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![Figure 5. The achieved vertical beam size at ATF2 facility [9]. The...](publication/350858262/figure/fig2/AS:1012476233674753@1618404553999/The-achieved-vertical-beam-size-at-ATF2-facility-9-The-latest-value-of-41-nm-is-within_Q320.jpg)
![Figure 8. Improvements by adding ILC data to the upgraded LHC data [9]....](publication/350858262/figure/fig4/AS:1012476237856768@1618404554119/Improvements-by-adding-ILC-data-to-the-upgraded-LHC-data-9-The-all-analyses-assume_Q320.jpg)
The discovery of Higgs particle has ushered in a new era of particle physics. Even though the list of members of the standard theory of particle physics is now complete, the shortcomings of the theory became ever more acute. It is generally considered that the best solution to the problems is an electron–positron collider that can study Higgs parti...
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... bunch contains 2 × 10 10 particles and its size (rms) at the collision point is 7.7 nm high, 516 nm wide, and 300 µm long; namely, it is ribbon-like-very flat and long. A schematic drawing of the machine is shown in Figure 1. ...
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... precision measurements make it possible to distinguish different new physics scenarios through the pattern of deviation from the Standard Theory. Figure 10 shows the separation power of the ILC Higgs factory for 9 models that are unlikely to be rejected by the upgraded LHC. The number in each grid is the number of standard deviations between the two models represented by the grid. ...
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... general, the discovery potential at the ILC extends essentially up to the beam energy for nearly all models and their parameter spaces. Figure 11 shows an example for the case where the new particle is smuon µ (the super partner of muon in supersymmetric models) decaying to a dark matter candidate and a muon. The dark matter candidate escapes without interaction with the detector, and the signature of event is a pair of soft muons. ...
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... discovery potential is seen to extend close to the beam energy. Figure 11. An example for pair creation of new particle that decays to the dark matter candidate and a muon: ...
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... the threshold, the production cross section as a function of collision energy gives information on key top parameters; in particular, the mass and the total decay rate as shown in Figure 12. The top mass measured by the shape of the production cross section is closely related to the so-called ms mass that is relevant to various theoretical applications. ...
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... is particularly true with the capability of a linear collider to polarize the incoming beams. Figure 13 shows the deviation from the Standard theory for the right-handed and left-handed couplings for a variety of models beyond the Standard Theory [24]. One can see that many new physics theories can be distinguished with the precision of the ILC. ...
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Citations
... Superconducting radio frequency (SRF) cavities are widely used in particle accelerators due to their lower wall losses and higher accelerating gradients as compared to normal conducting cavities [1]. In many large accelerator projects such as the international linear collider [2], the next-generation light source (e.g., Linac Coherent Light Source (LCLSII) [3], European X-Ray Free-Electron Laser Facility (E-XFEL) [4] and Subcritical Hybrid Intense Neutron Emitter (SHINE) [5]), China Spallation Neutron Source (CSNS-II) [6], China initiative Accelerator Driven System (CiADS) [7], compact energy recovery linac (cERL) [8], and Chinese Accelerator Driven System Front-end (CAFe) [9] SRF cavities are used. The SRF cavity is a vital part of modern accelerators and the stability of the accelerating field inside the cavities is very important for the desired parameters of charged particle beams. ...
The use of Disturbance Observer-based (DOB) control is widespread in stabilizing the electromagnetic field in superconducting radio frequency cavities to facilitate beam acceleration in particle accelerators. Repetitive disturbances such as beam loading and Lorentz force cavity detuning are compensated by DOB control, and their suppression is enhanced through the incorporation of a learning scheme into the conventional disturbance observer. This paper evaluated the performance of a learning-based disturbance observer for compensating beam loading and cavity detuning in pulsed superconducting radio frequency cavities and proposes modifications for better field stability. A superconducting cavity baseband model for π-mode was simulated in Matlab/Simulink with a trapezoidal beam pulse as the input disturbance and different cavity detuning values to analyze the controllers’ performance. The simulations were conducted for multiple observer filter bandwidths to evaluate the performance of the learning-based disturbance observer under plant model uncertainties and different detuning values. The results demonstrate that the learning-based disturbance observer yields faster convergence to the reference input and lower tracking errors during the flat top of pulse voltage in comparison to conventional disturbance observer control.
... we can see stronger relative suppression between the couplings, with a suppression factor, The grey shaded region is excluded by the LEP-II results for the Higgs boson search [5], and the red shaded region represents the prospective search reach of the proposed International Linear Collider (ILC) [6][7][8] The grey shaded region is excluded by the LEP-II results for the Higgs boson search [5]: Assuming the Higgs boson mass were 25 GeV, the Higgs boson coupling with the Z boson must be suppressed by a factor of sin 2 (θ) ≤ 0.02. The red shaded region represents the prospective search reach of the proposed International Linear Collider (ILC), as low as sin 2 (θ) 0.002 [6][7][8]. ...
