论文标题
棕色矮人的伽玛 - 射线通量极限：对暗物质的影响，将其歼灭成长寿的调解人
Gamma-ray flux limits from brown dwarfs: Implications for dark matter annihilating into long-lived mediators
论文作者
论文摘要
棕色矮人（BDS）是代表最少巨大的恒星和巨型气体行星之间联系的天体物体。在本文的第一部分中，我们在\ fermi-lat数据的13年中从附近的9个BDS方向执行了与模型无关的搜索。我们发现没有显着的伽马射线过量，因此，我们使用binned-likelihood方法在伽马射线通量上设定了95 \％置信度的上限。在本文的第二部分中，我们将这些界限解释为在BDS中提出的外来机制中：如果宇宙的暗物质（DM）由具有不可忽略的耦合的粒子构成，则BDS可能会通过散射通过散射来有效地积累它们。 DM颗粒最终会进行热度，并可以将其灭入光，寿命长的介体中，后来腐烂到BD以外的光子。在此框架内，当前的Fermi-LAT堆叠在所选BDS的伽马射线通量上的上限不会使设置在DM-Nucleon横截面上绑定。需要在伽马射线限制中提高大约9倍的倍数，以在散射横截面$σ_{χn} $ $ \ sim 10^{ - 36} $ cm $^{2} $以下的dm群体上获得界限。这种改进将涵盖介体衰减长度和DM质量中参数空间的较大部分。可以在\ github {https://gitlab.in2p3.fr/francesca.calore/brown-dwarfs-gamma}上获得重现这项研究结果的代码和数据。
Brown dwarfs (BDs) are celestial objects representing the link between the least massive main-sequence stars and giant gas planets. In the first part of this article, we perform a model-independent search of a gamma-ray signal from the direction of nine nearby BDs in 13 years of \Fermi-LAT data. We find no significant excess of gamma rays, and we, therefore, set 95\% confidence level upper limits on the gamma-ray flux with a binned-likelihood approach. In the second part of the paper, we interpret these bounds within an exotic mechanism proposed for gamma-ray production in BDs: If the dark matter (DM) of the universe is constituted of particles with non-negligible couplings to the standard model, BDs may efficiently accumulate them through scatterings. DM particles eventually thermalise, and can annihilate into light, long-lived, mediators which later decay into photons outside the BD. Within this framework, the current Fermi-LAT stacked upper limits on the gamma-ray flux of the selected BDs do not enable setting a bound on the DM-nucleon cross-section. An improvement of approximately a factor of 9 in the gamma-ray limits is required to obtain bounds on the scattering cross-section $σ_{χn}$ $\sim 10^{-36}$ cm$^{2}$ for DM masses below 10 GeV. This improvement would cover a larger portion of the parameter space in mediator decay length and DM mass. The code and data to reproduce the results of this study are available on GitLab at \github{https://gitlab.in2p3.fr/francesca.calore/brown-dwarfs-gamma}.
