利用S星围绕Sgr A*的运动探测张量场诱导的洛伦兹对称性破缺
Detecting Lorentz-violation induced by a tensor field with S-star's motion around Sgr A*
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中文总结 AI 辅助
本文利用S2、S38、S55星的轨道数据，通过MCMC方法探测Kalb-Ramond引力中的洛伦兹破缺参数ℒ，得到比事件视界望远镜更严格的约束，其中S2星给出最严格约束。
中文摘要 AI 辅助
在强引力场中检验洛伦兹对称性为探测标准模型的扩展提供了独特途径，S星围绕超大质量黑洞Sgr A*的轨道运动为此类检验提供了天然实验室。本文聚焦Kalb-Ramond引力中静态球对称黑洞，分析S2星的轨道数据，其中与广义相对论的偏差由Kalb-Ramond张量场引入的单个洛伦兹破缺参数ℒ编码。采用全14维马尔可夫链蒙特卡罗分析，在均匀和高斯先验下，分别得到1σ置信水平下ℒ = 1.60×10⁻⁵⁺¹.³⁸×¹⁰⁻⁴₋₁.₇₆×¹⁰⁻⁴和ℒ = -1.02×10⁻⁵⁺¹.²⁶×¹⁰⁻⁴₋₁.₁₉×¹⁰⁻⁴，这些约束比事件视界望远镜对Sgr A*成像得到的约束严格约三个数量级。我们还通过拟合S38和S55星的数据进行MCMC模拟，并开展联合分析，结果显示所有模拟中ℒ的最佳拟合值始终为10⁻⁵量级，且S2星因观测数据精度更高，相比另外两颗星公开数据更少，能给出最严格的参数约束。
英文摘要
Testing Lorentz symmetry in strong gravitational fields provides a unique probe of extensions to standard model. The orbiting motions of the S-stars around the supermassive black hole Sgr~A* provide a natural laboratory for such tests. In this paper, we analyze the S2 orbital data focusing on a static and spherically symmetric black hole within Kalb--Ramond gravity, where the deviations from general relativity are encoded in a single Lorentz-violating parameter $\ell$ introduced by the Kalb--Ramond tensor field. Using a full 14-dimensional Markov Chain Monte Carlo analysis under uniform and Gaussian priors, we obtain $\ell = {1.60 \times 10^{-5}}^{+1.38 \times 10^{-4}}_{-1.76 \times 10^{-4}} $ and $\ell = {-1.02 \times 10^{-5}}^{+1.26 \times 10^{-4}}_{-1.19 \times 10^{-4}} $ at $1σ$ confidence level, respectively. These constraints are about three orders of magnitude tighter than those from Event Horizon Telescope imaging of Sgr~A*. We also perform MCMC simulation by fitting data of S38 and S55 stars, as well as their joint analysis. Our results show that the best fit values of $\ell$ in all simulations are always of $10^{-5}$ order, but S2 star provides the most stringent constraints on the parameters because S2 star has higher precision observational data comparing to the fewer public data for other two stars.
