Related papers: On Bjorken sum rule: heavy quarks and analytic cou…
The concept of QCD sum rules is extended to bound states composed of particles with finite mass such as scalar quarks or strange quarks. It turns out that mass corrections become important in this context. The number of relevant corrections…
In this note we summarize the results from a longer article on obtaining the QCD phase diagram as a function of the temperature and chemical potential at large Nc and large Nf in the weak and the strong coupling limits. The weak coupling…
The quark number susceptibility, associated with the conserved quark number density, is closely related to the baryon and charge fluctuations in the quark-gluon plasma, which might serve as signature for the quark-gluon plasma formation in…
We investigate the target mass effects in QCD Bjorken sum rule. The magnitude of the target mass correction is estimated in a variety of methods employing positivity bound as well as the experimental data for the asymmetry parameters. It…
With the increasing experimental precision available at colliders, higher-order perturbative calculations are required to reduce the theory uncertainty in order to extract crucial QCD parameters, such as the strong coupling constant, to the…
By matching the world of hadrons to that of some effective chiral quark theory, we determine the induced condensates for QCD sum rules in the presence of an external pion field. The observed values of the strong and weak $\pi NN$ coupling…
This paper presents a summary of the current status of determinations of the strong coupling constant alpha_s. A detailed description of the definition, scale dependence and inherent theoretical ambiguities is given. The various physical…
We propose to increase the factual reliability of descriptions of exotic multiquark hadrons utilizing the approach to bound states of strongly interacting constituents known as QCD sum rules, by allowing exclusively all contributions that…
We perform perturbative QCD factorization of infrared radiations associated with an energetic $b$ quark from a polarized top quark decay, taking the semi-leptonic channel as an example. The resultant formula is expressed as a convolution of…
We estimate the couplings in the Heavy Hadron Chiral Theory (HHCT) lagrangian from the QCD sum rules in an external axial field. Stability of the sum rules at moderate values of the Borel parameter is poor that probably signals a slow…
We report on the extraction of the Q2-dependence of the Bjorken sum between 0.16 < Q2 < 1.1 GeV2. A twist analysis performed on these data shows that the higher twist corrections are small due to a cancellation between the twist-4 and 6…
We present the results of our QCD analysis for polarized quark distribution and structure function $xg_1 (x,Q^2)$. We use very recently experimental data to parameterize our model. New parameterizations are derived for the quark and gluon…
The contribution from hadronic vacuum polarisation effects is responsible for a large fraction of the theoretical uncertainty in the running of the QED coupling. The current level of uncertainty has become a limitation for electroweak…
Polarization studies for heavy quarks can lead to important tests of the Standard Model. Top quark pair production in $e^+e^-$ annihilation is considered near energy threshold. It is shown that for longitudinally polarized electrons the…
We unify two widely different approaches to understanding the infrared behaviour of quantum chromodynamics (QCD), one essentially phenomenological, based on data, and the other computational, realised via quantum field equations in the…
We compute the strong coupling constant $g_{P^* P \pi}$, with $P$ and $P^*$ respectively pseudoscalar and vector heavy mesons by using the QCD sum rules approach. Our computation is based on the evaluation of the time ordered product of…
The masses of excited heavy mesons are studied with sum rules in the heavy quark effective theory. A set of interpolating currents creating (annihilating) excited heavy mesons with arbitrary spin and parity are proposed and their properties…
Concepts and results of determinations of the strong coupling constant in hadron collisions are discussed. A recent alpha_s result from the inclusive jet cross section in pp-bar collisions at sqrt(s)=1.96 TeV is presented which is based on…
This is a short review of the present status of the dynamics of the heavy quarks extracted from QCD spectral sum rules. We discuss the determination of the ``perturbative" quark mass, the decay constants of the $D$ and $B$ mesons, the form…
The Principle of Maximum Conformality (PMC) provides scale-fixed perturbative QCD predictions which are independent of the choice of the renormalization scheme, as well as the choice of the initial renormalization scale. In this article, we…