arXiv subjects

She-Sheng Xue

Publications and source records attributed to She-Sheng Xue.

At least 19 recordsLinked to original sources

arXiv2026

Particle--antiparticle asymmetry from charge separation at expanding horizons

In a Friedmann universe with a time-varying cosmological term, massive particle--antiparticle pairs are produced continuously from the spacetime vacuum, and their members are separated by horizons. Along the cosmic history that explains $n_s$, $A_s$, $r$ and the low-$\ell$ power anomaly, we show how this separation generates the observed asymmetry. Horizons absorb the charge they separate, since gravity does not conserve global charges. Charge separation at the many horizons inside today's Hubble volume then acts as a volume violation of the U(1) charge, at a rate $Γ_C=κ_CΓ_M$ proportional to pair production. The sign requires a C- and CP-odd coupling to the time arrow. We describe both by an effective Lagrangian with a U(1)-violating coupling $g_c\,δ\mathcal O_SΦ^2$ to the spacetime vacuum and a time bias $-\partial_μf(R)\,J^μ$. For $f=c_a\ln|R|$ the chemical potential of producing a particle is $μ\simeq2c_a\dot H/H$. The asymmetry per pair reaches an attractor in the pair-dominated episode and freezes when the cosmological term is exhausted. The observed value requires $|c_a|/τ_S\simeq(0.65$--$1.0)\times10^{-4}$, with $T_S=τ_SH/2π$ the temperature of the spacetime vacuum, and its sign is fixed by the arrow of time. The Yukawa decays of the pairs transfer the asymmetry, with a uniform sign, to baryons and leptons and to dark-matter particles. The current of the charged decay products generates a magnetic field of $10^{-14}$--$10^{-11}$ G today on the coherence length of reheating.

hep-ph↗

arXiv2026

Searching for axion-like particles with space-based optical lattice clock networks

Axion like particles (ALPs) are particularly well motivated candidates for dark matter, and physics beyond the Standard Model more generally. However, direct detection remains extremely challenging due to the weakness of their interactions. In this work, we propose to employ space-based optical lattice clock networks (SOLCN), originally targeted to probe the stochastic gravitational wave background (SGWB), to detect axion dark matter through cosmic birefringence via minor modifications to their laser links. Searching for cross-correlated signals then provides significant sensitivity to low mass ALPs as a result of their large correlation lengths. In this work we focus on ALPs in the mass range $10^{-18.55}\text{eV}-10^{-14}\text{eV}$, For ALPs mass region $10^{-18}-10^{-14}\text{eV}$, finding that we can probe down to $g_{aγ}\geq 10^{-12}\,\text{GeV}^{-1}$. Moreover, we find that the SOLCN sensitivity to the ALP-photon coupling depends crucially on the frequency of the network link. With an $8$ GHz frequency link, we then have the potential to reach $g_{aγ}\geq10^{-16}\,\text{GeV}^{-1}$ in this region.

hep-ph↗

arXiv2026

Cosmic rate equation and massive particle--antiparticle pair production

In a Friedmann universe with a time-varying cosmological term, the production of massive particle--antiparticle pairs and their exchange of energy with the spacetime vacuum are described by a cosmic rate equation, $\dotρ_M+3Hρ_M=Γ_M(ρ_M^H-ρ_M)-Γ_M^{\rm de}ρ_M$. Together with the Friedmann equations, an energy-balance equation for the time-varying cosmological term, and a reheating equation for the radiation, it forms a closed set of four independent background equations. We derive this set from a complex scalar field with a global U(1) symmetry and a non-minimal coupling to curvature. In the adiabatic case, the occupation of non-relativistic modes gives $ρ_M^H=2χm^2H^2$. A kinetic equation, based on the pairwise coupling $ξR|Φ|^2$ to fluctuations of the spacetime vacuum, gives the relaxation rate $Γ_M$, and a Yukawa coupling gives the decay rate $Γ_M^{\rm de}$. In the fast-oscillating case, the Hubble function oscillates at twice the pair mass and locks in phase with the pairs, so that it exchanges no net energy with them. The energy of the created pairs is supplied instead by the decrease of the cosmological term in the time evolution, $-\dotρ_Λ=[(3-2ε) H+Γ_M^{\rm de}]ρ_M^H$. Averaging over the fast time gives the cosmic rate equation in the detailed-balance regime $Γ_M\gg H$. In this regime the closed set has an exact power-law solution with $ε=-\dot H/H^2=χm^2/m_{\rm pl}^2$. We discuss the application of the closed set to inflation, reheating and standard cosmology.

