arXiv subjects

Jian-Bin Chen

Publications and source records attributed to Jian-Bin Chen.

18 recordsLinked to original sources

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.

hep-ph↗

arXiv2022

The lepton flavor violating decays of vector mesons in the MRSSM

Recently several new bounds of the lepton flavor violating decays of the neutral vector mesons $J/ψ$ and $Υ(nS)$ are reported from the experiments. In the work, we analyze these processes in the scenario of the minimal R-symmetric supersymmetric standard model by means of the effective Lagrangian method. The predicted branching ratios are affected by the mass insertion parameters $δ^{ij}$ and the contributions from different parts are comparable. Taking account of the constraints on the mass insertion parameters from the experiments, the branching ratios for the most promising processes $Υ(nS)\rightarrow lτ$ are predicted to be ten orders of magnitude smaller than the present experimental bounds.

hep-ph↗

arXiv2020

$\bar{B}\to X_s γ$ in BLMSSM

Applying the effective Lagrangian method, we study the Flavor Changing Neutral Current $b\to sγ$ within the minimal supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries. Constraints on the parameters are investigated numerically with the experimental data on branching ratio of $\bar{B}\to X_sγ$. Additionally, we present the corrections to direct CP-violation in $\bar{B}\rightarrow X_sγ$ and time-dependent CP-asymmetry in $B\rightarrow K^*γ$. With appropriate assumptions on parameters, we find the direct CP-violation $A_{CP}$ is very small, while one-loop contributions to $S_{K^*γ}$ can be significant.

hep-ph↗

arXiv2020

GKZ-hypergeometric systems for Feynman integrals

Basing on the systems of linear partial differential equations derived from Mellin-Barnes representations and Miller's transformation, we obtain GKZ-hypergeometric systems of one-loop self energy, one-loop triangle, two-loop vacuum, and two-loop sunset diagrams, respectively. The codimension of derived GKZ-hypergeometric system equals the number of independent dimensionless ratios among the external momentum squared and virtual mass squared. Taking GKZ-hypergeometric systems of one-loop self energy, massless one-loop triangle, and two-loop vacuum diagrams as examples, we present in detail how to perform triangulation and how to construct canonical series solutions in the corresponding convergent regions. The series solutions constructed for these hypergeometric systems recover the well known results in literature.

hep-th↗

arXiv2019

$l_α\rightarrow 3l_β$ in Minimal R-symmetric Supersymmetric Standard Model

Lepton flavor violation decays are channels which may lead to fundamental discoveries in the forthcoming years and this make it an exciting research field for beyond the Standard Model searches. In this work, we present an analysis of the lepton flavor violation decays $l_α\rightarrow 3l_β$ in Minimal R-symmetric Supersymmetric Standard Model. The prediction for BR($l_α\rightarrow 3l_β$) depend on the off-diagonal entries of the slepton mass matrix. The contributions to Wilson coefficients can be classified into Higgs penguins, photon penguins, Z penguins, and box diagrams. It shows the contribution from Z penguins dominates the predictions for BR($l_α\rightarrow 3l_β$), and the contributions from Higgs penguins and box diagrams play different roles in different decay channels. The theoretical predictions for BR($l_α\rightarrow 3l_β$) can reach the future experimental limits, and there channels are very promising to be observed in near future experiment.

hep-ph↗

arXiv2019

The system of partial differential equations for the $C_{_0}$ function

We present an approach to analyze the scalar integrals of any Feynman diagrams in detail here. This method not only completely recovers some well-known results in the literature, but also produces some brand new results on the $C_{_0}$ function. The approach can be employed to evaluate the coefficient of arbitrary power of $\varepsilon$ in the expansion of a scalar integral, where $D=4-2\varepsilon$ denotes the time-space dimension.

