Constraints on inelastic dark matter from the CDEX-1B experiment
Authors
Y. F. Liang
L. T. Yang
Q. Yue
K. J. Kang
Y. J. Li
H. P. An
Greeshma C.
J. P. Chang
H. Chen
Y. H. Chen
J. P. Cheng
J. Y. Cui
W. H. Dai
Z. Deng
Y. X. Dong
C. H. Fang
H. Gong
Q. J. Guo
T. Guo
X. Y. Guo
L. He
J. R. He
H. X. Huang
T. C. Huang
S. Karmakar
Y. S. Lan
H. B. Li
H. Y. Li
J. M. Li
J. Li
M. C. Li
Q. Y. Li
R. M. J. Li
X. Q. Li
Y. L. Li
B. Liao
F. K. Lin
S. T. Lin
J. X. Liu
R. Z. Liu
S. K. Liu
Y. D. Liu
Y. Liu
Y. Y. Liu
H. Ma
Y. C. Mao
A. Mureed
H. Pan
N. C. Qi
J. Ren
X. C. Ruan
M. B. Shen
H. Y. Shi
M. K. Singh
T. X. Sun
W. L. Sun
C. J. Tang
Y. Tian
H. F. Wan
G. F. Wang
J. Z. Wang
L. Wang
Q. Wang
Q. Wang
Y. F. Wang
Y. X. Wang
H. T. Wong
Y. C. Wu
H. Y. Xing
K. Z. Xiong
R. Xu
Y. Xu
T. Xue
Y. L. Yan
N. Yi
C. X. Yu
H. J. Yu
X. Yu
M. Zeng
Z. Zeng
F. S. Zhang
P. Zhang
P. Zhang
Z. Y. Zhang
M. G. Zhao
J. F. Zhou
Z. Y. Zhou
J. J. Zhu
Abstract
We present limits on spin-independent inelastic weakly interacting massive particles (WIMP)-nucleus scattering using the 737.1 kg$\cdot$day dataset from the CDEX-1B experiment. Expected nuclear recoil spectra for various inelastic WIMP masses $m_χ$ and mass splittings $δ$ are calculated under the standard halo model. An accurate background model of CDEX-1B is constructed by simulating all major background sources. The model parameters are then determined through maximum likelihood estimation and Markov chain Monte Carlo fitting. The resulting 90\% confidence level upper limits on the WIMP-nucleon cross section $σ_{\mathrm{n}}$ exclude certain DAMA/LIBRA allowed regions: the $χ^2 < 4$ regions for $δ< 30$ keV at $m_χ= 250$ GeV and the $χ^2 < 9$ region for $δ< 50$ keV at $m_χ= 500$ GeV. The method is applicable to other inelastic dark matter scenarios, and the upcoming CDEX-50 experiment is expected to improve sensitivity by four orders of magnitude.
