结合DAMPE数据进行暗物质间接探测的本底研究

The measurements of cosmic ray antiprotons, electrons, positrons and gamma rays provide a unique method to search dark matter indirectly. The keypoint is that accurate cosmic ray backgounds should be calculated realiably. This work will mainly use the precise high energy data (including the proton spectrum, helium spectrum, elelctron spectrum and broton-to carbon ratio) measured by the Chinese mission DArk Matter Particle Explorer (DAMPE) as well as the results provided by PAMELA and AMS02 (especially deuteron/helium-4 ratio and helium-3/helium-4 ratio), to elaborately study the cosmic ray acceleration and propagation models. Besides, by combining the cosmic ray spectra in ISM published by Voyager1 and the periodic spectra measured by PAMELA and AMS02, we will study the solar modulation dependence on rigidity, time and charge. A more reasonable solar modulation approximation will be provided. This research will improve our understanding on cosmic ray acceleration and propagation mechanisms. Meanwhile it may also help us extract the possible signal from dark matter particles.

对宇宙线中反质子、电子、正电子及伽玛射线进行测量是寻找暗物质信号的独特手段，其中关键问题在于准确可靠的给出宇宙线本底信号。本项目将主要利用我国暗物质探测卫星DAMPE观测的高能高精度质子、氦核、电子能谱及硼碳比，以及国际宇宙线空间探测实验PAMELA、AMS02的测量结果，特别是氘核氦三核比及氦三核氦四核比，对宇宙线加速传播模型进行精细研究。同时，还将结合Voyager1测得的星际介质中的宇宙线能谱以及PAMELA和AMS02提供的周期性能谱，探讨太阳调制与磁刚度、时间、电荷数的关系，给出更合理的太阳调制近似。这一研究不仅能加深我们对宇宙线加速传播机制的理解，同时还将使我们对可能源于暗物质的特征信号有准确深入的认识。

准确的计算宇宙线本底一直是暗物质间接探测的关键问题之一。在本项目中，我们主要利用我国主导的暗物质探测卫星DAMPE、以及国际宇宙线探测实验PAMELA、AMS02的测量结果，对宇宙线加速传播模型进行了精细研究，重点探讨了：（1）2H/4He、3He/4He与B/C是否给出一致的宇宙线传播模型；（2）太阳调制是否依赖于磁刚度、电荷数等；（3）低能区宇宙线是否与高能区宇宙线行为一致。研究显示，2H/4He、3He/4He与B/C给出的结果在高能区较为一致，而在低能区存在较大差异。同时，依赖于磁刚度和带电符号的太阳调制模型相比力场近似能更好的解释数据。这一结果使我们进一步认识了宇宙线加速传播模型存在的不确定性，对推断和认识暗物质的本质具有重要意义。