gr-qc↗

arXiv2026

Scalar QED effective action in dS: implications for primordial magnetogenesis and the running of coupling constants

Particles creation and vacuum polarization under the influence of both an electromagnetic field and a de~Sitter (dS) spacetime nonperturbatively probes quantum electrodynamics (QED) and quantum gravitational effects. By applying the gamma-function regularization to the in-out formulation, we find the exact one-loop effective action in the proper-time integral representation for a charged scalar field in a uniform electric field and a parallel magnetic field in a dS spacetime. It reduces to the one-loop scalar QED Weisskopf-Schwinger effective action in the limit of Minkowski spacetime and the one-loop effective action in the pure dS spacetime. After carefully considering the different limiting cases, a striking result concerns the effective strengths of the coupling constants in the pure strong electric field limit. Our study provides further evidence for evolution of Newton's gravitational constant under the influence of the external fields. Remarkably, the analysis of the effective potential shows that the leading order contributions to the vacuum polarization amplitude, depending on the nonminimal coupling threshold, give a nonzero vacuum expectation value of the magnetic field. This mechanism generates a large magnetic field in the early dS stage of the expansion that may imply primordial magnetogenesis.

hep-th↗

arXiv2026

Trapped fireshell (halo) of photons and pairs around black-hole horizon: source for ultra-high-energy particles

We study the Compton-rocket effect of strong radiation force accelerating electrons in an opaque fireshell (or fire spot) of dense photons and electron-positron pairs, whose temperature is spatially inhomogeneous and exceeds the electron mass. We find the possibility of the charged-particle acceleration and the avalanche runaway process, leading to a non-trivial probability of ultra-high-energy (UHE) electrons and protons, which subsequently produce very-high-energy (VHE) photons and neutrinos. In a simplified one-dimensional model, we qualitatively show such peculiar dynamics using the fireball, Gamma-Ray Burst central engine, whose inner part inflows and forms a gravitationally trapped fireshell (halo) around the horizon of a black hole. The fireshell is metastable, cooling via UHE particle emissions and blackbody radiation. We calculate the UHE particle luminosity varying in time, and discuss the peculiar features of such produced UHE particles, which lead to VHE particles, in connection with possible numerical simulations, observations and experiments.

astro-ph.HE↗

arXiv2026

An Intertwined Short and Long GRB with 4-minute Separation

Gamma-ray bursts (GRBs), the most energetic transients in the Universe, are traditionally classified into long-duration ($T_{90}>2$ s) and short-duration ($T_{90}<2$ s) events, associated with the core collapse of massive stars (Type II) and the merger of compact binary systems (Type I), respectively. The two classes exhibit distinct observational properties that serve as key diagnostic criteria for classification. Here we report GRB 160425A, a peculiar event comprising two sub-bursts separated by four minutes: a short-duration burst ($G_1$) and a long-duration burst ($G_2$). Nearly all standard prompt-emission diagnostics, including pulse morphology, duration, hardness ratio, minimum variability timescale, spectral properties, and established empirical correlations, consistently categorize $G_1$ as a short-like (Type I, merger-origin) and $G_2$ as a long-like (Type II, collapsar-origin) GRB. The coexistence of merger and collapsar signatures in a single event challenges existing progenitor frameworks and calls for a re-evaluation of GRB classification schemes and progenitor scenarios.

astro-ph.HE↗

arXiv2025

Spacetime foam correlation renders the cosmological constant (dark energy)

Wheeler's spacetime foams (wormholes) at the Planck length undergo quantum nucleation, oscillation and annihilation. Their collective excitations over foamy spacetime interact with field operators at large distances. We describe such collective excitation and interaction using an effective ``foamon'' field coupled with field operators. The Wilson renormalisation group approach shows that the foamon field theory evolves from an infrared scaling invariant domain to an ultraviolet one, when numerous particles are present. In these domains, the foamon field induces an effective action of field operators, and its correlation length sets a natural scale. Applying this to cosmology, we obtain the effective Einstein action for the Ricci scalar and the cosmological constant (dark energy), including its equation of state and interaction with matter.

