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Spin observables for the reaction $\gamma p \rightarrow K^+ \Lambda$ are examined using three recent dynamical models and are compared to the general features of such observables deduced earlier by Fasano, Tabakin and Saghai. These general…

Nuclear Theory · Physics 2008-11-26 Bijan Saghai , Frank Tabakin

A quark model which includes both scalar and vector contributions to the reaction mechanism (SV quark model) is used in a DWBA calculation of $\bar \Lambda \Lambda$ production in $\bar p p$ interractions. Total and differential…

Nuclear Theory · Physics 2009-09-25 M. A. Alberg , E. M. Henley , L. Wilets , P. D. Kunz

The physics interpretation of the recent measurements of the spin polarization of $\Lambda$ hyperons produced in relativistic heavy-ion collisions is discussed. We suggest that the polarization measured in the $\Lambda$ rest frame should be…

High Energy Physics - Phenomenology · Physics 2022-09-07 Wojciech Florkowski , Radoslaw Ryblewski

The expressions for the differential cross section and of the polarization observables for the reaction $\bar p+p\rightarrow e^++e^-$ are given in terms of the nucleon electromagnetic form factors in the laboratory system. Radiative…

High Energy Physics - Phenomenology · Physics 2015-03-17 G. I. Gakh , N. P. Merenkov , E. Tomasi-Gustafsson

A quark model which includes both scalar and vector contributions to the reaction mechanism is used in a DWBA calculation of total and differential cross-sections, polarizations, and spin correlation coefficients for the reaction $\bar p p…

Nuclear Theory · Physics 2008-11-26 M. A. Alberg , E. M. Henley , L. Wilets , P. D. Kunz

We study inclusive Lambda hyperon production in pp collisions at BNL RHIC, with just one transversely polarized proton. We show that the measurement of the spin transfer between the initial proton and the produced Lambda is sensitive to the…

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

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

Polarized $\Lambda_b \to \Lambda \gamma$ decays at the Z pole are shown to be well suited for probing a large variety of New Physics effects. A new observable is proposed, the angular asymmetry between the $\Lambda_b$ spin and photon…

High Energy Physics - Phenomenology · Physics 2009-11-07 G. Hiller , A. Kagan

The longitudinal or transverse spin transfer to Lambda and anti-Lambda hyperons in polarized proton-proton collisions is expected to be sensitive to the helicity or transversity distributions of strange and anti-strange quarks of the…

High Energy Physics - Experiment · Physics 2018-12-31 Qing-Hua Xu

Transverse $\Lambda$ polarization observed over four decades ago contradicted expectations from early leading-order perturbative QCD calculations. Measurements of $\Lambda$ polarization from unpolarized $pp$ and $p$A collisions have been…

High Energy Physics - Experiment · Physics 2023-07-18 Cynthia Nunez

We explore some of the rich structure of the polarization observables recently developed for processes like $\gamma N\to\pi\pi N$ and $\gamma N\to K \bar{K} N$ in the framework of a specific model for the latter process. Emphasis is placed…

Nuclear Theory · Physics 2014-11-18 W. Roberts

Spin dependent phenomena in inclusive hadron production have been extensively investigated, yet their microscopic origin and universality across different hadrons are still not fully understood. In particular, it is presently unknown…

High Energy Physics - Experiment · Physics 2026-05-20 D. Alfs , D. Grzonka , G. Khatri , P. Kulessa , J. Ritman , T. Sefzick , J. Smyrski , V. Verhoeven , H. Xu , M. Zielinski

We propose to use an internal polarized hydrogen storage cell gas target in the AD ring to determine for the first time the two total spin-dependent pbar-p cross sections sigma_1 and sigma_2 at antiproton beam energies in the range from 50…

Nuclear Experiment · Physics 2019-08-13 C. Barschel , U. Bechstedt , J. Dietrich , N. Dolfus , R. Engels , R. Gebel , H. Hadamek , J. Haidenbauer , C. Hanhart , A. Kacharava , G. Krol , M. Kueven , G. Langenberg , A. Lehrach , B. Lorentz , R. Maier , S. Martin , U. -G. Meissner , M. Nekipelov , N. N. Nikolaev , D. Oellers , G. d'Orsaneo , D. Prasuhn , F. Rathmann , M. Retzlaff , J. Sarkadi , R. Schleichert , H. Seyfarth , A. Sibirtsev , D. Spoelgen , H. J. Stein , H. Stockhorst , H. Stroeher , Chr. Weidemann , D. Welsch , P. Wieder , L. Barion , S. Bertelli , V. Carassiti , G. Ciullo , M. Contalbrigo , A. Cotta-Ramusino , P. F. Dalpiaz , A. Drago , G. Guidoboni , P. Lenisa , L. Pappalardo , G. Stancari , M. Stancari , M. Statera , T. Azarian , A. Kulikov , V. Kurbatov , G. Macharashvili , S. Merzliakov , I. N. Meshkov , A. Smirnov , D. Tsirkov , Yu. Uzikov , S. Barsov , S. Belostotski , K. Grigoryev , P. Kravtsov , M. Mikirtychiants , S. Mikirtychiants , A. Vasilyev , F. M. Esser , R. Greven , G. Hansen , F. Jadgfeld , F. Klehr , H. Soltner , H. Straatmann , D. Chiladze , A. Garishvili , N. Lomidze , D. Mchedlishvili , M. Nioradze , M. Tabidze , N. Akopov , A. Avetisyan , G. Elbakyan , H. Marukyan , S. Taroian , P. Benati , W. Erven , F. J. Kayser , H. Kleines , P. Wuestner , D. Bruncko , J. Ferencei , J. Musinsky , J. Urban , W. Augustyniak , B. Marianski , A. Trzcinski , P. Zupranski , S. Dymov , A. Nass , E. Steffens , K. Rathsman , P. E. Tegner , P. Thoerngren Engblom , R. De Leo , G. Tagliente , B. Kaempfer , S. Trusov , N. Buttimore , H. O. Meyer

Spontaneous polarization of $\Lambda/\bar{\Lambda}$ in unpolarized hadron interactions has been observed experimentally for nearly half a century and still eludes a definitive explanation. One possible origin is the effect arising from…

High Energy Physics - Experiment · Physics 2024-02-06 Taoya Gao

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

It is shown that the longitudinal double spin asymmetry $A_{ll}$ in polarized diffractive $Q \bar Q$ production depends strongly on the spin structure of the quark-pomeron vertex. Relevant experiments will be possible at HERA with a…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. V. Goloskokov

Single nucleon knockout reactions must be described in a consistent framework in order to extract information about nuclear structure and reaction mechanisms. Consistent relativistic models for the direct knockout contribution to the (e,…

Nuclear Theory · Physics 2007-05-23 J. I. Johansson , H. S. Sherif

A general formalism for double and triple spin-correlations of the reaction NN -> DeltaN is developed for the case of collinear kinematics. A complete polarization experiment allowing to reconstruct all of the four amplitudes describing…

Nuclear Theory · Physics 2008-11-26 Yu. N. Uzikov , J. Haidenbauer

Positivity constraints have proved to be important for spin observables of exclusive reactions involving polarized initial and final particles. Attention is focused in this note on the photoproduction of pseudoscalar mesons from spin 1/2…

Nuclear Theory · Physics 2008-11-26 Xavier Artru , Jean-Marc Richard , Jacques Soffer