arXiv subjects

Tai-Fu Feng

Publications and source records attributed to Tai-Fu Feng.

At least 37 records · Page 2Linked to original sources

arXiv2025

Constraining modified theories of gravity through the detection of one extremely large mass-ratio inspiral

Extremely large mass-ratio inspirals (XMRIs), formed by brown dwarfs inspiraling into a massive black hole, emit gravitational waves (GWs) that fall within the detection band of future space-borne detectors such as LISA, TianQin, and Taiji. Their detection will measure the astrophysical properties of the MBH in the center of our galaxy (SgrA$^\ast$) with unprecedented accuracy and provide a unique probe of gravity in the strong field regime. Here, we estimate the benefit of using the GWs from XMRIs to constrain the Chern-Simons theory. Our results show that XMRI signals radiated from the late stages of the evolution are particularly sensitive to differences between Chern-Simons theory and general relativity. For low-eccentricity sources, XMRIs can put bounds on the Chern-Simons parameter $ζ$ at the level of $10^{-1}$ to an accuracy of $10^{-3}$. For high-eccentricity sources, XMRIs can put bounds on the parameter $ζ$ at the level of $10^{-1}$ to an accuracy of $10^{-6}$. Furthermore, using the time-frequency MCMC method, we obtain the posterior distribution of XMRIs in the Chern-Simons theory. Our results show that almost all the parameters can be recovered within $1σ$ confidence interval. For most of the intrinsic parameters, the estimation accuracy reaches $10^{-3}$. For the brown dwarf mass, the estimation accuracy reaches $10^{-1}$, while for $ζ$, the estimation accuracy reaches $Δ\log_{10}ζ=0.08$ for high eccentricity sources and 1.27 for low eccentricity sources.

gr-qc↗

arXiv2025

Probing the light charged Higgs boson, pseudoscalar Higgs boson, and $Z^\prime$ boson in the $U(1)_F$ model at the LHC

In this papar, we study the production and decay of a charged Higgs boson, a pseudoscalar Higgs boson, and a $Z'$ boson at the LHC within the flavor-dependent model (FDM), at the LHC. Considering the constraints from perturbative unitarity and experimental measurements (e.g., the flavor physics data, higgs signal strengths, electroweak precision observables), we investigate the relevant processes by analyzing several common LHC search channels. Motivated by the excess in $t \to b\bar{b}c$ reported by ATLAS, which suggests a charged Higgs boson with a mass near 130 GeV and consistent with B-anomaly expectations, we perform a dedicated simulation for a charged Higgs around this mass. Our results support the experimental hint and predict that this particle has a high discovery potential at the future High-Luminosity Large Hadron Collider (HL-LHC). In contrast, for the pseudoscalar and $Z'$ bosons predicted in our model, they remain beyond the reach of current experiments as well as the expected sensitivity at a 14 TeV collider with an integrated luminosity of 300 fb$^{-1}$.

hep-ph↗

arXiv2025

Lepton flavor violating decays of Higgs boson in the NB-LSSM

Lepton flavor violation (LFV) represents a clear new physics (NP) signal beyond the standard model (SM). NB-LSSM, the next to minimal supersymmetric extension of the SM with local B-L gauge symmetry, includes three Higgs singlets and three generations of right-handed neutrinos in the basis of MSSM, motivated by the new definition of SM-like Higgs resultly from the introducing of three Higgs singlets which mix with the two Higgs doublets at the tree level in the NB-LSSM. We calculate LFV processes $h\rightarrow l_i l_j$ in the mass eigenstate basis and the electroweak interaction basis separately, and the latter adopts the mass insertion approximation (MIA) method. In the suitable parameter space, we obtain the reasonable numerical results. At the same time, the corresponding constraints from the LFV rare decays $l_j\rightarrow l_iγ$ are considered to analyze the numerical results.

hep-ph↗

arXiv2025

A 95 GeV Higgs Boson in the $U(1)_X$SSM

The CMS and ATLAS Collaborations have recently reported their findings based on the comprehensive run 2 dataset, detailing their searches for a light Higgs boson with a mass of approximately 95 GeV. We investigate the excesses observed in the $γγ$ and $b{\bar b}$ data at approximately 95 GeV in the $U(1)_X$ extension of the minimal supersymmetric standard model ($U(1)_X$SSM). Additionally, it also mixes with the SM-like Higgs boson. Research indicates that, in this model, identifying the mixture of the singlet Higgs states as the lightest Higgs boson holds tremendous potential for explaining the excess observed at approximately 95 GeV. In our calculations, we maintain the masses of the lightest and next-to-lightest Higgs bosons at approximately 95 GeV and 125 GeV, respectively. The study finds that the theoretical predictions for the signal strengths $μ(h_{95})_{γγ}$ and $μ(h_{95})_{b{\bar b}}$ in the $U(1)_X$SSM align well with the excesses observed by CMS.

