arXiv subjects

Guo-Li Liu

Publications and source records attributed to Guo-Li Liu.

At least 19 recordsLinked to original sources

arXiv2025

The Lepton Flavor Changing Decays and One-loop Muon Anomalous Magnetic Moment in the Extended Mirror Twin Higgs Models

Mirror Twin Higgs(MTH) models always contain heavy gauge bosons and extra Higgses. Besides, to accommodate tiny neutrino masses via seesaw mechanism, new heavy neutrinos can also be introduced in MTH extension models. Such new particles and interactions may lead to new contributions to the lepton flavor violating (LFV) processes, including $\ell_i \to \ell_jγ$ and $\ell_i \to \ell_j\ell_k\ell_l$. We find that current experimental data can stringently constrain the parameter spaces and certain LFV processes can possibly be tested by the next generation colliders. One-loop contributions of the new particles to the muon anomalous magnetic momentumare also calculated. Such contributions can still not solve the discrepancy between the experiments and the prediction of the standard model.

hep-ph↗

arXiv2025

Ultra High Energy Cosmic Rays in light of the Lorentz Invariance Violation Effects within the Proton Sector

Tiny Lorentz Invariance Violation (LIV) effects, potentially arising from quantum gravity-induced spacetime structures, may also manifest in the proton sector, offering a plausible pathway to test Planck-scale physics through high-energy cosmic phenomena. Our analysis reveals that even minuscule LIV effects in the proton sector can significantly elevate the photon threshold energy for photopion production to $\cal {O}$(0.1 to $10^3$ eV), orders of magnitude higher than in Lorentz-symmetric scenarios. Consequently, protons in ultra-high-energy cosmic rays (UHECRs) can propagate for very long distances without significant energy loss via photopion interactions with cosmic microwave background (CMB) photons. This suppression of attenuation may provide a plausible explanation for the observed cosmic-ray events exceeding the Greisen-Zatsepin-Kuzmin (GZK) cutoff energy. We further demonstrate that when both leading-order and next-to-leading-order LIV effects are considered, higher-order LIV contributions induce discontinuous transitions in the GZK cutoff energy spectrum. Observations of proton-dominated UHECRs beyond the GZK threshold could provide constraints the LIV energy scale. Offering insights into the ultraviolet regime of LIV theories near the Planck scale, UHECRs may serve as a sensitive probe of LIV and provide a means to test quantum gravity predictions by constraining deviations from Lorentz symmetry in extreme-energy regimes.

hep-ph↗

arXiv2023

The influence of supersymmetric quirk particles on the W mass increment and the muon g-2 anomaly

In quirk assisted Standard Model, the couplings between the exotic particles "quirks" and the gauge bosons may contribute to the W mass and muon g-2 anomaly reported by FermiLab. We calculate the contributions from supersymmetric quirk particles as an example. Imposing the theoretical constraints, we found that the CDF II W-boson mass increment constrains strictly the mixing and coupling parameters and the quirk mass m_F, while muon g-2 anomaly cannot be explained by the exotic particles with their large masses.

hep-ph↗

arXiv2022

The Contribution of Charged Bosons with Right-Handed Neutrinos to the Muon g-2 Anomaly in the Twin Higgs Models

We examine the charged boson and right-handed neutrino contribution to the muon g-2 anomaly in the twin Higgs models with the joint constraints of the Higgs global fit data, the precision electroweak data, the leptonic flavor changing decay μ\to eγ, and the mass requirement of the heavy gauge bosons. It comes out with the conclusion that some parameters such as the coupling of charged Higgs to the lepton y_μ, the top Yukawa y_t, and the heavy gauge boson coupling to the lepton V_μare constrained roughly in the range of 0.12\lesssim y_μ\lesssim 0.4, 0.4\lesssim y_t\lesssim 0.9, and 0.47\lesssim V_μ\lesssim 1, respectively.

hep-ph↗

arXiv2022

Constraints from New CDF II W-Boson Mass On Top-Bottom Seesaw and the TopFlavor Models

In top-bottom seesaw and topflavor model, there may exist extra Higgses and vectorlike fermions, and we have examined the W mass anomaly reported by CDF II in these frames. We found that the CDF II W-boson mass data constrains the parameter r_t and z_t strictly in the two models, respectively, while the constraints on other parameters such as m_H, m_χare quite weak. Therefore, we conclude that in the two models, the W mass increment is sensitive to the extra fermions, but not the extra scalars. In topflavor model, we also consider the W mass increment induced by the mass mixing of the light and the heavy gauge bosons and the contribution is not too large and the constraints on the parameters x and y are weak.

