Magnetic field induced polarization difference between hyperons and anti-hyperons
Recent STAR measurements suggest a difference in the global spin polarization between hyperons and anti-hyperons, especially at relatively low collision beam energy. One possible cause of this difference is the potential presence of in-medium magnetic field. In this study, we investigate the phenome...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2019-11-01
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| Series: | Physics Letters B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269319306513 |
| _version_ | 1818875106023178240 |
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| author | Yu Guo Shuzhe Shi Shengqin Feng Jinfeng Liao |
| author_facet | Yu Guo Shuzhe Shi Shengqin Feng Jinfeng Liao |
| author_sort | Yu Guo |
| collection | DOAJ |
| description | Recent STAR measurements suggest a difference in the global spin polarization between hyperons and anti-hyperons, especially at relatively low collision beam energy. One possible cause of this difference is the potential presence of in-medium magnetic field. In this study, we investigate the phenomenological viability of this interpretation. Using the AMPT model framework, we quantify the influence of different magnetic field evolution scenarios on the size of the polarization difference in a wide span of collision beam energies. We find that such difference is very sensitive to the lifetime of the magnetic field. For the same lifetime, the computed polarization difference only mildly depends on the detailed form of its evolution. Assuming magnetic polarization as the mechanism to enhance anti-hyperon signal while suppress hyperon signal, we phenomenologically extract an upper limit on the needed magnetic field lifetime in order to account for the experimental data. The so-obtained lifetime values are in a quite plausible ballpark and follow approximately the scaling relation of being inversely proportional to the beam energy. Possible implications on other magnetic field related effects are also discussed. Keywords: Heavy ion collision, Vorticity, Global polarization, Magnetic field |
| first_indexed | 2024-12-19T13:21:13Z |
| format | Article |
| id | doaj.art-92cd70f6e93b47b3bcbff6fb3199a096 |
| institution | Directory Open Access Journal |
| issn | 0370-2693 |
| language | English |
| last_indexed | 2024-12-19T13:21:13Z |
| publishDate | 2019-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Physics Letters B |
| spelling | doaj.art-92cd70f6e93b47b3bcbff6fb3199a0962022-12-21T20:19:42ZengElsevierPhysics Letters B0370-26932019-11-01798Magnetic field induced polarization difference between hyperons and anti-hyperonsYu Guo0Shuzhe Shi1Shengqin Feng2Jinfeng Liao3College of Science, China Three Gorges University, Yichang 443002, ChinaDepartment of Physics, McGill University, 3600 University Street, Montreal, QC, H3A 2T8, Canada; Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408, USACollege of Science, China Three Gorges University, Yichang 443002, China; Corresponding authors.Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408, USA; Corresponding authors.Recent STAR measurements suggest a difference in the global spin polarization between hyperons and anti-hyperons, especially at relatively low collision beam energy. One possible cause of this difference is the potential presence of in-medium magnetic field. In this study, we investigate the phenomenological viability of this interpretation. Using the AMPT model framework, we quantify the influence of different magnetic field evolution scenarios on the size of the polarization difference in a wide span of collision beam energies. We find that such difference is very sensitive to the lifetime of the magnetic field. For the same lifetime, the computed polarization difference only mildly depends on the detailed form of its evolution. Assuming magnetic polarization as the mechanism to enhance anti-hyperon signal while suppress hyperon signal, we phenomenologically extract an upper limit on the needed magnetic field lifetime in order to account for the experimental data. The so-obtained lifetime values are in a quite plausible ballpark and follow approximately the scaling relation of being inversely proportional to the beam energy. Possible implications on other magnetic field related effects are also discussed. Keywords: Heavy ion collision, Vorticity, Global polarization, Magnetic fieldhttp://www.sciencedirect.com/science/article/pii/S0370269319306513 |
| spellingShingle | Yu Guo Shuzhe Shi Shengqin Feng Jinfeng Liao Magnetic field induced polarization difference between hyperons and anti-hyperons Physics Letters B |
| title | Magnetic field induced polarization difference between hyperons and anti-hyperons |
| title_full | Magnetic field induced polarization difference between hyperons and anti-hyperons |
| title_fullStr | Magnetic field induced polarization difference between hyperons and anti-hyperons |
| title_full_unstemmed | Magnetic field induced polarization difference between hyperons and anti-hyperons |
| title_short | Magnetic field induced polarization difference between hyperons and anti-hyperons |
| title_sort | magnetic field induced polarization difference between hyperons and anti hyperons |
| url | http://www.sciencedirect.com/science/article/pii/S0370269319306513 |
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