arXiv subjects

Hai-Bin Zhang

Publications and source records attributed to Hai-Bin Zhang.

At least 73 records · Page 4Linked to original sources

arXiv2018

Evaluating Feynman integrals by the hypergeometry

The hypergeometric function method naturally provides the analytic expressions of scalar integrals from concerned Feynman diagrams in some connected regions of independent kinematic variables, also presents the systems of homogeneous linear partial differential equations satisfied by the corresponding scalar integrals. Taking examples of the one-loop $B_{_0}$ and massless $C_{_0}$ functions, as well as the scalar integrals of two-loop vacuum and sunset diagrams, we verify our expressions coinciding with the well-known results of literatures. Based on the multiple hypergeometric functions of independent kinematic variables, the systems of homogeneous linear partial differential equations satisfied by the mentioned scalar integrals are established. Using the calculus of variations, one recognizes the system of linear partial differential equations as stationary conditions of a functional under some given restrictions, which is the cornerstone to perform the continuation of the scalar integrals to whole kinematic domains numerically with the finite element methods. In principle this method can be used to evaluate the scalar integrals of any Feynman diagrams.

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arXiv2017

Search for charged lepton flavor violation of vector mesons in BLMSSM model

We analyze the charged lepton flavor violating (CLFV) decays of vector mesons $V\rightarrow l_i^{\pm}l_j^{\mp}$ with $V\in\{ϕ, J/Ψ, Υ, ρ^0, ω\}$ in BLMSSM model. This new model is introduced as an supersymmetric extension of Standard Model (SM), where local gauged baryon number B and lepton number L are considered. The numerical results indicate BLMSSM model can produce significant contributions to such two-body CLFV decays. And the branching ratios for these CLFV processes can easily reach the present experimental upper bounds. Therefore, searching for CLFV processes of vector mesons may be an effective channels to study new physics.

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arXiv2017

$Z\rightarrow l_i^{\pm}l_j^{\mp}$ processes in the BLMSSM

In a supersymmetric extension of the Standard Model(SM) where baryon and lepton numbers are local gauge symmetries (BLMSSM), we investigate the charged lepton flavor violating (CLFV) processes $Z\rightarrow l_i^{\pm}l_j^{\mp}$ after introducing the new gauginos and the right-handed neutrinos. In this model, the branching ratios of $Z\rightarrow l_i^{\pm}l_j^{\mp}$ are around ($10^{-8}\sim10^{-10}$), which approach the present experimental upper bounds. We hope that the branching ratios for these CLFV processes can be detected in the near future.

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arXiv2017

Higgs boson mass corrections in the $μν$SSM with effective potential methods

To solve the $μ$ problem of the MSSM, the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM) introduces three singlet right-handed neutrino superfields $\hatν_i^c$, which lead to the mixing of the neutral components of the Higgs doublets with the sneutrinos, producing a relatively large CP-even neutral scalar mass matrix. In this work, we analytically diagonalize the CP-even neutral scalar mass matrix and analyze in detail how the mixing impacts the lightest Higgs boson mass. We also give an approximate expression for the lightest Higgs boson mass. Simultaneously, we consider the radiative corrections to the Higgs boson masses with effective potential methods.

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arXiv2017

125 GeV Higgs decay with lepton flavor violation in the $μν$SSM

Recently, the CMS and ATLAS Collaborations have reported direct searches for the 125 GeV Higgs decay with lepton flavor violation, $h\rightarrow μτ$. In this work, we analyze the signal of the lepton flavour violating (LFV) Higgs decay $h\rightarrow μτ$ in the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM) with slepton flavor mixing. Simultaneously, we consider the constraints from the LFV decay $τ\rightarrow μγ$, the muon anomalous magnetic dipole moment and the lightest Higgs mass around 125 GeV.

