Related papers: Nucleon Spin Sum Rules and Spin Polarizabilities a…
The theory of the `proton spin' effect proposed in our earlier papers is extended to include the chiral SU(3) symmetry breaking and flavour mixing induced by non-vanishing quark masses in QCD. The theoretical basis is the derivation of…
The theory of the strong force, Quantum Chromodynamics (QCD) remains one of the most important ways to understand the fundamental properties of ordinary matter. However, at low momentum transfer Q2, in the regime where the strong force…
Starting from a relativistic quantum field theory, we study the low energy scattering of two fermions of opposite spins interacting through a Chern-Simons field. Using the Coulomb gauge we implement the one loop renormalization program and…
I describe a few of the most exciting open questions in high energy spin physics. After a brief look at (g-2)_\mu and the muon electric dipole moment, I concentrate on QCD spin physics. Pressing questions include the interpretation of new…
We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in…
Motivated by the fact that a polarized ${}^3$He nucleus behaves as an `effective' neutron target, we examine manifestations of neutron electromagnetic polarizabilities in elastic Compton scattering from the Helium-3 nucleus. We calculate…
Effective field theories (EFT) parameterize the long-distance effects of short-distance dynamics whose details may or may not be known. It is known that EFT coefficients must obey certain positivity constraints if causality and unitarity…
Dipolar-octupolar (DO) pyrochlore systems Ce$_2$(Zr,Sn,Hf)$_2$O$_7$ have garnered much attention as recent investigations suggest that they may stabilize a novel quantum spin ice (QSI), a quantum spin liquid (QSL) with an emergent $U(1)$…
Chirality-induced spin selectivity is a spin-splitting phenomenon from a helical structure with a considerably effective spin-orbit coupling. This unexpectedly large spin-splitting phenomenon has been experimentally observed in chiral…
The contribution of the $G_2$ structure function to polarized deep inelastic scattering is slightly redefined in order to avoid kinematical zeros. Its strong $Q^2$-dependence implied by the Burkhardt-Cottingham (BC) sum rule naturally…
The neutron spin structure function, $g_{1n}$, has been of considerable interest recently in connection with the Bjorken sum rule and the proton spin crisis. Work on this problem has concentrated on measurements at low-$x$. We recall the…
A brief summary on the Wigner rotation effect in the understanding of the proton spin ``crisis" related with the Ellis-Jaffe sum rule violation, and on the proton-neutron isospin symmetry breaking explanation of the Gottfried sum rule…
The validity of some rules in the classical theory of spin, which are followed by the Bargmann--Michel--Telegdi formula for a relativistic particle spin rotation in a constant homogeneous magnetic field, is analyzed. In the framework of the…
The M{\o}ller polarimeter in Hall A at Jefferson Lab in Newport News, VA, has provided reliable measurements of electron beam polarization for the past two decades reaching the typically required $\pm$1\% level of absolute uncertainty.…
We review theoretical progress and prospects for determining the nucleon's static dipole polarisabilities from Compton scattering on few-nucleon targets, including new values; see Refs. [1-5] for details and a more thorough bibliography.
We review how RHIC is expected to deepen our understanding of the spin structure of longitudinally polarized nucleons. After briefly outlining the current status of spin-dependent parton densities and pointing out open questions, we focus…
We present the first measurement of the Q^2-dependence of the neutron spin structure function g_2^n at five kinematic points covering 0.57 (GeV/c)^2 <= Q^2 <= 1.34 (GeV/c)^2 at x~0.2. Though the naive quark-parton model predicts g_2=0,…
Making use of QCD sum rules a lower bound is found which relates the electromagnetic polarizability $\alpha_{_E}$ and mean-square radius $\langle r_\pi^2\rangle$ of charged pions through the intrinsic polarizability $\tilde\alpha_{_E}=…
A description of the generalized Gerasimov-Drell-Hearn sum rules for proton and neutron is suggested, using their relation to the Bjorken sum rule. The results support an earlier conjecture, that the structure function g_T features a smooth…
Spin correlations in an interacting electron liquid are studied in the high-frequency limit and in both two and three dimensions. The third-moment sum rule is evaluated and used to derive exact limiting forms (at both long- and…