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Using a simple quark-diquark model, we extract a set of unpolarized and polarized fragmentation functions for the $\Lambda$ based on the available unpolarized $\Lambda$ production data in $e^+ e ^- $ annihilation. It is found that there is…

High Energy Physics - Phenomenology · Physics 2016-09-06 Jian-Jun Yang

SU(3) symmetry relations between the octet baryons are introduced in order to connect both the unpolarized and polarized quark distributions of the octet baryons with those of the nucleon. Two different parametrizations of the nucleon quark…

High Energy Physics - Phenomenology · Physics 2009-11-07 Bo-Qiang Ma , Ivan Schmidt , Jacques Soffer , Jian-Jun Yang

Data on the nucleon spin structure suggests that the $u$ (and $d$) quark distributions in the $\Lambda$ hyperon may be polarized. If this correlation carries over into fragmentation, then the study of polarized $\Lambda$'s in the current…

High Energy Physics - Phenomenology · Physics 2010-01-06 R. L. Jaffe

The flavor and helicity distributions of the $\Lambda$ and $\bar{\Lambda}$ hyperons for both valence and sea quarks are calculated in a perturbative QCD (pQCD) based model. We relate these quark distributions to the fragmentation functions…

High Energy Physics - Phenomenology · Physics 2011-09-13 Bo-Qiang Ma , Ivan Schmidt , Jacques Soffer , Jian-Jun Yang

We consider the polarization of Lambda + Lambda-bar baryons produced in polarized Deep Inelastic Scattering at leading order, with various spin configurations: longitudinally polarized leptons and unpolarized nucleon; unpolarized leptons…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Anselmino , M. Boglione , F. Murgia

It is shown that a perturbative QCD (pQCD) based analysis and the SU(6) quark-diquark model give significant different predictions concerning the flavor and spin structure for the quark distributions of the $\Lambda$-baryon near $x=1$.…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bo-Qiang Ma , Ivan Schmidt , Jian-Jun Yang

The study of the longitudinal polarization of Lambda and Lambda-bar hyperons produced in polarized deep inelastic scattering, neutrino scattering, and in Z0 decays allows to access the spin dynamics of the quark fragmentation process.…

High Energy Physics - Phenomenology · Physics 2011-09-13 A. Kotzinian , A. Bravar , D. von Harrach

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…

High Energy Physics - Phenomenology · Physics 2010-02-17 C. Boros , J. T. Londergan , A. W. Thomas

The polarization of $\Lambda$ hyperons is preserved in the angular distribution of their decay products. This property allows one to study the spin structure of the $\Lambda$. In Semi-Inclusive Deep Inelastic Scattering where a high energy…

High Energy Physics - Experiment · Physics 2026-03-25 M. McEneaney , A. Vossen

Analytic formulae are given for QCD corrections to the lepton spectra in decays of polarised up and down type heavy quarks. These formulae are much simpler than the published ones for the corrections to the spectra of charged leptons…

High Energy Physics - Phenomenology · Physics 2010-11-01 A. Czarnecki , M. Jeżabek

Calculations of the polarization of $\Lambda$ and $\bar{\Lambda}$ particles after fragmentation of a polarized quark produced in processes like $Z$-decay and deep inelastic polarized lepton scattering must include $\Lambda$ and…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. Ashery , H. J. Lipkin

The flavor and spin structure for the quark distributions of the $\Lambda$-baryon is studied in a perturbative QCD (pQCD) analysis and in the SU(6) quark-diquark model, and then applied to calculate the $\Lambda$-polarization of…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bo-Qiang Ma , Ivan Schmidt , Jian-Jun Yang

It is shown that $\Lambda$-hyperon fragmentation in charged lepton deep inelastic scattering (DIS) on a polarized nucleon target can provide sensitive information concerning the quark helicity and transversity distributions for both nucleon…

High Energy Physics - Phenomenology · Physics 2014-11-17 Bo-Qiang Ma , Ivan Schmidt , Jacques Soffer , Jian-Jun Yang

We present a general analysis of the spin transfer for $\Lambda$ and $\bar{\Lambda}$ production in deep-inelastic scattering of polarized charged leptons on the nucleon, and find that the pattern of different behaviors of $\Lambda$ and…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bo-Qiang Ma , Ivan Schmidt , Jacques Soffer , Jian-Jun Yang

It is shown that neutrino and antineutrino deep inelastic scattering of unpolarized and polarized $\Lambda$ and $\bar{\Lambda}$ productions, can provide a clean separation of unpolarized and polarized fragmentation functions of a quark into…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bo-Qiang Ma , Jacques Soffer

By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton's spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global…

High Energy Physics - Phenomenology · Physics 2009-10-28 Chung-Yi Wu

We perform a study on the struck quark to the $\Lambda$-hyperon fragmentation processes by taking into account the anti-quark fragmentations and intermediate decays from other hyperons. We concentrate on how the longitudinally polarized…

High Energy Physics - Phenomenology · Physics 2013-10-09 Yujie Chi , Bo-Qiang Ma

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…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Anselm , M. Anselmino , F. Murgia , M. G. Ryskin

The longstanding problem of explaining the observed polarization of Lambda hyperons inclusively produced in the high energy collisions of unpolarized hadrons is tackled by considering spin and k_T dependent quark fragmentation functions.…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Anselmino , D. Boer , U. D'Alesio , F. Murgia

Compact analytic expressions have been obtained for the first order perturbative QCD corrections to the inclusive spectra of the leptons in the semileptonic decays of polarised heavy quarks. Charmed and beautiful $\Lambda$ baryons from…

High Energy Physics - Phenomenology · Physics 2007-05-23 Marek Jezabek
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