Related papers: Hyperfine Interaction in Quarkonia
In this work, we present an updated study about the interactions of quarkonia with surrounding hadronic medium. The meson-meson interactions are described with a chiral effective Lagrangian within the framework of unitarized coupled channel…
Quarkonia provide a sensitive probe of the properties of the hot dense medium created in high energy heavy ion collisions. Hard scattering processes result in the production of heavy quark pairs that interact with the collision medium…
Measurements of quarkonia production in peripheral and ultraperipheral heavy-ion collisions are sensitive to photon-photon and photon-nucleus interactions, the partonic structure of nuclei, and the mechanisms of vector-meson production. In…
The leading nonperturbative effects to the fine and hyperfine splitting were calculated some time ago. Recently, they have been used in order to obtain realistic numerical results for the lower levels in bottomonium systems. We point out…
Quarkonia provide a sensitive probe of the properties of the hot dense medium created in high energy heavy ion collisions. Hard scattering processes result in the production of heavy quark pairs that interact with the collision medium…
The current status of the experimental investigation of quarkonia in heavy-ion collisions as probes for deconfinement is reviewed. The emphasis is put on the qualitative understanding of charmonia (ccbar bound states) and bottomonia (bbbar)…
Valuable data on quarkonia (the bound states of a heavy quark Q=c,b and the corresponding antiquark) have recently been provided by a variety of sources, mainly e+ e- collisions, but also hadronic interactions. This permits a thorough…
Charmonium production in heavy-ion collisions is investigated within a kinetic theory framework incorporating in-medium properties of open- and hidden-charm states in line with recent QCD lattice calculations. A continuously decreasing…
In the interaction of two electric quadrupoles, there is at short distances a contact term proportional to the second derivative of a delta function. This contact term contributes to the hyperfine splitting of bound states of two particles…
The hyperfine spin splittings in heavy quarkonia are studied using the recently developed renormalization group improved spin-spin potential which is independent of the scale parameter $\mu$. The calculated energy difference between the…
A formula for an improved spin--dependent potential between a heavy quark and a heavy antiquark was developed using Heavy Quark Effective Theory techniques. The leading logarithmic quark mass terms emerging from loop contributions were…
In this article, we study the vector meson transitions among the charmonium and bottomonium states with the heavy quark effective theory in an systematic way, and make predictions for the ratios among the vector meson decay widths of a…
We present a new method to study the properties of heavy quarks at finite temperature. It combines non-relativistic QCD with an improved gluonic action on anisotropic lattices. The efficiency of the approach is demonstrated by the first…
A theoretical explanation of the observed splittings among the P~states of charmonium is given with the use of a nonsingular potential model for heavy quarkonia. We also show that the recently observed mass difference between the center of…
We report recent progress on theoretical investigations of quarkonia at finite temperature. We discuss medium modification of charmonia and bottomonia from a viewpoint of local operators and point out that while charmonia are sensitive to…
In this work an improved potential model for quarkonium spectra (charmonium, bottomonium) is constructed. Beside the one-gluon exchange and a linear confinement potential, the model includes systematically effects from two-gluon exchange…
We compute the hyperfine splitting of P-wave heavy quarkonium states with next-to-next-to-next-to-next-to-leading-order accuracy. The resummation of logarithms with next-to-next-to-next-to-next-to-leading-logarithmic accuracy is also…
We review recent progress made in the theory of quarkonium production in hadronic collisions.
Uncertainty of the theoretical prediction for the hyperfine splitting in the ground state of muonium is considered. It is compared with the respective discussion in the two most recent CODATA adjustments of the fundamental physical…
The direct charmonium and bottomonium production rate observed at high-pt in pp-bar collisions at the Tevatron is factors of ten larger than predictions based on conventional perturbative QCD. We show that this excess can be accounted for…