arXiv subjects

Zhaoxia Heng

Publications and source records attributed to Zhaoxia Heng.

At least 19 recordsLinked to original sources

arXiv2026

Constraining the light Higgs bosons in the GNMSSM with recent Higgs data

The search for light scalar and pseudoscalar particles provides a promising avenue for probing physics beyond the Standard Model (SM). In this study, we investigated the exotic decay channels of the 125 GeV SM-like Higgs boson into pairs of light CP-odd ($a_s$) or CP-even ($h_s$) Higgs bosons within the framework of the General Next-to-Minimal Supersymmetric Standard Model (GNMSSM). A comprehensive parameter space scan is performed using the MultiNest algorithm, incorporating constraints from $ \textsf{HiggsSignals-2.6.2} $, $ \textsf{HiggsBounds-5.10.2} $, and ATLAS experimental searches, under two distinct scenarios where either the lightest ($h_1$) or next-to-lightest ($h_2$) CP-even state is the observed Higgs boson ($h$). Our results demonstrate that $ \textsf{HiggsBounds} $ imposes the most stringent exclusion limits due to its sensitivity to direct searches for non-SM Higgs bosons. In the $h_2$ scenario, $ \textsf{HiggsSignals} $ can additionally exclude regions with suppressed exotic branching ratios (e.g., $ Br(h \to a_sa_s \to ττbb) \leq 2.5\%$), due to its sensitivity to indirect deviations caused by the kinematically enhanced decay $ h \to h_sh_s $. Under combined constraints from $ \textsf{HiggsTools} $, $h$ must retain at least 93\% SM-like component ($ V_h^\text{SM} \geq 0.93 $) with no more than 32\% singlet admixture ($ V_h^\text{S} \leq 0.32 $); in the $ h_2 $ case, the lightest scalar $ h_s $ exhibits high singlet purity ($ V_{h_s}^\text{S} \geq 0.94 $). Furthermore, dark matter (DM) phenomenology indicates that singlino- or higgsino-dominated DM is viable in the $ h_1 $ scenario, with dominant annihilation channels including $ \tildeχ_1^0\tildeχ_1^0 \to h_sa_s $ for singlino-like DM and chargino co-annihilation for higgsino-like DM, whereas the $ h_2 $ scenario favors higgsino-dominated DM.

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arXiv2025

New Physics Search at the CEPC: a General Perspective

The Circular Electron-Positron Collider (CEPC), a proposed next-generation Higgs factory, provides new opportunities to explore physics beyond the Standard Model (SM). With its clean electron-positron collision environment and the ability to collect large samples of Higgs, W, and Z bosons, the CEPC enables precision measurements and searches for new physics. This white paper outlines the CEPC's discovery potential, including studies of exotic decays of the Higgs, Z, and top quarks, dark matter and dark sector phenomena, long-lived particles, supersymmetry, and neutrino-related signatures. Advanced detector technologies and reconstruction techniques, such as one-to-one correspondence reconstruction and jet origin identification, significantly improve sensitivity to rare and weakly interacting processes. The CEPC is particularly well suited to probe the electroweak phase transition and test models of electroweak baryogenesis and dark sector interactions. In addition, global fit analyses highlight the CEPC's complementary role in constraining a wide range of new physics scenarios. These features position the CEPC as a powerful tool for exploring the next frontier in fundamental particle physics in the post-Higgs discovery era.

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arXiv2023

Properties of Heavy Higgs Bosons and Dark Matter under Current Experimental Limits in the $μ$NMSSM

Searches for new particles beyond the Standard Model (SM) are an important task for the Large Hadron Collider (LHC). In this paper, we investigate the properties of the heavy non-SM Higgs bosons in the $μ$-term extended Next-to-Minimal Supersymmetric Standard Model ($μ$NMSSM). We scan the parameter space of the $μ$NMSSM considering the basic constraints from Higgs data, dark matter (DM) relic density, and LHC searches for sparticles. And we also consider the constraints from the LZ2022 experiment and the muon anomaly constraint at 2$σ$ level. We find that the LZ2022 experiment has a strict constraint on the parameter space of the $μ$NMSSM, and the limits from the DM-nucleon spin-independent (SI) and spin-dependent (SD) cross-sections are complementary. Then we discuss the exotic decay modes of heavy Higgs bosons decaying into SM-like Higgs boson. We find that for doublet-dominated Higgs $h_3$ and $A_2$, the main exotic decay channels are $h_3\rightarrow Z A_1$, $h_3\rightarrow h_1 h_2$, $A_2\rightarrow A_1 h_1$ and $A_2\rightarrow Z h_2$, and the branching ratio can reach to about 23$\%$, 10$\%$, 35$\%$ and 10$\%$ respectively. At the 13 TeV LHC, the production cross-section of $ggF\rightarrow h_3\rightarrow h_1 h_2$ and $ggF\rightarrow A_2\rightarrow A_1 h_1$ can reach to about $10^{-11}$pb and $10^{-10}$pb, respectively.

