Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Direct constraints on minimal supersymmetry from Fermi-LAT observations of the dwarf galaxy Segue 1
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Show others and affiliations
2010 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, no 1, 31-50 p.Article in journal (Refereed) Published
Abstract [en]

The dwarf galaxy Segue 1 is one of the most promising targets for the indirect detection of dark matter. Here we examine what constraints 9 months of Fermi-LAT gamma-ray observations of Segue 1 place upon the Constrained Minimal Supersymmetric Standard Model (CMSSM), with the lightest neutralino as the dark matter particle. We use nested sampling to explore the CMSSM parameter space, simultaneously fitting other relevant constraints from accelerator bounds, the relic density, electroweak precision observables, the anomalous magnetic moment of the muon and B-physics. We include spectral and spatial fits to the Fermi observations, a full treatment of the instrumental response and its related uncertainty, and detailed background models. We also perform an extrapolation to 5 years of observations, assuming no signal is observed from Segue 1 in that time. Results marginally disfavour models with low neutralino masses and high annihilation cross-sections. Virtually all of these models are however already disfavoured by existing experimental or relic density constraints.

Place, publisher, year, edition, pages
2010. no 1, 31-50 p.
Keyword [en]
dark matter theory, dwarfs galaxies, supersymmetry and cosmology, gamma ray theory
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:su:diva-38209DOI: 10.1088/1475-7516/2010/01/031OAI: oai:DiVA.org:su-38209DiVA: diva2:308042
Available from: 2010-04-01 Created: 2010-04-01 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Searches for Particle Dark Matter: Dark stars, dark galaxies, dark halos and global supersymmetric fits
Open this publication in new window or tab >>Searches for Particle Dark Matter: Dark stars, dark galaxies, dark halos and global supersymmetric fits
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The identity of dark matter is one of the key outstanding problems in both particle and astrophysics. In this thesis, I describe a number of complementary searches for particle dark matter. I discuss how the impact of dark matter on stars can constrain its interaction with nuclei, focussing on main sequence stars close to the Galactic Centre, and on the first stars as seen through the upcoming James Webb Space Telescope. The mass and annihilation cross-section of dark matter particles can be probed with searches for gamma rays produced in astronomical targets. Dwarf galaxies and ultracompact, primordially-produced dark matter minihalos turn out to be especially promising in this respect. I illustrate how the results of these searches can be combined with constraints from accelerators and cosmology to produce a single global fit to all available data. Global fits in supersymmetry turn out to be quite technically demanding, even with the simplest predictive models and the addition of complementary data from a bevy of astronomical and terrestrial experiments; I show how genetic algorithms can help in overcoming these challenges.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2010. 84 p.
Keyword
dark matter, supersymmetry, gamma rays, dwarf galaxies, stellar evolution, cosmological perturbations, phase transitions, statistical techniques
National Category
Subatomic Physics Subatomic Physics Astronomy, Astrophysics and Cosmology Subatomic Physics Other Physics Topics Astronomy, Astrophysics and Cosmology Astronomy, Astrophysics and Cosmology
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:su:diva-38221 (URN)978-91-7447-031-4 (ISBN)
Public defence
2010-05-04, FD5, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 15:15 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Accepted. Paper 6: Submitted. Available from: 2010-04-12 Created: 2010-04-01 Last updated: 2010-04-07Bibliographically approved
2. Supersymmetry vis-à-vis Observation: Dark Matter Constraints, Global Fits and Statistical Issues
Open this publication in new window or tab >>Supersymmetry vis-à-vis Observation: Dark Matter Constraints, Global Fits and Statistical Issues
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Weak-scale supersymmetry is one of the most favoured theories beyond the Standard Model of particle physics that elegantly solves various theoretical and observational problems in both particle physics and cosmology. In this thesis, I describe the theoretical foundations of supersymmetry, issues that it can address and concrete supersymmetric models that are widely used in phenomenological studies. I discuss how the predictions of supersymmetric models may be compared with observational data from both colliders and cosmology. I show why constraints on supersymmetric parameters by direct and indirect searches of particle dark matter are of particular interest in this respect. Gamma-ray observations of astrophysical sources, in particular dwarf spheroidal galaxies, by the Fermi satellite, and recording nuclear recoil events and energies by future ton-scale direct detection experiments are shown to provide powerful tools in searches for supersymmetric dark matter and estimating supersymmetric parameters. I discuss some major statistical issues in supersymmetric global fits to experimental data. In particular, I further demonstrate that existing advanced scanning techniques may fail in correctly mapping the statistical properties of the parameter spaces even for the simplest supersymmetric models. Complementary scanning methods based on Genetic Algorithms are proposed.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2011. 142 p.
Keyword
supersymmetry, cosmology of theories beyond the Standard Model, dark matter, gamma rays, dwarf galaxies, direct detection, statistical techniques, scanning algorithms, genetic algorithms, statistical coverage
National Category
Subatomic Physics Astronomy, Astrophysics and Cosmology Subatomic Physics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:su:diva-57194 (URN)978-91-7447-312-4 (ISBN)
Public defence
2011-06-07, room FA32, AlbaNova University Center, Roslagstullsbacken 21, Stockholm, 13:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.Available from: 2011-05-12 Created: 2011-05-03 Last updated: 2011-06-28Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Scott, P.Conrad, JanEdsjö, JoakimBergström, LarsAkrami, Yashar
By organisation
Department of Physics
In the same journal
Journal of Cosmology and Astroparticle Physics
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 49 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf