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arXiv 2407.01064hep-lathep-phnucl-th
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通过格点QCD研究八重态重子的磁极化率

Magnetic Polarisability of Octet Baryons via Lattice QCD

Thomas Kabelitz, Ryan Bignell, Waseem Kamleh, Derek Leinweber

AI总结:

本文利用格点QCD背景场技术从第一性原理计算八重态重子磁极化率,结合组分夸克模型和有效场论,实现了与实验(含质子和中子)的极好吻合。

摘要:

借鉴格点QCD背景场技术的最新进展,从QCD的第一性原理出发计算了八重态重子的磁极化率。结果在新的组分夸克模型计算的背景下呈现,为理解格点结果以及与在非物理夸克质量下的模拟结果进行直接比较提供了一个框架。利用涂抹夸克源、低阶拉普拉斯本征模投影和末态朗道模投影,我们在确保格点关联函数中单态隔离方面投入了相当大的关注。我们还引入了新的加权方法,以降低对关联函数拟合的敏感性,基于拟合的全关联χ²所得到的优值对多个拟合进行平均。这些技术在PACS-CS合作组提供的32³×64、2+1味动力学费米子格点上实现,此前已引入量子化到可用的最低非平凡值的均匀磁场。在对组分夸克模型参数进行一些微调后,我们发现该模型很好地捕捉了格点QCD结果中观察到的模式,为支撑磁极化率的物理提供了重要见解。最后,与最新实验结果的比较通过一个有效场论形式进行,该形式在结果被带到物理点时纳入了有限体积修正和小电淬灭修正的估计。我们发现与现有实验(包括质子和中子极化率)具有极好的一致性。

英文摘要:

Drawing on recent advances in lattice-QCD background-field techniques, the magnetic polarisability of octet baryons is calculated from the first principles of QCD. The results are presented in the context of new constituent quark-model calculations providing a framework for understanding the lattice results and a direct comparison with simulation results at unphysical quark masses. Using smeared quark sources, low-lying Laplacian eigenmode projection and final-state Landau mode projection, considerable attention is devoted to ensuring single-state isolation in the lattice correlation functions. We also introduce new weighting methods to reduce the sensitivity to correlation-function fits, averaging over many fits based on merit drawn from the full correlated $χ^2$ of the fits. The techniques are implemented on the $32^3 \times 64$, 2+1-flavour dynamical-fermion lattices provided by the PACS-CS collaboration following the introduction of uniform magnetic fields quantised to the lowest nontrivial values available. After some fine tuning of the constituent quark model parameters, we find the model captures the patterns observed in the lattice QCD results very well, providing important insights into the physics underpinning the magnetic polarisabilities. Finally, comparison with the most recent results from experiment proceeds through an effective field theory formalism which incorporates estimates of finite-volume corrections and small electro-quenching corrections as the results are brought to the physical point. We find excellent agreement with experiment where available, including the proton and neutron polarisabilities.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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