{"title":"Hadronic scattering effects on Λ polarization in relativistic heavy ion collisions","authors":"Haesom Sung , Che Ming Ko , Su Houng Lee","doi":"10.1016/j.physletb.2024.139004","DOIUrl":null,"url":null,"abstract":"<div><p>The Λ hyperon spin flip and non-flip cross sections are calculated in a simple hadronic model by including both the <em>s</em>-channel process involving the spin 3/2, positive parity <span><math><msup><mrow><mi>Σ</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>(</mo><mn>1358</mn><mo>)</mo></math></span> resonance and the <em>t</em>-channel process via the exchange of a scalar <em>σ</em> meson. Because of its large mass, the Λ spin flip to non-flip cross sections is negligibly small in the <em>t</em>-channel process compared to the constant value of 1/3.5 in the <em>s</em>-channel process. With the <em>s</em>-channel <span><math><mi>Λ</mi><mo>−</mo><mi>π</mi></math></span> spin-dependent cross sections included in a schematic kinetic model, the effects of hadronic scatterings on the Λ spin polarization in Au-Au collisions at <span><math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>7.7</mn></math></span> GeV are studied. It is found that the Λ spin polarization only decreases by 7-12% during the hadronic stage of these collisions, which justifies the assumption in theoretical studies that compare the Λ polarization calculated at the chemical freezeout to the measured one at the kinetic freezeout.</p></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":"858 ","pages":"Article 139004"},"PeriodicalIF":4.3000,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0370269324005628/pdfft?md5=b73f69021e18f09691976f24ebfa7bfe&pid=1-s2.0-S0370269324005628-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics Letters B","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0370269324005628","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
The Λ hyperon spin flip and non-flip cross sections are calculated in a simple hadronic model by including both the s-channel process involving the spin 3/2, positive parity resonance and the t-channel process via the exchange of a scalar σ meson. Because of its large mass, the Λ spin flip to non-flip cross sections is negligibly small in the t-channel process compared to the constant value of 1/3.5 in the s-channel process. With the s-channel spin-dependent cross sections included in a schematic kinetic model, the effects of hadronic scatterings on the Λ spin polarization in Au-Au collisions at GeV are studied. It is found that the Λ spin polarization only decreases by 7-12% during the hadronic stage of these collisions, which justifies the assumption in theoretical studies that compare the Λ polarization calculated at the chemical freezeout to the measured one at the kinetic freezeout.
期刊介绍:
Physics Letters B ensures the rapid publication of important new results in particle physics, nuclear physics and cosmology. Specialized editors are responsible for contributions in experimental nuclear physics, theoretical nuclear physics, experimental high-energy physics, theoretical high-energy physics, and astrophysics.