arXiv subjects

Hai-Bin Zhang

Publications and source records attributed to Hai-Bin Zhang.

At least 19 recordsLinked to original sources

arXiv2026

$B \to X_{\mathrm{s}} l^{+} l^{-}$ in the $μ$ from $ν$ Supersymmetric Standard Model

We investigate the impact of new physics on the rare inclusive decay $B \to X_{\mathrm{s}} l^{+} l^{-}$ within the framework of the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM). The dominant contributions to the relevant Wilson coefficients and their corresponding particles are identified and analyzed. By performing a systematic scan over the relevant parameter space, we elucidate the underlying physical mechanisms governing these dominant contributions and demonstrate their consistency with the experimentally allowed regions. Experimental constraints from the decays $\bar{B} \to X_{\mathrm{s}}γ$, $B_{\mathrm{s}}^{0} \to μ^{+} μ^{-}$, and the $125\,\text{GeV}$ SM-like Higgs boson are also incorporated. We perform a systematic interference decomposition of the Wilson-coefficient contributions to the forward-backward asymmetry, identifying the $C_7C_{10}$ and $C_9C_{10}$ interference terms as the dominant contributions governing its behavior in both the low- and high-$q^2$ regions.

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arXiv2025

Explaining the possible 95 GeV excesses in the B-L symmetric SSM

Motivated by the excesses around 95 GeV observed in the diphoton and $b\bar b$ data, this study focuses on investigating these two excesses within the framework of the $B-L$ supersymmetric model (B-LSSM), due to the existence of two light Higgs bosons in the model. Considering the two-loop effective potential corrections, it is found that the B-LSSM is hard to fit the 125 GeV Higgs signal strengths and the two excesses around 95 GeV in the experimental $1σ$ intervals, while the model can reproduce them in the experimental $2σ$ intervals simultaneously. And considering the two loop effective potential corrections to the squared Higgs mass matrix is important to account for the mixing effects among Higgs sector.

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arXiv2025

GKZ hypergeometric systems of the four-loop vacuum Feynman integrals

Basing on Mellin-Barnes representations and Miller's transformation, we present the Gel'fand-Kapranov-Zelevinsky (GKZ) hypergeometric systems of 4-loop vacuum Feynman integrals with arbitrary masses. Through the GKZ hypergeometric systems, the analytical hypergeometric solutions of 4-loop vacuum Feynman integrals with arbitrary masses can be obtained in neighborhoods of origin including infinity. The analytical expressions of Feynman integrals can be formulated as a linear combination of the fundamental solution systems in certain convergent region, which the combination coefficients can be determined by the integral at some regular singularities, the Mellin-Barnes representation of the integral, or some mathematical methods.

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arXiv2025

$B_s^0 \rightarrow μ^+ μ^-$ in a flavor violating extension of MSSM

$B$ meson rare decays play a crucial role in exploring new physics beyond the standard model. In this study, we explore the rare decay process $B_s^0 \rightarrow μ^+ μ^-$ in a flavor violating extension of the Minimal Supersymmetric Standard Model (MSSM), namely the $μ$-from-$ν$ SSM ($μν$SSM). Combined with the decay $\bar{B}\rightarrow X_sγ$, the numerical results indicate that the $μν$SSM can successfully accommodate the experimental data for $B_s^0 \rightarrow μ^+ μ^-$ and additionally narrow down the parameter space.

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arXiv2024

Gauss Relations in Feynman Integrals

Embedding Feynman integrals in Grassmannians, we can write Feynman integrals as some finite linear combinations of generalized hypergeometric functions. In this paper we present a general method to obtain Gauss relations among those generalized hypergeometric functions. The hypergeometric expressions of Feynman integral are continued from a connected component to another by the inverse Gauss relations, then continued to the whole domain of definition by the Gauss-Kummer relations. The Laurent series of the Feynman integral around the space-time dimension $D=4$ is obtained by the Gauss adjacent relations where the coefficient of the term with power of $D-4$ is given as the linear combinations of hypergeometric functions with integer parameters. As examples, we illustrate how to obtain the expressions for the Feynman integrals of the 1-loop self-energy and a 2-loop massless triangle diagram in the domains of definition.

