Searcharxiv⌕ Search

arXiv subjects

Jianhong Ruan

Publications and source records attributed to Jianhong Ruan.

At least 19 recordsLinked to original sources
arXiv2026

A Unified Explanation of Gamma-Ray and Neutrino Spectra from Astrophysical Sources Based on the Gluon Condensation Model

The advent of multi-messenger astronomy has provided abundant information for understanding the acceleration and particle-production mechanisms of cosmic rays. In this work, we present a unified study of cosmic gamma-ray and neutrino spectra within the Gluon Condensation (GC) model. Derived from Quantum Chromodynamics (QCD), the GC model predicts that, in high-energy hadronic processes, gluons may condense near a critical momentum, leading to a dramatic enhancement in secondary-pion production and imprinting a characteristic broken power-law feature on the gamma-ray spectrum. Within this framework, we first derive the neutrino spectrum corresponding to the GC scenario and then investigate three astrophysical sources with both gamma-ray observations and neutrino candidate signals: the active galactic nuclei TXS 0506+056 and NGC 1068, and the supernova remnant G54.1+0.3. Using the GC model, we fit the observed gamma-ray spectra of these sources and predict their corresponding neutrino spectra. Our results show that the gamma-ray spectra of TXS 0506+056 and NGC 1068 are well described by the GC model, and that the predicted neutrino spectra are consistent with IceCube observations within uncertainties; in particular, clear relations are found between their relative magnitudes. For SNR G54.1+0.3, however, the GC-predicted neutrino spectrum exhibits continuous hardening after the break, deviating from the typical power-law behavior expected for cosmic-ray secondaries and thus disfavoring a common GC origin. This study represents the first systematic attempt to correlate gamma-ray and neutrino spectra within the GC framework, offering a new perspective on multi-messenger emission from high-energy astrophysical sources.

astro-ph.HE↗
arXiv2026

Description of Charged\text{-}Particle Multiplicity Distributions in High\text{-}Energy Proton\text{-}Proton Collisions Based on a Two-Component Model and Examination of Parton Distribution Functions

High-energy proton-proton collisions at the LHC offer a stringent test of Quantum Chromodynamics (QCD) in the small-$x$, gluon-dominated regime. This study focus on a minimal, gluon-driven framework to describe the charged-particle multiplicities and their pseudorapidity densities in high energy collisions. The two-component model taken here includes the hard gluon-gluon fusion process and the soft quark recombination process, which directly relates to both integrated and unintegrated parton distributions. We begin by evolving Parton Distribution Functions (PDFs) using the Modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (MD-DGLAP) equations. These PDFs are then converted into unintegrated PDFs (UPDFs) via the Kimber-Martin-Ryskin (KMR) scheme. The resulting PDFs and UPDFs are incorporated into the two-component model to predict the charged-particle pseudorapidity density $\left(1 / N_{\mathrm{ev}}\right) d N_{\mathrm{ch}} / d η$ in $pp$ collisions at LHC energies. Our predictions are compared to the data from the ATLAS experiment, revealing that the model effectively captures the features of the observed pseudorapidity distributions, despite its simplicity. Within this framework, the gluon-gluon fusion processes are found to dominate particle production for $\sqrt { s } \ge 9 0 0 \ \mathrm { GeV }$.These findings provide phenomenological support for MD-DGLAP-based PDFs and the associated small-$x$ gluon dynamics. Furthermore,a comparative analysis of results from alternative PDF sets--including CTEQ, MSHT, NNPDF, HERAPDF, and GRV--is performed, with particular focus on examining their consistency with the relative shapes of experiment data in the small-$x$ region.

hep-ph↗
arXiv2025

Gluon Condensation as a Unifying Mechanism for Special Spectra of Cosmic Gamma Rays and Low-Momentum Pion Enhancement at the Large Hadron Collider

Decoding the internal structure of the proton is a fundamental challenge in physics. Historically, any new discovery about the proton has fuelled advances in several scientific fields. We have reported that gluons inside the proton accumulate near the critical momentum due to chaotic phenomena, forming gluon condensation. Surprisingly, the pion distribution predicted by this gluon distribution for the production of high-energy proton collisions could answer two puzzles in astronomy and high-energy physics. We find that during ultrahigh-energy cosmic ray collisions, gluon condensation may abruptly produce a large number of low-momentum pions, whose electromagnetic decays have the typical breakout properties appearing in various cosmic gamma-ray spectra. On the other hand, the Large Hadron Collider (LHC), which is well below the cosmic ray energy scale, also shows weak but recognisable signs of gluon condensation, which had been mistaken for BEC pions. The connection between these two phenomena, which occur at different scales in the Universe, supports the existence of a new structure within the proton-gluon condensation.

