Related papers: StringSpinner -- adding spin to the PYTHIA string …
We calculate the spin density matrix of the hadron $h$ created via quark fragmentation in the process $e^-e^+ \to q\bar q \to h + X$. In the case of $h=\Lambda$ the experimental data could possibly elucidate the problem of $s$-quark…
The Sivers effect describes the correlation of the unpolarized parton's transverse momentum with the transverse spin of the nucleon. It manifests as a sine modulation of the cross section for single hadron semi-inclusive deep inelastic…
The description of particles with spin can be attained by using a spin density matrix in high energy reaction. In this paper we present a parametrization of the spin density matrix for spin -3/2 particles in the Cartesian form. Comparing…
Spin transfer in high energy fragmentation process is determined by the hadronization mechanism and spin structure of hadrons.It can be studied by measuring the polarizations of hyperons and/or vector mesons in e+e- annihilation, in the…
Massive spin 1/2 particles require 2-spinors for rotations, 4-spinors for rotations and boosts with parity. Including translations requires 8-spinors. Adapting 4-spinor field theory to 8-spinor fields with translation symmetry is discussed…
In the standard pQCD picture particles are produced via the parton jet fragmentation process. However, there are also other production mechanisms like higher twist (HT) processes. A usual example of a HT process is a direct production of an…
SPYTHIA is an event level Monte Carlo program which simulates particle production and decay at lepton and hadron colliders in the Minimal Supersymmetric Standard Model (MSSM). It is an extension of PYTHIA 5.7, with all of its previous…
We present an updated set of parameters for the PYTHIA 8 event generator. We reevaluate the constraints imposed by LEP and SLD on hadronization, in particular with regard to heavy-quark fragmentation and strangeness production. For hadron…
We discuss the single-spin asymmetry in semi-inclusive DIS, $e p^\uparrow \to e \pi X$, based on the twist-3 mechanism in the collinear factorization relevant for the pion production with the large transverse-momentum. This updates our…
Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized nucleon targets have been under intense experimental investigation over the past few years. They provide new insights into QCD and the nucleon…
The transversity was recently extracted from data on the production of hadron pairs in semi-inclusive deep-inelastic scattering. This analysis can be conveniently performed in the framework of collinear factorization where the elementary…
Semiclassical expansion of the Wigner function for spin-1/2 fermions having an effective spacetime-dependent mass is used to analyze spin-polarization effects. The existing framework is reformulated to obtain a differential equation…
To identify some way to measure the quark transversity, this thesis analyzes one-particle and two-particle inclusive deep inelastic scattering, where one and two of the outgoing hadrons are detected in coincidence with the electron. It is…
We propose a spintronic device to generate spin polarization in a mesoscopic region by purely electric means. We show that the spin Hall effect in combination with the stirring effect are sufficient to induce measurable spin polarization in…
It has been proposed to search for thermal and collective properties arising from parton-fragmentation processes by examining high jet charged-constituent multiplicities ($N_{\rm j,ch}$) in proton-proton (pp) collisions. This proposal was…
In a string picture of hadrons, spins are distributed over the whole configuration of string. According to this picture, spin of hadron is discussed in a dual gravity theory of QCD, towards realistic mass formulae of hadrons including…
We present a detailed study, performed in the framework of LO perturbative QCD with the inclusion of spin and k_T effects, of unpolarized cross sections for the Drell-Yan process and for inclusive pion and photon production in hadronic…
The production of vector mesons in the fragmentation process of polarized quarks is studied within the recursive String+${}^3P_0$ model, improving a previous version of the model in which the production of pseudoscalar mesons only was…
A phenomenological description of single transverse spin effects in hadron-hadron inclusive processes is proposed, assuming a generalized factorization scheme and pQCD hard interactions. The transverse momentum, k_T, of the quarks inside…
We study the single spin asymmetry (SSA) for the pion production with large transverse momentum p_T in semi-inclusive deep inelastic scattering $ep^\uparrow\to e\pi X$. We derive the twist-3 cross section formula for SSA, focussing on the…