The nature of dark matter remains obscure in spite of decades of experimental\nefforts. The mass of dark matter candidates can span a wide range, and its\ncoupling with the Standard Model sector remains uncertain. All these unknowns\nmake the etection of dark matter extremely challenging. Ultralight dark matter,\nwith $m \\sim10^{-22}$ eV, is proposed to reconcile the disagreements between\nobservations and predictions from simulations of small-scale structures in the\ncold dark matter paradigm, while remaining consistent with other observations.\nBecause of its large de Broglie wavelength and large local occupation number\nwithin galaxies, ultralight dark matter behaves like a coherently oscillating\nbackground field with an oscillating frequency dependent on its mass. If the\ndark matter particle is a spin-1 dark photon, such as the $U(1)_B$ or\n$U(1)_{B-L}$ gauge boson, it can induce an external oscillating force and lead\nto displacements of test masses. Such an effect would be observable in the form\nof periodic variations in the arrival times of radio pulses from highly stable\nmillisecond pulsars. In this study, we search for evidence of ultralight dark\nphoton dark matter (DPDM) using 14-year high-precision observations of 26\npulsars collected with the Parkes Pulsar Timing Array. While no statistically\nsignificant signal is found, we place constraints on coupling constants for the\n$U(1)_B$ and $U(1)_{B-L}$ DPDM. Compared with other experiments, the limits on\nthe dimensionless coupling constant $\\epsilon$ achieved in our study are\nimproved by up to two orders of magnitude when the dark photon mass is smaller\nthan $3\\times10^{-22}$~eV ($10^{-22}$~eV) for the $U(1)_{B}$ ($U(1)_{B-L}$)\nscenario.\n
Authors: Xiao Xue, Zi-Qing Xia, X. J. Zhu, Yue Zhao, Jing Shu, Qiang Yuan, N. D. R. Bhat, A D Cameron, Shi Dai, Yi Feng, B. Goncharov, G. Hobbs, Eric Howard, R. N. Manchester, A. Parthasarathy, Daniel J. Reardon, Craig Russell, R. M. Shannon, R. Spiewak, Nithyanandan Thyagarajan, Jingbo Wang, Lei Zhang, Songbo Zhang
DOI: https://doi.org/10.1103/physrevresearch.4.l012022
Publish Year: 2022
