Constraining Dark Matter Models with a Light Mediator at the PandaX-II Experiment.

Xiangxiang Ren,Qibin Zheng,Di Huang,Yonglin Ju,Xiangdong Ji,Changda He,Yao Li,Siguang Wang,Hai-Bo Yu,Pengwei Xie,Xuyuan Guo,Hongwei Wang,Jianglai Liu,Xun Chen,Qiuhong Wang,Jifang Zhou,Jianfeng Yue,Yugang Ma,Linhui Gu,Jingkai Xia,Binbin Yan,Meng Wang,Abdusalam Abdukerim,Shengming He,Huaxuan Liu,Li Zhao,Xiuli Wang,Jijun Yang,Xiaopeng Zhou,Karl Giboni,Yunhua Chen,Jinhua Ning,Tao Zhang,Changbo Fu,Andi Tan,Deqing Fang,K Han ,Y Yang ,K Ni ,N Zhou ,X F Cui ,Y Mao ,Huibin Lin ,X T Huang ,M Xiao ,Shengji Wu ,F Giuliani ,Zhongqiang Huang

doi:10.1103/physrevlett.121.021304

Abstract

We search for nuclear recoil signals of dark matter models with a light mediator in PandaX-II, a direct detection experiment in the China Jinping underground laboratory. Using data collected in 2016 and 2017 runs, corresponding to a total exposure of 54ton day, we set upper limits on the zero-momentum dark matter-nucleon cross section. These limits have a strong dependence on the mediator mass when it is comparable to or below the typical momentum transfer. We apply our results to constrain self-interacting dark matter models with a light mediator mixing with standard model particles, and set strong limits on the model parameter space for the dark matter mass ranging from 5GeV to 10TeV.

Highlights

We search for nuclear recoil signals of dark matter models with a light mediator in PandaX-II, a direct detection experiment in the China Jinping underground laboratory
We apply our results to constrain self-interacting dark matter models with a light mediator mixing with standard model particles, and set strong limits on the model parameter space for the dark matter mass ranging from 5 GeV to 10 TeV
In this Letter, we report upper limits on the dark matter (DM)-nucleon scattering cross section induced by a light mediator and interpret them to constrain the self-interacting DM (SIDM) models proposed in Ref. [4]

Summary

Published by the American Physical Society

Signal event in direct detection can be enhanced towards low recoil energies, a smoking-gun signature of SIDM [4,6,7,18]. Z v≥vmin d3vvfðv; tÞ; ð2Þ where ρ is the local DM density which we set to be 0.3 GeV=cm, mχ is the DM particle mass, fðv; tÞ is the time-dependent DM velocity distribution relative to the detector, and vmin is the minimum DM velocity that results in a recoil energy E This analysis uses the same data sets as the recent WIMP search (unblind) in PandaX-II [22], consisting of 80 live days of exposure in 2016 and 77 live days of exposure in 2017, the largest published data set of its kind to date. We plot PandaX-II detection efficiency as a function of S1 (magenta) It is nearly a constant over the range of 10–45 PE, but is reduced dramatically for S1 < 10 PE, where the event rate of the light-mediator model is maximized.

Detection efficiency

CMB excluded