ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-05042007-121621


Tipo di tesi
Tesi di laurea specialistica
Autore
Tamburini, Matteo
URN
etd-05042007-121621
Titolo
A Minimal Model for Dark Matter. New Multiplet of Elementary Particles with Electroweak Gauge Coupling
Dipartimento
SCIENZE MATEMATICHE, FISICHE E NATURALI
Corso di studi
SCIENZE FISICHE
Relatori
Relatore Strumia, Alessandro
Parole chiave
  • Non Perturbative
  • Boltzmann equations
  • Dark Matter
Data inizio appello
25/05/2007
Consultabilità
Non consultabile
Data di rilascio
25/05/2047
Riassunto
There is a compelling observational evidence of the existence of Dark Matter (DM). The agreement between Big Bang Nucleosynthesis and WMAP predictions set an upper limit to the baryonic matter abundance which is much less than the observed mass abundancecalling for new physics beyond the Standard Model (SM).
In this thesis I focus on DM candidates that are minimal in the sense that only (or dominantly) couple via gauge interactions: elementary particles that fill one multiplet of dimension n of weak SU(2).
At classical level all components (neutral and charged) have the same mass. Due to spontaneous symmetry breakdown induced by Higgs’ doublet, quantum corrections generate a mass splitting. I renormalize the theory identifying in which cases the DM physics is predicted (and the lightest component turns out to be neutral) in terms of only one extra parameter beyond the SM: the tree level DM mass.
It is very likely that such a DM, like other SM particles, is a thermal relic of a primordial Big Bang. This last assumption allows to fix the tree level mass equating the thermal relic abundance to the observed DM abundance (assuming that this is the leading contribution to DM mass).
I computed the mass splitting (checking the renormalizability of the model), the DM annihilation cross section into SM particles (beyond the S-wave approximation) and solved the Boltzmann equations that describe DM freeze out, finding the DM thermal relic abundance and therefore the predicted DM mass.
The work presented in this thesis will be part of a future work, M. Cirelli, A. Strumia, M. Tamburini, to appear.
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