arXiv subjects

Nasuf Sonmez

Publications and source records attributed to Nasuf Sonmez.

9 recordsLinked to original sources

arXiv2019

Exploring the prominent channel: Charged Higgs pair production in supersymmetric Two-parameter Non-Universal Higgs Model

In this study, the charged Higgs pair production is calculated in the context of the supersymmetry at a $γγ$-collider. The channel is explored in Two-parameter Non-Universal Higgs Model where the model provides relatively light neutral and charged Higgs bosons. The computation is extended to one loop-level, and the divergence arising in the loop-diagrams are cured with the radiative photon correction. The production rate of the charged Higgs pair reaches up to $\hatσ_\text{UU}^\text{LO+NLO}=121\text{ fb}$ at $\sqrt{\hat{s}}=635\text{ GeV}$. The analysis of the cross-section is also given varying the parameters $m_A$ and $\tanβ$. The total convoluted cross-section with the photon luminosity in an $e^+e^-$ machine is calculated as a function of the center-of-mass energy up to $1\text{ TeV}$, and it gets up to $42\text{ fb}$ at $\sqrt{s}=900 \text{ GeV}$ depending on the polarization of the initial electron and laser photon.

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arXiv2019

Production of neutral Higgs bosons associated with Z-boson and photon in 2HDM at future lepton colliders

Inspired by precision tests of the Standard Model in future lepton colliders, the numerical analysis of the following scattering processes, $e^+e^- \rightarrow Z h^0γ$ and $e^+e^- \rightarrow Z H^0 γ$, are carried at the tree level including all possible diagrams in the two-Higgs-doublet model (2HDM). This model has many free parameters, but the parameters which take part in the scattering amplitudes of these two processes are primarily the mixing angle parameter, $s_{β-α}$, and the masses of the neutral Higgs bosons, ($h^0, H^0$). Therefore, measuring the production rates of $Z h^0γ$ and $Z H^0 γ$ final states open another test for the scalar sectors of the 2HDM. The numerical analysis is performed under the current experimental constraints. The production rates and the asymmetry in the forward-backward direction are presented as a function of the center-of-mass energy covering the future lepton colliders. The unpolarized cross-section gets up to 6.19 (4.86) fb at $\sqrt{s} = 350$ (500) GeV and 0.164 (0.157) fb at $\sqrt{s} = 350$ (500) GeV for $e^+e^- \rightarrow Z h^0γ$ and $e^+e^- \rightarrow Z H^0 γ$, respectively. The polarization of the incoming $e^+e^-$ beams are studied for various configurations, and it enhances the cross-section by a factor of 1.78 in both processes for $P_{e^+,e^-}=(+0.6,-0.8)$.

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arXiv2019

Pair production of the lightest chargino at $γγ$-collider

Chargino pair production via photon-photon collision is investigated in the Minimal Supersymmetric Standard Model at a future linear collider. The process is computed using all the possible diagrams at the next-to-leading order, including box, triangle, and self-energy diagrams. The numerical analysis is carried out for the production rates of the lightest chargino pair in RNS, NS, mSUGRA, BB, and NUGM scenarios. These distinct benchmark models were introduced in the light of the LHC results presented at $\sqrt{s}=7-8\text{ TeV}$. Among these scenarios, the RNS has the highest production rate for the $γγ\rightarrow \tildeχ_1^+ \tildeχ_1^-$. The partonic cross section reaches up to $3.94\text{ pb}$ at $\sqrt{\hat{s}}=310\text{ GeV}$. The total convoluted cross section with the photon luminosity in a $e^+e^-$ machine is calculated as a function of the center-of-mass energy up to $1\text{ TeV}$. The convoluted cross section is $\sim1.05\text{ pb}$ at $\sqrt{s}=350\text{ GeV}$ depending on the polarization of the initial electron and laser polarization. The RNS along with the BB scenarios are accessible at $\sqrt{s}=500\text{ GeV}$ with a $γγ$ collision mode on $e^+e^-$-collider.

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arXiv2018

Measuring the triple Higgs self-couplings in two Higgs doublet model

The determination of the Higgs self-coupling in the Standard Model is one of the primary motivations among all the future lepton colliders. Extending the scalar sector of the Standard Model by a new Higgs doublet with a quadratic Higgs potential gives many new features to the model, and most importantly additional Higgs self-couplings emerge. Measuring these couplings is the only way to reconstruct the shape of the scalar potential. In this study, the numerical analysis of several scattering processes is carried out for the two-Higgs-doublet model to determine all these Higgs self-couplings. These processes are selected among various possible combinations of additional Higgs states. The computation is carried out in the exact alignment limit ($s_{βα}=1$). The distribution of the cross sections is presented regarding the polarization of the incoming beams and up to $\sqrt{s}=3\text{ TeV}$. A strategy for extracting the Higgs self-couplings are considered in 2HDM and at the future lepton colliders. Possible final states that could be used for each of the processes are investigated using the decays of the final state particles.

