High Energy Physics Seminar

Sub-GeV dark matter is challenging to probe via traditional elastic recoils measurements, but can leave measurable signals via inelastic processes such as ionization and phonons in semiconductor detectors. Dark matter only coupling to nucleons can still give rise to ionization via the Migdal effect, where a small nuclear recoil is accompanied by a prompt electron emission. In this talk, I will discuss how to quantify the Migdal effect in semiconductors in the regime of low momentum transfer where the final state of the nucleus is no longer well described by a plane wave,  allowing the Migdal effect in semiconductors to be evaluated even for the lightest dark matter candidates (m_{dm} ~ 1 MeV) that can kinematically excite electrons. In this regime the Migdal electron may be accompanied by a single phonon or multiphonon signal. I will discuss the prospect of measuring phonon signals in next generation detectors, as well as the backgrounds those measurements are subject to. 

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