Properties Of Heavy Quarkonia Research Articles

Properties and Behaviors of Heavy Quarkonia: Insights through Fractional Model and Topological Defects

In this study, we investigated the impact of a topological defect (λ) on the properties of heavy quarkonia using the extended Cornell potential. We solved the fractional radial Schrödinger equation (SE) using the extended Nikiforov-Uvarov (ENU) method to obtain the eigenvalues of energy, which allowed us to calculate the masses of charmonium and bottomonium. One significant observation was the splitting between nP and nD states, which attributed to the presence of the topological defect. We discovered that the excited states were divided into components corresponding to 2l+1, indicating that the gravity field induced by the topological defect interacts with energy levels like the Zeeman effect caused by a magnetic field. Additionally, we derived the wave function and calculated the root-mean radii for charmonium and bottomonium. A comparison with the classical models was performed, resulting in better results being obtained. Furthermore, we investigated the thermodynamic properties of charmonium and bottomonium, determining quantities such as energy, partition function, free energy, mean energy, specific heat, and entropy for P-states. The obtained results were found to be consistent with experimental data and previous works. In conclusion, the fractional model used in this work proved an essential role in understanding the various properties and behaviors of heavy quarkonia in the presence of topological defects.

Hadrons at high temperature: An update from the FASTSUM collaboration

We present the most recent results from the FASTSUM collaboration for hadron properties at high temperature. This includes the temperature dependence of the light and charmed meson and baryon spectrum, as well as properties of heavy quarkonia. The results are obtained using anisotropic lattices with a fixed scale approach. We also present the status of our next generation gauge ensembles.

Heavy quarkonia in a bulk viscous medium

We study the properties of heavy quarkonia in a quark gluon plasma in the presence of bulk viscous effects. Within the hard thermal loop approximation at one-loop, the dielectric permittivity of a quark gluon plasma is computed, where the bulk viscous effect enters through the deformation of the distribution functions of thermal quarks and gluons. Based on the modified dielectric permittivity, we compute the in-medium heavy quark potential, that includes non-pertubative string-like terms as well as the perturbative Coulombic term. We discuss how the bulk viscous effect modify the real and imaginary parts of the in-medium potential. Several prescriptions are examined as to how to include the string-like non-perturbative potentials. Using the deformed potential, we compute the wave functions, binding energies, and decay widths of heavy quarkonia in a bulk viscous medium, and study their sensitivity to the strength of the bulk viscous effect. An estimate of the melting temperatures is given.

Quarkonium Production in the QGP

We report on recent theory progress in understanding the production of heavy quarkonium in heavy-ion collisions based on the in-medium heavy-quark potential extracted from lattice QCD simulations. On the one hand, the proper in-medium potential allows us to study the spectral properties of heavy quarkonium in thermal equilibrium, from which we estimate the ψ ′ to J / ψ ratio in heavy-ion collisions. On the other hand, the potential provides a central ingredient in the description of the real-time evolution of heavy-quarkonium formulated in the open-quantum-systems framework.

Heavy quarkonium properties from Cornell potential using variational method and supersymmetric quantum mechanics

Using the variational method and supersymmetric quantum mechanics we calculated, in an approximate way, the eigenvalues, eigenfunctions and wave functions at the origin of the Cornell potential. We compared results with numerical solutions for heavy quarkonia $c\bar {c}$ , $b\bar {b}$ and $b\bar {c}$ .

