arXiv subjects

Xiu-Yi Yang

Publications and source records attributed to Xiu-Yi Yang.

18 recordsLinked to original sources

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

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

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arXiv2021

Double peaks of gravitational wave spectrum induced from inflection point inflation

We investigate the possibility to induce double peaks of gravitational wave(GW) spectrum from primordial scalar perturbations in inflationary models with three inflection points.Where the inflection points can be generated from a polynomial potential or generated from Higgs like $ϕ^4$ potential with the running of quartic coupling.In such models, the inflection point at large scales predicts the scalar spectral index and tensor-to-scalar ratio consistent with current CMB constraints, and the other two inflection points generate two large peaks in the scalar power spectrum at small scales, which can induce GWs with double peaks energy spectrum. We find that for some choices parameters the double peaks spectrum can be detected by future GW detectors, and one of the peaks around $f\simeq10^{-9}\sim10^{-8}$Hz can also explain the recent NANOGrav signal. Moreover, the peaks of power spectrum allow for the generation of primordial black holes, which account for a significant fraction of dark matter.

astro-ph.CO↗

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.

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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.

hep-ph↗

arXiv2018

Two loop electroweak corrections to $\bar B\rightarrow X_sγ$ and $B_s^0\rightarrow μ^+μ^-$ in the B-LSSM

The rare decays $\bar B\rightarrow X_sγ$ and $B_s^0\rightarrow μ^+μ^-$ are important to research new physics beyond standard model. In this work, we investigate two loop electroweak corrections to $\bar B\rightarrow X_sγ$ and $B_s^0\rightarrow μ^+μ^-$ in the minimal supersymmetric extension of the SM with local $B-L$ gauge symmetry (B-LSSM), under a minimal flavor violating assumption for the soft breaking terms. In this framework, new particles and new definition of squarks can affect the theoretical predictions of these two processes, with respect to the MSSM. Considering the constraints from updated experimental data, the numerical results show that the B-LSSM can fit the experimental data for the branching ratios of $\bar B\rightarrow X_sγ$ and $B_s^0\rightarrow μ^+μ^-$. The results of the rare decays also further constrain the parameter space of the B-LSSM.

hep-ph↗

arXiv2018

Top quark decays with flavor violation in the B-LSSM

The decays of top quark $t\rightarrow cγ,\;t\rightarrow cg,\;t\rightarrow cZ,\;t\rightarrow ch$ are extremely rare processes in the standard model (SM). The predictions on the corresponding branching ratios in the SM are too small to be detected in the future, hence any measurable signal for the processes at the LHC is a smoking gun for new physics. In the extension of minimal supersymmetric standard model with an additional local $U(1)_{B-L}$ gauge symmetry (B-LSSM), new gauge interaction and new flavor changing interaction affect the theoretical evaluations on corresponding branching ratios of those processes. In this work, we analyze those processes in the B-LSSM, under a minimal flavor violating assumption for the soft breaking terms. Considering the constraints from updated experimental data, the numerical results imply $Br(t\rightarrow cγ)\sim5\times10^{-7}$, $Br(t\rightarrow cg)\sim2\times10^{-6}$, $Br(t\rightarrow cZ)\sim4\times10^{-7}$ and $Br(t\rightarrow ch)\sim3\times10^{-9}$ in our chosen parameter space. Simultaneously, new gauge coupling constants $g_{_B},\;g_{_{YB}}$ in the B-LSSM can also affect the numerical results of $Br(t\rightarrow cγ,\;cg,\;cZ,\;ch)$.

hep-ph↗

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.

hep-ph↗

arXiv2016

Inflection point in running kinetic term inflation

In this work, we consider inflection point inflation in the framework of running kinetic term inflation in supergravity. We study the inflationary dynamics and show that the predicted value of the scalar spectral index and tensor-to-scalar ratio can lie within the $1σ$ confidence region allowed by the result of Planck 2015.

hep-ph↗

arXiv2014

Oblique parameters in gauged baryon and lepton numbers with a 125GeV Higgs

In an extension of the standard model where baryon number and lepton number are local gauge symmetries, we analyze the effect of corrections from exotic fermions and scalars on the oblique parameters $S,\;T,\;U$. Because a light neutral Higgs $h_0$ with mass around $124-126{\rm GeV}$ strongly constrains the corresponding parameter space of this model, we also investigate the gluon fusion process $gg\rightarrow h_0$ and two photon decay of lightest neutral Higgs $h_0\rightarrowγγ$ at the Large Hadron Collider.

