Related papers: Transverse Lambda polarization in unpolarized semi…
We present the systematic results for three dimensional fragmentation functions defined via the quark-quark correlator for hadrons with spin 0, 1/2 and 1 respectively. These results are presented in terms of a spin independent part, a…
The production of Lambda and Lambda-bar hyperons by polarized muons of 160 GeV/c on a polarized 6LiD target has been studied using the COMPASS spectrometer. First preliminary results on the longitudinal polarization of Lambda and Lambda-bar…
We present the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed ${\cal O}(1/Q^2)$ terms in the Wandzura--Wilczek-type approximation which consists in…
The HERMES experiment has measured the transverse polarization of Lambda and Lambda-bar hyperons produced inclusively in quasireal photoproduction at a positron beam energy of 27.6 GeV. The transverse polarization of the Lambda hyperon is…
We study the measurement of the quark fragmentation functions for spin-1/2 baryon production ($\Lambda$ and $\bar \Lambda$, in particular) in unpolarized $e^+e^-$ annihilation. The spin-dependent fragmentation functions $\hat g_1(z)$ and…
We describe a general approach to quark flavor tagging in polarized hadronic processes, with particular emphasis on semi-inclusive deep inelastic scattering. A formalism is introduced that allows one to relate chosen quark flavor…
We provide a comprehensive overview of transversely polarized $\Lambda$ production at the future Electron-Ion Collider (EIC). In particular, we study both spontaneous transverse $\Lambda$ polarization as well as the transverse spin transfer…
Generalized parton distributions describe the distribution of partons in the transverse plane. For transversely polarized quarks and/or nucleons, these impact parameter dependent parton distributions are not axially symmetric. These…
We performed feasibility studies for various measurements that are related to unpolarized TMD distribution and fragmentation functions. The processes studied include semi-inclusive Deep inelastic scattering (SIDIS) where single hadrons…
We discuss the recent interpretation of quark-distribution functions in the plane transverse to the light-cone direction. Such a mapping is model independent and allows one to build up multidimensional pictures of the hadron and to develop…
We discuss interplay of the scalar and vector diquarks which decide the characteristics of the spin polarization as functions of $p_T$ and $x_F$ in the wide kinematical range. We demonstrate a significant effect of quark masses on the…
In the fragmentation of a transversely polarized quark a left-right asymmetry, the Collins asymmetry, is expected for each hadron produced in the process $\mu N \rightarrow \mu ' h^{+} h^{-} X$. Similarly, an asymmetry is also expected for…
We give a short overview of the phenomenology of azimuthal and transverse single spin asymmetries in (un)polarized high-energy hadronic collisions. We briefly summarize a transverse momentum dependent, generalized parton model approach to…
Partonic intrinsic transverse momentum can be essential for the explanation of large single spin asymmetries in hadronic reactions in the framework of perturbative QCD. The status of an ongoing program investigating in a consistent way the…
We investigate the inclusive and semi-inclusive productions of spin-3/2 hadrons, such as $\Omega$, in unpolarized $e^+ e^-$ annihilation. The general differential cross sections are expressed in terms of structure functions in accordance to…
The semi-inclusive production of identified hadrons in deeply inelastic lepton scattering on polarized nucleons allows to probe the spin structure of the nucleon target in a more detailed level than through fully inclusive processes. We…
We discuss the quark parton structure of the $\Lambda$ baryon and the fragmentation of quarks into $\Lambda$ baryons. We show that the hyperfine interaction, responsible for the $\Delta$-$N$ and $\Sigma^0$-$\Lambda$ mass splittings, leads…
In this paper, some subtleties in the measurement of the transverse polarization of the produced hadrons on symmetric colliders -- such as the Large Hadron Collider when conducting the $pp$ collisions -- are revealed. It can be proved that…
The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a…
The $Q^2$ evolution of polarised parton fragmentation functions is discussed using Altarelli-Parisi evolution equations. The first moments of both polarised quark and gluon fragmentation functions are shown to behave in a similar fashion at…