Exclusive charmonium production frome+e−annihilation round theZ0peak

We make a comparative and comprehensive study on the charmonium exclusive productions at the $e^+e^-$ collider with the collision energy either round the $Z^0$-boson mass for a super $Z$ factory or equals to 10.6 GeV for the $B$ factories as Belle and BABAR. We study the total cross sections for the charmonium production via the exclusive processes $e^+e^- \to \gamma^*/Z^0 \to H_{1}+H_{2}$ and $e^+e^- \to \gamma^*/Z^0 \to H_{1} +\gamma$, where $H_{1}$ and $H_{2}$ represent the dominant color-singlet $S$-wave and $P$-wave charmonium states respectively. Total cross sections versus the $e^+e^-$ collision energy $\sqrt{s}$, together with their uncertainties, are presented, which clearly show the relative importance of these channels. At the $B$ factory, the production channels via the virtual $\gamma^*$ propagator are dominant over the channels via the $Z^0$ propagator by about four orders. While, at the super $Z$ factory, due to the $Z^0$-boson resonance effect, the $Z^0$ boson channels shall provide sizable or even dominant contributions in comparison to the channels via the $\gamma^*$ propagator. Sizable exclusive charmonium events can be produced at the super $Z$ factory with high luminocity up to $10^{36}{\rm cm}^{-2}{\rm s}^{-1}$, especially for the channel of $e^+e^- \to Z^0 \to H_{1} +\gamma$, e.g. by taking $m_c=1.50\pm0.20$ GeV, we shall have $(5.0^{+0.8}_{-0.6})\times10^4$ $J/\psi$, $(7.5^{+1.1}_{-0.9})\times10^3$ $\eta_c$, $(6.2^{+3.3}_{-1.9})\times10^3$ $h_{c}$, $(3.1^{+1.7}_{-0.9})\times10^2$ $\chi_{c0}$, $(2.2^{+1.0}_{-0.4})\times10^3$ $\chi_{c1}$, and $(7.7^{+4.1}_{-2.4})\times10^2$ $\chi_{c2}$ events by one operation year. Thus, in addition to the $B$ factories as BABAR and Belle, such a super $Z$ factory shall provide another useful platform for studying the heavy quarkonium properties and for testing QCD theories.

Heavy quarkonium production through the semi-exclusivee+e−annihilation channels round theZ0peak

Within the framework of the nonrelativistic quantum chromodynamics, we present a detailed discussion on the heavy quarkonium production at the leading order in ${\ensuremath{\alpha}}_{s}$ at a ${e}^{+}{e}^{\ensuremath{-}}$ collider with the collision energy around the ${Z}^{0}$ peak. Quarkonia are produced through the semi-exclusive channels ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}|{H}_{Q\overline{Q}}⟩+X$ with $X=Q\overline{Q}$ or $gg$, where $Q$ indicates a heavy quark (respectively, $b$ or $c$). It is noted that in addition to the color-singlet $1S$-level quarkonium states, the $2S$ and $1P$ color-singlet states and the color-octet $|(Q\overline{Q})[1^{3}S_{1}^{(\mathbf{8})}]g⟩$ state also provide sizable contributions. The heavy quarkonium transverse momentum and rapidity distributions for the ${e}^{+}{e}^{\ensuremath{-}}$ collision energy ${E}_{\mathrm{cm}}={m}_{Z}$ are presented. For both charmonium and bottomonium production via the ${Z}^{0}$ propagator, there is approximate ``spin degeneracy'' between the spin-triplet and spin-singlet quarkonium states. Uncertainties for the total cross sections are estimated by taking ${m}_{c}=1.50\ifmmode\pm\else\textpm\fi{}0.15\text{ }\text{ }\mathrm{GeV}$ and ${m}_{b}=4.90\ifmmode\pm\else\textpm\fi{}0.15\text{ }\text{ }\mathrm{GeV}$. Around ${E}_{\mathrm{cm}}={m}_{Z}$, due to the ${Z}^{0}$-boson resonance effect, total cross sections for the channels via the ${Z}^{0}$-propagator become much larger than the channels via the virtual photon propagator. We conclude that, in addition to the $B$ factories such as BABAR and Belle, and the hadronic colliders such as Tevatron and LHC, such a super $Z$ factory will present an excellent platform for studying the heavy quarkonium properties.

