发表机构
Central (Pulkovo) Astronomical Observatory of the Russian Academy of Sciences; Institute for Nuclear Research of the Russian Academy of Sciences; Faculty of Physics, M.V. Lomonosov Moscow State University; Institute of Applied Astronomy of the Russia Academy of Sciences（俄罗斯科学院中央（普尔科沃）天文台; 俄罗斯科学院核物理研究所; 莫斯科国立大学物理系; 俄罗斯科学院应用天文学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过拟合27个球状星团的多波段观测数据，结合先进恒星演化模型，约束轴子-电子耦合常数等新粒子物理参数，未发现异常能量损失迹象，给出95%置信水平下的g_ae上限。
AI 中文摘要
红巨星的演化对恒星核心中的非标准能量损失通道十分敏感，因此可作为探测新物理的探针。这类能量损失会提升红巨星分支顶端（TRGB）的光度，TRGB是赫罗图中红巨星达到的最亮位置。此前对球状星团TRGB光度的分析已对轴子-电子耦合常数g_ae施加了严格限制，但受限于观测和理论不确定性。为改进这些约束，我们使用27个球状星团的一组新的均匀参数，这些参数来自我们对Stetson地面观测数据、哈勃空间望远镜（HST）数据和盖亚（Gaia）数据的等时线拟合，拟合所用的等时线来自达特茅斯恒星演化数据库、恒星轨迹与等时线集合（Bag of Stellar Tracks and Isochrones），以及最先进的恒星天体物理学实验模块（MESA）模型。对每个星团，我们识别出最亮的非变光红巨星，通过最佳拟合等时线推断其光度，并应用基于蒙特卡洛的校正，以处理红巨星分支的离散采样及变光星的排除。我们为每个星团单独将TRGB光度建模为g_ae及其不确定性的函数，并在似然分析中合并结果。我们未发现异常能量损失的迹象，在95%置信水平下得到g_ae<3.8×10^(-14)，TRGB热绝对星等的中位数为-3.53±0.05等。我们简要讨论了其对中微子磁偶极矩、毫带电粒子及其他新物理的意义。
英文摘要
Red-giant evolution is sensitive to non-standard channels of energy loss in stellar cores and therefore provides a probe of new physics. Such losses increase the luminosity of the tip of the red-giant branch (TRGB), the brightest point reached by a red giant in the color-magnitude diagram. Previous analyses of TRGB luminosities in globular clusters placed stringent bounds on the axion-electron coupling g_ae, but were limited by observational and theoretical uncertainties. To obtain a homogeneous and systematically controlled constraint, we use new parameters and TRGB estimates for 27 globular clusters, derived from Stetson, Hubble Space Telescope, and Gaia photometry and cluster-specific MESA calculations. Our primary likelihood uses 24 clusters after excluding three hot-flasher systems and adopts the brightest non-variable or well-sampled variable red giants. Finite sampling of the upper RGB is described by the full conditional distribution, and shared observational and stellar-physics uncertainties are retained as correlated nuisance parameters. A 95% power-constrained profile-likelihood limit is g_ae<6.4e-14. The median TRGB bolometric absolute magnitude is -3.54+-0.05 mag. We briefly discuss the implications for the neutrino magnetic dipole moment, millicharged particles, and other new physics.
Comments56 pages, 14 figures. V2: statistical analysis updated, new bound g13<0.64