... we can see stronger relative suppression between the couplings, with a suppression factor, The grey shaded region is excluded by the LEP-II results for the Higgs boson search [5], and the red shaded region represents the prospective search reach of the proposed International Linear Collider (ILC) [6][7][8] The grey shaded region is excluded by the LEP-II results for the Higgs boson search [5]: Assuming the Higgs boson mass were 25 GeV, the Higgs boson coupling with the Z boson must be suppressed by a factor of sin 2 (θ) ≤ 0.02. The red shaded region represents the prospective search reach of the proposed International Linear Collider (ILC), as low as sin 2 (θ) 0.002 [6][7][8]. We also calculate the trilinear coupling g h 1 h 1 h 2 with the same parameter choice. ...
... Using the SM-like Higgs boson total decay width to SM particles Γ h→SM = 4.07 MeV [14], the branching ratio to a pair of h 2 is defined as Shaded regions correspond to bounds from the proposed ILC, blue for bounds on the branching ratio [6][7][8], and red for bounds on sin 2 (θ) [9,10]. The grey shaded regions are excluded by ATLAS(h 1 → h 2 h 2 → bbbb) [11,12] and LEP-II for M h 2 = 25GeV [13]. ...
We consider a classically conformal $U(1)$ gauge extension of the Standard Model (SM), in which the $U(1)$ gauge symmetry is radiatively broken by the Coleman-Weinberg mechanism. This breaking triggers the electroweak (EW) symmetry breaking through a mixed quartic coupling between the $U(1)$ Higgs field and the SM Higgs doublet. For two Higgs boson mass eigenstates after the symmetry breaking, $h_1$ (SM-like Higgs boson) and $h_2$ (SM singlet-like Higgs boson), we calculate the Higgs boson trilinear coupling ($g_{h_{1} h_{2} h_{2}}$) in the model by setting the Higgs boson mass spectrum to be $M_{h_1} > 2 M_{h_2}$. For a common Higgs mass spectrum and mixing angle between two Higgs fields, we find that $g_{h_{1} h_{2} h_{2}}$ in the classically conformal model is highly suppressed compared to that calculated for the conventional Higgs potential, where the $U(1)$ and EW symmetry breaking originate from the negative squared masses for the Higgs fields at the tree-level. Thus, this coupling suppression is a striking nature of the radiative origin of EW symmetry breaking. We then consider how to distinguish this origin at the proposed International Linear Collider (ILC) via precise measurements of anomalous SM Higgs boson couplings and the search for anomalous SM Higgs boson decay $h_1 \rightarrow h_2 h_2$ followed by $h_2 \to b \bar{b}$. We conclude that once the anomalous couplings are measured at the ILC, the observation of the anomalous Higgs boson decay is promising in the conventional Higgs potential, while this decay process is highly suppressed and undetectable for the classically conformal model.
... However, in this article we will focus on the most conservative scenario. The Higgs production crosssections are σ h ≈ 620 fb and σ h ≈ 510 fb for √ s = 250 GeV and √ s = 500 GeV, respectively (see ref. [57]). Therefore, the expected numbers of produced Higgs bosons (N h ), after 20 years of operation, are as given in table 1. ...
A bstract
We investigate rare decays of Higgs via exchange of two almost degenerate heavy on-shell Majorana neutrinos N j ( j = 1, 2): Γ ± = Γ( h → ν k N j → ν k ℓ ± π ∓ ), and into the open quark channels Γ ± = Γ( h → ν k N j → ν k ℓ ± UD ), where UD are two jets of open quarks ( $$ \overline{U}D $$ U ¯ D , or $$ U\overline{D} $$ U D ¯ , where U = u , c and D = d , s ). The related CP violation asymmetry A CP = (Γ − − Γ + )/(Γ − + Γ + ) is studied in detail. We take into account the N 1 - N 2 overlap and oscillation effects. We can see that for certain, presently acceptable, range of input parameters, such decays with open quark channels, and their asymmetries, could be detected in the International Linear Collider (ILC).
... (38). This then implies that the general expression for the effective decay width is obtained from the expression (53) with the replacement of the θ N -dependent exponents and 2π/L osc (θ N ) there by integration over 2πd cos θ N and dividing by the overall factor 4π ...