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arXiv2023

The Phenomenological Research on Higgs and dark matter in the Next-to-Minimal Supersymmetric Standard Model

The $Z_3$-invariant next-to-minimal supersymmetric standard model (NMSSM) can provide a candidate for dark matter (DM). It can also be used to explain the hypothesis that the Higgs signal observed on the Large Hadron Collider (LHC) comes from the contribution of the two lightest CP-even Higgs bosons, whose masses are near 125 GeV. At present, XENON1T, LUX, and PandaX experiments have imposed very strict restrictions on direct collision cross sections of {dark matter}. In this paper, we consider a scenario that the observed Higgs signal is the superposition of two mass-degenerate Higgs in the $Z_3$-invariant NMSSM and scan the seven-dimension parameter space composing of $λ, κ, \tanβ, μ, A_k, A_t, M_1$ via the Markov chain Monte Carlo (MCMC) method. We find that the DM relic density, as well as the LHC searches for sparticles, especially the DM direct detections, has provided a strong limit on the parameter space. %Please check intended meaning has been retained. The allowed parameter space is featured by a relatively small $μ\le 300$ GeV and about $\tanβ\in(10,20)$. In addition, the DM is Higgsino-dominated because of $|\frac{2κ}λ|>1$. Moreover, the co-annihilation between $\tildeχ_1^0$ and $\tildeχ_1^\pm$ must be taken into account to obtain the reasonable DM relic density.

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arXiv2022

The mass-degenerate SM-like Higgs and anomaly of $(g-2)_μ$ in $μ$-term extended NMSSM

We chose the $μ$-term extended next-to-minimal supersymmetric standard model ($μ$NMSSM) for this work, and the phenomenological research is based on the assumption of double Higgs resonance state as the Standard Model (SM)-like Higgs considering the recent $(g-2)_μ$ result. The study also take into account a variety of experimental results, including direct detection of dark matter (DM) and searching results for sparticles at the Large Hadron Collider (LHC). We study the characteristic of DM confronted with limitations of direct detection experiments. Following that, we concentrate on the properties of the mass-degenerate SM-like Higgs bosons and explaining the anomaly of $(g-2)_μ$. We conclude that the anomaly of $(g-2)_μ$ can be explained in the scenario with two mass-degenerate SM-like Higgs, and there are samples that meet all current constraints and outperform SM in fitting Higgs data.

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arXiv2019

Charged Higgs bosons in the NMSSM under current LHC constraints

Charged Higgs boson is a crucial prediction of new physics beyond the SM. In this work, we perform a comprehensive scan over the parameter space of NMSSM considering various experimental constraints including the direct search limits from the 13 TeV LHC, and consider the scenario that the next-to-lightest CP-even Higgs boson is SM-like. We find that the masses of charged Higgs bosons can be as light as 350 GeV, the lightest CP-even Higgs boson $h_1$ is predominantly singlet and can be as light as 48 GeV, and the lightest CP-odd Higgs boson $a_1$ is also singlet-dominated and can be as light as 82 GeV. The charged Higgs bosons mainly decay to $t\bar{b}$ or $\bar{t} b$, but the branching ratio of the exotic decays $H^\pm\to W^\pm h_1$ and $H^\pm\to W^\pm a_1$ can maximally reach to 20\% and 11\%, respectively, which can be used to distinguish the NMSSM from MSSM. Such a heavy charged Higgs boson is unaccessible at the 13 TeV LHC with a luminosity of 36.1 $\rm fb^{-1}$ and its detection needs higher energy and/or higher luminosity.

