相关论文: Limitations on using the operator product expansio…
We review both the counting rule and the influence of the evolution in $Q^2$ for the large $x_{Bj}$ behaviour of the valance quark distribution functions. Based on a factorization procedure we present a more general perturbative treatment…
The behavior of the gluon distribution function and the reduced cross section considered from the proton structure function and its derivatives at low values of $x$. These behaviors studied and compared with the experimental data. These…
Regge theory provides an excellent description of small-$x$ structure-function data from $Q^2=0$ up to the highest available values. The large-$Q^2$ data should also be described by perturbative QCD: the two descriptions must agree in the…
In many quantum field theories (such as higher-dimensional holomorphic field theories or raviolo theories), operator product expansions of local operators can have as coefficients not only ordinary functions but also 'derived' functions…
When the bilocal heavy-quark effective theory (HQET) operator for the B-meson distribution amplitude has a light-like distance t between the quark and antiquark fields, the scale \sim 1/t separates the UV and IR regions, which induce the…
We study twist operators in higher dimensional CFT's. In particular, we express their conformal dimension in terms of the energy density for the CFT in a particular thermal ensemble. We construct an expansion of the conformal dimension in…
The leading short-distance contributions to hadronic hard-scattering cross sections in the operator product expansion are described by twist-two quark and gluon operators. The anomalous dimensions of these operators determine the splitting…
We review the status of the practical operator product expansion (OPE), when applied to two-point correlators of QCD currents which interpolate to mesonic resonances, in view of the violations of local quark-hadron duality. Covered topics…
We revise the operator-norm convergence of the Trotter product formula for a pair {A,B} of generators of semigroups on a Banach space. Operator-norm convergence holds true if the dominating operator A generates a holomorphic contraction…
Factorization of the $N$-tachyon amplitudes in two-dimensional $c=1$ quantum gravity is studied by means of the operator product expansion of vertex operators after the Liouville zero mode integration. Short-distance singularities between…
Bounds on anomalous dimensions of scalar operators in 4d superconformal field theory are explored through perturbative viewpoint. Following the recent work of Green and Shih, in which a conjecture involved this issue is verified at the NLO,…
The higher twist contributions to the deeply inelastic structure functions $F_2^{p}(x,Q^2)$ and $F_2^{d}(x,Q^2)$ for larger values of the Bjorken variable $x$ are extracted extrapolating the {twist--2} contributions measured in the large…
We propose an operator product expansion for planar form factors of local operators in $\mathcal{N}=4$ SYM theory. This expansion is based on the dual conformal symmetry of these objects or, equivalently, the conformal symmetry of their…
We present an analytical parametrization of the QCD description of the small x behaviour of parton distribution functions in the leading twist approximation of the Wilson operator product expansion, in the case of soft initial conditions.…
We study the constraints that the operator product expansion imposes on large $N_c$ inspired QCD models for current-current correlators. We focus on the constraints obtained by going beyond the leading-order parton computation. We…
We use the operator product expansion to derive exact results for the momentum distribution and the static structure factor at high momentum for a jellium model of electrons in both two and three dimensions. It is shown that independent of…
The not necessarily unitary evolution operator of a finite dimensional quantum system is studied with the help of a projection operators technique. Applying this approach to the Schr\"odinger equation allows the derivation of an alternative…
The operator product expansion (OPE) for heavy-light-quark pseudoscalar mesons (D-mesons and B-mesons) in medium is determined, both for a moving meson with respect to the surrounding medium as well as for a meson at rest. First of all, the…
We show that if $T$ is a narrow operator on $X=X_{1}\oplus_{1} X_{2}$ or $X=X_{1}\oplus_{\infty} X_{2}$, then the restrictions to $X_{1}$ and $X_{2}$ are narrow and conversely. We also characterise by a version of the Daugavet property for…
We present progress in the QCD analysis of the Bjorken sum rule at low momentum transfers. We study asymptotic structure of the perturbative QCD expansion at low $Q^2$ scales based on analysis of recent accurate data on the Bjorken sum rule…