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arXiv2018

Charged Higgs-boson pair production in association with the $Z^0$ boson at electron-positron colliders

In this paper, the production of the charged Higgs pair associated with the $Z^0$ boson is analyzed in the minimal extension of the standard model the so-called two-Higgs-doublet model (2HDM). The process $e^+e^- \rightarrow H^+H^-Z^0$ is calculated at the tree level including all the possible diagrams in 2HDM. The numerical analysis is performed in consideration of the current experimental constraints and various scenarios for the free parameters of the model. The results are presented as a function of center-of-mass energy, the charged Higgs mass ($m_{H^\pm}$), and the ratio of the vacuum expectation values ($t_β$). The unpolarized cross section, taking into account the results in the flavor physics, gets up to $0.278\text{ fb}$ for $m_{H^\pm}=175\text{ GeV}$, and it declines with decreasing $m_{H^\pm}$ in Type-I. However, it gets down to $0.073\text{ fb}$ for $m_{H^\pm}=500\text{ GeV}$ in Type-II. Further, the calculation is also carried out in the non-alignment scenario and low-$m_{h^0}$ scenario. The effect of the polarized incoming $e^+$ and $e^-$ beams shows that the cross section is enhanced by a factor up to 2.5 at P(+0.60,-0.80) polarization configuration. Decay channels of the charged Higgs, possible final states of the process, and some differential distributions belong to the charged Higgs and $Z^0$ boson are examined for each scenario. The analysis shows that some channels have higher branching ratio such as $H^+\rightarrow t \bar{b}$, $H^+\rightarrow W^+h^0$, and $H^+\rightarrow W^+H^0$. These decay channels are essential for the charged Higgs searches in the lepton colliders regarding the scenarios interested. The detection of the charged Higgs is a powerful sign for the extended scalar sectors, and the results show the potential of a future lepton collider.

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arXiv2018

Deep-Learning in Search of Light Charged Higgs

In this work, we deep-learn light charged Higgs signal in top quark decays which poses difficulties due to strong W boson contamination. We construct Deep Neural Networks (DNN) with appropriate architecture and determine signal extraction efficiency by considering various features (kinematical and human engineered parameters). Results show that DNN gives better performance than the classical neural networks and has ability to find regions of high efficiency even the input features are not human-engineered. In a sense, human-engineered high-level features are offset by DNNs with different combinations of the low-level kinematical features. Additionally, it is shown that increasing the number of processing units in DNNs does not necessarily cause an increase in efficiency due mainly to increased complexity. Our method and results can set an example of signal extraction from strong backgrounds.

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arXiv2016

Charged Higgs Pair Production in THDM Through Photon-photon Collisions at the ILC

In this study, the charged Higgs pair production is analyzed for the minimal extension of the standard model called two-higgs-doublet model. The process $γγ\rightarrow H^+H^-$ is calculated at the tree level for the ILC and the numerical analysis is presented for various parameters. The production rate of the charged Higgs boson pair as a function of center-of-mass (CM) energy and the differential cross section as a function of angle between photon and positive charged Higgs boson is presented. The cross section gets high at the low charged Higgs mass and low CM energies. The total integrated cross section of the process is also calculated at a $e^+e^-$-collider by convoluting the $γγ\rightarrow H^+H^-$ subprocess with the photon luminosity of the backscattered photons. The total integrated cross section peaks around $\sqrt{s}=650 \;\text{GeV}$ and have a value of $1.4 \;\text{pb}$ for $m_{H^\pm}=100\;\text{GeV/c}^2$. Charged Higgs detection is very important sign for the new physics and the results shows the potential of the ILC for the search of the new physics signals.

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arXiv2016

Neutralino Pair Production at the Photon-Photon Collider for the $\tildeτ$-Coannihilation Scenario

Supersymmetry (SUSY) is a theory that gives an explanation for the strong and electroweak interactions from the grand unification scale down to the weak scale. The search for supersymmetric particles still continues at full speed at the LHC without success. The main tasks at the ILC is complementing the LHC result and also search for new physics. In this study, the neutralino pair production via photon-photon collision is studied for the $\tilde{t}$-coannihilation scenario in the context of MSSM at the ILC. In the calculation, all the possible one-loop diagrams are taken into account for the photon-photon interaction. We present the production cross section and distribution of various observables for the lightest and next-to-lightest neutralino pairs for benchmark models which are specifically presented in the light of LHC8 data analysis, employing these benchmark models for neutralino pair production could show the potential of the ILC concerning the dark matter searches in supersymmetry.

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arXiv2014

Investigation of Neutralino Pair Production in Photon-Photon Collider at ILC

Neutralino pair production via photon-photon collisions is analyzed in the context of Minimal Supersymmetric Standard Model at future linear collider. Since photon does not have self coupling, this process is only possible at Next-to-Leading order and all the possible terms are calculated for the photon-photon interaction, including box, triangles and quartic coupling diagrams. Numerical analysis of the production rates for $ \tildeχ^0_1 \tildeχ^0_1$, $ \tildeχ^0_1 \tildeχ^0_2$ and $ \tildeχ^0_2 \tildeχ^0_2$ are presented for four new distinct benchmark models which are presented in the light of LHC8. Angular dependence of each neutralino pairs for the benchmark points are also presented. Total integrated photonic cross section goes up to $1.23\;fb$ and $1.26\;fb$ for the $ \tildeχ^0_1 \tildeχ^0_1$ and $ \tildeχ^0_2 \tildeχ^0_2$ pairs, respectively for the Radiatively driven natural susy benchmark point.

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