Related papers: QCD Effective Coupling in the Infrared Region
I present the highlights of a recent study of the effective QCD phase diagram on the temperature T and quark chemical potential mu plane, where the strong interactions are modeled using the linear sigma model coupled to quarks. The phase…
We review the results of large scale simulations of noncompact quenched $QED$ which use spectrum and Equation of State calculations to determine the theory's phase diagram, critical indices, and continuum limit. The resulting anomalous…
We have measured the running of the effective QED coupling constant $\alpha(s)$ in the time-like region $0.6<\sqrt s< 0.975$ GeV with the KLOE detector at DA$\Phi$NE using the Initial State Radiation process $e^+e^-\to\mu^+ \mu^-\gamma$. It…
An approach to QCD vacuum as a medium describable in terms of statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon fields is briefly reviewed. These fields play the role of the confining medium for color…
In this article, we study the structure of the \rho meson in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with a confining effective potential. The u and d quark propagators get…
Theoretical understanding of experimental results from relativistic heavy-ion collisions requires a microscopic approach to the behavior of QCD n-point functions at finite temperatures, as given by the hierarchy of Dyson-Schwinger…
As a quark and an antiquark cannot be isolated, the intrinsic motion of a composite $q \bar q$ system in its lowest-energy states lies predominantly in 1+1 dimensions, as in an open string with the quark and the antiquark at its two ends.…
We extend to regular QCD the derivation of a confining $ q \bar{q}$ Bethe--Salpeter equation previously given for the simplest model of scalar QCD in which quarks are treated as spinless particles. We start from the same assumptions on the…
We extract the spectral function of quarks using the QCD functional formalism.The reliability of approximations is controlled by the masses and decays of pseudoscalar mesons. For light quarks, we select the pion; for charm quarks, we choose…
We report our finding of a two scale cut off structure in the infrared nonperturbative dynamics of Pade couplant QCD, in the flavor states $N_{f} \le 8$. We argue that these two NPQCD momentum scales $Q_{c}(Y_{1})$ and $Q_{c}(Y_{2})$ can be…
We perform a precise extraction of the QCD coupling at the $\tau$-mass scale, $\alpha_s(m_\tau)$, from a new vector isovector spectral function which combines ALEPH and OPAL distributions for the dominant channels, $\tau\to\pi…
We perform an integral reduction for the 3-loop effective gauge coupling and screening mass of QCD at high temperatures, defined as matching coefficients appearing in the dimensionally reduced effective field theory (EQCD). Expressing both…
We investigate the properties of light scalar and pseudoscalar mesons at finite (light) quark chemical potential. To this end we solve a coupled set of (truncated) Dyson-Schwinger equations for the quark and gluon propagators in…
We solve the Bethe-Salpeter equation for a system of a heavy quark-antiquark pair interacting with a screened linear confining potential. First we show the spinless QFT model is inadequate and fail to describe even gross feature of the…
Scattering amplitudes of partons in QCD contain infrared divergences which can be resummed to all orders in terms of an anomalous dimension. Independently, in the limit of high-energy forward scattering, large logarithms of the energy can…
This thesis describes work done by me during my tenure as a Ph.D. student at the Centre for High Energy Physics, Indian Institute of Science, Bangalore. Chapter 1 is a brief introduction to QCD. In Chapter 2, we formulate QCD in the…
Schwinger-Dyson equations are used to study the phase diagram of QED in three dimensions. This computation is made with full frequency-dependence in the two-point function gap equations for the first time. We also demonstrate that reliable…
We review the ALPHA collaboration strategy for obtaining the QCD coupling at high scale. In the three-flavor effective theory it avoids the use of perturbation theory at $\alpha > 0.2$ and at the same time has the physical scales small…
By requiring the correct Regge behavior in both meson and nucleon sectors, we determine the infrared asymptotic behavior of various background fields in the soft-wall AdS/QCD model, including the dilaton, the warp factor, and the scalar…
We study the heavy-heavy-light quark ($QQq$) potential in SU(3) quenched lattice QCD, and discuss one of the roles of the finite-mass valence quark in the inter-quark potential. Monte Carlo simulations are performed with the standard gauge…