hep-ph↗

arXiv2021

Gluino-SUGRA scenarios in light of FNAL muon g-2 anomaly

Gluino-SUGRA ($\tilde{g}$SUGRA), which is an economical extension of the predictive mSUGRA, adopts much heavier gluino mass parameter than other gauginos mass parameters and universal scalar mass parameter at the unification scale. It can elegantly reconcile the experimental results on the Higgs boson mass, the muon $g-2$, the null results in search for supersymmetry at the LHC and the results from B-physics. In this work, we propose several new ways to generate large gaugino hierarchy (i.e. $M_3\gg M_1,M_2$) for $\tilde{g}$SUGRA model building and then discuss in detail the implications of the new muon $g-2$ results with the updated LHC constraints on such $\tilde{g}$SUGRA scenarios. We obtain the following observations: (i) For the most interesting $M_1=M_2$ case at the GUT scale with a viable bino-like dark matter, the $\tilde{g}$SUGRA can explain the muon $g-2$ anomaly at $1σ$ level and be consistent with the updated LHC constraints for $6\leq M_3/M_1 \leq 9$ at the GUT scale; (ii) For $M_1:M_2=5:1$ at the GUT scale with wino-like dark matter, the $\tilde{g}$SUGRA model can explain the muon $g-2$ anomaly at $2σ$ level and be consistent with the updated LHC constraints for $3\leq M_3/M_1 \leq 3.2$ at the GUT scale; (iii) For $M_1:M_2=3:2$ at the GUT scale with mixed bino-wino dark matter, the $\tilde{g}$SUGRA model can explain the muon $g-2$ anomaly at $1σ$ level and be consistent with the updated LHC constraints for $6.9\leq M_3/M_1 \leq 7.5$ at the GUT scale. Although the choice of heavy gluino will always increase the FT involved, some of the $1σ/2σ$ survived points of $Δa_μ^{combine}$ can still allow low EWFT of order several hundreds and be fairly natural. Constraints from (dimension-five operator induced) proton decay are also discussed.

hep-ph↗

arXiv2020

Top Rare Decays t-> cV in the Mirror Twin Higgs Models

The decay t -> c V (V=γ, Z, g) process in the mirror twin Higgs models with the colorless top partners are studied in this paper. We found that the branching ratios of these decays can in some parameter spaces alter the standard model expectations greatly and may be detectable according to the currently precision electroweak measurements. Thus, the constraints on the model parameters may be obtained from the branching fraction of the decay processes, which may serve as a robust detection to this new physics model.

hep-ph↗

arXiv2019

NMSSM with generalized deflected mirage mediation

We propose to generate a realistic soft SUSY breaking spectrum for Next-to-Minimal Supersymmetric Standard Model (NMSSM) with a generalized deflected mirage mediation scenario, in which additional Yukawa and gauge mediation contributions are included to deflect the renormalization group equation(RGE) trajectory. Based on the Wilsonian effective action obtained by integrating out the messengers, the NMSSM soft SUSY breaking spectrum can be given analytically at the messenger scale. We find that additional contributions to $m_S^2$ can possibly ameliorate the stringent constraints from the electroweak symmetry breaking (EWSB) and 125 GeV Higgs mass. Constraints from dark matter and fine-tuning are also discussed. The Barbieri-Giudice fine-tuning measure and electroweak fine-tuning measure in our scenario can be as low as ${\cal O}(1)$, which possibly indicates that our scenario is natural.

hep-ph↗

arXiv2019

Muon g-2 Anomaly confronted with the higgs global data in the Left-Right Twin Higgs Models

We will examine the Left-Right Twin Higgs(LRTH) Models as a solution of muon g-2 anomaly with the background of the Higgs global fit data. In the calculation, the joint constrains from the theory, the precision electroweak data, the 125 GeV Higgs data, the leptonic flavor changing decay μ\to eγdecays, and the constraints m_{ν_R}>m_T>m_{W_H} are all considered. And with the small mass of the ϕ^0, the direct searches from the $h\to ϕ^0ϕ^0$ channels can impose stringent upper limits on Br(h\to ϕ^0ϕ^0) and can reduce the allowed region of m_{ϕ^0} and f. It is concluded that the muon g-2 anomaly can be explained in the region of 200 GeV \leq M\leq 500 GeV, 700 GeV \leq f\leq 1100 GeV, 13 GeV \leq m_{ϕ^0}\leq 55 GeV, 100 GeV \leq m_{ϕ^\pm}\leq 900 GeV, and m_{ν_R}\geq 15 TeV after imposing all the constraints mentioned above.