physics.gen-ph↗

arXiv2025

Muon anomalous magnetic moment and Right handed sterile neutrino

The muon's magnetic moment is a fundamental quantity in particle physics and the deviation of its value from quantum electrodynamics (QED), motivates research beyond the standard models (SM). In this study, we utilize the effective coupling of right-handed sterile neutrinos with SM gauge bosons to calculate the muon anomalous magnetic moment ($\boldsymbolμ$AMM) at one-loop level. The contribution of the sterile neutrino interactions on the $\boldsymbolμ$AMM is calculated by considering the standard and non-standard neutrino interactions. Our results show that the standard sterile neutrino interactions give a negligible contribution to $Δa_{\boldsymbolμ}$ while the non-standard neutrino interactions can play a significant role in explaining the muon $(g-2)$ anomaly. In the context of the non-standard neutrino interaction, our calculation shows that a Dirac mass scale $M_D$ around $100\,\text{GeV}$ could explain the muon anomaly if the right handed sterile neutrino's coupling with SM particles is about $\mathcal{G}_R\approx 10^{-3}$. We have also plotted the allowed region of the model parameters that satisfy the experimental data on $Δa_{\boldsymbolμ}^{SN}$ and discuss the percentage of the ${\boldsymbolμ}$ anomaly compensation in terms of the coupling constant $\mathcal{G}_R$.

hep-ph↗

arXiv2025

Collimated and spinning fireballs for ultra-relativistic jets: long vs short Gamma-ray bursts by angular momentum and mass ratio

In this study, we investigate the gravitational collapses of rotating stellar systems accounting for Gamma-Ray Burst jet progenitors. Based on the virial theorem of hadron collisional relaxations and Newtonian slow-rotating approximation, we analyze the conversion of gravitational binding energy into kinetic energy of hadrons, whose collisions produce photons and electron-positron pairs forming fireballs. Our qualitative analysis implies that rotation effects collimated and spinning fireballs with nontrivial angular momenta along the propagating direction, thus making ultra-relativistic jets. Results reveal the possible trends that the fireball becomes more collimated and the jet angle decreases as the total angular momentum and mass ratio $J/M$ of the slow-rotating collapsing core increases. Discussing the extrapolation of these trends to fast-rotating collapsing systems, we speculate that the ratio $J/M$ should be a key quantity for differentiating long bursts (massive core collapses) from short bursts (binary coalescence). We derive the intrinsic correlations of collimated fireball quantities that should be imprinted on a large sample of observed GRB data as empirical correlations.

astro-ph.HE↗

arXiv2025

Particle-antiparticle oscillation modes crossing horizon: baryogenesis and dark-matter waves

Quantum massive particle and antiparticle pair production and oscillation during reheating result in a holographic and massive pair plasma state. Perturbations in the densities of particles and antiparticles within this plasma form acoustic waves, characterized by symmetric and asymmetric density contrasts. By deriving the acoustic wave equations and identifying the frequencies of the lowest-lying perturbation modes (with zero wave number), the study shows that the wavelengths of these modes, when compared with the horizon size, suggest the possibility of superhorizon crossing during reheating. This crossing leads to particle-antiparticle asymmetry observable by an observer inside the horizon. The decay of massive particles and antiparticles into baryons generates a net baryon number, potentially explaining baryogenesis. The calculated baryon number-to-entropy ratio aligns with observational data. This crossing also accounts for dark matter particle-antiparticle asymmetry in the present Universe. The study also explores perturbation modes with nonzero wave numbers, representing dark-matter acoustic waves. These modes exited the horizon and re-entered after recombination, potentially imprinting on the matter power spectrum at large length scales and influencing the formation of large-scale structures and galaxies.

gr-qc↗

arXiv2024

Generation of the CMB cosmic Birefringence through Axion-like particles, Sterile and Active neutrinos

