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The Electroweak Phase Transition within natural GNMSSM models

Image courtesy of: http://www.symmetrymagazine.org/article/october-2012/what-else-could-the-higgs-be. The Electroweak Phase Transition within natural GNMSSM models. Presenter: Christopher Harman Supervisor: Dr. Stephan Huber University of Sussex. What is supersymmetry?.

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The Electroweak Phase Transition within natural GNMSSM models

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  1. Image courtesy of: http://www.symmetrymagazine.org/article/october-2012/what-else-could-the-higgs-be The Electroweak Phase Transition within natural GNMSSM models Presenter: Christopher Harman Supervisor: Dr. Stephan Huber University of Sussex

  2. What is supersymmetry? SUPERSYMMETRY INVARIANT THEORY SUSY STAN

  3. What is supersymmetry? SUPERSYMMETRY INVARIANT THEORY SUSY STAN

  4. What is natural supersymmetry? FESTIVE EDITION

  5. What is natural supersymmetry? unnatural natural

  6. What is natural supersymmetry? excluded unnatural natural

  7. What is the MSSM? MSSM: Minimal Supersymmetric Standard Model Motivation: To address deviations (?) and physics not addressed by the Standard Model Theory: A type II 2HDM with supersymmetry invariance at the high-scale and soft SUSY broken terms to describe the low energy scales

  8. What is the NMSSM? NMSSM: Next-to-MSSM Motivation: To resolve the μ-problem Theory: Include a singlet chiral superfield into the Higgs sector of the MSSM

  9. What is the GNMSSM? GNMSSM: Generalised NMSSM Motivation: Include all possible renormalisable terms in the superpotential Not in the scale-invariant NMSSM

  10. Aim of the project

  11. Aim of the project

  12. The one loop zero temperature potential The (effective) potential is given by with CP violating phases ``switched off’’. It contains the following free parameters

  13. Parameter point scan

  14. Parameter point scan Randomly assign a (natural) value

  15. Parameter point scan Randomly assign a (natural) value Ensure: • No linear term in S at the zero field value • Zero field minimum and EW broken minimum are degenerate (CHOICE!)

  16. Parameter point scan Randomly assign a (natural) value Ensure: • No linear term in S at the zero field value • Zero field minimum and EW broken minimum are degenerate (CHOICE!) Record parameter points satisfying certain criteria, e.g.: stable potential, physical masses.

  17. At tree level At tree level, we find but this is insufficient for a 125 GeV Higgs… … go to one-loop level!

  18. Aim of the project

  19. Aim of the project

  20. Parameter point scan

  21. Parameter point scan Choose a specific stop structure: • No gauge eigenstate mixing: • Stop soft mass deviation:

  22. Parameter point scan Choose a specific stop structure: • No gauge eigenstate mixing: • Stop soft mass deviation: Assign a value to Δm3 and scan over natural values of mQ3 until a 125 GeV Higgs is obtained

  23. Parameter point scan (two distinct potential shapes) TYPE 1 Tree 1 loop

  24. Parameter point scan (two distinct potential shapes) TYPE 1 1 loop

  25. Parameter point scan (two distinct potential shapes) TYPE 2 Tree 1 loop

  26. Parameter point scan (two distinct potential shapes) TYPE 2 1 loop

  27. Aim of the project

  28. Aim of the project

  29. One loop finite temperature potential Include to the potential the following term: We implement this into our program and obtain values for the critical temperature and critical VEV by numerical means

  30. One loop level (finite temperature) We implement this into our program and obtain values for the critical temperature and critical VEV by numerical means Tree 1 loop (0T) 1 loop (finite T) TYPE 1 TYPE 2

  31. Aim of the project

  32. Aim of the project

  33. Aim of the project

  34. Outlook CONCLUSIONS: • Can have a 125 GeV Higgs in the GNMSSM • EWPT is found to be rather strongly first order for around 200 natural parameter points FUTURE WORK: • Relax some of our choices: • Tree-level minima degeneracy (Aλ choice); • No stop mixing (At choice); • Stop soft mass deviation (Δm3 choice) • Repeat the analysis

  35. Thank you! S. Martin, A SUSY Primer: http://arxiv.org/abs/hep-ph/9709356 U. Ellwanger, The NMSSM: http://arxiv.org/abs/arXiv:0910.1785 G. Ross et al., The GNMSSM at one loop: fine tuning and phenomenology G. Anderson and L. Hall, The Electroweak phase transition and baryogenesis

  36. The tree-level potential • Gauge eigenstate basis: • Mass eigenstate basis: CP-even part CP-odd part Charged part

  37. One-loop level (zero temperature) Green – Exact solution with degenerate stops Red – Naïve solution with non-degenerate stops

  38. One-loop level (finite temperature) Include to the potential the following term: Piece-wise analytic function can be constructed

  39. Finite temperature potential (analytic)

  40. Parameter scan statistics Models with an unstable singlet potential only: 17.9477 % Models with at least one unphysical mass only: 6.40353 % Models with both of the above issues: 73.7124 % Models with none of the above issues: 1.93641 % Runs: 20192 Successes: 20192

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