Computation of Dark Matter Signals in Graphene Detectors
Typ
Examensarbete för kandidatexamen
Program
Publicerad
2020
Författare
Andersson, Julia
Grönfors, Ebba
Hellekant, Christoffer
Lindblad, Ludvig
Resare, Fabian
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Modern cosmology proposes the existence of some unknown substance constituting
85% of the mass of the universe. This substance has been named dark matter and
has been hypothesised to be composed of an as of yet unknown weakly interacting
particle. Recently, the use of graphene as target material for the direct detection
of dark matter has been suggested. This entails the study of the dark matter induced
ejection of graphene valence electrons. In this thesis, we calculate the rate
of graphene valence electron ejection under the assumption of different dark matter
models, specifically where the squared modulus of the scattering amplitude scales
like |q|2 or |q|4, where q is the momentum transfer. These models have not previously
been considered. We initially derive analytic expressions for the electron
ejection rate of these models, which we then evaluate numerically through the use
of Python. The ejection rate is then plotted as a function of the electron ejection
energy. We find that the electron ejection rate declines less rapidly in the models
studied here than in the case of a constant scattering amplitude, i.e. the only case
previously studied. The main challenge in these calculations is the high complexity
of multidimensional integrals, the evaluation of which necessitated approximately
15,000 core hours.
Beskrivning
Ämne/nyckelord
Dark matter , WIMP , SHM , Graphene , Scattering amplitude , Electron ejection rate