Fig. 3: Millicharged particles interacting with electrons, ε = 10−4. | Communications Physics

Fig. 3: Millicharged particles interacting with electrons, ε = 10−4.

From: Collective excitations and low-energy ionization signatures of relativistic particles in silicon detectors

Fig. 3

a The differential cross section of millicharged particle with charge ε = 10−4e− scattering in a silicon target, given in units of cm2 eV−1 per unit cell. Blue line corresponds to the Lindhard model68, orange and green lines corresponds to DarkELF (Mermin) and DarkELF (GPAW) respectively24,25, and the red line corresponds to QCDark28. The black line assumes the Photo Absorption Ionization (PAI) model57,58 in which the dielectric function is inferred exclusively from optical measurements. The QCDark rates are calculated by screening the QCDark Im\(\left\{\epsilon (\omega ,k)\right\}\) with a Lindhard \({\left\vert \epsilon (\omega ,k)\right\vert }^{2}\) (see Eq. (7)), and are Gaussian smoothed with σω = 0.5 eV, while the DarkELF and Lindhard lines use a fully self-consistent ϵ(ω, k). b The cross section calculated as a function of the number of electron-hole pairs created, where we use the secondary ionization model from ref. 88 at 100 K. Note the peaks at Q = 4 e− and Q = 5 e−.

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