Hot and dark matter

In this thesis, we build new Effective Field Theory tools to describe the propagation of energetic partons in hot and dense media, and we propose two new reactions for dark matter in the early universe. In the first part, we analyze the transverse momentum broadening in the absence of radiation of an energetic parton propagating through quark-gluon plasma via Soft Collinear Effective Theory (SCET). We show that the probability for picking up transverse momentum ki is given by the Fourier transform of the expectation value of two transversely separated light-like path-ordered Wilson lines. We evaluate the result for the strongly coupled plasma of N = 4 SYM theory by using gauge/gravity duality, and for the weakly coupled QCD plasma by using perturbation theory. In the second part, we introduce two new dark matter reactions, called "semi-annihilation" and "assimilation". The semi-annihilation reaction takes the schematic form [psi]i[psi]j -> [psi]k[psi], where [psi]i are stable dark matter particles and # is an unstable state. They lead to non-trivial dark matter dynamics in the early universe, and they might also take place today in the Milky Way, enriching the (semi-)annihilation final state spectrum observed in indirect detection experiments. The "assimilation" reaction efficiently destroy singlet dark matter particles, but dark matter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) dark matter as well as (asymmetric) standard model baryons.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2012

Author dc:creator

• D'Eramo, Francesco

Advisor dc:contributor.advisor

• Hong Liu, Krishna Rajagopal and Jesse Thaler.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/76977

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/76977