... This distribution is obtained by simulating 10 6 Higgs bosons produced in a e + e − collider, using Mad-Graph5 aMC@NLO [49], Pythia8 [50] and Delphes [51], for the ILC conditions for The integrated luminosities (based on 20 years of operation) expected at ILC are 1150 fb −1 and 1600 fb −1 for √ s = 250 GeV and √ s = 500 GeV, respectively (see Ref. [52]). The Higgs production cross-sections are σ h ≈ 620 fb and σ h ≈ 510 fb for √ s = 250 GeV and √ s = 500 GeV, respectively (see Ref. [53]). Therefore, the expected numbers of produced Higgs bosons (N h ), after 20 years of operation, are as given in Table I. ...
We investigate rare decays of Higgs via exchange of two almost degenerate heavy on-shell Majorana neutrinos $N_j$ ($j=1,2$): $\Gamma_{\pm} = \Gamma(h \to \nu_k N_j \to \nu_k \ell^{\pm} \pi^{\mp})$, and into the open quark channels $\Gamma_{\pm} = \Gamma(h \to \nu_k N_j \to \nu_k \ell^{\pm} U D)$, where $U D$ are two jets of open quarks (${\bar U} D$, or $U {\bar D}$, where $U=u, c$ and $D=d, s$). The related CP violation asymmetry $A_{\rm CP} = (\Gamma_{-} - \Gamma_{+})/(\Gamma_{-} + \Gamma_{+})$ is studied in detail. We take into account the $N_1$-$N_2$ overlap and oscillation effects. We can see that for certain, presently acceptable, range of input parameters, such decays with open quark channels, and their asymmetries, could be detected in the International Linear Collider (ILC).
... The main interest of this article is investigation of the CP violation in the electron-positron annihilation into a pair of top quarks decaying into W bosons and bottom quarks. Such process is planned to be explored at future electron-positron colliders like International Linear Collider (ILC) [1][2][3] and Compact Linear Collider (CLIC) [4][5][6][7][8]. The ILC will start at the center-of-mass (CM) energy of 250 GeV followed by 500 GeV upgrade [7,9]. ...
... At present there are no unique constraints on values of the anomalous couplings in Eqs. (3) and (4). An overview of the global analysis of the couplings is given in [31]. ...
Joint energy distribution of the bottom quark and antiquark from decays of the top quark and antiquark produced in the reaction $e^+ e^- \to t \bar{t}$ is studied. Main emphasis is put on $CP$-violation effects in the interaction of the photon and $Z$ boson with the top quarks. Energy asymmetries of $b$ and $\bar{b}$ quarks, which give access to the $CP$-violating terms, are considered. To estimate the magnitude of these asymmetries, the $CP$-violating $\gamma t \bar{t} $ and $Z t \bar{t}$ couplings are calculated in one-loop model with exchange of the Higgs boson. Interaction of this boson with the top quarks is assumed to include scalar and pseudoscalar couplings. Values of these couplings are constrained from the recent CMS analysis. Energy dependence of the asymmetries of $b$ and $\bar{b}$ quarks is calculated up to $\sqrt{s}=1.2$ TeV and some interesting features of their behavior are observed. These observables can be of interest for future studies at electron$-$positron colliders CLIC and ILC.
Предложена аналитическая аппроксимация для определения распределения неупругих потерь энергии заряженных фрагментов ядерных реакций в столкновении протонов, гамма-квантов и электронов с ядром кремния. Показано, что в диапазоне энергии 3–10 ГэВ влияние процесса адронизации на это распределение для вторичных тяжелых ионов возрастает с увеличением энергии падающего излучения. Сильная асимметрия рассчитанного распределения при столкновениях с релятивистскими электронами указывает на передачу импульса только небольшому фрагменту ядра.
Joint energy distribution of the bottom quark and antiquark from decays of the top quark and antiquark produced in the reaction $e^+ e^- \to t \bar{t}$ is studied. Main emphasis is put on $CP$-violation effects in the interaction of the photon and $Z$ boson with the top quarks. Energy asymmetries of $b$ and $\bar{b}$ quarks, which give access to the $CP$-violating terms, are considered. To estimate the magnitude of these asymmetries, the $CP$-violating $\gamma t \bar{t} $ and $Z t \bar{t}$ couplings are calculated in one-loop model with exchange of the Higgs boson. Interaction of this boson with the top quarks is assumed to include scalar and pseudoscalar couplings. Values of these couplings are constrained from the recent CMS analysis. Energy dependence of the asymmetries of $b$ and $\bar{b}$ quarks is calculated up to $\sqrt{s}=1.2$ TeV and some interesting features of their behavior are observed. These observables can be of interest for future studies at electron--positron colliders CLIC and ILC.
