arXiv subjects

Min-Di Zheng

Publications and source records attributed to Min-Di Zheng.

7 recordsLinked to original sources

arXiv2025

Explaining the $B_{d(s)} \rightarrow K^{(\ast)}\bar{K}^{(\ast)}$ puzzle via chiral-flip in $R$-parity violating MSSM with seesaw mechanism

We study the non-leptonic puzzle of $B_{d(s)} \rightarrow K^{(\ast)}\bar{K}^{(\ast)}$ decay in the $R$-parity violating minimal supersymmetric standard model (RPV-MSSM) extended with the inverse seesaw mechanism. In this model, the chiral flip of sneutrinos can contribute to the observables $L_{K\bar{K}}$ and $L_{K^{\ast}\bar{K}^{\ast}}$, that is benefit for explaining the relevant puzzle. We also find that this unique effect can engage in the $B_s$-$\bar{B}_s$ mixing. We utilize the scenario of complex $λ^\prime$ couplings to fulfill the recent stringent constraint of $B_s$-$\bar{B}_s$ mixing, and examine other related bounds of $B,K$-meson decays, lepton decays, neutrino data, $Z$ decays, oblique parameters, CP violations (CPV), etc. Besides, inspired by the new measurement of ${\cal B}(B^+ \rightarrow K^+ν\barν)$ by Belle II, which shows about $2.7σ$ higher than the Standard Model (SM) prediction, we also investigate the New Physics (NP) enhancement to this observable.

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arXiv2023

The $W\ellν$-vertex corrections to W-boson mass in the R-parity violating MSSM

Inspired by the astonishing $7σ$ discrepancy between the recent CDF-II measurement and the standard model prediction on the mass of $W$-boson, we investigate the $λ'$-corrections to the vertex of $μ\toν_μe\bar{ν_e}$ decay in the context of the $R$-parity violating minimal supersymmetric standard model. These corrections can raise the $W$-boson mass independently. Combined with recent $Z$-pole and kaon decay measurements, $m_W \lesssim 80.37$ GeV can be reached. We find that these vertex corrections cannot explain the CDF result entirely at the $2σ$ and even $3σ$ levels. However, these corrections together with the oblique contributions can be accordant with the CDF-II result and relevant bounds at the $3σ$ level.

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arXiv2022

Nonperturbative effects in neutrino magnetic moments

In this paper, we calculate the QCD nonperturbative contributions of the neutrino-quark tensor operators to the neutrino magnetic moments by matching onto the chiral perturbation theory at low energies. These nonperturbative contributions can be compared to the perturbative ones, which are induced from one-loop mixing when performing the renormalization group evolutions from $μ=m_W$ down to $μ=2~\mathrm{GeV}$. We then constrain the dipole and tensor Wilson coefficients of the low-energy neutrino effective field theory (LNEFT) separately from the neutrino-electron scattering with Borexino data and coherent elastic neutrino-nucleus scattering (CE$ν$NS) with COHERENT data to show the competition between these two contributions, at the renormalization scales $μ=2~\mathrm{GeV}$ and $μ=m_W$ in the $\bar{\mathrm{MS}}$ scheme. In the neutrino-electron scattering, it is found that the nonperturbative contributions dominate for the coefficients involving up and down quarks, while they are expected to be of the same order of magnitude as the perturbative contributions for the coefficients involving strange quark. As for constraints in the CE$ν$NS, the tensor operators can contribute to the process through either direct or indirect way. As a result, the indirect contributions including nonperturbative and perturbative parts for all couplings become negligible in comparison with the direct ones. As the nonperturbative contributions crucially depend on the value of $c_T$, its inputs will affect the extraction of limits on the tensor LNEFT Wilson coefficients. We compute the upper bounds on these coefficients with $c_T$ quoting from the model and lattice estimates.

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arXiv2022

Explaining anomalies of $B$-physics, muon $g-2$ and $W$ mass in $R$-parity violating MSSM with seesaw mechanism

The recent experimental results including $R_{K^{(\ast)}}$, $R_{D^{(\ast)}}$, $(g-2)_μ$ and $W$ mass show deviations from the standard model (SM) predictions, implying the clues of new physics (NP). In this work, we investigate the explanations of these anomalies in the $R$-parity violating minimal supersymmetric standard model (RPV-MSSM) extended with the inverse seesaw mechanism. The non-unitarity extent $η_{ee}$ and the loop corrections from the interaction $λ'\hat L \hat Q \hat D$ are utilized to raise the prediction of $W$ mass through muon decays. We also find that the interaction $λ'\hat L \hat Q \hat D$ involved with right-handed (RH)/singlet (s)neutrinos can explain the $R_{K^{(\ast)}}$ and $R_{D^{(\ast)}}$ anomalies simultaneously when considering nonzero $λ'_{1jk}$. For nonzero $λ'_{2jk}$, this model fulfills the whole $b\to s\ell^+\ell^-$ fit but cannot be accordant with $R_{D^{(\ast)}}$ measurements. The explanations in both cases are also favored by $(g-2)_μ$ data, neutrino oscillation data and the relevant constraints we scrutinized. Furthermore, this model framework can be tested in future experiments covering, e.g., the predicted lepton flavor violations (LFV) at Belle II and the Future Circular Collider with $e^+e^-$ beams (FCC-ee), as well as the heavy neutrinos at future colliders.