hep-ph↗
arXiv2024

Explaining muon excess in cosmic rays using the gluon condensation model

Ultrahigh-energy cosmic rays are often characterized indirectly by analyzing the properties of secondary cosmic ray particles produced in the collisions with air nuclei. The particle number $N_μ$ of muon and the depth of shower maximum $X_\mathrm{max}$ after air shower cascade are mostly studied to infer the energy and mass of the incident cosmic rays. Research have shown that there is a significant excess in the observed number of muons arriving at the ground from extensive air showers (EAS) compared to the simulations using the existing cosmic ray hadronic interaction model. To explain this muon excess phenomenon, a new theoretical model, the gluon condensation model (GC model), is introduced in this paper and simulated by using the AIRES engine. We assume that the GC effect appears mainly in the first collision of the cascade leading to a significant increase in the strangeness production, consequently, the production rate of kaons is increased and $n_K/n_π$ is greater than the value of the usual hadronic interaction process. In the calculation, the model assumes that only pions and kaons are produced in GC state. The increase of strange particle yield would mean that the energy transferred from the hadronic cascade to electromagnetic cascade through $π^{0} \rightarrow 2γ$ decay is reduced. This would in turn increase the number of muons at the ground level due to meson decays.Our model provides a new theoretical possibility to explain the muon excess puzzle.

astro-ph.HE↗
arXiv2024

A Collaborative Explanation of Cosmic Ray Spectrum Based on the Gluon Condensation Model

Based on the Gluon Condensation (GC) model, the relationship between the spectra of electrons, $γ$ rays, and neutrinos in cosmic rays can be deduced. It has been found that these particles share the same parameter, $β_p$, and have an identical GC threshold values. This paper explores the connection between the second excess spectra of electron and the spectra of gamma rays and neutrinos. According to the observed gamma-ray data, it is suggested that the source LHAASO J2108+5157 might contribute to the second excess of electron.

astro-ph.HE↗
arXiv2022

Warning: The mini gamma-ray-bursts in planning hadron colliders beyond the LHC energies

Gluons may converge to a stable state at a critical momentum in nucleon. This gluon condensation will greatly increase the proton-proton cross section provided that the collision energies exceed the gluon condensation threshold. Based on the analyses of cosmic gamma-ray spectra, we find that the $p-Pb$ and $Pb-Pb$ collisions at the LHC are close to the energy region of the gluon condensation effect. We warn that for the next generation of hadron colliders increasing the collision energies, the extremely strong gamma-rays will be emitted in a narrow space of the accelerator due to the gluon condensation effect. Such artificial mini gamma-ray-bursts in the laboratory may damage the detectors.

hep-ph↗
arXiv2022

The gluon condensation in hadron collisions

Gluons may converge to a stable state at a critical momentum in hadrons. This gluon condensation is predicted by a nonlinear QCD evolution equation. We review the understanding of the gluon condensation and present a clear physical picture that produces the gluon condensation from the colour glass condensate. We summarize the applications of the GC effect in the $p-p(A)$ collisions and predict that the $p-Pb$ and $Pb-Pb$ collisions at the LHC are close to the energy region of the gluon condensation. We warn that for the next generation of hadron colliders with the increasing of the collision energy, the extremely strong gamma-rays will be emitted in a narrow space of the accelerator due to the gluon condensation effect. Such artificial mini gamma-ray bursts in the laboratory may damage the detectors.

hep-ph↗
arXiv2021

The current recorded signals of ultrahigh-energy $γ$-rays may come from EeVatrons in the galaxy

A hard $γ$-ray spectrum of supernova remnant G106.3+2.7 can be explained by using the hadronic model with the gluon condensation effect. This implies that not only PeVatrons but also EeVatrons generally exist in the universe including our galaxy, and they can accelerate protons to beyond "ankle" ($10^{19}~eV$). Although these proton beams are very weak in the galaxy and cannot be observed individually on the earth, the gluon condensation effect may greatly enhance the proton-proton cross section, which can compensate for the weak proton flux and produce the observed $γ$-rays. We also show that the gluon condensation effect in proton provides an efficient conversion mechanism for kinetic energy into $γ$-rays in the universe.

astro-ph.HE↗
arXiv2020

Looking for the possible gluon condensation signature in sub-TeV gamma-ray spectra: from active galactic nuclei to gamma ray bursts

The gluon condensation in the proton as a dynamical model is used to treat a series of unsolved puzzles in sub-TeV gamma ray spectra, they include the broken power-law of blazar's radiation, the hardening confusion of 1ES 1426+428, Mkn 501, and the recently recorded sub-TeV gamma spectra of GRB 180720B and GRB 190114C. We find that the above anomalous phenomena in gamma ray energy spectra can be understood with the simple broken power law based on a QCD gluon condensation effect.

astro-ph.HE↗
arXiv2020

Anomalous bremsstrahlung and the structure of cosmic ray electron-positron fluxes at the GeV-TeV energy range