The cosmic birefringence (CB) angle refers to the rotation of the linear polarization plane of Cosmic Microwave Background (CMB) radiations when parity-violating theories are considered. We analyzed the Quantum Boltzmann equation for an ensemble of CMB photons interacting with the right-handed sterile neutrino dark matter (DM) and axion-like particles (ALPs) DM in the presence of the scalar metric perturbation. We used the birefringence angle of CMB to study those probable candidates of DM. It is shown that the CB angle contribution of sterile neutrino is much less that two other sources considered here. Next, we combined the results of the cosmic neutrinos' contribution and the contribution of the ALPs to producing the CMB birefringence and discussed the uncertainty on the parameter space of axions caused by the share of CMB-cosmic neutrino interaction in generating this effect. Finally, we plotted the EB power spectrum of the CMB and showed that this spectrum behaves differently in the presence of cosmic neutrinos and ALPs interactions in small $l$. Hence, future observed data for $C^{l}_{EB}$, will help us to distinguish the CB angle value due to the various sources of its production.

hep-ph↗

arXiv2024

Searching for exclusive leptoquarks with the Nambu-Jona-Lasinio composite model at the LHC and HL-LHC

We present a detailed study concerning a new physics scenario involving four fermion operators of the Nambu-Jona-Lasinio type characterized by a strong-coupling ultraviolet fixed point where composite particles are formed as bound states of elementary fermions at the scale $Λ={\cal O}(\text{TeV})$. After implementing the model in the Universal FeynRules Output format, we focus on the phenomenology of the scalar leptoquarks at the LHC and the High-Luminosity option. Leptoquark particles have undergone extensive scrutiny in the literature and experimental searches, primarily relying on pair production and, more recently, incorporating single, t-channel, and lepton-induced processes. This study marks, for the first time, the examination of these production modes at varying jet multiplicities. Novel mechanisms emerge, enhancing the total production cross-section, especially for leptoquarks couplings to higher fermion generations. A global strategy is devised to capture all final state particles produced in association with leptoquarks or originating from their decay, which we termed ``exclusive'', in an analogy to the nomenclature used in nuclear reactions. The assessment of the significance in current and future LHC runs, focusing on the case of leptoquark coupling to a muon - $\textit{c}$ quark pair, reveals superior sensitivity compared to ongoing searches. Given this heightened discovery potential, we advocate the incorporation of exclusive leptoquark searches in future investigations at the LHC.

hep-ph↗

arXiv2024

Holographic massive plasma state in Friedman Universe: cosmological fine-tuning and coincidence problems

Massive particle and antiparticle pair production and oscillation on the horizon form a holographic and massive pair plasma state in the Friedman Universe. Via this state, the Einstein cosmology term (dark energy) interacts with matter and radiation and is time-varying $\tildeΛ$ in the Universe's evolution. It is determined by a close set of ordinary differential equations for dark energy, matter, and radiation energy densities. The solutions are unique, provided the initial conditions given by observations. In inflation and reheating, dark energy density decreases from the inflation scale, converting to matter and radiation energy densities. In standard cosmology, matter and radiation energy densities convert to dark energy density, reaching the present Universe. By comparing with $Λ$CDM, quintessence and dark energy interacting models, we show that these results can be the possible solutions for cosmological fine-tuning and coincidence problems.

gr-qc↗

arXiv2024

Dark energy and matter interacting scenario to relieve $H_0$ and $S_8$ tensions

We consider a new cosmological model (called $\tildeΛ$CDM) in which the vacuum energy interacts with matter and radiation, and test this model using the current cosmological observations. Using the CMB+BAO+SN (CBS) dataset to constrain the model, we find that $H_0$ and $S_8$ tensions are relieved to $2.87σ$ and $2.77σ$, respectively. However, in this case, the $\tildeΛ$CDM model is not favored by the data, compared with $Λ$CDM. We find that when the $H_0$ and $S_8$ data are added to the data combination, the situation is significantly improved. In the CBS+$H_0$ case, the model relieves the $H_0$ tension to $0.47σ$, and the model is favored over $Λ$CDM. In the CBS+$H_0$+$S_8$ case, we obtain a synthetically best situation, in which the $H_0$ and $S_8$ tensions are relieved to $0.72σ$ and $2.11σ$, respectively. In this case, the model is most favored by the data. Therefore, this cosmological model can greatly relieve the $H_0$ tension and simultaneously effectively alleviate the $S_8$ tension.