hep-th↗

arXiv2019

The LFV decays of Z boson in Minimal R-symmetric Supersymmetric Standard Model

A future $Z$-factory will offer the possibility to study rare $Z$ decays $Z\rightarrow l_1l_2$, as those leading to Lepton Flavor Violation final states. In this work, by taking account of the constraints from radiative two body decays $l_2\rightarrow l_1γ$, we investigate the Lepton Flavor Violation decays $Z\rightarrow l_1l_2$ in the framework of Minimal R-symmetric Supersymmetric Standard Model with two benchmark points from already existing literatures. The flavor violating off-diagonal entries $δ^{12}$, $δ^{13}$ and $δ^{23}$ are constrained by the current experimental bounds of $l_2\rightarrow l_1γ$. Considering recent experimental constraints, we also investigate Br($Z\rightarrow l_1l_2$) as a function of $M_D^W$. The numerical results show that the theoretical prediction of Br($Z\rightarrow l_1l_2$) in MRSSM are several orders of magnitude below the current experimental bounds. The Lepton Flavor Violation decays $Z\rightarrow eτ$ and $Z\rightarrow μτ$ may be promising to be observed in future experiment.

hep-ph↗

arXiv2019

One loop correction to $Z\rightarrow νν$ in the Minimal R-symmetric Supersymmetric Standard Model

We analyze the one loop correction to $Z\rightarrow νν$ decay in framework of Minimal R-symmetric Supersymmetric Standard Model(MRSSM) in detail with normal and inverse neutrino mass orderings, as a function of $\tanβ$, Dirac mass parameters $M_D^W$ and $μ_u(μ_d)$, slepton mass $m_l$ that parameterize the mass matrices. The numerical results indicate that the branching ratio for $Z\rightarrow νν$ decay is compatible with the experimental measurement and the SM expectation at $2σ$ level. For inverse neutrino mass ordering, the prediction exceeds the SM expectation at $1σ$ level. The prediction on $Br(Z\rightarrow νν)$ increases proportionally to $\tanβ$ and inversely proportionally to $m_l$. For normal neutrino mass ordering, the peak value of the prediction on $Br(Z\rightarrow νν)$ exceeds the SM expectation at $1σ$ level.

hep-ph↗

arXiv2018

Higgs boson decay $h^0\rightarrow m_VZ$ in the BLMSSM

In the framework of BLMSSM, the Higgs decays $h^0\rightarrow Zγ$ and $h^0\rightarrow m_VZ$ are studied where $m_V$ represents a vector meson($ρ, ω, ϕ, J/ψ, Υ$ etc.). Corrections to the CP-even and CP-odd $h^0γZ$ couplings occur via loop diagrams where new particles are involved. Actually both of them obviously influence the decay rates of $h^0\rightarrow Zγ$ and $h^0\rightarrow m_VZ$. Concretely, our obtained numerical result shows that the decay width of $h^0\rightarrow Zγ$ can be 1.3 times larger than the prediction of the Standard Model(SM). For the light mesons ($ρ,ω$), the corrections to $h^0\rightarrow m_VZ$ are within $15\%\sim 20\%$ still consistent with the SM results. The results of this work would encourage a detection on $h^0\rightarrow Zγ$ at LHC for exploring new physics beyond SM.

hep-ph↗

arXiv2018

The extended BLMSSM with a 125 GeV Higgs boson and dark matter

To extend the BLMSSM, we not only add exotic Higgs superfields $(Φ_{NL},φ_{NL})$ to make the exotic lepton heavy, but also introduce the superfields($Y$,$Y^\prime$) having couplings with lepton and exotic lepton at tree level. The obtained model is called as EBLMSSM, which has difference from BLMSSM especially for the exotic slepton(lepton) and exotic sneutrino(neutrino). We deduce the mass matrices and the needed couplings in this model. To confine the parameter space, the Higgs boson mass $m_{h^0}$ and the processes $h^0\rightarrow γγ$, $h^0\rightarrow VV, V=(Z,W)$ are studied in the EBLMSSM. With the assumed parameter space, we obtain reasonable numerical results according to data on Higgs from ATLAS and CMS. As a cold dark mater candidate, the relic density for the lightest mass eigenstate of $Y$ and $Y'$ mixing is also studied.

hep-ph↗

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.

hep-ph↗

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.

