2,672 research outputs found
Proton transversity and intrinsic motion of the quarks
The spin structure of the system of quasifree fermions having total angular
momentum is studied in a consistently covariant approach. Within this
model the relations between the spin functions are obtained. Their particular
cases are the sum rules Wanzura - Wilczek, Efremov - Leader - Teryaev,
Burkhardt - Cottingham and also the expression for the Wanzura - Wilczek twist
2 term . With the use of the proton valence quark distributions as
an input, the corresponding spin functions including transversity are obtained.Comment: Prepared for the conference SPIN200
Relativistic wave equations with fractional derivatives and pseudo-differential operators
The class of the free relativistic covariant equations generated by the
fractional powers of the D'Alambertian operator is studied.
Meanwhile the equations corresponding to n=1 and 2 (Klein-Gordon and Dirac
equations) are local in their nature, the multicomponent equations for
arbitrary n>2 are non-local. It is shown, how the representation of generalized
algebra of Pauli and Dirac matrices looks like and how these matrices are
related to the algebra of SU(n) group. The corresponding representations of the
Poincar\'e group and further symmetry transformations on the obtained equations
are discussed. The construction of the related Green functions is suggested.Comment: 29 pages, Tex. In the corrected version a small bug in
cross-references to some equations is removed. Minor text corrections are
done and some references are adde
Kinematics of deep inelastic scattering in leading order of the covariant approach
We study the kinematics of deep inelastic scattering corresponding to the
rotationally symmetric distribution of quark momenta in the nucleon rest frame.
It is shown that rotational symmetry together with Lorentz invariance can in
leading order impose constraints on the quark intrinsic momenta. Obtained
constraints are discussed and compared with the available experimental data.Comment: 4 pages, 2 figures, the version 2 is accepted to Phys.Rev.
Role of gluons and the quark sea in the proton spin
The real, interacting elementary particle always consits of a 'bare' particle
and a cloud of virtual particles mediating a self-interaction and/or the bond
inside a composite object. In this letter we discuss the question of spin
content of the virtual cloud in two different cases: electron and quark.
Further, the quark spin is discussed in the context of proton spin, which is
generated by the interplay of quarks and virtual gluons. We present a general
constraint on the gluon contribution and make a comparison with the
experimental data.Comment: 8 pages, 3 figures, 1 table, the final and enlarged version is
accepted to Phys.Lett.
A statistical analysis of two-dimensional patterns and its application to astrometry
Here we develop a general statistical procedure for the analysis of finite
two-dimensional (2D) patterns inspired by the analysis of heavy-ion data. The
method is used in the study of publicly available data obtained by the Gaia-ESA
mission. We prove that the procedure can be sensitive to the limits of accuracy
of measurement, and can also clearly identify the real physical effects on the
large background of random distributions. As an example, the method confirms
the presence of binary and ternary star systems in the studied data. At the
same time, the possibility of the statistical detection of the gravitational
microlensing effect is discussed.Comment: 12 pages, 14 figures, 1 table. This version is accepted for
publication in Astronomy & Astrophysic
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