Ground-state Vector Mesons Research Articles

Predictions of the missing excited vector heavy–light mesons: the mass difference method

A prediction study for the not yet discovered cs¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c\\overline{s}$$\\end{document} and bs¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$b\\overline{s}$$\\end{document} meson states of the 13D1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1^{3}D_1$$\\end{document} quantum numbers is conducted, denoted as Ds\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_s$$\\end{document} and Bs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B_s$$\\end{document}, respectively. By employing our method, both states of ground and excited vector mesons are considered, which predominantly correspond to the ground state vector mesons with quantum numbers n2S+1LJ=13S1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n~ ^{2S+1}L_{J} = 1 ~ ^{3}S_1$$\\end{document} and to the orbitally excited vector mesons with quantum numbers n2S+1LJ=13D1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n~ ^{2\\,S+1}L_{J} = 1~ ^{3}D_1$$\\end{document}. The considered method depends on the difference in the masses for the relevant states from orbitally and ground state vector mesons. Theoretical calculations are in good agreements with newly published data.

Excited vector mesons: phenomenology and predictions for a yet unknown vector ss state with a mass of about 1.93 GeV

The firm understanding of standard quark-antiquark states (including excited states) is necessary to search for non-conventional mesons with the same quantum numbers. In this work, we study the phenomenology of two nonets of excited vector mesons, which predominantly correspond to radially excited vector mesons with quantum numbers n2S+1LJ = 23S1 and to orbitally excited vector mesons with quantum numbers n2S+1LJ = 13D1. We evaluate the decays of these mesons into two pseudoscalar mesons and into a pseudoscalar and a ground-state vector meson by making use of a relativistic quantum field theoretical model based on flavor symmetry. Moreover, we also study the radiative decays into a photon and a pseudoscalar meson by using vector meson dominance. We compare our results to the PDG and comment on open issues concerning the corresponding measured resonances. Within our approach, we are also able to make predictions for a not-yet discovered ss state in the n2S+1LJ = 13D1 nonet, which has a mass of about 1.93 GeV. This resonance can be searched in the upcoming GlueX and CLAS12 experiments which take place at the Jefferson Lab.

On Radiative Decay of Heavy Vector Mesons <i>V</i> → <i>Pγ</i> in the Scalar Strong Interaction Hadron Theory

Radiative decay of heavy ground state vector meson V → Pγ is treated semi-classically in the scalar strong interaction hadron theory. The treatment successfully employs the new wave function of the vector meson updated here. The ratio of the available J/ψ and decay rates agrees with prediction. The values of the predicted rates are also in order of magnitude agreement with measurements. These agreements are the only ones directly computed from a first principles’ theory.

Strong and radiative decays of excited vector mesons and predictions for a new ϕ(1930) resonance

We study the phenomenology of two nonets of excited vector mesons, $\{\rho(1450)$, $K^{\ast}(1410)$, $\omega(1420)$, $\phi(1680)\}$ and $\{\rho(1700),$ $K^{\ast}(1680),\omega(1650),$ $\phi(???)\},$ which (roughly) correspond to radially excited $2^{3}S_{1}$ and to orbitally excited $1^{3}D_{1}$ vector mesons. We evaluate the strong and radiative decays of these mesons into pseudoscalar and ground-state vector mesons by using an effective relativistic QFT model based on flavour symmetry. We compare decay widths and branching ratios with various experimental results listed in the PDG. An overall agreement of theory with experiment reinforces the standard quark-antiquark assignment of the resonances mentioned above. Predictions for not yet measured quantities are also made. In particular, we shall also make predictions for the not-yet discovered $s\bar{s}$ state of the $1^{3}D_{1}$ nonet, denoted as $\phi(???)$. Its mass can be estimated to be about $1930$ MeV, hence we shall call this putative state $\phi(1930).$ Its main decays are into $KK^{\ast}(892)$ (about $200$ MeV) and $KK$ (about $100$ MeV). Since this state couples also to $\gamma\eta,$ it can be searched in the near future in the photoproduction-based experiments GlueX and CLAS12 at Jefferson Lab.

