Few-Body Systems最新文献

The objective of this work is to study the motion of an infinitesimal particle in the gravitational field of three big bodies in a ring configuration consisting of two peripheral and one central bodies, when the energy of the particle does not allow the escape from the potential well of the system. We have numerically determined the basins of escape using a new surface of section. Additionally, we have computed and analyzed the geometry of the set of asymptotic trajectories of the periodic orbit that governs the escape from the neighborhood of one of the two satellites, which also defines the limiting curves of the basins of escape from this region.

A novel approach is introduced for obtaining precise solutions of the pairing Hamiltonian for tetraquarks, which utilizes an algebraic technique in infinite dimensions. The parameters involved in the transition phase are calibrated based on potential tetraquark candidates derived from phenomenology. Our investigation shows that the rotation and vibration transitional theory delivers a reasonable agreement with other works for heavy tetraquarks compared to other methods. To illustrate the concept, we compute the spectra of several tetraquarks, namely charm, bottom, bottom–charm and open charm and bottom systems, and contrast them with those of other particles.

We consider a light-front dressed quark state, per se, instead of a proton state, we consider a simple composite spin-1/2 state of a quark dressed with a gluon. This perturbative model incorporates gluonic degrees of freedom, which enable us to evaluate the gravitational form factors (GFFs) of the quark as well as the gluon in this model (More et al. Phys Rev D 105(5):056017, 2022. arXiv:2112.06550, https://doi.org/10.1103/PhysRevD.105.056017; Gluon contribution to the mechanical properties of a dressed quark in light-front Hamiltonian QCD, 2023. arXiv:2302.11906). We employ the Hamiltonian framework and choose the light-front gauge (A^+=0). We calculate the four GFFs and corroborate the sum rules that GFFs satisfy. The GFF DD is attributed to information like pressure, shear, and energy distributions. We analyze some of these distributions for a dressed quark state at one loop in QCD.

Strange quark production in relativistic heavy-ion collisions is used as a diagnostic tool as well as a signature for QGP formation. Strong interactions in the QGP medium generate strange quarks and antiquarks which don’t exist in normal matter. The reason being shortly after their production, they undergo decay via weak interactions. Its unique mass which is expected close to the temperature at which protons, neutrons and other hadrons turn into quarks. Hence, these strange quarks, antiquarks are sensitive to the conditions, structure and dynamics of the deconfined state of matter. It can be said that the deconfined state is reached if there is an abundance of strange quarks. In this proceedings we are going to discuss about the different hyperon yields ((Lambda , Xi , Omega )) calculated using AMPT and UrQMD model.

A minimal truncated set of the integral Dyson–Schwinger equations, in Minkowski spacetime, that allows to explore QED beyond its perturbative solution is derived for general linear covariant gauges. The minimal set includes the equations for the fermion and photon propagators, the photon-fermion vertex, and the two-photon-two-fermion one-particle-irreducible diagram. If the first three equations are exact, to build a closed set of equations, the two-photon-two-fermion equation is truncated ignoring the contribution of Green functions with large number of external legs. It is shown that the truncated equation for the two-photon-two-fermion vertex reproduces the lowest-order perturbative result in the limit of the small coupling constant. Furthermore, this equation allows to define an iterative procedure to compute higher order corrections in the coupling constant. The Ward–Takahashi identity for the two-photon-two-fermion irreducible vertex is derived and solved in the soft photon limit, where one of the photon momenta vanish, in the low photon momenta limit and for general kinematics. The solution of the Ward–Takahashi identity determines the longitudinal component of the two-photon-two-fermion irreducible vertex, while it is proposed to use the Dyson–Schwinger equation to determine the transverse part of this irreducible diagram. The two-photon-two-fermion DSE is solved in heavy fermion limit, considering a simplified version of the QED vertices. The contribution of this irreducible vertex to a low-energy effective photon-fermion vertex is discussed and the fermionic operators that are generated are computed in terms of the fermion propagator functions.

In this paper, we have obtained the analytical and numerical mass spectra of the charmonium and bottomonium mesons using the non-relativistic Schrödinger equation under a spin–spin, spin–orbit and tensor coupled Cornell potential energy. We adopted the Wentzel–Kramers–Brilluoin approximation method to obtain the energy bound equation in closed form. We obtained the potential free parameters by fitting the mass spectra equation to the experimental data of the Particle Data Group. The hyperfine mass splitting of the mesons are obtained for different singlet ((s=0)) and triplet ((s=1)) quantum states ((n^{2s+1}l_{j})). Also, the hyperfine multiplet splitting for (l>0) and total angular momentum quantum number (j=l, j=lpm 1) were obtained. The results revealed that the charmonium masses (psi (n^{3}S_{1})) and (eta _{c}(n^{1}S_{0})) ((n=2, 3,4,5,6)) and bottomonium masses ((eta _{b}(n^{1}S_{0}))) and (Upsilon (n^{3}S_{1})) ((n=2, 3, 4, 6)) for the s-wave quantum states are in good agreement with the results obtained by other methods in the existing literature and available experimental data. For (l>0), the charmonia masses (chi _{c_{j}}(n^{3}P_{j})) (psi _{1}left( {1^{3}D}_{1} right) ) and (psi _{2}left( {2^{3}D}_{1} right) ) agreed with the works obtained using other potential models and observed data. In comparison to experimental data, the total absolute deviation error of 3.21% and 1.06% was obtained for the respective charmonium and bottomonium masses. The proposed potential model provides a satisfying account for the mass spectra of the heavy mesons and may be extended to study other spectroscopic parameters.

We introduce an exactly soluble model for a fermion-antifermion pair exposed to magnetic flux in the hyperbolic wormhole. This model is based on an analytical solution of the corresponding two-body Dirac equation. We show a non-perturbative wave equation for such a pair in exactly soluble form. This makes it possible to acquire a complete energy spectrum. Results clearly show the effects of the magnetic flux as well as the wormhole background on the dynamics of the considered pair and such a composite system may behave as a single fermion or a single boson by depending on the magnetic flux. This implies that one can control the dynamics of such a pair in an optical background with constant negative Gaussian curvature.

Outstanding vertexing performance and low-background environment are key enablers of a systematic Belle II program targeted at measurements of charm baryon lifetimes. Recent results from measurements of the (varLambda _{c}^{+}) and (varOmega _{c}^{0}) baryon lifetimes are presented. The former result is the most precise to date.

Within the framework of the Dyson-Schwinger/Bethe-Salpeter equations of quantum chromodynamics, we investigate the electromagnetic form factors of pseudoscalar and vector mesons with different hidden-flavor, from light to heavy quark sectors, and compare the results with those of the single-pole vector meson dominance (VMD) model. It is found that the charge radius of vector meson is larger than that of its pseudoscalar counterpart. As the current-quark mass increases, the electric form factor of the vector meson tends to approach that of its pseudoscalar counterpart, and gradually deviates from the prediction of the VMD model.

Chiral symmetry and its spontaneous breaking is an essential property of the QCD vacuum and is closely related to the generation of hadron mass. J-PARC E16 experiment measures dielectron spectra in p+A collisions at 30 GeV to study the in-medium spectral change of vector mesons that signals the partial restoration of the broken symmetry. The experiment uses the primary proton beam available at the high-momentum beam line of the J-PARC hadron experimental facility. We performed three proton-beam runs intended for beamline and detector commissioning. We are preparing for the next commissioning run in 2023 and the first physics run. We present the experimental setup, some of the expected results, preparation status, and some findings in the commissioning runs.