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arXiv2016

The one loop contributions to c(t) electric dipole moment in the CP violating BLMSSM

In the CP violating supersymmetric extension of the standard model with local gauged baryon and lepton symmetries(BLMSSM), there are new CP violating sources which can give new contributions to the quark electric dipole moment (EDM). Considering the CP violating phases, we analyze the EDMs of the quarks c and t. We take into account the contributions from the one loop diagrams. The numerical results are analyzed with some assumptions on the relevant parameter space. The numerical results for the c and t EDMs can reach large values.

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arXiv2016

$B\rightarrow X_{_S}l^+l^-$ in the minimal gauged $(B-L)$ supersymmetry

Applying the effective Hamilton for $b\rightarrow sl^+l^-,\;(l=e,\;μ)$ in the framework of minimal supersymmetric extension of the standard model with local $B-L$ gauge symmetry, we investigate branching ratios and forward-backward asymmetries of rare decay $B\rightarrow X_{_S}l^+l^-$ in low and high $q^2$ regions, respectively. In addition we also study the $CP$ asymmetries depending on new $CP$ phases from soft breaking terms in low and high $q^2$ regions. With some assumptions on parameter space of the model, the numerical analyses of the supersymmetric contributions to the branching ratios, forward-backward and $CP$ asymmetries of $B\rightarrow X_{_S}l^+l^-$ are presented in low and high $q^2$ regions, respectively.

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arXiv2016

Computations of superstring amplitudes in pure spinor formalism via Cadabra

The discovery of pure spinor formalism makes the computation of superstring scattering amplitudes possible. In this paper, we will illustrate how computer algebra system Cadabra is used in computing the supersymmetric amplitude in pure spinor formalism and provide the source code that computes the tree-level massless 5-gluon amplitude.

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arXiv2016

The one loop corrections to the neutrino masses in BLMSSM

The neutrino masses and mixings are studied in the model which is the supersymmetric extension of the standard model with local gauged baryon and lepton numbers(BLMSSM). At tree level the neutrinos can obtain tiny masses through the See-Saw mechanism in the BLMSSM. The one-loop corrections to the neutrino masses and mixings are important, and they are studied in this work with the mass insertion approximation. We study the numerical results and discuss the allowed parameter space of BLMSSM. It can contribute to study the neutrino masses and to explore the new physics beyond the standard model(SM).

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arXiv2016

$B_{s,d}^0\rightarrow l^+l^-$ in the minimal gauged $(B-L)$ supersymmetry

Complete expressions of effective Hamilton for $b\rightarrow sl^+l^-\;(l=μ,\;τ)$ are derived in the framework of minimal supersymmetric extension of the standard model with local $B-L$ gauge symmetry. With some assumptions on parameters of the model, a numerical analysis of the supersymmetric contributions to the branching ratios of $B_s^0\rightarrow l^+l^-\;(l=μ,\;τ)$ is presented.

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arXiv2016

The Feynman rules for neutrinos and new neutralinos in BLMSSM

In a supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries(BLMSSM), we deduce the Feynman rules for neutrinos and new neutralinos. We briey introduce the mass matrices for the particles and the related couplings in this work, which are very useful to research the neutrinos and new neutralinos.

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arXiv2016

The LHC 750 GeV diphoton excess in supersymmetry with gauged baryon and lepton numbers

The significance of discovering the boson of 750 GeV is beyond finding a single heavy boson, because it may hint the location of the scale for new physics beyond the standard model which is the target of long-time exploration. There have been many models to explain the diphoton excess observed by the ATLAS and CMS collaborations and the BLMSSM is one of them. The BLMSSM is an extension of the minimal supersymmetric model where baryon and lepton numbers are local gauge symmetries. We analyze the decay channels $Φ\rightarrow gg$, $Φ\rightarrowγγ$, $Φ\rightarrow Zγ$, and $Φ\rightarrow \bar{t}t,\;VV\;(V=Z,\;W)$ with the mass of the CP-odd scalar $Φ=A_{_B}^0$ being around $750\;{\rm GeV}$ in this model. Within a certain parameter space, the scenario can account for the experimental data on the diphoton excess.

