arXiv subjects

P. Suebka

Publications and source records attributed to P. Suebka.

7 recordsLinked to original sources

arXiv2015

Meson cloud contributions to baryon axial form factors

The axial form factor as well as the axial charge of octet baryons are studied in the perturbative chiral quark model (PCQM) with the quark wave functions predetermined by fitting the theoretical results of the proton charge form factor to experimental data. The theoretical results are found, based on the predetermined quark wave functions, in good agreement with experimental data and lattice values. This may indicate that the electric charge and axial charge distributions of the constituent quarks are the same. The study reveals that the meson cloud plays an important role in the axial charge of octet baryons, contributing 30%-40% to the total values, and strange sea quarks have a considerable contribution to the axial charge of the $Σ$ and $Ξ$.

hep-ph↗

arXiv2009

Electron-Positron to Nucleon-Antinucleon Pair at Threshold and Proton Form Factor

The reactions of electron-positron to nucleon-antinucleon pair at energy threshold are studied in a non-perturbative quark model. The puzzling experimental result that the ratio of the cross section of electron-positron to proton-antiproton to the one of electron-positron to neutron-antineutron is smaller than 1 can be understood in the framework of the phenomenological nonrelativistic quark model and the theoretical predictions for the time-like proton form factor at energy threshold are well consistent with the experimental data. The work suggests that the two-step process, in which the primary quark-antiquark pair forms first a vector meson which in turn decays into a hadron pair, is dominant over the one-step process in which the primary quark-antiquark pair is directly dressed by additional quark-antiquark pairs to form a hadron pair. The experimental data on the reactions of electron-positron to nucleon-antinucleon strongly suggest the reported vector meson omega(1930) to be a 2D-wave particle, while the vector meson rho(2000) is preferred to be a mixture of 3S and 2D states.

hep-ph↗

arXiv2008

Reaction of electron-positron to omega and pi mesons and rho(1450) and rho(1700) mesons in quark model

The investigation in the work of the reaction electron-positron to omega and pi0 mesons in the 3P0 nonrelativistic quark model reveals that the reaction electron-positron to omega and pi0 mesons process at the energy region from the omega and pi mesons threshold to 2.0 GeV is dominated by the two-step process in which the primary quark-antiquark pair first forms rho and rho' mesons and then the vector mesons decay into omega and pi. With rho(1450) and rho(1700) mainly in 2S and 1D states respectively, the experimental data for the cross section of the reaction electron-positron to omega and pi0 mesons are well produced in the 3P0 quark model. The work supports the argument that rho(1450) is mainly a 2S meson and rho(1700) a 1D meson.

hep-ph↗

arXiv2008

Antiproton-deuteron atoms in models of realistic potentials

The antiproton-deuteron atoms are studied in models of various realistic, popular nucleon-antinucleon potentials. The small energy shifts and decay widths of the atoms, which stem from the short-ranged strong interactions between the antiproton and deuteron, are evaluated in a well-established, accurate approach based on the Sturmian functions. The investigation reveals that none of the employed potentials, which reproduce the nucleon-antinucleon scattering data quite well, is able to reproduce the experimental data of the energy shifts of the 2p antiproton-deuteron atomic states. The energy shifts of the 2p antiproton-deuteron atomic states are very sensitive to the nucleon-antinucleon strong interactions, hence the investigation of the antiproton-deuteron atoms is expected to provide a good platform for refining the nucleon-antinucleon interaction, especially at zero energy.

physics.atom-ph↗

arXiv2007

Bottom Baryon Decays in Non-relativistic Quark Model

The reactions $Σ_b^* \to Λ_b π$, $Σ_b \to Λ_b π$, and $Ξ_b^* \to Ξ_b π$ are studied in the $^3P_0$ non-relativistic quark model with all the model parameters fixed in the sector of light quarks. The theoretical predictions for the decay widths $Γ_{Σ_b^* \to Λ_b π}$ and $Γ_{Σ_b \to Λ_b π}$ are consistent with the experimental data of the CDF Collaboration. Using as an input the recent mass of $Ξ_b$ and the theoretical predictions mass of $Ξ_b^{*}$, a narrow decay width about 1 MeV is predicted for the bottom baryon $Ξ_b^*$. The work suggests that the $^3P_0$ quark dynamics is of independence of environments where heavy quarks may or may not be a component of baryons.

hep-ph↗

arXiv2004

Electron-Positron Annihilation into Hadron-Antihadron Pairs

The reactions of electron-positron to nucleon-antinucleon pairs are studied in a non-perturbative quark model. The work suggests that the two-step process, in which the primary quark-antiquark pair forms first a vector meson which in turn decays into a hadron pair, is dominant over the one-step process in which the primary quark-antiquark pair is directly dressed by additional quark-antiquark pairs to form a hadron pair. To reproduce the experimental data of the reactions of electron-positron to proton-antiproton and electron-positron to neutron-antineutron a D-wave omega-like vector meson with a mass of around 2 GeV has to be introduced.

hep-ph↗

arXiv2004

Photon number emission in synchrotron radiation: Systematics for high-energy particles

A recent derivation of an explicit elementary expression for the mean number $ $ of photons emitted per revolution in synchrotron radiation allows a systematic high-energy analysis leading to the result $ \simeq 5πα/\sqrt{3(1-β^2)}+a_0α+πα\sqrt{1-β^2}/10\sqrt{3}$ where $a_0$ is a constant, with relative errors of 2.2%, 0.64%, 0.017%, in comparison to the well-known formula tabulated in the literature of 160%, 82%, 17% for $β=0.8$, 0.9, 0.99, respectively.

hep-ph↗