hep-ph↗

arXiv2025

Probing the Extreme-Mass-Ratio Inspirals Population Constraints with TianQin

Extreme-mass-ratio inspirals (EMRIs), consisting of a massive black hole and a stellar compact object, are one of the most important sources for space-borne gravitational wave detectors like TianQin. Their population study can be used to constrain astrophysical models that interpret the EMRI formation mechanisms. In this paper, as an initial attempt, we employ a parametrization method to describe the EMRI population model in the loss cone formation channel. This approach, however, can be extended to other models such as the accretion disc driven formation channel. We present the phenomenological characteristic of the MBH mass, spin, and redshift distributions. Then, we investigate the posterior distribution of the hyper-parameters that describe this population model. The optimistic results show that TianQin could recover almost all the posterior of the hyper-parameters within $1σ$ confidence interval. The hyper-parameters $α_1, α_2, b$, which describe the MBH mass distribution, could be measured with an accuracy of $46.4\%$, $12.6\%$, and $3\%$, respectively. The hyper-parameters $μ_z$, and $σ_z$, which describe the redshift distribution, could be measured with an accuracy of $15.4\%$ and $21.1\%$. With this estimation accuracy, the EMRI population characteristics can be effectively demonstrated, potentially serving as evidence for EMRI formation in the future studies. Furthermore, with an increasing number of detectable events, the parameter estimation for the hyper-parameters will improve and the confidence intervals will be narrowed.

astro-ph.HE↗

arXiv2025

Mass spectra and wave functions of toponia

In this article, {we solve the instantaneous Bethe-Salpeter equation with Cornell potential and Coulomb potential} and conduct a meticulous study of the mass spectrum and wave function of toponium. Our investigation reveals that, owing to the exceedingly heavy mass of the top quark, the mass splitting between singlet and triplet states, as well as within the triplet states, is negligible. Consequently, relativistic corrections can be safely disregarded in the study of toponium. As such, we present the nonrelativistic wave functions for $S$-wave, $P$-wave, and $D$-wave toponia and study the decays $η_t\to γγ$, $η_t\to gg$, and $Θ\to \ell^+\ell^-$.

hep-ph↗

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.

hep-ph↗

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.

hep-ph↗

arXiv2025

Electroweak baryogenesis and electron EDM in the TNMSSM

We have studied the impact of CP-violating (CPV) effects on electroweak baryogenesis (EWBG) and the electric dipole moment (EDM) of electron ($d_e$), the electric dipole moment (EDM) of mercury neutron ($d_n$) and the electric dipole moment (EDM) of ($d_{Hg}$) in an extension of the Minimal Supersymmetric Standard Model (MSSM). The model incorporating a $SU(2)$ triplet with hypercharges of $\pm1$ and a gauge singlet from the standard model that is mutually coupled, is collectively referred to as the next-to-minimal supersymmetric standard model with triplets (TNMSSM). Furthermore, we discuss the strong first-order phase transition (PT) achieved by this model via tree-level effects. The numerical results indicate that the TNMSSM can account for the observed baryon asymmetry. Additionally, the regions favored by EWBG can be compatible with the corresponding electron EDM bounds when different contributions to the $d_e$ cancel each other out.

hep-ph↗

arXiv2025

Electric dipole moments from the perspective of a scalar triplet and singlet extension of the MSSM: A study of neutrons, electrons, mercury, and b and c quarks

In the framework of the minimal supersymmetric model extension with new scalar triplets and singlet (TNMSSM), we analyze the electric dipole moment (EDM) of neutron ($d_n$), electron EDM($d_e$), the mercury EDM($d_{Hg}$), $b$ quark ($d_b$) and $c$ quark ($d_c$) by considering the contributions from the one-loop diagrams, some two-loop diagrams and the Weinberg operators. The effects of TNMSSM specific CPV sources $χ_d,\;χ_t$ on $d_n$, $d_e$, $d_{Hg}$, $d_b$, $d_c$ are specialized, it is found that they have significant contributions to these EDMs, and the current upper bounds on $d_n$ impose strict constraints on $χ_d,\;χ_t$. The theoretical predictions on $d_b$, $d_c$ can reach about $10^{-22}$ e$\cdot$cm and $10^{-23}$ e$\cdot$cm respectively by taking the upper bounds on $d_n$, $d_e$, $d_{Hg}$ into account, which have great potential to be observed in future.

hep-ph↗

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.

