arXiv subjects

Ke-Sheng Sun

Publications and source records attributed to Ke-Sheng Sun.

At least 19 recordsLinked to original sources

arXiv2026

Rare B meson decays in the Minimal R-symmetric Supersymmetric Standard Model

Taking into account the constraints imposed by experimental data on the parameter space, we analyze the lepton flavor violating decays of B meson in the scenario of the minimal R-symmetric supersymmetric standard model. The prediction of the branching ratios is strongly affected by $\tan\beta$ and the off-diagonal entries in the slepton and squark mass matrices. The off-diagonal entries in the slepton mass matrix are constrained by the experimental limits of radiative two body decays of leptons. The off-diagonal entries in the squark mass matrix are constrained by the experimental limits of low energy observables related to B meson physics. The branching ratio of $B^0_d\rightarrow \mu \tau$ is predicted to be four orders of magnitude below the future experimental sensitivity and the decay $B^0_d\rightarrow \mu \tau$ has a higher chance of being observed in the future.

hep-ph↗

arXiv2025

Lepton-flavor violation in the MRSSMSeesaw

The Minimal R-symmetric Supersymmetric Standard Model with Seesaw (MRSSMSeesaw) extends the MRSSM by incorporating right-handed neutrinos to generate neutrino masses via the Type-I seesaw mechanism. This work presents a detailed analysis of lepton flavor violation (LFV) processes, including $\ell_i \rightarrow \ell_j \gamma$, $\ell_i \rightarrow 3\ell_j$, and Higgs decays $h \rightarrow \ell_i \ell_j$, Based on the current experimental limitations, we carry out detailed parameter scanning and numerical calculations to analyse the effects of different sensitive parameters on LFV.The numerical results show that the non-diagonal elements involving the initial and final leptons are main sensitive parameters and LFV sources.

hep-ph↗

arXiv2025

$S, T, U$ Parameters in The B-LSSM

Using the pinch technique, we compute the one-loop vertices of weak interactions in the B-LSSM and incorporate their pinch contributions into the gauge boson self-energies. Compared to the definitions of the $S, T,$ and $U$ parameters in the Standard Model based on the $SU(2)_L \otimes U(1)_Y$ group, the corresponding parameters in the local B-L gauge symmetry (B-LSSM) are modified. We provide these redefined $S, T,$ and $U$ parameters and demonstrate the convergence of the results. In the framework of the low-energy effective Lagrangian for weak interactions, the $S, T,$ and $U$ parameters can be expressed as functions of certain parameters in the B-LSSM. The updated experimental and fitting results constrain the parameter space of the B-LSSM strongly.

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arXiv2023

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 $\gamma$, $g$, 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., $\chi$-chargino and $\rho$-chargino. The numerical results reveal that gluino or $\rho$-chargino predominantly dictate the predictions for BR($t\rightarrow qV,qh$), while the impact of neutralino or $\chi$-chargino contributions is insignificant. By incorporating the constraints imposed by the squark mixing parameters from $\bar{B}\rightarrow X_s\gamma$ and $B^0_{d,s}\rightarrow \mu^+\mu^-$, 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($t\rightarrow q\gamma,qZ,qh$) are predicted to be at least four orders of magnitude below the current experimental limits.

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↗

arXiv2021

Searching for lepton flavor violating decays tau to Pl in Minimal R-symmetric Supersymmetric Standard Model

We analyze the lepton flavor violating decays $τ\rightarrow Pl$ ($P=π,η,η';\;l=e,μ$) in the scenario of the minimal R-symmetric supersymmetric standard model. The prediction on the branching ratios BR$(τ\rightarrow P e)$ and BR$(τ\rightarrow P μ)$ is affected by the mass insertion parameters $δ^{13}$ and $δ^{23}$, respectively. These parameters are constrained by the experimental bounds on the branching ratios BR($τ\rightarrow e (μ) γ$) and BR($τ\rightarrow 3e(μ)$). The result shows $Z$ penguin dominates the prediction on BR($τ\rightarrow Pl$) in a large region of the parameter space. The branching ratios for BR($τ\rightarrow Pl$) are predicted to be, at least, five orders of magnitude smaller than present experimental bounds and three orders of magnitude smaller than future experimental sensitivities.

hep-ph↗

arXiv2020

125 GeV Higgs boson decay to a pair of muons in the $μν$SSM

Recently, the ATLAS and CMS Collaborations measured the 125 GeV Higgs boson decay to a pair of muons $h\rightarrow μ\barμ$, which reported the signal strength relative to the standard model (SM) prediction is $1.2\pm0.6$ and $1.19^{+0.40+0.15}_{-0.39-0.14}$, respectively. In this work, we investigate the 125 GeV Higgs boson decay $h\rightarrow μ\barμ$ at one-loop level in the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM). Compared to the SM prediction, the decay width of $h\rightarrow μ\barμ$ in the $μν$SSM can boost up about 10\%, considering the constraint from the muon anomalous magnetic dipole moment.

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

Muon conversion to electron in nuclei in Minimal R-symmetric Supersymmetric Standard Model

We analyze the lepton flavor violating process $μ-e$ conversion in the framework of the minimal R-symmetric supersymmetric standard model. The theoretical predictions are determined by considering the experimental constraint on parameter $δ^{12}$ from the lepton flavor violating decay $μ\rightarrow e γ$. The numerical results show that $γ$ penguins and Z penguins dominate the predictions on CR($μ-e$,Nucleus), and the contributions from Higgs penguins and box diagrams are insignificant. The theoretical predictions on conversion rate CR($μ-e$,Nucleus) in a Al or Ti target can be enhanced close to the future experimental sensitivities and are very promising to be observed in near future experiment.

hep-ph↗

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 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

The LFV decays $B^0_{d,s}\rightarrow eμ(eτ,μτ)$ with one neutral singlet scalar

Taking account of the constraint from radiative two body decays $l_i\rightarrow l_jγ$, we investigate the Lepton Flavor Violation decays $B^0_q\rightarrow\bar{l_l}l_k$ in the framework of the minimal extension of the Standard Model with one neutral singlet scalar. The couplings $C_{eμ}$, $C_{eτ}$ and $C_{μτ}$ between the different generation leptons and scalar $S^0$ are constrained by the current bounds of $l_i\rightarrow l_jγ$. The numerical results show that the theoretical prediction of $B^0_q\rightarrow\bar{l_l}l_k$ strongly depend on the couplings $C_{qb}$ ($q=d\;or\; s$) between down type quarks and new scalar. The contributions from couplings $C_{uc}$, $C_{ut}$ and $C_{ct}$ between up type quark and new scalar are less dominant.

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.

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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.

hep-th↗

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.

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 decays of vector mesons in unparticle physics

We investigate the lepton flavor violation decays of vector mesons in the scenario of the unparticle physics by considering the constraint from $μ-e$ conversion. In unparticle physics, the predictions of LFV decays of vector mesons depend strongly on the scale dimension $d_{\mathcal{U}}$. The predictions of LFV decays of vector mesons can reach the detective sensitivity in experiment in region of $3\le d_{\mathcal{U}}\le 4$, while the prediction of $μ-e$ conversion rate can meet the experimental upper limit. For the searching of the lepton flavor violation processes of charged lepton sector in experiment, the process $Υ\rightarrow eμ$ may be a promising one to be observed.

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.

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