Related papers: A Connection Between The Perturbative QCD Potentia…
Non-relativistic bound state theories for QED and QCD have become fairly mature and amenable to a textbook-level understanding and computation. In this talk we give an introductory review of the following subjects related to the recent…
We consider a general scheme for calculating the leptonic constant of heavy quarkonium QQ-bar in the framework of nonrelativistic quantum chromodynamics, NRQCD, operating as the effective theory of nonrelativistic heavy quarks. We explore…
We review standard applications of perturbative QCD to baryon production, and argue by examining data that it is generally relevant at high but experimentally feasible momentum transfers. Then we consider some new initiatives, particularly…
We compute the energy levels of some of the lower-lying heavy quarkonium states perturbatively up to O(alpha_s^5*m) and O(alpha_s^5*m*log[alpha_s]). Stability of the predictions depends crucially on the unknown 4-loop pole-MSbar mass…
We formulate a QCD-based effective theory approach to heavy quarkonia-like systems as $\bar{c} c$ and $\bar{b} b$ resonances and $B_c$ states. We apply the method to inclusive decays, working out a few examples in detail.
Combining recent perturbative analyses on the static QCD potential and the quark pole mass, we find that, for the heavy quarkonium states $c\bar{c}$, $b\bar{b}$ and $t\bar{t}$, (1) ultra-soft (US) corrections in the binding energies are…
By making use of the finite-temperature real-time static potential that was introduced and computed to leading non-trivial order in Hard Thermal Loop resummed perturbation theory in recent work, and solving numerically a Schr\"odinger-type…
We consider a different power counting in potential NRQCD by incorporating the static potential exactly in the leading order Hamiltonian. We compute the leading relativistic corrections to the inclusive electromagnetic decay ratios in this…
We have investigated the spectra of light-heavy quarkonia with the use of a quantum-chromodynamic potential model which is similar to that used earlier for the heavy quarkonia. An essential feature of our treatment is the inclusion of the…
recently proposed strictly phenomenological static quark-antiquark potential belonging to the generality $V(r)=-Ar^{-\alpha}+\kappa r^{\beta}+V_{0}$ is tested with heavy quarkonia in the context of the shifted large N-expansion method. This…
We compare the perturbatively calculated QCD potential to that obtained from lattice calculations in the theory without light quark flavours. We examine E_tot(r) = 2 m_pole + V_QCD(r) by re-expressing it in the MSbar mass m =…
Although individual levels of toponium will be unobservable, the top--anti--top system near threshold fulfills all requirements of a rigorous perturbation theory in QCD for weakly bound systems. Corresponding techniques from positronium may…
I discuss viscosity corrections to thermal effects on the static QCD potential within hard-thermal loop resummed perturbation theory and for a strongly coupled, large-N_c conformal field theory dual to five-dimensional Gauss-Bonnet gravity.…
We consider the scattering of two color dipoles (e.g., heavy quarkonium states) at low energy - a QCD analog of Van der Waals interaction. Even though the couplings of the dipoles to the gluon field can be described in perturbation theory,…
Mass spectra of quarkonium systems can be described by different phenomenological potentials. In the present work, the {\color{black}resonance} states of heavy quarkonium like ($c\bar{c}$ and $b\bar{b}$) are considered as the rovibrational…
The total energy of a static quark-antiquark pair $E_{\rm tot}(r)=2m_{\rm pole}+V_{\rm QCD}(r)$ is known to be predictable up to ${\cal O}(\Lambda_{\rm QCD}^3 r^2)$ and ${\cal O}(\frac{\Lambda_{\rm QCD}^3}{\overline{m}^2})$ renormalon…
The electric dipole transitions $\chi_{bJ}(1P)\to \gamma\Upsilon(1S)$ with $J=0,1,2$ and $h_{b}(1P)\to \gamma\eta_{b}(1S)$ are computed using the weak-coupling version of a low-energy effective field theory named potential non-relativistic…
Potential-NRQCD offers an effective-theory based approach to heavy-quark physics. While meson Q-anti_Q computations are tractable in pure alpha_s-perturbation theory, more complex many-body quark systems transcend it. A possibility…
We clarify the difference among potential models so far proposed to explain mass spectra of heavy-light mesons via transformations of the vacuum. Applying our idea to QQ-bar quarkonium, we obtain the extra term, 1/r^2 with positive…
Recent evidence for the top mass in the region of 160 $GeV$ for the first time provides an opportunity to use the full power of relativistic quantum field theoretical methods, available also for weakly bound systems. Because of the large…