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

Search for $Z'$ via $ZH$ associated production at LHC

Many new physics models predict the existence of extra neutral gauge bosons ($Z'$). Inspired by the recent development on Higgs search, we study the properties of $Z'$ via the Higgs and $Z$ boson associated production. The couplings of $Z'$ to quarks can be investigated through $pp \to Z'\to ZH\to l^+l^-b \bar b$ process, which also provides extraordinary signal for understanding the properties of $Z'ZH$ interaction. The standard model background processes can be significantly suppressed by adopting appropriate kinematic cuts. The charged lepton angular distributions are related to the ratio of chiral couplings of $Z'$ to quarks via $Z'ZH$ interaction.

hep-ph↗

arXiv2010

Heavy fermions and two loop electroweak corrections to $b\rightarrow s+γ$

Applying effective Lagrangian method and on-shell scheme, we analyze the electroweak corrections to the rare decay $b\rightarrow s+γ$ from some special two loop diagrams in which a closed heavy fermion loop is attached to the virtual charged gauge bosons or Higgs. At the decoupling limit where the virtual fermions in inner loop are much heavier than the electroweak scale, we verify the final results satisfying the decoupling theorem explicitly when the interactions among Higgs and heavy fermions do not contain the nondecoupling couplings. Adopting the universal assumptions on the relevant couplings and mass spectrum of new physics, we find that the relative corrections from those two loop diagrams to the SM theoretical prediction on the branching ratio of $B\rightarrow X_{_s}γ$ can reach 5% as the energy scale of new physics $Λ_{_{\rm NP}}=200$ GeV.

hep-ph↗

arXiv2009

Renormalization and two loop electroweak corrections to lepton anomalous dipole moments in the standard model and beyond (I): heavy fermion contributions

Applying effective Lagrangian method and on-shell scheme, we analyze the electroweak corrections to anomalous dipole moments of lepton from some special two loop diagrams in which a closed heavy fermion loop is attached to the virtual gauge bosons or Higgs fields. As the masses of virtual fermions in inner loop are much heavier than the electroweak scale, we verify the final results satisfying the decoupling theorem explicitly if the interactions among Higgs and heavy fermions do not contain the nondecoupling couplings. At the decoupling limit, we also present the leading corrections to lepton anomalous dipole moments from those two loop diagrams in some popular extensions of the standard model, such as the fourth generation, supersymmetry, universal extra dimension, and the littlest Higgs with T-parity.

hep-ph↗

arXiv2008

Electroweak and supersymmetric two-loop corrections to lepton anomalous magnetic and electric dipole moments

Using the effective Lagrangian method, we analyze the electroweak corrections to the anomalous dipole moments of lepton from some special two-loop diagrams where a closed neutralino/chargino loop is inserted into relevant two Higgs doublet one-loop diagrams in the minimal supersymmetric extension of the standard model with CP violation. Considering the translational invariance of loop momenta and the electromagnetic gauge invariance, we get all dimension 6 operators and derive their coefficients. After applying equations of motion to the external leptons, we obtain the anomalous dipole moments of lepton. The numerical results imply that there is parameter space where the contributions to the muon anomalous dipole moments from this sector may be significant.

hep-ph↗

arXiv2008

The two loop supersymmetric corrections to lepton anomalous dipole moments in split supersymmetry scenarios

An analysis of electroweak corrections to the anomalous dipole moments of lepton from some special two-loop diagrams where a closed neutralino/chargino loop is inserted into relevant one-loop diagrams of the standard model is presented in the split supersymmetry scenarios. Considering the translational invariance of the inner loop momenta and the electromagnetic gauge invariance, we get all dimension 6 operators and their coefficients. After applying equations of motion to the external leptons, we obtain the anomalous dipole moments of lepton. The numerical results imply that there is parameter space where the contribution to the muon anomalous magnetic dipole moment from this sector is perhaps significant, and the contribution to the electron electric dipole moment from this sector is sizable enough to be observed in next generation experiments.

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