Strong Decays of Excited Vector Mesons

We study two nonets of excited vector mesons, predominantly corresponding to radially excited vector mesons with quantum numbers $n\hspace{0.08cm} ^{2S+1}L_{J}$ $=2^3S_1$ and to orbitally excited vector mesons with quantum numbers $n\hspace{0.08cm} ^{2S+1}L_{J}=1^3D_1$. We evaluate two types of decays of these mesons: into two pseudoscalar mesons and into a pseudoscalar and a ground-state vector meson. We compare the results with experimental data taken from PDG. We also make predictions for the strange-antistrange state in the $1^3D_1$ nonet denoted as $\phi(1930)$, which has not yet been discovered.

Magnetic properties of ground-state mesons

Starting with the bag model a method for the study of the magnetic properties (magnetic moments, magnetic dipole transition widths) of ground-state mesons is developed. We calculate the M1 transition moments and use them subsequently to estimate the corresponding decay widths. These are compared with experimental data, where available, and with the results obtained in other approaches. Finally, we give the predictions for the static magnetic moments of all ground-state vector mesons including those containing heavy quarks. We have a good agreement with experimental data for the M1 decay rates of light as well as heavy mesons. Therefore, we expect our predictions for the static magnetic properties (usual magnetic moments) to be of sufficiently high quality, too.

Relevance of various Dirac covariants in hadronic Bethe-Salpeter wave functions in electromagnetic decays of ground state vector mesons

In this work we have employed Bethe-Salpeter equation (BSE) under covariant instantaneous ansatz (CIA) to study electromagnetic decays of ground state equal mass vector mesons: $\rho$, $\omega$, $\phi$, $\psi$ and $Y$ through the process $V\rightarrow\gamma*\rightarrow e^+ + e^-$. We employ the generalized structure of hadron-quark vertex function $\Gamma$ which incorporates various Dirac structures from their complete set order-by-order in powers of inverse of meson mass. The electromagnetic decay constants for the above mesons are calculated using the leading order (LO) and the next-to-leading order (NLO) Dirac structures. The relevance of various Dirac structures in this calculation is studied.

Vector meson form factors and their quark-mass dependence

The electromagnetic form factors of vector mesons are calculated in an explicitly Poincar\'e covariant formulation, based on the Dyson-Schwinger equations of QCD, that respects electromagnetic current conservation and unambiguously incorporates effects from vector meson poles in the quark-photon vertex. This method incorporates a two-parameter effective interaction, where the parameters are constrained by the experimental values of chiral condensate and ${f}_{\ensuremath{\pi}}$. This approach has successfully described a large amount of light-quark meson experimental data, including ground-state pseudoscalar masses and their electromagnetic form factors and ground-state vector meson masses and strong and electroweak decays. Here we apply it to predict the electromagnetic properties of vector mesons. The results for the static properties of the \ensuremath{\rho} meson are as follows: charge radius $\ensuremath{\langle}{r}_{\ensuremath{\rho}}^{2}\ensuremath{\rangle}=0.54\phantom{\rule{0.3em}{0ex}}{\mathrm{fm}}^{2}$, magnetic moment $\ensuremath{\mu}=2.01$, and quadrupole moment $\mathcal{Q}=\ensuremath{-}0.41$. We investigate the quark-mass dependence of these static properties and find that our results at the charm quark mass are in agreement with recent lattice simulations. The charge radius decreases with increasing quark mass, but the magnetic moment is almost independent of the quark mass.

Vector dominance, q2 dependence and radial excitations

An extended vector meson dominance model which includes both radial excitations of the vector mesons, and q 2 dependence of the photon-vector meson coupling is applied to radiative decays and photoproduction of the vector mesons. The parameters estimated from Ψ radiative decay, define a phenomenological prescription in which the radiative excitations play a minor role compared with the ground state vector mesons. Various predictions are made for cross sections and decay widths.