arXiv subjects

Bao-Dong Sun

Publications and source records attributed to Bao-Dong Sun.

13 recordsLinked to original sources

arXiv2025

Gravitational $p \to Δ^+ $ transition form factors in chiral perturbation theory

The proton to $Δ^+$ resonance transitional gravitational form factors are calculated to leading one-loop order using chiral perturbation theory in our recent work [1]. We take into account the leading electromagnetic and strong isospin-violating effects to obtain non-vanishing contributions. The loop contributions to the transition form factors are found to be free of power-counting violating pieces, which is consistent with the absence of tree-level diagrams at the considered order. Our results involve no free parameters and can be regarded as predictions of chiral perturbation theory.

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arXiv2023

Generalized parton distributions of $Δ$ resonance in a diquark spectator approach

The generalized parton distributions (GPDs) for the spin-3/2 $Δ^+$ resonance are studied numerically by using a diquark spectator approach. Our results show that symmetric constraints from time reversal on GPDs are satisfied. The axial vector form factors of the system are also provided and compared with the lattice QCD calculation. Furthermore, the structure functions are obtained from GPDs in the forward limit. The evolution of structure functions to the scales up to 4 GeV are carried out as predictions for the possible lattice QCD calculations.

hep-ph↗

arXiv2022

Generalized parton distributions in spin-3/2 particles

Generalized parton distribution functions (GPDs) of spin-3/2 particles are defined for the first time in this paper. Eight unpolarized and eight polarized GPDs are found. In the forward limit of GPDs, the structure functions and parton distribution functions are obtained. Then, the sum rules that connect the GPDs with the electromagnetic and gravitational form factors are explicitly displayed. Finally, the relations between GPDs and the helicity amplitudes of the system are derived.

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arXiv2022

Mechanical structure of a spin-1 particle

We investigate the mechanical structure of a spin-1 particle. Introducing three different frameworks, i.e., the three-dimensional (3D) Breit frame, the two-dimensional (2D) Breit frame, and the 2D infinite momentum frame (equivalently the two-dimensional Drell-Yan frame), we scrutinize the 2D and 3D energy-momentum tensor (EMT) distributions in these frames. We first derive the EMT distributions in the 2D Breit frame by performing the Abel transformation. The mass distribution in the 2D Breit frame contains an additional monopole contribution induced geometrically. The pressure distribution in the 2D Breit frame also gets an induced monopole structure. When the Lorentz boost is carried out, the mass distribution in the 2D infinite-momentum frame acquires the induced dipole term. Similarly, we also have the induced dipole contributions to the pressure and shear-force densities. We visualize the 2D mass distributions when the spin-1 particle is polarized along the $x$- and $z$-axes. We observe that the 2D mass distribution in the infinite momentum frame exhibit clearly the induced dipole structure when the spin-1 particle is polarized along the $x$-axis. We also discuss the strong force fields inside a polarized spin-1 particle.

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arXiv2022

Electromagnetic and gravitational form factors of $Δ$ resonance in a covariant quark-diquark approach

In this work, the electromagnetic and gravitational form factors of a spin-$3/2$ particle, $Δ$ resonance, are simultaneously calculated with the help of a relativistic covariant quark-diquark approach. The two kinds of form factors are separately extracted from the matrix elements of the electromagnetic current and of the energy-momentum tensor of the system. Our numerical results show that the approach can well reproduce the electromagnetic monopole, dipole, quadrupole, and octupole form factors comparing to the Lattice calculations. Our obtained electromagnetic moments are also comparable with some other approaches. Moreover, the obtained gravitational form factors, which give the mechanical properties of the system like the mass and spin distributions, are also displayed for the $Δ$ isobar. In addition, some discussions of the sign and the interpretation of the D-term are particularly given.

hep-ph↗

arXiv2021

Thermodynamics of the system of massive Dirac fermions in a uniform magnetic field

We construct the grand partition function of the system of massive Dirac fermions in a uniform magnetic field from Landau levels, through which all thermodynamic quantities can be obtained. Making use of the Abel-Plana formula, these thermodynamic quantities can be expanded as power series with respect to the dimensionless variable $b=2eB/T^{2}$. The zero-field magnetic susceptibility is expanded at zero mass, and the leading order term is logarithmic. We also calculate scalar, vector current, axial vector current and energy-momentum tensor of the system through ensemble average approach. Mass correction to chiral separation effect is discussed. For massless chiral fermions, our results recover the chiral magnetic effect for right- and left-handed fermions, as well as chiral separation effect.

