Related papers: Toponium as Nonabelian Positronium ?
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…
Recent results on the QCD analysis of bound states of heavy $\bar{q}q$ quarks are reviewed, paying attention to what can be derived from the theory with a reasonable degree of rigour. We report a calculation of $\bar{b}c$ bound states; a…
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…
The quantum bootstrap method is applied to determine the bound-state spectrum of Quarkonium systems using a non-relativistic potential approximation. The method translates the Schr\"odinger equation into a set of algebraic recursion…
In this talk I briefly review the recent progress in calculation of the high order corrections to the parameters of the nonrelativistic heavy quark-antiquark system in the effective theory approach.
Bound states of heavy $\bar{q}q$ quarks are reviewed within the context of QCD. First of all, we consider the calculations which can be performed {\sl ab initio}, which includes $\bar{t}t$ with principal quantum number $n$ up to four,…
We report new aspects of the recent theoretical progress in heavy quarkonium physics. (1) Contrary to wide beliefs, the gross structure of the bottomonium spectrum is described well by the non-relativistic boundstate theory based on…
In this talk I review the calculation of the third order corrections to the heavy quarkonium spectrum in the nonrelativistic effective theory framework and its application to the phenomenology of top quark threshold production.
In order to fulfill Low's theorem requirements, a new lowest order basis for bound state decay computations is proposed, in which the binding energy is treated non-perturbatively. The properties of the method are sketched by reviewing…
Heavy quarks have been instrumental for progress in our exploration of strong interactions. Quarkonium in particular, a heavy quark-antiquark nonrelativistic bound state, has been at the root of several revolutions. Quarkonium is endowed…
The variational method and the Hamiltonian formalism of QCD are used to derive relativistic, momentum space integral equations for a quark-antiquark system with an arbitrary number of gluons present. As a first step, the resulting infinite…
We compute masses of bottomonium and charmonium bound states using a Schr\"odinger equation with a heavy quark-antiquark potential including $1/m$ and $1/m^2$ corrections previously derived in potential Non-Relativistic QCD and computed…
Positronium annihilation amplitudes that are computed by assuming a factorization approximation with on-shell intermediate leptons, do not exhibit good analytical behavior. We propose an ansatz which allows to include binding energy…
We investigate the recently reported threshold enhancement in top-antitop production at the LHC in a finite, gauge-covariant, entire-function-regulated nonlocal quantum field theory framework. Our results demonstrate that the observed…
In the QCD-inspired potential model where the quark-antiquark interaction consists of the usual one-gluon-exchange and the mixture of long-range scalar and vector linear confining potentials with the lowest order relativistic correction, we…
We show the results of a quark model calculation of the bottomonium spectrum with self energy corrections due to the coupling to the meson-meson continuum. The bare masses used in the calculation are computed within the relativized quark…
We investigate the pseudoscalar ($\eta_t$) and vector ($\psi_t$) toponium states, as well as the triply-top baryon ($\Omega_{ttt}$), using the QCD sum-rule method. This study was motivated by the recent observation of a pseudoscalar…
Using the quark-antiquark interactions obtained in the framework of the bootstrap method we construct a potential model, investigate the possibility of describing of heavy quarkonia and calculate the bottomonium spectrum. The potential of…
We propose a systematic, model-independent treatment of electric dipole transitions of heavy quarkonium. Within an effective field theory, concretely potential non-relativistic QCD, the relativistic corrections of relative order $v^2$ to…
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…