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arXiv2018

Pair production of Higgs boson in NMSSM at the LHC with next-to-lightest CP-even Higgs boson being SM-like

The next-to-minimal supersymmetric standard model (NMSSM) more naturally accommodates a Higgs boson with a mass of approximately 125 GeV than the minimal supersymmetric standard model (MSSM). In this work, we assume that the next-to-lightest CP-even Higgs boson $h_2$ is the SM-like Higgs boson $h$, whereas the lightest CP-even Higgs boson $h_1$ is dominantly singlet-like. We discuss the $h_1h_1$, $h_2h_2$, and $h_1h_2$ pair production processes via gluon-gluon fusion at the LHC for an collision energy of 14 TeV, and we consider the cases in which one Higgs boson decays to $b\bar b$ and the other one decays to $γγ$ or $τ^+τ^-$. We find that, for $m_{h_1} \lesssim$ 62 GeV, the cross section of the $gg \to h_1 h_1$ process is relatively large and maximally reaches 5400 fb, and the production rate of the $h_1h_1\to b\bar b τ^+τ^-$ final state can reach 1500 fb, which make the detection of this final state possible for future searches of an integrated luminosity of 300 and 3000 $fb^{-1}$. This is mainly due to the contributions from the resonant production process $pp\to h_2\to h_1h_1$ and the relatively large branching ratio of $h_1\to b\bar b$ and $h_1\toτ^+τ^-$. The cross sections of the $pp \to h_2h_2$ and $pp \to h_1 h_2$ production processes maximally reach 28 fb and 133 fb, respectively.

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arXiv2016

The properties of the Higgs bosons and Pair Production of the SM-like Higgs Boson in λ-SUSY at the LHC

Compared with the MSSM or the NMSSM with a low λ, λ-SUSY theory with a large λaround one has been deemed as a most natural realization of NMSSM. In this work, we treat the next-to-lightest CP-even Higgs boson as the SM-like Higgs boson in λ-SUSY and study the properties of the Higgs bosons and the pair production of the SM-like Higgs boson by considering various experiment constraints. We find that naturalness plays an important role in selecting the parameter space of λ-SUSY. In the most natural region of parameter space, the triple self coupling of the SM-like Higgs boson compared with its SM prediction may get enhanced by a factor about 7, and the most dominant contribution to the Higgs pair production comes from the triple self coupling of the SM-like Higgs boson and the production rate can be greatly enhanced, maximally 10 times larger than the SM prediction.

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arXiv2014

Higgs-strahlung production process e^+ e^- \to Z h at the future Higgs factory in the Minimal Dilaton Model

We investigate the Higgs-strahlung production process e^+ e^- \to Z h at the future Higgs factory such as TLEP by including radiative corrections in the Minimal Dilaton Model (MDM), which extends the SM by one singlet scalar called dilaton. We consider various theoretical and experimental constraints on the model, and perform fits to the Higgs data taken from ATLAS, CMS and CDF+D0. Then for the 1σsurviving samples, we calculate the MDM predictions on the inclusive production rate σ(e^+e^-\to Zh) at the 240-GeV Higgs factory, and also the signal rates of e^+e^-\to Zh with the Higgs boson decaying to b\bar b and γγ. We have following observations: (1) In the heavy dilaton scenario, the deviation of σ(e^+e^-\to Zh) from its SM prediction can vary from -15\% to 85\%, which mainly arises from the modification of the tree-level hZZ coupling and also the radiative correction induced by possibly large Higgs self-couplings. (2) The processes e^+e^-\to Zh at the Higgs factory and pp\to hh at 14-TeV LHC are complementary in limiting the MDM parameter space. Requiring the deviation of σ(e^+e^-\to Zh) from its SM prediction to be less than 1\% and that of σ(p p \to h h) to be less than 50\%, \tan θ_S in the MDM will be limited to be -0.1<\tanθ_S<0.3, and the deviations of the signal rates are constrained to be |R_{b\bar b}|<2\% and |R_{γγ}|<7\%. Especially, the Higgs self-coupling normalized to its SM prediction is now upper bounded by about 4. (3) In the light dilaton scenario, the deviation of σ(e^+e^-\to Zh) may reach -7\%, and requiring its size to be less than 1\% will result in 0<\tanθ_S<0.1, and -10\% < R_{b\bar b}, R_{γγ} < 1\%.

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arXiv2014

Pair production of 125 GeV Higgs boson in the SM extension with color-octet scalars at the LHC

Although the Higgs boson mass and single production rate have been determined more or less precisely, its other properties may deviate significantly from its predictions in the standard model (SM) due to the uncertainty of Higgs data. In this work we study the Higgs pair production at the LHC in the Manohar-Wise model, which extends the SM by one family of color-octet and isospin-doublet scalars. We first scanned over the parameter space of the Manohar-Wise model considering exprimental constraints and performed fits in the model to the latest Higgs data by using the ATLAS and CMS data separately. Then we calculated the Higgs pair production rate and investigated the potential of its discovery at the LHC14. We conclude that: (i) Under current constrains including Higgs data after Run I of the LHC, the cross section of Higgs pair production in the Manohar-Wise model can be enhanced up to even $10^3$ times prediction in the SM. (ii) Moreover, the sizable enhancement comes from the contributions of the CP-odd color-octet scalar $S^A_I$. For lighter scalar $S^A_I$ and larger values of $|λ_I|$, the cross section of Higgs pair production can be much larger. (iii) After running again of LHC at 14 TeV, most of the parameter spaces in the Manohar-Wise model can be test. For an integrated luminosity of 100 fb$^{-1}$ at the LHC14, when the normalized ratio $R=10$, the process of Higgs pair production can be detected.

