}$对撞机与质心能量$800, 1000, 1500$ $GeV$和光度1000 $fb^{-1}$。我们的分析也扩展到一个中心的质量能量3 $TeV$和光度为1000 $fb^{-1}$和5000 $fb^{-1}$。我们发现，对于过程$e^{+}e^{-}\to b \bar b HH$，完整的计算与近似计算$e^{+}e^{-}\to ZHH(Z\to b\bar b)$仅相差3%，而对于过程$e^{+}e^{-}\to t \bar tHH$，考虑到$t$和$H$的衰变产物，预期的事件数不足以获得三重希格斯玻色子自耦合的准确测定。
The Standard Model prediction on the forward-backward asymmetry for $b\bar b$ production ($A^b_{FB}$) is well consistent with the data of LEP I at the Z-pole, but deviates from the data at $\sqrt s=89\; 93$ GeV which are slightly away from the pole. This deviation implies that there still is room for new physics. We calculate the $A^b_{FB}$ at vicinity of Z-pole in the Little Higgs Model as well as other measurable parameters such as $R_b$ and $R_c$, by which we may constrain the parameter space of the Little Higgs Model. This can be tested in the newly proposed tera-Z factory. With the fitted…
Many extensions of the standard model predict the existence of extra neutral vector bosons, generically referred as $Z^\prime$. This boson may be discovered at the LHC but in this case it will be necessary to study the respective parameters in order to discriminate to which model it belongs to. This is a task for a much clean lepton linear collider as the future ILC. In this paper we develop an exemplary study of the capability of several asymmetries on and off $Z^\prime$ peak in discriminating among those extensions with (almost) no ambiguities.
A precise calculation of the top quark pair production associated with a hard photon is essential for testing the electroweak property of the top quark in the Standard Model (SM). We investigate the one-loop QCD corrections to the process $e^{+}e^{-} \to t\bar{t}γ$ at the International Linear Collider (ILC), and find that the $K$-factor can be as large as 1.238 (1.105, 1.060) for a center-of-mass energy $\sqrt{s}=500 (800, 1500)$ GeV. The transverse momentum distributions of the top quark and photon are respectively shown at leading order (LO) and next-to-leading order(NLO). Due to the asymmet…
The measurement of Higgs self-coupling is one of the most crucial physics goals at the future colliders. At the LHC, the di-Higgs production is a main way to measure the Higgs trilinear coupling. As a complementary to the di-Higgs production, $t \bar{t} hh$ process may open a new avenue to measure di-Higgs physics at the LHC and a future 100 TeV $pp$ collider or a high energy $e^+e^-$ collider since the extra $t\bar t$ in the final states may efficiently suppress the backgrounds. However, such a kind of process is also controlled by the top-Higgs coupling. In this work, we investigate the impa…
In this work we study the sensitivity on the anomalous magnetic and electric dipole moments of the tau-neutrino in the framework of the $SU(2)_L\times U(1)_Y\times U(1)_{B-L}$ electroweak model at future $e^+e^-$ linear colliders as the ILC and CLIC. For our study we consider the process $e^{+}e^{-}\rightarrow ( Z, Z', γ) \to ν_τ\bar ν_τγ$. For center-of-mass energies of $\sqrt{s}=1000-3000\hspace{0.8mm}GeV$ and integrated luminosities of ${\cal L}=500-2000\hspace{0.8mm}fb^{-1}$, we derive $95 \% \hspace{1mm}$ C.L. limits on the dipole moments $|μ_{ν_τ}(μ_B)| \leq 6.28 \times 10^{-9}$ and $|d_…
The precision measurements of the Higgs properties is crucial for a better understanding of electroweak symmetry breaking. It can be first achieved at the ILC\pcite{Behnke2013} at $\sqrt{s}=250\rm ~GeV$ via the Higgs-strahlung production process $e^+e^-\rightarrow ZH$. The hadronic decay mode $Z\rightarrow \bar{q}q$ constitutes more than $65%$ of the total, a factor 10 more than $Z\rightarrow μμ$. An analysis based solely on the $Z$ jet pair information could thus lead to a high statistics and provide a minimum biased Higgs sample. A study of the feasibility of such analysis is shown here, bas…
In this work we study the potential of the processes $e^+e^- \to e^+γ^* e^- \to e^+τ\barν_τν_e $ and $e^+e^- \to e^+γ^* γ^* e^- \to e^+ν_τ\barν_τe^- $ at a future high-energy and high-luminosity linear electron positron collider, such as the ILC and CLIC to study the sensibility on the anomalous magnetic and electric dipole moments of the tau-neutrino. For integrated luminosity of 590\hspace{1mm}$fb^{-1}$ and center-of-mass energy of 3\hspace{1mm}$TeV$, we derive $95 \% \hspace{1mm}C. L.$ limits on the dipole moments: $μ_{ν_τ}\leq 1.44 \times 10^{-6}μ_B$ and $d_{ν_τ}\leq 2.78 \times 10^{-17}\h…
We investigate $e^{+}e^{-}\to γγ$ process within the Seiberg-Witten expanded noncommutative standard model(NCSM) scenario in the presence of anomalous triple gauge boson couplings. This study is done with and without initial beam polarization and we restrict ourselves to leading order effects of non commutativity i.e. $O(Θ)$. The non commutative(NC) corrections are sensitive to the electric component($\vecΘ_E$) of NC parameter. We include the effects of earth rotation in our analysis. This study is done by investigating the effects of non commutativity on different time averaged cross section …
This document discusses for the first time the experimental prospects on the measurement of cross section and the forward-backward asymmetry in $e^{-}e^{+}\rightarrow c\bar{c}$ collisions at 250 GeV at the International Linear Collider operating polarised beams. The cross section will be normalised to the total hadronic cross section. We discuss the results for an analysis assuming the integrated luminosity of 2000 fb$^{-1}$ foreseen in the baseline project. The measurement requires determining the charge of both jets identified as originated by a $c$-quark. The charge measurement is optimally…
We derive the fully differential cross section of the Higgs-strahlung process $f \bar{f} \to Z \to Z (\to f_Z \bar{f}_Z) X (\to f_X \bar{f}_X)$, where $f$, $f_Z$, and $f_X$ are arbitrary fermions and $X$ is a spin-zero particle with arbitrary couplings to $Z$ bosons and fermions. This process with $f = e$ and $X = h$ ($h$ denotes the Higgs boson) is planned to be measured at the ILC to put constraints on the couplings $g_1$, $g_2$, $g_3$ of the Higgs boson to $Z$ bosons. Using the obtained fully differential cross section, we define observables measurement of which yields the tightest constrai…
The recent discovery of a Higgs boson at the LHC, while establishing the Higgs mechanism as the way of electroweak symmetry breaking, started an era of precision measurements involving the Higgs boson. In an effective Lagrangian framework, we consider the $e^+e^-\rightarrow ZHH$ process at the ILC running at a centre of mass energy of 500 GeV to investigate the effect of the $ZZH$ and $ZZHH$ couplings on the sensitivity of $HHH$ coupling in this process. Our results show that the sensitivity of the trilinear Higgs self couplings on this process has somewhat strong dependence on the Higgs-gauge…