In-medium hadron properties from lattice QCD

I review recent results from lattice QCD calculations on the in-medium hadron properties. I discuss the thermal dilepton rates, heavy quarkonium properties as well as the chiral and $U(1)_A$ symmetries at finite temperature.

Holographic Mesons in D4/D6 Model Revisited

We revisit holographic mesons in the D4/D6 model to study holographic light vector mesons and the properties of heavy quarkonium in confining and deconfining phases. To treat the light mesons and heavy quarkonium on the same footing, we use the same compactification scale MKK in both systems. We observe that like scalar and pseudo-scalar mesons the vector meson mass is linearly proportional to the square root of the quark mass, when the quark mass is large. With a MKK fixed by light meson masses, we calculate the mass of heavy quarkonium in confining and deconfining phases. We also obtain the inmedium dispersion relation for heavy quarkonium, which is important to understand the dissociation and the screening mass of heavy quarkonium in quark-gluon plasma.

Effective field theories for the heavy quarkonium

We briefly review how nonrelativistic effective field theories give us a definition of the QCD potentials and a coherent field-theory-derived quantum-mechanical scheme to calculate the properties of bound states made by two or more heavy quarks. In this framework heavy quarkonium properties depend only on the QCD parameters (quark masses and α s ) and nonpotential corrections are systematically accounted for. The relation between the form of the nonperturbative potentials and the low-energy QCD dynamics is also discussed.

Effective-field theories for heavy quarkonium

We briefly review how nonrelativistic effective field theories give us a definition of the QCD potentials and a coherent field-theory-derived quantum-mechanical scheme to calculate the properties of bound states made by two or more heavy quarks. In this framework heavy quarkonium properties depend only on the QCD parameters (quark masses and αs) and nonpotential corrections are systematically accounted for. The relation between the form of the nonperturbative potentials and the low-energy QCD dynamics is also discussed.

Spin-Dependent Relativistic Effect on Heavy Quarkonium Thermal Properties

Spin-dependent relativistic effect on binding and dissociation properties of heavy quarkonium in a thermal environment is investigated. The result shows that fine and hyperfine interactions influence the description of the thermal properties of the heavy quarkonium, such as ηc and J/ψ.

Study of the relativistic effect on heavy quarkonium properties in a thermal environment

The relativistic effect on heavy quarkonium properties in a thermal environment is discussed in this paper. It is shown that this effect cannot be ignored relative to the non-relativistic calculation.

Charmonium spectrum with open channel effects in the complex-scaled Kogut-Susskind model.

The naive quark model which enjoyed considerable success in various properties of heavy quarkonia must be modified near and above the threshold due to light quark pair creation. We discuss this open channel effect on the charmonium spectrum in a framework of the ``Kogut-Susskind model'' by solving exactly a complex-scaled coupled channel equation. The numerical analyses show that the mass and decay width of the 3 $^{3}$${\mathit{S}}_{1}$ state can be well reproduced as a result of coupling to a nearby ${\mathit{D}}^{\mathrm{*}}$D\ifmmode\bar\else\textasciimacron\fi{} $^{\mathrm{*}}$ pole, while those of the 1S and 2S states remain the same as in the single cc\ifmmode\bar\else\textasciimacron\fi{} channel prediction.

Properties of heavy quarkonia and related states

Mass levels and widths of very heavy quarkonia and similar onium resonances of squarks, color octet and sextet constituents are studied in the mass range of 50 to 1000 GeV. The heavy quark potential with QCD two-loop improved short-distance behavior that gives a good description of the charmonium and bottomonium spectra is used, and the results are given for several values of the QCD scale parameter Λ MS (4) in the range between 0.1 and 0.4 GeV. We present parametrizations for the first ten S-wave quarkonium resonances, which are relevant if the top quark is relatively light ( m t≲125 GeV) or if a heavy fourth-generation quark with suppressed weak decay rates exists. We also discuss the onset of coulombic behavior and the possible effects of Higgs boson exchange on superheavy quarkonia.