Related papers: Recent positivity constraints for spin observables…
Modeling the rotation history of solar-type stars is still an unsolved problem in modern astrophysics. One of the main challenges is to explain the dispersion in the distribution of stellar rotation rate for young stars. Previous works have…
Spin polarizabilities of the nucleon are discussed in the framework of fixed-t and backward-angle dispersion relations, chiral perturbation theory, and the non-relativistic quark model. Calculations with the dispersion relations generally…
It is generally believed that dispersive polarimetric detection of collective angular momentum in large atomic spin systems gives rise to: squeezing in the measured observable, anti-squeezing in a conjugate observable, and collective spin…
Recent progresses of the proton structure measurements and determination of parton distribution functions by $ep$ collisions at HERA are introduced.
The soft physics approach to Compton scattering at moderately large momentum transfer is reviewed. It will be argued that in that approach the Compton cross section as well as other exclusive observables exhibit approximate scaling in a…
Nuclear parton distributions and structure functions are determined in an effective chiral quark theory. We also discuss an extension of our model to fragmentation functions.
The connection between parton distributions as a function of the impact parameter and off-forward parton distributions is discussed in the limit of vanishing skewedness parameter $\zeta$, i.e. when the off-forwardness is purely transverse.…
We examine the recent COMPASS data on the spin structure function g_1 singlet. We show that it is rather difficult to use the data in the present form in order to draw conclusions on the initial parton densities. However, our tentative…
We present the first results of a new global next-to-leading order analysis of spin-dependent parton distribution functions from the most recent world data on inclusive polarized deep-inelastic scattering, focusing in particular on the…
We have studied anomalous diffusion of a particle in a random medium in which the passage of the particle may modify the state of the visited sites. The simplicity of the dynamics allows analytic solution. Interesting propagation and…
There is a renewed interest to study spin-polarized transport and spin dynamics in various electronic materials. The motivation to examine the spin degrees of freedom (mostly in electrons, but also in holes and nuclei) comes from various…
The twenty years since the announcement of the proton spin crisis by the European Muon Collaboration has seen tremendous progress in our knowledge of the distribution of spin within the proton. The problem is reviewed, beginning with the…
The theoretical status of the `proton spin' effect is reviewed. The conventional QCD parton model analysis of polarised DIS is compared with a complementary approach, the composite operator propagator-vertex (CPV) method, each of which…
The subject of low energy polarized Compton scattering from the proton, which is characterized by phenomenological spin-polarizabilities, is introduced and connection is made to new theoretical and experimental developments which were…
We analyze different prescriptions for the inclusion of target mass effects in the extraction of parton distributions from the measured structure functions. As a main result, the problem of defining parton distributions in the presence of…
The spin 0 generalized phase space approach provides a general expression for local current which depends on the choice of distribution function and generally deviates from the Schrodinger current. It is shown that the continuity equation…
We derive new effective field theory (EFT) positivity bounds on the elastic $2\to2$ scattering amplitudes of massive spinning particles from the standard UV properties of unitarity, causality, locality and Lorentz invariance. By bounding…
I briefly review the physics of skewed parton distributions. Special emphasis is put on the relevance of target polarization, and on the different roles of small and of intermediate x_B.
A recently reported discrepancy between experimental and theoretical values of the muon's g-2 factor is interpreted as due to small violations of the conservation of P and T in the spin-rotation coupling. The experiments place an upper…
Recently, a new set of positivity bounds with $t$ derivatives have been discovered. We explore the generic features of these generalized positivity bounds with loop amplitudes and apply these bounds to constrain the parameters in chiral…