Related papers: Renormalons and Higher-Twist Contributions to Stru…
The spin dependent structure function, g2ww(x,Q^2), is calculated in the valon model. A simple approach is given for the determination of the twist-3 part of the g2(x, Q^2) in Mellin space; thus, enabling us to obtain the full transverse…
In two lectures, we overview the renormalon and renormalon-related techniques and their phenomenological applications. We begin with a single renormalon chain which is a well defined and systematic way to specify the character of…
Higher-twist effects in the low-order moments of the longitudinal and transverse structure functions of proton and deuteron have been analyzed using available phenomenological fits of existing data in the Q**2 range between 1 and 20…
The evaluation of the higher twist contributions to Deep Inelastic Scattering amplitudes involves a non trivial choice of operator bases for the higher orders of the OPE expansion of the two hadronic currents. In this talk we discuss the…
We present a sketchy review of renormalon-based phenomenology. In particular, the leading, 1/Q corrections to various observables, KLN cancellations for power-suppressed corrections and the fixation of operator matrix elements are…
The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron $g_1$ structure functions are extracted from the world data on $g_1(x,Q^2)$ in a model independent way and found to be non-negligible. Their role in…
The QCD effects of twist-4 operators on the first moment of nucleon spin-dependent structure function $g_1(x, Q^2 )$ are studied in the framework of operator product expansion and renormalization group method. We investigate the operator…
The experimental data on F2 structure functions of the proton and deuteron were used to construct their moments. In particular, recent measurements performed with CLAS detector at Jefferson Lab allowed to extend our knowledge of structure…
We analyze the twist-4 contributions to Bjorken and Ellis-Jaffe sum rules for spin-dependent structure function $g_1(x, Q^2 )$. We investigate the anomalous dimensions of the twist-4 operators which determine the logarithmic correction to…
We investigate the nucleon's transverse spin-dependent structure function g_2(x, Q^2) in the framework of the operator product expansion and the renormalization group. We construct the complete set of the twist-3 operators for the flavor…
We study power corrections to the spin-averaged structure functions F_2 and F_L in the semi-inclusive region. The dramatic breakdown of the operator product expansion at large Bjorken x due to the formation of a narrow jet with invariant…
We elaborate on the structure of the conformal anomaly effective action up to 4-th order, in an expansion in the gravitational fluctuations $(h)$ of the background metric, in the flat spacetime limit. For this purpose we discuss the…
Target mass corrections to the twist-4 terms $\tilde f_2^{p,n,d}$ as well as to the leading-twist $\tilde a_2$ are discussed.
We consider the effect of higher twist operators of the Wilson operator product expansion in the structure function $F_{2}(x,Q^{2})$ at small-$x$, taking into account QCD effective charges whose infrared behavior is constrained by a…
The twist-2 contributions to the polarized structure functions in deep inelastic lepton--hadron scattering are calculated including the exchange of weak bosons and using both the operator product expansion and the covariant parton model. A…
We develop a framework for the reconstruction of the non-forward kernels which govern the evolution of twist-two distribution amplitudes and off-forward parton distributions beyond leading order. It is based on the knowledge of the special…
We identify the independent dimension 6 twist 4 gluon operators and calculate their renormalization in the pure gauge theory. By constructing the renormalization group invariant combinations, we find the scale invariant condensates that can…
We critically analyse the data available on the reduced cross-section in deeply inelastic $e p$ scattering from the H1 collaboration at HERA. We use available data on the longitudinal structure function to deduce the nature of $\d F_2/\d\ln…
The impact of recently calculated next-to-next-to-leading order QCD corrections and soft gluon resummations on the extraction of higher twist contributions to the deep-inelastic structure function F_2 is studied using the BCDMS and SLAC…
We calculate the chiral odd quark distributions and the corresponding structure functions $h_T(x,Q^2)$ and $h_L(x,Q^2)$ within the Nambu-Jona-Lasinio chiral soliton model for the nucleon. The $Q^2$ evolution of the twist-2 contributions is…