hep-ph↗

arXiv2017

Constraints on parameter space of BLMSSM from particle mass

To explaine the matter-antimatter asymmetry, a supersymmetric extention of the standard model is proposed where baryon and lepton numbers are local gauged(BLMSSM), and exotic superfields are introduced when gauge group is enlarged to $SU(3)_C\otimes SU(2)_L\otimes U(1)_Y \otimes U(1)_B \otimes U(1)_L$. As signals of new physics have not been observed on Large Hadron Collider, the parameter space relevant to the masses of new particles is stringently constrainted. By diagonalizing the mass squared matrices for neutral scalar sectors and the mass matrices for exotic quarks, we plot the masses of new particles varying with different parameters with some assumptions, so the constraints on model parameter is obtained with different lower limit on particle mass.

hep-ph↗

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.

hep-ph↗

arXiv2014

125 GeV Higgs boson decays in the $μ$ from $ν$ supersymmetric standard model

Recently the ATLAS and CMS Collaborations have reported significant events that are attributed to the neutral Higgs boson with mass around 125 GeV. In this work, we investigate the signals of the Higgs boson decay channels $h\rightarrowγγ$, $h\rightarrow VV^*$ ($V=Z,W$), and $h\rightarrow f\bar{f}$ ($f=b,τ$) in the $μ$ from $ν$ supersymmetric standard model ($μν$SSM). In the numerical results, we show the light stop and stau effects on the signal strengths for the 125 GeV Higgs boson decay channels in the $μν$SSM, which can account for the updated experimental data on Higgs.

hep-ph↗

arXiv2013

Lepton flavor violation in inverse seesaw model

We analyze the lepton flavor violation processes $μ-e$ conversion, $l_i\rightarrow l_jγ$ and $l_i\rightarrow 3l_j$ in framework of the Standard Model (SM) extended with inverse seesaw mechanism, as a function of $\tildeη = 1 -|Det(\tilde {U}_{PMNS})|$ that parameterizes the departure from unitary of the light neutrino mixing sub-matrix $\tilde {U}_{PMNS}$. In a wide range of $\tildeη$, the predictions on the $μ-e$ conversion rates and the branching ratio of $μ\rightarrow eγ$ are sizeable to be compatible with the experimental upper limits or future experimental sensitivities. For large scale of $\tildeη$, the predictions on branching ratios of other lepton flavor processes can also be reach the experimental upper limits or future experimental sensitivities. The value of $\tildeη$ depends on the determinant of the Majorana mass term $M_μ$. Finally, searching for lepton flavor violation processes in experiment provides us more opportunities for the searches of seesaw nature of the neutrino masses.

hep-ph↗

arXiv2013

t-c gamma and t-cg in warped extra dimensions

In this work, we calculate the top quark rare decays t-cgamma and t-cg in the framework where the standard model is embedded in a warped extra dimension with the custodial symmetry SU(3)c*SU(2)L*SU(2)R*U(1)x*PLR. Adopting reasonable assumptions on the parameter space,we numerically find the branching ratios of t-cgamma exceeding 10^-6 and that of t-cg exceeding 10^-5 respectively, which can be detected in near future.

hep-ph↗

arXiv2011

Residue theorem and summing over Kaluza-Klein excitations

Applying the equations of motion together with corresponding boundary conditions of bulk profiles at infrared and ultraviolet branes, we verify some lemmas on the eigenvalues of Kaluze-Klein modes in framework of warped extra dimension with the custodial symmetry $SU(3)_c\times SU(2)_L\times SU(2)_R\times U(1)_X\times P_{LR}$. Using the lemmas and performing properly analytic extensions of bulk profiles, we present the sufficient condition for a convergent series of Kaluze-Klein excitations and sum over the series through the residue theorem. The method can also be applied to sum over the infinite series of Kaluze-Klein excitations in unified extra dimension. Additional, we analyze the possible connection between the propagators in five dimensional full theory and the product of bulk profiles with corresponding propagators of exciting Kaluze-Klein modes in four dimensional effective theory, and recover some relations presented in literature for warped and unified extra dimensions respectively. As an example, we demonstrate that the corrections from neutral Higgs to the Wilson coefficients of relevant operators for $B\rightarrow X_sγ$ contain the suppression factor $m_b^3m_s/m_{_{\rm w}}^4$ comparing with that from other sectors, thus can be neglected safely.

hep-ph↗