Search for a drifting proton electron mass ratio from H2
Search for a drifting proton electron mass ratio from H2
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寻找 H2 的漂移质子电子质量比
DOI：
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发表时间：
2016
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影响因子：
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通讯作者：
W. Ubachs
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文献类型：
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作者：
W. Ubachs
本文综述了用H2类星体吸收方法研究质子电子质量比μ = mp/me在宇宙学时间尺度上的可能变化[1]。该方法是基于在H2莱曼和维尔纳波段的吸收线的波长之间的比较，在高红移与零红移在实验室中测量的相同的线的波长。对于这种比较，计算所有单个线的μ相对变化的灵敏度系数，并将其包括在计算μ/μ值的程序中。天文光谱分析的细节，获得与大型8 - 10米级光学望远镜，配备高分辨率中阶梯光栅光谱仪，进行了解释。本文综述了H2分子光谱学的实验室研究方法和结果，特别是用于测定莱曼带和维尔纳带吸收线的静止波长的激光计量学研究。布里里将讨论提供变化μ的基本原理的理论物理方案，以及探测μ变化的替代光谱方法，而不是H2方法。此外，最近的一种方法来检测质子与电子的质量比对环境条件的依赖性，如强引力ELD的存在，将突出显示。目前已知约56种H2吸收系统。它们的有用性检测μ变化进行了讨论，在柱密度和亮度的背景类星体源，沿着与未来的观测策略。到目前为止，对10个类星体系统的天文观测分析对质子-电子质量比的变化设定了一个限制，|μ/μ| < 5 × 10−6（3-σ），这是一个零结果，适用于z = 2.0 − 4.2范围内的红移。这相当于宇宙历史的10 124亿年的回顾时间。试图解释这10个H2吸收器的结果在μ的空间变化方面目前受到小样本大小和它们在天空中相对狭窄的波段中的巧合分布的阻碍。
An overview is presented of the H2 quasar absorption method to search for a possible variation of the proton electron mass ratio μ = mp/me on a cosmological time scale [1]. The method is based on a comparison between wavelengths of absorption lines in the H2 Lyman and Werner bands as observed at high redshift with wavelengths of the same lines measured at zero redshift in the laboratory. For such comparison sensitivity coe cients to a relative variation of μ are calculated for all individual lines and included in the tting routine deriving a value for ∆μ/μ. Details of the analysis of astronomical spectra, obtained with large 8 10 m class optical telescopes, equipped with high-resolution echelle grating based spectrographs, are explained. The methods and results of the laboratory molecular spectroscopy of H2, in particular the laser-based metrology studies for the determination of rest wavelengths of the Lyman and Werner band absorption lines, are reviewed. Theoretical physics scenarios delivering a rationale for a varying μ will be discussed brie y, as well as alternative spectroscopic approaches to probe variation of μ, other than the H2 method. Also a recent approach to detect a dependence of the proton-to-electron mass ratio on environmental conditions, such as the presence of strong gravitational elds, will be highlighted. Currently some 56 H2 absorption systems are known. Their usefulness to detect μ-variation is discussed, in terms of column densities and brightness of background quasar sources, along with future observational strategies. The astronomical observations of ten quasar systems analyzed so far set a constraint on a varying proton-electron mass ratio of |∆μ/μ| < 5 × 10−6 (3-σ), which is a null result, holding for redshifts in the range z = 2.0 − 4.2. This corresponds to look-back times of 10 12.4 billion years into cosmic history. Attempts to interpret the results from these 10 H2 absorbers in terms of a spatial variation of μ are currently hampered by the small sample size and their coincidental distribution in a relatively narrow band across the sky.