2021 Fiscal Year Research-status Report
Connecting the QCD vacuum with experimental observables through realistic proton-nucleus reaction simulations
| Project/Area Number |
20K03940
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| Research Institution | Japan Atomic Energy Agency |
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Principal Investigator |
GUBLER PHILIPP 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 先端基礎研究センター, 研究職 (00632390)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | chiral symmetry / transport simulation / phi meson / nuclear matter |
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| Outline of Annual Research Achievements |
The goal of this KAKENHI research project is to perform realistic proton-nucleus reaction simulations to study the creation and behavior of phi mesons in nuclear matter. The phi meson decays into dileptons and kaon pairs, which can both be used to measure its properties in dense matter. This will eventually help to clarify the origin of hadronic masses in the strong interaction. The purpose of the numerical simulations of this project is to connect the data of proton-nucleus reactions to various modification scenarios of phi meson properties (mass shift and/or broadening) and to determine which scenario is most consistent with the experimental data.
After learning about the usage of the PHSD simulation code and performing some first simulations of 12 GeV proton-carbon and proton-copper reactions (corresponding to the KEK E325 experiment) during the first year of the project, I improved the accuracy of the simulations by accumulating more statistics and newly taking into account effects of the electromagnetic interactions on the phi meson decay products and their scattering on the material surrounding the reaction region. Furthermore, while so far mostly focusing on the dilepton decay of the phi meson, I started new simulations studying also its K+K- decay, having in mind a new proposal at the J-PARC E16 experiment to measure this decay in addition to the already ongoing dilepton measurement. The thus obtained simulation results were used to convince the J-PARC program advisory
committee to allow this proposal to go forward to the next planning stage.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
To take into account electromagnetic and other experimental effects on the dilepton spectrum emerging from the phi meson decay to study the KEK E325 experimental data, was somewhat more time consuming than expected, especially as information about the E325 experiment, which was conducted more that 10 years ago, was not easily available. This task is now mainly resolved and I will be able to focus on the simulation of the presently ongoing J-PARC E16 experiment next.
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| Strategy for Future Research Activity |
After writing a paper about the obtained results on the KEK E325 experiment, I will turn my focus on the reactions measured at the J-PARC E16 experiment, for which multiple new observables and features can be studied.
These new items include the K+K- channel including the final state interactions of the kaons with the surrounding nucleons of the target nuclei and angular dependences of of the dilepton and K+K- decay products, which could be used to obtain information about the longitudinal and transverse polarizations modes of the phi meson, which can generally behave differently at finite density.
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| Causes of Carryover |
新型コロナウイルス感染症流行の影響を受け、令和3年度に予定していた国内外の研究会や国際会議の全てが中止またはオンライン開催となり、旅費の支出が発生しなかったため、次年度使用額が生じた。
次年度使用額は、令和4年度分経費と合わせて、国内外の国際会議及び共同研究者がいるドイツ・フランクフルトへ出張等に係る費用として使用する。
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Research Products
(16 results)