hep-ph↗

arXiv2018

Explain DAMPE Results by Dark Matter With Hierarchical Lepton-Specific Yukawa Interactions

We propose to interpret the DAMPE electron excess at 1.5 TeV through scalar or Dirac fermion dark matter (DM) annihilation with doubly charged scalar mediators that have lepton-specific Yukawa couplings. Hierarchy of such lepton-specific Yukawa couplings is generated through the Froggatt-Nielsen mechanism, so that the dark matter annihilation products can be dominantly electrons. Stringent constraints from LEP2 on intermediate vector boson production can be evaded in our scenarios. In the case of scalar DM, we discuss one scenario with DM annihilating directly to leptons and the other scenario with DM annihilating to scalar mediators followed by their decays. We also discuss the Breit-Wigner resonant enhancement and the Sommerfeld enhancement in case that the s-wave annihilation process is small or helicity suppressed. With both types of enhancement, constraints on the parameters can be relaxed and new ways for model building will be open in explaining the DAMPE results.

hep-ph↗

arXiv2017

Probing Lepton Flavor Violation Signal via γγ\to l_i\barl_j in the Left-Right Twin Higgs Model at the ILC

To explain the small neutrino masses, heavy Majorana neutrinos are introduced in the left-right twin Higgs model. The heavy neutrinos, together with the charged scalars and the heavy gauge bosons, may contribute large mixings between the neutrinos and the charged leptons, which may induce some distinct lepton flavor violating processes. We will check the \bar \ell_i \ell_j (i,j= e,μ,τ,i\neq j) productions in the γγcollision in the left-right twin Higgs model, and find that the production rates may be large in some specific parameter space, in the optimal cases even possible to be detected with reasonable kinematical cuts. we have also shown that these collisions can constrain effectively the model parameters such as the Higgs vacuum expectation value and the right-handed neutrino mass, etc., and may serve as a sensitive probe of this new physics model.

hep-ph↗

arXiv2015

Bounds on Higgs And Top Quark Masses From The Other Degenerate Vacua Near The Planck Scale With Gravitational Contributions

Based on the weak coupling expansion of gravity, we calculate the gravitational contributions to yukawa coupling, scalar quartic coupling as well as gauge couplings with general Landau-DeWitt gauge-fixing choice and a gauge preserving (of SM gauge group) cut off regularization scheme. We find that the results depend on the Landau-DeWitt gauge-fixing parameter. Based on the two loop RGE of SM couplings with one loop full gravitational contributions in harmonic gauge, we study the constraints on the higgs and top quark mass from the requirement of existing the other degenerate vacua at the Planck-dominated region. Our numerical calculations show that nature will not develop the other degenerate vacua at the Planck-dominated region with current higgs and top quark masses. On the other hand, requiring the existence of the other degenerate vacua at the Planck-dominated region will constrain the higgs and top mass to lie at approximately 130 and 174 GeV, respectively.

hep-ph↗

arXiv2015

Charged Higgs Pair Production at the LHC as a Probe of the Top-Seesaw Assisted Technicolor Models

The top-seesaw assisted technicolor (TC) model, which was proposed recently to explain the 126 GeV Higgs mass discovered by the Large Hadron Colliders (LHC), predicts light and heavy charged Higgs bosons in addition to the neutral Higgses. In this paper we will study the pair productions of the charged Higgs, proceeding through gluon-gluon fusion and quark-anti-quark annihilation, at the LHC in the frame of the top-seesaw assisted TC model. We find that in a large part of parameter space the production cross sections of the light charged Higgs pair at the LHC can be quite large compared with the low standard model backgrounds, while it is impossible for the pair production of the heavy ones to be detected with the strong final mass suppression. Therefore, at the LHC future experiments, the light charged Higgs pair production may be served as a probe of this new TC model.

