Related papers: Radiatively Generated Isospin Violations in the Nu…
A Comment on the recently published reevaluation of the polarization-averaged parton distribution of strange quarks in the nucleon using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering is…
We briefly recall the main physical features of the parton distributions in the quantum statistical picture of the nucleon. Some predictions from a next-to-leading order QCD analysis are successfully compared to recent unpolarized and…
Using a recursive algorithm to solve the renormalization group equations of N=1 QCD (DGLAP), we describe the most general supersymmetric evolution of the parton distributions. The analysis involves the regular DGLAP evolution, a partial…
A key question in understanding the structure of nucleons involves the role of sea quarks in their ground state electromagnetic properties such as charge and magnetism. Parity-violating electron scattering, when combined with determination…
Recent calculations of charge symmetry violation(CSV) in the valence quark distributions of the nucleon have revealed that the dominant symmetry breaking contribution comes from the mass associated with the spectator quark system.Assuming…
Isospin symmetry is explicitly broken in the Standard Model by the non-zero differences of mass and electric charge between the up and down quarks. Both of these corrections are expected to have a comparable size of the order of one percent…
We calculate the strange quark and antiquark distributions of the nucleon by using the effective chiral quark model, and find that the strange-antistrange asymmetry can bring a contribution of about 60--100% to the NuTeV deviation of…
It has been revealed from the path-integral formulation of the hadronic tensor that there are connected sea and disconnected sea partons. The former is responsible for the Gottfried sum rule violation primarily and evolves the same way as…
We show how some parton distribution functions related to the transverse spin of nucleons can be extracted point by point from combinations of proton and deuteron observables. In particular, we present a determination of the valence and sea…
Unintegrated parton distributions in the proton and nucleus are predicted by a modified DGLAP equation incorporating the shadowing corrections, which include exact energy-momentum conservation in each splitting and fusion vertices. We find…
The nucleon is an ideal laboratory to solve QCD in the nonperturbative regime. There are several experimental observations that still lack a rigorous interpretation; they involve the nucleon as a (polarized) target as well as a beam (in…
A surprisingly large charge symmetry violation of the sea quarks in the nucleon has been proposed in a recent article by Boros et al. as an explanation of the discrepancy between neutrino (CCFR) and muon (NMC) nucleon structure function…
Experimental tests of QCD through its predictions for the strange-quark content of the proton have been drastically restricted by our lack of knowledge of the violation of charge symmetry (CSV). We find unexpectedly tiny CSV in the proton's…
We investigate an asymmetry in the angular distribution of hard elastic proton-neutron scattering with respect to 90deg center of mass scattering angle. We demonstrate that the magnitude of the angular asymmetry is related to the…
In processes taking place at energies much higher than the weak scale, electroweak corrections can be taken into account by using electroweak evolution equations, that are analogous to the DGLAP equations in QCD. We show that weak isospin…
We discuss the bounds on polarized parton distributions which follow from their definition in terms of cross section asymmetries. We spell out how the bounds obtained in the naive parton model can be derived within perturbative QCD at…
It is shown that the QCD anomaly may lead to an abnormal mixing behavior of the axial vector mesons similar to the pseudoscalar mesons. These mixing effects, involving a gluonic axial vector state, generate a non-vanishing strange quark…
We derive a generalized form of Altarelli-Parisi equations to decribe the time evolution of parton distributions in a nuclear medium. In the framework of the leading logarithmic approximation, we obtain a set of coupled integro-…
Understanding the differences between the distribution of quarks bound in protons and neutrons is key for constraining the mechanisms of SU(6) spin-flavor symmetry breaking in Quantum Chromodynamics (QCD). While vast amounts of proton…
It is of general agreement that a quantum gravity theory will most probably mean a breakdown of the standard structure of space-time at the Planck scale. This has motivated the study of Planck-scale Lorentz Invariance Violating (LIV)…