278 research outputs found
On the renormalization of quasi parton distribution
Recent developments showed that light-cone parton distributions can be
studied by investigating the large momentum limit of the hadronic matrix
elements of spacelike correlators, which are known as quasi parton
distributions. Like a light-cone parton distribution, a quasi parton
distribution also contains ultraviolet divergences and therefore needs
renormalization. The renormalization of non-local operators in general is not
well understood. However, in the case of quasi quark distribution, the bilinear
quark operator with a straight-line gauge link appears to be multiplicatively
renormalizable by the quark wave function renormalization in the axial gauge.
We first show that the renormalization of the self energy correction to the
quasi quark distribution is equivalent to that of the heavy-light quark vector
current in heavy quark effective theory at one-loop order. Assuming this
equivalence at two-loop order, we then show that the multiplicative
renormalizability of the quasi quark distribution is true at two-loop order.Comment: 14 pages, 4 figure
Stable sets and mean Li-Yorke chaos in positive entropy systems
It is shown that in a topological dynamical system with positive entropy,
there is a measure-theoretically "rather big" set such that a multivariant
version of mean Li-Yorke chaos happens on the closure of the stable or unstable
set of any point from the set. It is also proved that the intersections of the
sets of asymptotic tuples and mean Li-Yorke tuples with the set of topological
entropy tuples are dense in the set of topological entropy tuples respectively.Comment: The final version, reference updated, to appear in Journal of
Functional Analysi
QCD Factorization for Spin-Dependent Cross Sections in DIS and Drell-Yan Processes at Low Transverse Momentum
Based on a recent work on the quantum chromodynamic (QCD) factorization for
semi-inclusive deep-inelastic scattering (DIS), we present a set of
factorization formulas for the spin-dependent DIS and Drell-Yan cross sections
at low transverse momentum.Comment: 12 pages, two figures include
One-Loop Matching for Generalized Parton Distributions
We present the one-loop matching condition for the unpolarized and polarized
generalized quark distributions in the non-singlet case. The matching condition
links the quasi distributions defined in terms of spacelike correlators at
finite nucleon momentum to the light-cone distributions, and is useful for
extracting the latter from the former in a lattice QCD calculation. Our results
show that at one-loop and leading power accuracy the matching for the
light-cone generalized quark distribution () is non-trivial,
whereas no matching is required for (). Therefore, () can be smoothly approached by its quasi counterpart in the large momentum
limit. We also present the matching for the distribution amplitude of the pion.Comment: 16 pages, 1 figur
One-Loop Matching for Parton Distributions: Non-Singlet Case
We derive one-loop matching condition for non-singlet quark distributions in
transverse-momentum cut-off scheme, including unpolarized, helicity and
transversity distributions. The matching is between the quasi-distribution
defined by static correlation at finite nucleon momentum and the light-cone
distribution measurable in experiments. The result is useful for extracting the
latter from the former in a lattice QCD calculation.Comment: 10 pages, 1 figur
Spin Decomposition of Electron in QED
We perform a systematic study on the spin decomposition of an electron in QED
at one-loop order. It is found that the electron orbital angular momentum
defined in Jaffe-Manohar and Ji spin sum rules agrees with each other, and the
so-called potential angular momentum vanishes at this order. The calculations
are performed in both dimensional regularization and Pauli-Villars
regularization for the ultraviolet divergences, and they lead to consistent
results. We further investigate the calculations in terms of light-front wave
functions, and find a missing contribution from the instantaneous interaction
in light-front quantization. This clarifies the confusing issues raised
recently in the literature on the spin decomposition of an electron, and will
help to consolidate the spin physics program for nucleons in QCD.Comment: 8 page
Threshold Resummation for Higgs Production in Effective Field Theory
We present an effective field theory to resum the large double logarithms
originated from soft-gluon radiations at small final-state hadron invariant
masses in Higgs and vector boson (\gamma^*, and ) production at hadron
colliders. The approach is conceptually simple, indepaendent of details of an
effective field theory formulation, and valid to all orders in sub-leading
logarithms. As an example, we show the result of summing the
next-to-next-to-next leading logarithms is identical to that of standard pQCD
factorization method.Comment: A version to appear in Phys. Rev.
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