astro-ph.CO↗

arXiv2023

Constraints on NJL four-fermion effective interactions from neutrinoless double beta decay

We study the contribution of a heavy right-handed Majorana neutrino to neutrinoless double beta decay ($0νββ$) via four-fermion effective interactions of Nambu-Jona-Lasinio (NJL) type. In this physical scenario, the sterile neutrino contributes to the nuclear transition through gauge, contact, and mixed interactions. Using the lower limit on the half-life of $0νββ$ from the KamLAND-Zen experiment, we then constrain the effective right-handed coupling between the sterile neutrino and the $W$ boson: $\mathcal{G}^{W}_{R}$. Eventually, we show that the obtained bounds are compatible with those found in the literature, which highlights the complementarity of this type of phenomenological study with high-energy experiments.

hep-ph↗

arXiv2023

Massive particle pair production and oscillation in Friedman Universe: reheating energy and entropy, and cold dark matter

Suppose that the early Universe starts with a cosmological $Λ$-term originating from quantum spacetime at the Planck scale. Dark energy drives inflation and reheating by reducing its value for massive particle-antiparticle pairs production and oscillation, resulting in a holographic and massive pair plasma state. The back-and-forth reaction of dark energy and massive pairs slows inflation to its end and starts reheating by rapidly producing stable and unstable pairs. We introduce the Boltzmann-type rate equation describing the back-and-forth reaction. It forms a close set with Friedman equations and reheating equations for unstable pairs decay to relativistic particles. The numerical solutions show preheating, massive pairs dominated and genuine reheating episodes. We obtain the reheating temperature and entropy in terms of the tensor-to-scalar ratio $0 < r < 0.047$ consistently with observations. Stable massive pairs represent cold dark matter particles and weakly interact with dark energy. The resultant cold dark matter abundance $Ω_c\sim 10^{-1}$ is about a constant in time.

gr-qc↗

arXiv2023

Higgs boson origin from a gauge symmetric theory of massive composite particles and massless $W^\pm$ and $Z^0$ bosons at the TeV scale

The ultraviolet completion is the Standard Model (SM) gauge-symmetric four-fermion couplings at the high-energy cutoff. Composite particles appear in the gauge symmetric phase in contrast with SM particles in the spontaneous symmetry-breaking phase. The critical point between the two phases is a weak first-order transition. It relates to an ultraviolet fixed point for an SM gauge symmetric theory of composite particles in the strong coupling regime. The low-energy SM realizes at an infrared fixed point in the weak coupling regime. Composite bosons dissolve into SM particles at the phase transition, and in the top-quark channel, they become a composite SM Higgs boson and three Goldstone bosons. Extrapolation of SM renormalization-group solutions to high energies implies that the gauge-symmetric theory of composite particles has a characteristic scale of about $5.1$ TeV. We discuss the phenomenological implications of composite SM Higgs boson in the gauge symmetry-breaking phase and massive composite bosons coupling to massless $W^\pm$ and $Z^0$ gauge bosons in the gauge symmetric phase.

hep-ph↗

arXiv2023

Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

We study the classical Friedman equations for the time-varying cosmological term $\tildeΛ$ and Hubble function $H$, together with quantised field equations for the production of massive $M\gg H$ particles, namely, the $\tildeΛ$CDM scenario of dark energy and matter interactions. Classical slow components ${\mathcal O}(H^{-1})$ are separated from quantum fast components ${\mathcal O}(M^{-1})$. The former obeys the Friedman equations, and the latter obeys a set of nonlinear differential equations. Numerically solving equations for quantum fast components, we find the production and oscillation of massive particle-antiparticle pairs in microscopic time scale ${\mathcal O}(M^{-1})$. Their density and pressure averages over microscopic time do not vanish. It implies the formation of a massive pair plasma state in macroscopic time scale ${\mathcal O}(H^{-1})$, whose effective density and pressure contribute to the Friedman equations. Considering the inflation driven by the time-varying cosmological term and slowed down by the massive pair plasma state, we obtain the relation of spectral index and tensor-to-scalar ratio in agreement with recent observations. We discuss the singularity-free pre-inflation, the CMB large-scale anomaly, and dark-matter density perturbations imprinting on power spectra.

gr-qc↗