hep-th↗

arXiv2024

Right-handed neutrino dark matter in $U(1)_X$SSM

There is strong evidence for the existence of dark matter in a number of current experiments. We study dark matter using the $U(1)_X$SSM obtained from the $U(1)_X$ extension of the minimal supersymmetric standard model (MSSM). In the $U(1)_X$SSM, we use the right-handed neutrino as a dark matter candidate, whose lightest mass eigenstate has cold dark matter features. In this paper, the relic density of right-handed neutrino as dark matter is investigated. For dark matter scattering, both spin-independent and spin-dependent cross sections are studied. In the final numerical results obtained, some parameter spaces can satisfy the constraints of the relic density and dark matter direct detection experiments.

hep-ph↗

arXiv2024

Neutralino dark matter in the extension of MSSM with two triplets and singlet

In an extension of MSSM with two triplets and a singlet, called the TNMSSM, there are seven neutralinos which can enrich the study of cold dark matter if one expects that the weakly interacting massive particle (WIMP) is responsible for the observation of Planck satellite. Such a model, compared to the MSSM, can naturally offer a solution to the $μ$ problem, and its lightest neutralino, which is bino-like, can also provide a correct relic density by using the coannihilation mechanism due to the newly added triplinos. Taking into account the related experimental measurements, such as the bound on the SM-like Higgs mass, the $B$ meson rare decays, the anomalous magnetic moment of the muon $a_μ$, the Large Hadron Collider (LHC) measurements and the latest dark matter direct detection experiment LUX-ZEPLIN (LZ), the TNMSSM parameter space can be strictly limited. In respect to all the constraints mentioned above, we find that a bino-like neutralino with a mass in the region $[100, 450]~\rm{GeV}$ can successfully account for the correct dark matter relic density. Additionally, most of the viable parameter space can be tested in the near future experiments such as the Xenon-nT experiment or LHC.

hep-ph↗

arXiv2024

Lepton-flavor violation in the left-right supersymmetric standard model

In the Standard Model (SM), the charged lepton-flavor violation (CLFV) processes are forbidden, so the observation of CLFV represents a clear signal of new physics that goes beyond the Standard Model. In this work, we focus on the CLFV processes $l_{j}^{-}\to l_{i}^{-}γ$ and $l_{j}^{-}\to l_{i}^{-}l_{i}^{-}l_{i}^{+}$ in LRSSM. Considering the constraints of the updated experimental datas, the numerical results show that the new contributions of $SU{{\left( 2 \right)}_{R}}$ gauge interaction and a large number of other new particles, such as ${{Z}^{'}}$ boson, double-charged Higgs-bosons in LRSSM can make significant contributions to the CLFV processes $l_{j}^{-}\to l_{i}^{-}γ$ and $l_{j}^{-}\to l_{i}^{-}l_{i}^{-}l_{i}^{+}$, which is much different from the ones predicted in other SUSY models. This work provide a theoretical base for finding the LFV phenomena in new physics.

hep-ph↗

arXiv2024

W boson mass in the NP models with extra $U(1)$ gauge group

The precise measurement of the W boson mass is closely related to the contributions of new physics (NP), which can significantly constrain the parameter space of NP models, particularly those with an additional $U(1)$ local gauge group. The inclusion of a new $Z'$ gauge boson and gauge couplings in these models can contribute to the oblique parameters $S$, $T$, $U$ and W boson mass at tree level. Taking into account the effects of kinetic mixing, we calculate and analyze the oblique parameters $S$, $T$, $U$ and W boson mass in such NP models in this study. It is found that the kinetic mixing effects can make significant contributions to the W boson mass, which can satisfy the recently measured W boson mass at CDF II or ATLAS by choosing appropriate values of gauge coupling constants and extra $U(1)$ group charges of leptons or scalar doublets. In addition, if the leptonic Yukawa couplings are invariant under the extra $U(1)$ local gauge group, these contributions can be eliminated by redefining the gauge boson fields through eliminating the neutral currents involving charged leptons, even with nonzero kinetic mixing effects.

hep-ph↗

arXiv2024

The Higgs boson decay $h \rightarrow bs$ in the $U(1)_X$SSM

In the $U(1)_X$SSM, we delve into the flavor violation of $h \rightarrow bs$, where $h$ is identified with the SM-like Higgs boson discovered at the LHC. As the U(1) extension of the minimal supersymmetric standard model (MSSM), the U(1)XSSM has new super fields such as right-handed neutrinos and three Higgs singlets. We conduct a thorough analysis of the underlying mechanisms and parameter dependencies of $h \rightarrow bs$ in the $U(1)_X$SSM. In the $U(1)_X$SSM, we discover that the Br$(h \rightarrow bs)$ for the Higgs decay to $bs$ could significantly differ from the expectation in the standard model (SM), depending on the values of the new parameters introduced in the model. Our research not only contributes to a deeper understanding of Higgs physics within the $U(1)_X$SSM, but also provides valuable guidance for new physics (NP).

hep-ph↗

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.

hep-ph↗

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.

hep-ph↗