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arXiv2013

Pair production of a 125 GeV Higgs boson in MSSM and NMSSM at the ILC

In this work we investigate the Higgs pair production in the MSSM and NMSSM at the photon-photon collision of the ILC. We consider various experimental constraints and scan over the parameter space of the MSSM and NMSSM. Then we calculate the cross section of Higgs pair production in the allowed parameter space and compare the results with the predictions in the SM. We find that the large enhancement of the cross section in the MSSM is mainly due to the contributions from the loops mediated by the stau, while in the NMSSM it is mainly due to the contributions from the top-squark loops. For light $m_{\tildeτ_1}$ and large $μ\tanβ$, the production rate can be enhanced by a factor of 18 in the MSSM (relative to the SM prediction). And for a large trilinear soft breaking parameter $A_t$ and a moderately light top-squark, it can also be enhanced by a factor of 2 in the NMSSM. Moreover, we also calculate the $χ^2$ values with the LHC Higgs data and display the results for the parameter space with $χ^2$ better than the SM value.

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arXiv2013

Pair Production of a 125 GeV Higgs Boson in MSSM and NMSSM at the LHC

In light of the recent LHC Higgs search data, we investigate the pair production of a SM-like Higgs boson around 125 GeV in the MSSM and NMSSM. We first scan the parameter space of each model by considering various experimental constraints, and then calculate the Higgs pair production rate in the allowed parameter space. We find that in most cases the dominant contribution to the Higgs pair production comes from the gluon fusion process and the production rate can be greatly enhanced, maximally 10 times larger than the SM prediction (even for a TeV-scale stop the production rate can still be enhanced by a factor of 1.3). We also calculate the chi-square value with the current Higgs data and find that in the most favored parameter region the production rate is enhanced by a factor of 1.45 in the MSSM, while in the NMSSM the production rate can be enhanced or suppressed (σ_{SUSY}/σ_{SM} varies from 0.7 to 2.4).

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arXiv2012

A 125 GeV Higgs and its di-photon signal in different SUSY models: a mini review

In this note we briefly review our recent studies on a 125 GeV Higgs and its di-photon signal rate in different low energy supersymmetric models, namely the minimal supersymmetric standard model (MSSM), the next-to-minimal supersymmetric standard model (NMSSM), the nearly minimal supersymmetric standard model (nMSSM) and the constrained MSSM. Our conclusion is: (i) In the allowed parameter space the SM-like Higgs boson can easily be 125 GeV in the MSSM, NMSSM and nMSSM, while it is hard to realize in the constrained MSSM; (ii) The di-photon Higgs signal rate in the nMSSM and constrained MSSM is suppressed relative to the prediction of the SM, while the signal rate can be enhanced in the MSSM and NMSSM; (iii) The NMSSM may allow for a lighter top-squark than the MSSM, which can thus ameliorate the fine-tuning problem.

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arXiv2012

Status of low energy SUSY models confronted with the LHC 125 GeV Higgs data

Confronted with the LHC data of a Higgs boson around 125 GeV, different models of low energy SUSY show different behaviors: some are favored, some are marginally survived and some are strongly disfavored or excluded. In this note we update our previous scan over the parameter space of various low energy SUSY models by considering the latest experimental limits like the LHCb data for B_s->μ^+μ^- and the XENON 100(2012) data for dark matter-neucleon scattering. Then we confront the predicted properties of the SM-like Higgs boson in each model with the combined 7 TeV and 8 TeV Higgs search data of the LHC. For a SM-like Higgs boson around 125 GeV, we have the following observations: (i) The most favored model is the NMSSM, whose predictions about the Higgs boson can naturally (without any fine tuning) agree with the experimental data at 1-sigma level, better than the SM; (ii) The MSSM can fit the LHC data quite well but suffer from some extent of fine tuning; (iii) The nMSSM is excluded at 3-sigma level after considering all the available Higgs data; (iv) The CMSSM is quite disfavored since it is hard to give a 125 GeV Higgs boson mass and at the same time cannot enhance the di-photon signal rate.

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arXiv2012

Higgs decay to dark matter in low energy SUSY: is it detectable at the LHC ?

