Prospects for detection of target-dependent annual modulation in direct dark matter searches

Understand

Earth's rotation about the Sun produces an annual modulation in the expected scattering rate at direct dark matter detection experiments.

• The annual modulation as a function of the recoil energy $E_\text{R}$ imparted by the dark matter particle to a target nucleus is expected to vary depending on the detector material.
• However, for most interactions a change of variables from $E_\text{R}$ to $v_\text{min}$, the minimum speed a dark matter particle must have to impart a fixed $E_\text{R}$ to a target nucleus, produces an annual modulation independent of the target element.
• We recently showed that if the dark matter-nucleus cross section contains a non-factorizable target and dark matter velocity dependence, the annual modulation as a function of $v_\text{min}$ can be target dependent.