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We briefly report our recent progress on the study of the polarized fragmentation functions of $\Lambda$ hyperon in unpolarized semi-inclusive deep-inelastic scatterings and electron-positron annihilations at low energies. In particular, we…

High Energy Physics - Phenomenology · Physics 2023-01-18 Shu-yi Wei

Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. $\Lambda_b$ ,…

High Energy Physics - Phenomenology · Physics 2009-10-31 Gary R. Goldstein

We present new sets of next-to-leading order fragmentation functions for the production of K0short and Lambda particles from the gluon and from each of the quarks, obtained by fitting to all relevant data sets from e+e- annihilation. The…

High Energy Physics - Phenomenology · Physics 2009-09-29 S. Albino , B. A. Kniehl , G. Kramer

We present a model for dihadron fragmentation functions, describing the fragmentation of a quark into two unpolarized hadrons. We tune the parameters of our model to the output of the PYTHIA event generator for two-hadron semi-inclusive…

High Energy Physics - Phenomenology · Physics 2008-11-26 Alessandro Bacchetta , Marco Radici

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

We make a systematic study of the isospin symmetry of fragmentation functions by taking decay contributions into account. We assume the isospin symmetry in strong interactions and show that in the unpolarized case the isospin symmetry is…

High Energy Physics - Phenomenology · Physics 2021-03-24 Kai-bao Chen , Zuo-tang Liang , Yan-lei Pan , Yu-kun Song , Shu-yi Wei

The transverse polarization observed in the inclusive production of Lambda hyperons in the high energy collisions of unpolarized hadrons is tackled by considering a new set of spin and kT dependent quark fragmentation functions. Simple…

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

The importance of polarised gluons fragmenting into $\Lambda$ in the polarised $e^+ e^-$ annihilation is discussed using the Altarelli-Parisi evolution equations satisfied by the quark and gluon fragmentation functions. In this context, the…

High Energy Physics - Phenomenology · Physics 2014-11-17 V. Ravindran

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 discuss Lambda polarization in semi-inclusive proton-proton collisions, with one of the protons longitudinally polarized. The hyperfine interaction responsible for the $\Delta$-$N$ and $\Sigma$-$\Lambda$ mass splittings gives rise to…

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

The long-standing problem of transverse Lambda polarization in high-energy collisions of unpolarized hadrons can be tackled by considering new, spin and k_T-dependent quark fragmentation functions for an unpolarized quark into a polarized,…

High Energy Physics - Phenomenology · Physics 2015-06-25 M. Anselmino , D. Boer , U. D'Alesio , 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

Within the context of flux tube models, heavy quark fragmentation takes place through the breaking of flux tubes with the production of a (di)quark-anti(di)quark pair. It is found that the (di)quark produced are more likely to be found in…

High Energy Physics - Phenomenology · Physics 2007-05-23 Chi-Keung Chow

We study the production of longitudinally polarized Lambda-baryons in single-spin pp collisions at RHIC and HERA-N as a means of determining the spin-dependent Lambda fragmentation functions. It is shown that a measurement of the rapidity…

High Energy Physics - Phenomenology · Physics 2009-10-31 D. de Florian , M. Stratmann , W. Vogelsang

Distinctions between quark to $\Lambda$ and $\bar\Lambda$ longitudinal spin transfers in the semi-inclusive deep inelastic scattering process were observed by the E665 and COMPASS Collaborations. There are suggestions that the difference…

High Energy Physics - Phenomenology · Physics 2017-03-13 Xiaozhen Du , Bo-Qiang Ma

We estimate the non-perturbative power-suppressed corrections to heavy flavour fragmentation and correlation functions in e^+e^- annihilation, using a model based on the analysis of one-loop Feynman graphs containing a massive gluon. This…

High Energy Physics - Phenomenology · Physics 2009-10-30 P. Nason , B. R. Webber

We demonstrate that spontaneous transverse polarization of Lambda baryon ($\Lambda$) production in $e^+e^-$ annihilation can be described using the transverse momentum dependent polarizing fragmentation functions (TMD PFFs). Using a simple…

High Energy Physics - Phenomenology · Physics 2020-11-18 Daniel Callos , Zhong-Bo Kang , John Terry

Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. The resulting…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. Adamov , Gary R. Goldstein

We present a phenomenological study on the role of charm contribution and $SU(2)$ isospin symmetry in the extraction of the $\Lambda$ polarizing fragmentation functions from $e^+e^- \to \Lambda^\uparrow (\bar\Lambda^\uparrow) \,h + X$…

High Energy Physics - Phenomenology · Physics 2023-07-06 Umberto D'Alesio , Leonard Gamberg , Francesco Murgia , Marco Zaccheddu

We calculate the polarization of Lambda and Anti-Lambda particles produced in deep inelastic polarized lepton scattering. We use two models: the naive quark model and a model in which SU(3)$_F$ symmetry is used to deduce the spin structure…

High Energy Physics - Phenomenology · Physics 2009-10-31 D. Ashery , H. J. Lipkin