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arXiv2021

Studying the $b\rightarrow s \ell^+\ell^-$ anomalies and $(g-2)_μ$ in $R$-parity violating MSSM framework with the inverse seesaw mechanism

Inspired by the recent experimental results which show deviations from the standard model (SM) predictions of $b\rightarrow s \ell^+\ell^-$ transitions, we study the $R$-parity violating minimal supersymmetric standard model (RPV-MSSM) extended by the inverse seesaw mechanism. The trilinear $R$-parity violating terms, together with the chiral mixing of sneutrinos, induce the loop contributions to the $b\rightarrow s \ell^+\ell^-$ anomaly. We study the parameter space of the single-parameter scenario $C^{\rm NP}_{9,μ}=-C^{\rm NP}_{10,μ}=C_{\rm V}$ and the double-parameter scenario $(C_{\rm V},C_{\rm U})$, respectively, constrained by other experimental data such as $B_s-\bar{B}_s$ mixing, $B\rightarrow X_s γ$ decay, the lepton flavour violating decays, etc. Both the single-parameter and the double-parameter scenario can resolve the long existing muon anomalous magnetic moment problem as well, and allow the anomalous $t\rightarrow cg$ process to reach the sensitivity at the Future Circular hadron-hadron Collider (FCC-hh).

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arXiv2020

Revisiting the $B$-physics anomalies in $R$-parity violating MSSM

In recent years, several deviations from the Standard Model predictions in semileptonic decays of $B$-meson might suggest the existence of new physics which would break the lepton-flavour universality. In this work, we have explored the possibility of using muon sneutrinos and right-handed sbottoms to solve these $B$-physics anomalies simultaneously in $R$-parity violating minimal supersymmetric standard model. We find that the photonic penguin induced by exchanging sneutrino can provide sizable lepton flavour universal contribution due to the existence of logarithmic enhancement for the first time. This prompts us to use the two-parameter scenario $(C^{\rm V}_9, \, C^{\rm U}_9)$ to explain $b \to s \ell^+ \ell^-$ anomaly. Finally, the numerical analyses show that the muon sneutrinos and right-handed sbottoms can explain $b \to s \ell^+ \ell^-$ and $R(D^{(\ast)})$ anomalies simultaneously, and satisfy the constraints of other related processes, such as $B \to K^{(\ast)} ν\barν$ decays, $B_s-\bar B_s$ mixing, $Z$ decays, as well as $D^0 \to μ^+ μ^-$, $τ\to μρ^0$, $B \to τν$, $D_s \to τν$, $τ\to K ν$, $τ\to μγ$, and $τ\to μμμ$ decays.

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arXiv2019

$B_{s(d)}-\bar{B}_{s(d)}$ Mixing and $B_s\toμ^+μ^-$ Decay in the NMSSM with the Flavour Expansion Theorem

In this paper, motivated by the observation that the Standard Model predictions are now above the experimental data for the mass difference $ΔM_{s(d)}$, we perform a detailed study of $B_{s(d)}-\bar{B}_{s(d)}$ mixing and $B_s\toμ^+μ^-$ decay in the $\mathbb{Z}_3$-invariant NMSSM with non-minimal flavour violation, using the recently developed procedure based on the Flavour Expansion Theorem, with which one can perform a purely algebraic mass-insertion expansion of an amplitude written in the mass eigenstate basis without performing any diagrammatic calculations in the interaction/flavour basis. Specifically, we consider the finite orders of mass insertions for neutralinos but the general orders for squarks and charginos, under two sets of assumptions for the squark flavour structures (\textit{i.e.}, while the flavour-conserving off-diagonal element $δ_{33}^\text{LR}$ is kept in both of these two sectors, only the flavour-violating off-diagonal elements $δ_{23}^\text{LL}$ and $δ_{i3}^\text{RR}$ ($i=1,2$) are kept in the \text{LL} and \text{RR} sectors, respectively). Our analytic results are then expressed directly in terms of the initial Lagrangian parameters in the interaction/flavour basis, making it easy to impose the experimental bounds on them. It is found numerically that the NMSSM effects with the above two assumptions for the squark flavour structures can accommodate the observed deviation for $ΔM_{s(d)}$, while complying with the experimental constraints from the branching ratios of $B_s\to μ^+ μ^-$ and $B\to X_sγ$ decays.

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