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arXiv2024

Study lepton flavor violation $B^0\rightarrow{{l_i}^{\pm}{l_j}^{\mp}}$ within the Mass Insertion Approximation

We study lepton flavor violating (LFV) decays $B^0\rightarrow{{l_i}^{\pm}{l_j}^{\mp}}$ ($B^0\rightarrow eμ$, $B^0\rightarrow eτ$ and $B^0\rightarrow μτ$) in the $U(1)_X$SSM (SSM is acronym for the supersymmetric standard model), which is the $U(1)_X$ extension of the minimal supersymmetric standard model (MSSM). The local gauge group of $U(1)_X$SSM is $SU(3)_C\times SU(2)_L \times U(1)_Y \times U(1)_X$. These processes ($B^0\rightarrow eμ$, $B^0\rightarrow eτ$ and $B^0\rightarrow μτ$) are strictly forbidden in the standard model (SM), but these LFV decays are a signal of new physics (NP). We use the Mass Insertion Approximation (MIA) to find sensitive parameters that directly influence the result of the branching ratio of LFV decay $B_d\rightarrow{{l_i}^{\pm}{l_j}^{\mp}}$. Combined with the latest experimental results, we analyze the relationship between different sensitive parameters and the branching ratios of the three processes. According to the numerical analysis, these elements are very restricted from the non observation of CLFV.

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arXiv2024

Rare top quark decays in the minimal R-symmetric supersymmetric standard model

The one-loop contributions to the flavor-changing neutral current decays of the top quark into a light quark and a gauge boson or Higgs boson, namely $t\rightarrow qV,qh$, with $q$ being $u$ or $c$, and $V$ being $γ$, $g$, or $Z$, are analyzed in this study within the framework of the minimal R-symmetric supersymmetric standard model. The charginos in this model have been separated into two sets, i.e., $χ$-chargino and $ρ$-chargino. The numerical results reveal that gluino or $ρ$-chargino predominantly dictate the predictions for BR($t\rightarrow qV,qh$), while the impact of neutralino or $χ$-chargino contributions is insignificant. By incorporating the constraints imposed by the squark mixing parameters from $\bar{B}\rightarrow X_sγ$ and $B^0_{d,s}\rightarrow μ^+μ^-$, the theoretical predictions for BR($t\rightarrow qg$) can be significantly augmented to approximately $\mathcal O(10^{-5}-10^{-6})$. On the other hand, the values of BR($t\rightarrow qγ,qZ,qh$) are predicted to be at least four orders of magnitude below the current experimental limits.

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arXiv2024

Transition magnetic moment of Majorana neutrinos in the triplets next-to-minimal MSSM

The TNMSSM is an attractive extension of the Standard Model. It combines the advantages of the NMSSM and the TMSSM to give three tiny Majorana neutrinos masses via a type I+II seesaw mechanism. With the on-shell renormalization scheme, we consider the neutrino masses up to one loop approximation. Applying the effective Lagrangian method, we study the transition magnetic moments of Majorana neutrinos and consider the normal hierarchy (NH) and inverse hierarchy (IH) neutrino mass spectra within the constraints of experimental data on neutrino oscillations. The solar neutrino transition magnetic moment is further deduced, and compared with the XENONnT experiment limit.

