Target dependence of the annual modulation in direct dark matter searches

Understand

Due to Earth's revolution around the Sun, the expected scattering rate in direct dark matter searches is annually modulated.

• This modulation is expected to differ between experiments when given as a function of recoil energy $E_\text{R}$, e.g.
• due to the gravitational focusing effect of the Sun.
• A better variable to compare results among experiments employing different targets is the minimum speed $v_\text{min}$ a dark matter particle must have to impart a recoil energy $E_\text{R}$ to a target nucleus.