http://arxiv.org/abs/1810.00399
We derive model-independent astrophysical constraints on leptophilic dark matter (DM), considering its thermal production in a supernova core and taking into account core temperature fluctuations within the framework of $q$-deformed Tsallis statistics. In an effective field theory approach, where the DM fermions interact with the Standard Model via dimension-six operators of either scalar-pseudoscalar, vector-axial vector, or tensor-axial tensor type, we obtain lower bounds on the effective cut-off scale $\Lambda$ from supernova cooling and free-streaming of DM from supernova core, and upper bounds on $\Lambda$ from thermal relic density considerations, depending on the DM mass and the $q$-deformation parameter. Using Raffelt’s criterion on the energy loss rate from SN1987A, we obtain a lower bound on $\Lda \gtrsim 3$ (12) TeV corresponding to $q = 1.0~(1.1)$ and an average supernova core temperature of $T_{\rm SN}=30$ MeV. From the optical depth criterion on the free-streaming of DM fermions from the outer 10\% of the SN1987A core, we obtain a weaker lower bound on $\Lda \gtrsim 1$ TeV. Both cooling and free-streaming bounds are insensitive to the DM mass $m_\chi$ for $m_\chi\lesssim T_{\rm SN}$, whereas for $m_\chi\gg T_{\rm SN}$, the bounds weaken significantly due to the Boltzmann-suppression of the DM number density. We also calculate the thermal relic density of the DM particles in this setup and find that it imposes an upper bound on $\Lambda^4/m_\chi^2$, which is in conflict with the supernova cooling/free-streaming bounds for a wide range of DM mass. From this, we obtain a model-independent {\it lower} bound of $m_\chi \gtrsim$ 200 MeV–1 GeV on the leptophilic DM, which only depends on the operator type and $q$-deformation parameter.
A. Guha, P. Dev and P. Das
Tue, 2 Oct 18
73/84
Comments: 24 pages, 9 figures
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