【学术视频】江苏省物理学会春季学术会议2019 | 南京大学刘学文

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图 | 刘学文

题   目：Two-mediator dark matter models and cosmic electron excess

报告人：刘学文

单   位：南京大学

时   间：2019-05-11

地   点：扬州大学

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报告摘要

The cosmic electron energy spectrum recently observed by the DAMPE experiment exhibits two interesting features, including a break around 0.9 TeV and a sharp resonance near 1.4 TeV. In this analysis, we propose a dark matter explanation to both exotic features seen by DAMPE. In our model, dark matter annihilates in the galaxy via two different channels that lead to both a narrow resonance spectrum near 1.4 TeV and electron excess events over an extended energy range thus generating the break structure around TeV. The two annihilation channels are mediated by two gauge bosons that interact both with dark matter and with the standard model fermions. Dark matter annihilations through the s-channel process mediated by the heavier boson give rise to monoenergetic electron-positron pairs. The lighter boson has a mass smaller than the dark matter such that they can be on-shell produced in dark matter annihilations in the galaxy; the lighter bosons in the final state subsequently decay to generate the extended excess events due to the smeared electron energy spectrum in this process. We further analyze constraints from various experiments, including HESS, Fermi, AMS, and LHC, to the parameter space of the model where both excess events can be accounted for. In order to interpret the two new features in the DAMPE data, dark matter annihilation cross sections in the current galaxy are typically much larger than the canonical thermal cross section needed for the correct dark matter relic abundance. This discrepancy, however, is remedied by the non-perturbative Sommerfeld enhancement because of the existence of a lighter mediator in the model. 

个人简介

刘学文博士于2016年在南开大学物理科学学院获得理论物理博士学位。在2016年-2018年期间，在南京大学从事博士后研究工作。合作导师为国际著名教授刘佐伟老师。其主要研究方向为暗物质寻找即直接，间接探测，以及相应的新物理模型的构造。

会议简介

江苏省物理学会春季学术会议（JSPSSpring Meeting）是由江苏省物理学会主办的年度学术会议，会议旨在增进江苏物理学界的学术交流，提高学术水平，促进物理学科的全面发展和人才培养。2019年5月10-12日，江苏省物理学会第三届春季学术会议在扬州召开，本届会议由扬州大学物理学院承办。

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