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arXiv2020

Gravitational form factors of a baryon with spin-3/2

The energy-momentum tensor (EMT) for a spin-3/2 baryon is related to \emph{seven} mechanical quantities. In this work, we provide the general form of the gravitational form factors (GFFs) for a spin-3/2 baryon by using the multipole expansion and interesting relations between the EMT densities and the GFFs. To verify those general relations, we study the nucleon and the $Δ$ GFFs within the SU(2) Skyrme model based on the large $N_{c}$ limit.

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arXiv2020

Gravitational form factors of $ρ$ meson with a light-cone constituent quark model

The $ρ$ meson gravitational form factors are studied based on a light-front constituent quark model which has been successfully employed to calculate its generalized parton distributions and some low-energy observables. The distributions of energy, spin, pressures, and shear forces inside the $ρ$ meson are explicitly given.

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arXiv2019

Gravitational form factors of a spin one particle

We define the form factors of the quark and gluon symmetric energy-momentum tensor (EMT). The static EMT is related to the spatial distributions of energy, spin, pressure and shear forces. They are obtained in the form of a multipole expansion. The relations between gravitational form factors and the generalised parton distributions are given.

hep-ph↗

arXiv2019

Polarized GPDs and structure functions of $ρ$ meson

The $ρ$ meson polarized generalized parton distribution functions, its structure functions $g_1$ and $g_2$ and its axial form factors ${\tilde G}_{1,2}$ are studied based on a light-front quark model for the first time. Comparing our obtained moments of $g_1$ to lattice QCD calculation, we find that our results are reasonably consistent to the Lattice predictions.

hep-ph↗

arXiv2018

$Ω(2012)$ through the looking glass of flavour SU(3)

We perform the flavour $SU(3)$ analysis of the recently discovered $Ω(2012)$ hyperon. We find that well known (four star) $Δ(1700)$ resonance with quantum numbers of $J^P=3/2^-$ is a good candidate for the decuplet partner of $Ω(2012)$ if the branching for the three-body decays of the latter is not too large $\le 70$\%. That implies that the quantum numbers of $Ω(2012)$ are $I(J^P)=0(3/2^-)$. The predictions for the properties of still missing $Σ$ and $Ξ$ decuplet members are made. We also discuss the implications of the ${ \overline{ K} Ξ(1530)}$ molecular picture of $Ω(2012)$. Crucial experimental tests to distinguish various pictures of $Ω(2012)$ are suggested.

hep-ph↗

arXiv2018

$ρ$ meson impact parameter distributions

In this paper, the $ρ$ meson impact parameter dependent parton distributions and the impact parameter dependent form factors are introduced and discussed. By employing a Gaussian form wave packet, we calculate the impact parameter distributions of $ρ$ meson based on a light-front constituent quark model.

hep-ph↗

arXiv2017

$ρ$ meson unpolarized generalized parton distributions with a light-front constituent quark model

We study $ρ$ meson unpolarized generalized parton distributions based on a light-front constituent quark model where the quark-antiquark-meson vertex is constructed under the symmetric loop momentum convention. The form factors and some other low-energy observables of the $ρ$ meson are calculated. Moreover, the contributions to the form factors and generalized parton distributions from the valence and nonvalence regimes are discussed and analyzed in detail. In the forward limit, the usual structure functions are estimated as well. In addition, by evolving the moments of the obtained structure functions to the scale of the lattice calculation, we give the factorization scale of our quark model. It is found that the present phenomenological model is reasonable to describe the general properties of $ρ$ meson.

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