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arXiv2015

Lepton flavor violation in the BLMSSM

In a supersymmetric extension of the standard model with local gauged baryon and lepton numbers (BLMSSM), there are new sources for lepton flavor violation, because the right-handed neutrinos and new gauginos are introduced. In BLMSSM, we study the charged lepton flavor violating processes $l_j\rightarrow l_i+γ$ and $l_j\rightarrow 3l_i$ in detail. The numerical results show that in some parameter space the branching ratios for charged lepton flavor violating processes can be large enough to be detected in the near future.

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arXiv2015

The study of lepton EDM in CP violating BLMSSM

In the supersymmetric model with local gauged baryon and lepton numbers(BLMSSM), the CP violating effects are considered to study the lepton electric dipole moment(EDM). The CP violating phases in BLMSSM are more than those in the standard model(SM) and can give large contributions. The analysis of the EDMs for the leptons $e,μ, τ$ is shown in this work. It is in favour of exploring the source of CP violation and probing the physics beyond SM.

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arXiv2014

$\bar{B}\rightarrow X_sγ$ in the $μν$SSM

The $μν$SSM, one of supersymmetric extensions beyond the Standard Model, introduces three singlet right-handed neutrino superfields to solve the $μ$ problem and can generate three tiny Majorana neutrino masses through the seesaw mechanism. In this work, we investigate the rare decay process $\bar{B}\rightarrow X_sγ$ in the $μν$SSM, under a minimal flavor violating assumption for the soft breaking terms. Constrained by the SM-like Higgs with mass around 125 GeV, the numerical results show that the new physics can fit the experimental data for $\bar{B}\rightarrow X_sγ$ and further constrain the parameter space.

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arXiv2014

${B^0} - {{\bar B}^0}$ mixing in supersymmetry with gauged baryon and lepton numbers

We perform an analysis on ${B^0} - {{\bar B}^0}$ mixing in the extension of the minimal supersymmetric standard model where baryon and lepton numbers are local gauge symmetries (BLMSSM) by using the effective Hamiltonian method. And the constraint of a 125 GeV Higgs to the parameter space has also been consid-ered. The numerical results indicate that the contributions of the extra particles can be sizeable in ${B^0} - {{\bar B}^0}$ mixing. For certain parameter sets, the theoretical prediction of mass differences $Δm_{B}$ agrees with the current experimental result. Furthermore, ${B^0} - {{\bar B}^0}$ mixing in the BLMSSM can preliminarily constrain the parameter space. With the development of more precise theoretical analysis and experimental determina-tions, the ${B^0} - {{\bar B}^0}$ mixing in the BLMSSM will have a clearer picture and the parameter space in this model will also be further constrained.

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arXiv2014

Top quark decay to a 125GeV Higgs in BLMSSM

In this paper, we calculate the top quark rare decay t-ch in a supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries. Adopting reasonable assumptions on the parameter space, we find that the branching ratios of t-ch can reach 10^-3, which can be detected in near future.

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arXiv2014

The corrections from one loop and two-loop Barr-Zee type diagrams to muon MDM in BLMSSM

In a supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries(BLMSSM) and the Yukawa couplings between Higgs doublets and exotic quarks are considered, we study the one loop diagrams and the two-loop Barr-Zee type diagrams with a closed Fermi(scalar) loop between the vector Boson and Higgs. Using the effective Lagrangian method, we deduce the Wilson coefficients of dimension 6 operators contributing to the anomalous magnetic moment of muon, which satisfies the electromagnetic gauge invariance. In the numerical analysis, we consider the experiment constraints from Higgs and neutrino data. In some parameter space, the new physics contribution is large and even reaches $24\times10^{-10}$, which can remedy the deviation well.

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