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arXiv2024

Lepton flavor violating decays $Z\rightarrow l^{\pm}_{i}l^{\mp}_{j}$ in the B-L Supersymmetric Standard Model

Lepton flavor violation (LFV) represents a clear new physics (NP) signal beyond the standard model (SM). In this paper, we study LFV decays $Z\rightarrow l^{\pm}_{i}l^{\mp}_{j}$ in the B-L Supersymmetric Standard Model(B-LSSM). We calculate these processes separately in the mass eigenstate basis and the electroweak interaction basis, and the latter adopt the mass insertion approximation (MIA) method. The MIA clearly shows the effect of parameters on the LFV decays $Z\rightarrow l^{\pm}_{i}l^{\mp}_{j}$ in the analytic level, which provides a new way for us to analyze the LFV processes. At the same time, the corresponding constraints from the LFV decays $l^{-}_{j} \rightarrow l^{-}_{i} γ$ and $(g-2)_μ$ are considered to analyze the numerical results.

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arXiv2024

The flavor-dependent $U(1)_F$ model

A flavor-dependent model (FDM) is proposed in this work. The model extends the Standard Model by an extra $U(1)_F$ local gauge group, two scalar doublets, one scalar singlet and two right-handed neutrinos, where the additional $U(1)_F$ charges are related to the particles' flavor. The new fermion sector in the FDM can explain the flavor mixings puzzle and the mass hierarchy puzzle simultaneously, and the nonzero Majorana neutrino masses can be obtained naturally by the Type I see-saw mechanism. In addition, the $B$ meson rare decay processes $\bar B \to X_sγ$, $B_s^0 \to μ^+μ^-$, the top quark rare decay processes $t\to ch$, $t\to uh$ and the $τ$ lepton flavor violation processes $τ\to 3e$, $τ\to 3μ$, $μ\to 3e$ predicted in the FDM are analyzed.

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arXiv2024

A mechanism relating the fermionic mass hierarchy to the flavor mixing

Considering the hierarchical structure of fermionic masses and the fermionic flavor mixing puzzles in the Standard Model, we propose to relate them by the see-saw mechanism, i.e. only the third generation of quarks and charged leptons achieve the masses at the tree level, the first two generations achieves masses through the mixings with the third generation, and the neutrinos achieve tiny Majorana masses by the so-called Type-I see-saw mechanism. This new picture at the fermion sector can explain simultaneously the flavor mixing puzzle and mass hierarchy puzzle in the SM. In addition, a flavor-dependent model (FDM) is proposed to realize the new mechanism, and observing the top quark rare decay processes $t\to ch$, $t\to uh$ and the lepton flavor violation processes $μ\to3e,\;τ\to3e,\;μ\to3μ$ is effective to test the proposed FDM.

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arXiv2024

95 GeV excess in a $CP$-violating $μ$-from-$ν$ SSM

The CMS and ATLAS have recently reported their results searching for light Higgs boson with mass around 95 GeV, based on the full Run 2 data set. In the framework of the CP-violating (CPV) $μν$SSM, we discuss a $\sim$ 2.9$σ$ (local) excess at 95 GeV in the light Higgs boson search in the diphoton decay mode as reported by ATLAS and CMS, together with a $\sim$ 2$σ$ excess (local) in the $b\bar{b}$ final state at LEP in the same mass range. By introducing CPV phases as well as by mixing CP-even Higgs and CP-odd Higgs, a lighter Higgs boson in the $μν$SSM can be produced, which can account for the "di-photon excess".

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arXiv2023

Lepton flavor violating decays $l_j\rightarrow l_i γγ$

In this paper, we study the lepton flavor violating decays of the $l_j\rightarrow l_i γγ$ (j=2, 3; i=1, 2) processes under the $U(1)_X$SSM. The $U(1)_X$SSM is the addition of three singlet new Higgs superfields and right-handed neutrinos to the minimal supersymmetric standard model (MSSM). Based on the latest experimental constraints of $l_j\rightarrow l_i γγ$, we analyze the effects of different sensitive parameters on the results and made reasonable predictions for future experimental development. Numerical analysis shows that many parameters have a greater or lesser effect on lepton flavor violation(LFV), but the main sensitive parameters and sources leading to LFV are the non-diagonal elements involving the initial and final leptons. This work could provide a basis for the discovery of the existence of new physics (NP).