Due to the limited statistics so far accumulated in the Higgs boson search at the LHC, the Higgs boson property has not yet been tightly constrained and it is still allowed for the Higgs boson to decay invisibly to dark matter with a sizable branching ratio. In this work, we examine the Higgs decay to neutralino dark matter in low energy SUSY by considering three different models: the minimal supersymmetric standard model (MSSM), the next-to-minimal supersymmetric standard models (NMSSM) and the nearly minimal supersymmetric standard model (nMSSM). Under current experimental constraints at 2-sigma level (including the muon g-2 and the dark matter relic density), we scan over the parameter space of each model. Then in the allowed parameter space we calculate the branching ratio of the SM-like Higgs decay to neutralino dark matter and examine its observability at the LHC by considering three production channels: the weak boson fusion VV->h, the associated production with a Z-boson pp->hZ+X or a pair of top quarks pp->htt_bar+X. We find that in the MSSM such a decay is far below the detectable level; while in both the NMSSM and nMSSM the decay branching ratio can be large enough to be observable at the LHC.

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arXiv2012

A SM-like Higgs near 125 GeV in low energy SUSY: a comparative study for MSSM and NMSSM

Motivated by the recent LHC hints of a Higgs boson around 125 GeV, we assume a SM-like Higgs with the mass 123-127 GeV and study its implication in low energy SUSY by comparing the MSSM and NMSSM. We consider various experimental constraints at 2-sigma level (including the muon g-2 and the dark matter relic density) and perform a comprehensive scan over the parameter space of each model. Then in the parameter space which is allowed by current experimental constraints and also predicts a SM-like Higgs in 123-127 GeV, we examine the properties of the sensitive parameters (like the top squark mass and the trilinear coupling A_t) and calculate the rates of the di-photon signal and the VV^* (V=W,Z) signals at the LHC. Our typical findings are: (i) In the MSSM the top squark and A_t must be large and thus incur some fine-tuning, which can be much ameliorated in the NMSSM; (ii) In the MSSM a light stau is needed to enhance the di-photon rate of the SM-like Higgs to exceed its SM prediction, while in the NMSSM the di-photon rate can be readily enhanced in several ways; (iii) In the MSSM the signal rates of pp -> h -> VV^* at the LHC are never enhanced compared with their SM predictions, while in the NMSSM they may get enhanced significantly; (iv) A large part of the parameter space so far survived will be soon covered by the expected XENON100(2012) sensitivity (especially for the NMSSM).

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arXiv2012

Current experimental constraints on the lightest Higgs boson mass in the constrained MSSM

We examine the parameter space of the constrained MSSM by considering various experimental constraints. For the dark matter sector, we require the neutralino dark matter to account for the relic density measured by the WMAP and satisfy the XENON limits on its scattering rate with the nucleon. For the collider constraints, we consider all relevant direct and indirect limits from LEP, Tevatron and LHC as well as the muon anomalous magnetic moment. Especially, for the limits from B_s->μ^+μ^-, we either directly consider its branching ratio with the latest LHC data or alternatively consider the double ratio of the purely leptonic decays defined by [Br(B_s->μ^+μ^-)/Br(B_u->τν_τ)]/[Br(D_s->τν_τ)/Br(D->τμ_τ)]. We find that under these constraints, the mass of the lightest Higgs boson (h) in both the CMSSM and the NUHM2 is upper bounded by about 124 GeV (126 GeV) before (after) considering its theoretical uncertainty. We also find that for these models the di-photon Higgs signal at the LHC is suppressed relative to the SM prediction, and that the lower bound of the top-squark mass goes up with m_h, reaching 600 GeV for m_h=124 GeV.

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arXiv2011

Di-photon Higgs signal at the LHC: a comparative study for different supersymmetric models

As the most important discovery channel for a light Higgs boson at the LHC, the di-photon signal $gg->h->γγ$ is sensitive to underlying physics. In this work we investigate such a signal in a comparative way by considering three different supersymmetric models, namely the minimal supersymmetric standard model (MSSM), the next-to-minimal supersymmetric standard model (NMSSM) and the nearly minimal supersymmetric standard model (nMSSM). Under the current collider and cosmological constraints we scan over the parameter space and obtain the following observation in the allowed parameter space: (i) In the nMSSM the signal rate is always suppressed; (ii) In the MSSM the signal rate is suppressed in most cases, but in a tiny corner of the parameter space it can be enhanced (maximally by a factor of 2); (iii) In the NMSSM the signal rate can be enhanced or suppressed depending on the parameter space, and the enhancement factor can be as large as 7.

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