We reveal that the energy spectra of electrons-positrons in primary cosmic rays measured at atmosphere top have double structures: an excess component $Φ^s_{e^+}(E)=Φ^s_{e^-}(E)$ around $400 GeV$, which origins from a strong $e^+e^-$-source and the distorted background $Φ^0_{e^-}(E)$. We supposed that the difference between AMS-CALET and Fermi-LAT-DAMPE data origins from the energy loss of the fluxes due to the anomalous bremsstrahlung effect at a special window. The evolution of spectra under anomalous bremsstrahlung effect satisfies an improved electromagnetic cascade equation. The above spectra are parameterized and they can be regarded as the subjects exploring new physics. We suggest to check the previous applications of the Bethe-Heitler formula in the study of the propagation of high energy electrons and photons.

astro-ph.HE↗
arXiv2019

A speculation about a puzzled result in energy spectrum of cosmic-ray electrons around TeV energies

Nuclear Coulomb potential at completely ionized and extremely thin atmosphere can leaks to a macroscopic spatial scale. This effect is used to explain the difference between the energy spectra of cosmic-ray electrons around $1 TeV$ measured by different experimental groups. The result inspires us to review the traditional electromagnetic shower theory at the extreme conditions. It is also reminds us that the energy spectrum of cosmic-ray electrons, which are measured by Fermi-LAT and DAMPE at a higher altitude is more closer to a true signature.

astro-ph.HE↗
arXiv2018

Looking for the gluon condensation signature in proton using the Earth limb gamma-ray spectra

A new type of gamma ray spectrum is predicted in a general hadronic framework if considering the gluon condensation effects in proton. The result presents the power-law with a sharp break in the gamma ray spectra at the TeV-band. We suggest to probe this GC-signature in the Earth limb gamma-ray spectra using the DArk Matter Particle Explorer and the CALorimetric Electron Telescope on orbit.

hep-ph↗
arXiv2018

Understanding the electromagnetic 4-potential in the tetrad bundle

Separation of the spin and orbital angular momenta of the electromagnetic field has been discussed frequently in recent years. The spin and orbital angular momenta cannot be made simultaneously gauge invariant and Lorentz covariant and are not conserved separately. After analyzing the source of the problem, we find that the electromagnetic 4-potential depends on the local reference frame instead of the global reference frame. The transformation of the local reference frame is the intrinsic degree of freedom of the electromagnetic field. Therefore, considering only the Lorentz transformation of the global reference frame and neglecting the Lorentz transformation of the local reference frame may lead to the noncovariance of the electromagnetic 4-potential. Accordingly, we redescribe these difficulties of the electromagnetic field from the perspective of quantum field theory. By using the behavior of the electromagnetic 4-potential that satisfies the Coulomb gauge in Lorentz coordinate transformation, we can construct the electromagnetic vector in the tetrad bundle. The various physical quantities that are induced by this electromagnetic vector satisfy Lorentz covariance in the tetrad bundle. This electromagnetic vector, which is projected onto space-time, is an electromagnetic 4-potential that satisfies the Coulomb gauge; thus, the electromagnetic vector is gauge invariant.

physics.class-ph↗
arXiv2018

The Gluon condensation in high energy cosmic rays

The gluon condensation (GC)-effects in high energy cosmic rays are investigated. After a brief review of the GC, several examples including gamma-, electron-, and positron-spectra in a broad GeV$\sim $TeV region can be explained by the GC-effects. We find that the GC may break the power-law of the cosmic ray spectra if the energy of accelerated protons exceeds the GC-threshold. The GC is a new phenomenon that is not yet known, it provides a new window to understand the high energy cosmic ray spectra.

hep-ph↗
arXiv2017

Looking for quark saturation in proton and nuclei

The quark saturation behavior at low $Q^2$ is shown in a numeric solution of the DGLAP equation with parton recombination corrections, which resembles the widely discussed JIMWLK saturation of gluons. Our calculation suggests that the partonic saturation can be interpreted as a dynamical balance between the splitting and the fusion processes of partons, without any other condensation mechanisms added. The nuclear shadowing saturation at small $x$ resulted from the proposed quark saturation is also discussed.

hep-ph↗
arXiv2016

Partonic structure of proton in the resonance region

We separate the contributions of parton distributions from higher twist corrections to the deeply inelastic lepton-proton scattering in the resonance region using the Jefferson Lab data at low $Q^2$. The study indicates that the concept of the valence quarks and their distributions are indispensable even at $Q^2<1GeV^2$. The quark-hadron duality is also discussed.

hep-ph↗
arXiv2016

The chaotic effects in a nonlinear QCD evolution equation

The corrections of gluon fusion to the DGLAP and BFKL equations are discussed in a united partonic framework. The resulting nonlinear evolution equations are the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the available saturation models as input, we find that the new evolution equation has the chaos solution with positive Lyaponov exponents in the perturbative range. We predict a new kind of shadowing caused by chaos, which blocks the QCD evolution in a critical small $x$ range. The blocking effect in the evolution equation may explain the Abelian gluon assumption and even influence our expectations to the projected Large Hadron Electron Collider (LHeC), Very Large Hadron Collider (VLHC) and the upgrade (CppC) in a circular $e^+e^-$ collider (SppC).

hep-ph↗