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arXiv2023

The flavor transition process $b\rightarrow sγ$ in the $U(1)_X$SSM with the mass insertion approximation

People extend the MSSM with the local gauge group $U(1)_X$ to obtain the $U(1)_X$SSM. In the framework of the $U(1)_X$SSM, we study the flavor transition process $b\rightarrow{sγ}$ with the mass insertion approximation (MIA). By the MIA method and some reasonable parameter assumptions, we can intuitively find the parameters that have obvious effect on the analytic results of the flavor transition process $b\rightarrow{sγ}$. By means of the influences of different sensitive parameters, we can obtain reasonable results to better fit the experimental data.

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arXiv2023

Lightest Higgs boson decays $h\rightarrow MZ$ in the $μ$ from $ν$ supersymmetric standard model

We study the lightest Higgs boson decays $h\rightarrow MZ$ in the $μ$ from $ν$ supersymmetric standard model ($μν$SSM), where $M$ is a vector meson $(ρ,ω,ϕ,J/Ψ,Υ)$. Compared to the minimal supersymmetric standard model (MSSM), the $μν$SSM introduces three right-handed neutrino superfields, which lead to the mixing of the Higgs doublets with the right-handed sneutrinos. The mixing affects the lightest Higgs boson mass and the Higgs couplings. In suitable parameter space, the $μν$SSM can give large new physics (NP) contributions to the signal strengths of $h\rightarrow MZ$ and $h\rightarrow γγ$, which may be detected by a 100 TeV collider or the other future high energy colliders.

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arXiv2023

GKZ hypergeometric systems of the three-loop vacuum Feynman integrals

We present the Gel'fand-Kapranov-Zelevinsky (GKZ) hypergeometric systems of the Feynman integrals of the three-loop vacuum diagrams with arbitrary masses, basing on Mellin-Barnes representations and Miller's transformation. The codimension of derived GKZ hypergeometric systems equals the number of independent dimensionless ratios among the virtual masses squared. Through GKZ hypergeometric systems, the analytical hypergeometric series solutions can be obtained in neighborhoods of origin including infinity. The linear independent hypergeometric series solutions whose convergent regions have non-empty intersection can constitute a fundamental solution system in a proper subset of the whole parameter space. The analytical expression of the vacuum integral can be formulated as a linear combination of the corresponding fundamental solution system in certain convergent region.

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arXiv2023

GKZ-system of the 2-loop self energy with 4 propagators

Applying the system of linear partial differential equations derived from the Mellin-Barnes representation and the Miller transformation, we present the GKZ-system of the Feynman integral of the 2-loop self energy diagram with 4 propagators. The codimension of the derived GKZ-system equals the number of independent dimensionless ratios among the external momentum squared and virtual mass squared. In total 536 hypergeometric functions are obtained in the neighborhoods of the origin and infinity, in which 30 linearly independent hypergeometric functions whose convergent regions have nonempty intersection constitute a fundamental solution system in a proper subset of the whole parameter space.

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arXiv2023

Study on muon MDM and lepton EDM in BLMSSM via the mass insertion approximation

In the framework of the MSSM extension with local gauged baryon and lepton numbers (BLMSSM), we calculate the muon anomalous magnetic dipole moment (MDM) and lepton $(e, μ, τ)$ electric dipole moment (EDM), and discuss how the muon MDM and lepton EDM depend on the parameters within the mass insertion approximation. Among many parameters, $\tanβ$,~$g_L$,~$m_L$ and $μ_H$ are more sensitive parameters for $a^{BL}_μ$. Considering the experimental limitations, our best numerical result of $a^{BL}_μ$ is around $2.5 \times 10^{-9}$, which can well compensate the departure between the experiment data and Standard Model (SM) prediction. The CP violating phases in BLMSSM are more than those in the MSSM, including new parameters $θ_{μ_L}$ and $θ_{L}$. They can give large contributions, which play an important role in exploring the source of CP violation and probing new physics beyond SM.

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