hep-ph↗

arXiv2014

The lepton flavor violating signal of the charged scalar ϕ^\pm and ϕ^{\pm\pm} in photon-photon collision at the ILC

The hitherto unconstrained lepton flavor mixing, induced by the new charged scalar ϕ^\pm and ϕ^{\pm\pm} predicted by many new physics models such as higgs triplet models, may lead to the lepton flavor violating productions of τ\bar μ, τ\bar e and μ\bar e in photon-photon collision at the proposed international linear collider. In this paper, we consider the contributions of the ϕ^\pm and ϕ^{\pm\pm} in the context of the higgs triplet models to the processes γγ\to l_i\bar l_j (i, j= e, μ, τ, i\neq j) and find that they can be good channels to probe these new physics models. The lepton flavor violating processes γγ\to l_i\bar l_j (i, j= e, μ,τ,i\neq j) occur at a high rate due to the large mixing angle and the large flavor changing coupling, so, in view of the low standard model backgrounds, they may reach the detectable level of the ILC for a large part of the parameter space. Since the rates predicted by the standard model are far below the detectable level, these processes may serve as a sensitive probe for such new physics models.

hep-ph↗

arXiv2013

Charged Higgs Production in Association With W^{\pm} at Large Hadron Colliders

Many new physics models beyond the standard model, such as the littlest higgs models and the left right twin higgs models, predict the existence of the large charged higgs couplings H^-q\bar b and H^+b\bar q, where q=t or the new vector-like heavy quark T; On the other hand, some new physics models like the littlest higgs also predict the gauge-higgs couplings. Such couplings may have rich collider phenomenology. We focus our attention on these couplings induced by the littlest higgs models and the left right twin higgs models models and consider their contributions to the production cross section for W^\pm H^\mp production at the large hadron colliders. We find that the cross sections, in the littlest higgs models, on the parton level gg \to W^\pm H^\mp and q\bar q \to W^\pm H^\mp (q=u,d,s,c,b) may reach tens of several dozen femtobarns in reasonable parameters space at the collision energy of 14 TeV and that the total cross section can even reach a few hundred femtobarns in certain favored space. While in the left right twin higgs models, the production rates are basically one order lower than these in littlest higgs. Therefore, due to the large cross sections of that in the littlest higgs, it may be possible to probe the charged higgs via this process in a large parameter space.

hep-ph↗

arXiv2012

PGB pair production at LHC and ILC as a probe of the topcolor-assisted technicolor models

The topcolor-assisted technicolor (TC2) model predicts some light pseudo goldstone bosons (PGBs), which may be accessible at the LHC or ILC. In this work we study the pair productions of the charged or neutral PGBs at the LHC and ILC. For the productions at the LHC we consider the processes proceeding through gluon-gluon fusion and quark-antiquark annihilation, while for the productions at the ILC we consider both the electron-positron collision and the photon-photon collision. We find that in a large part of parameter space the production cross sections at both colliders can be quite large compared with the low standard model backgrounds. Therefore, in future experiments these productions may be detectable and allow for probing TC2 model.

hep-ph↗

arXiv2010

Single top or bottom production associated with a scalar in γp collision as a probe of topcolor-assisted technicolor

In the framework of the topcolor-assisted technicolor (TC2) models, we study the productions of a single top or bottom quark associated with a scalar in γ-p collision, which proceed via the subprocesses cγ-> tπ_t^0, cγ-> t h_t^0 and cγ-> bπ^+_t mediated by the anomalous top or bottom coupling tcπ_t^0, tch_t^0 and bcπ_t^+. These productions, while extremely suppressed in the Standard Model, are found to be significantly enhanced in the large part of the TC2 parameter space, especially the production via cγ-> bπ^+ can have a cross section of 100 fb, which may be accessible and allow for a test of the TC2 models.

hep-ph↗

arXiv2010

Probing topcolor-assisted technicolor models from like-sign tau pair production in e gamma collisions

We consider the contributions of the extra gauge boson Z' to the like sign $τ$ production process $e^-γ\to e^+(μ^+)τ^-τ^-$, induced by the tree-level flavor changing interactions. Since these rare production are far below the observable level in the Standard Model and other popular new physics models such as the minimal supersymmetric model, we find that Z' can give significant contributions to this process, and with reasonable values of the parameters in TC2 models, the cross section can reach several tens of fb and may be detected at the $eγ$ collisions.

hep-ph↗