| 1. |
- Calibbi, Lorenzo, et al.
(författare)
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Constraints on baryon number violation in supersymmetry from searches for neutron-antineutron oscillations and other observables
- 2016
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Ingår i: Proceedings of Science. - 1824-8039. ; Part F128560
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Konferensbidrag (refereegranskat)abstract
- Baryon number violation (BNV) in R-parity violating (RPV) supersymmetry is studied with a focus on ΔB = 2 processes which allow neutron-anti-neutron (n-n) oscillations. Simplified RPV-SUSY models, including only the relevant superpartners and couplings, are considered. Constraints from flavour physics, searches at the Large Hadron Collider and searches at dedicated BNV experiments are quantified for the various scenarios at the TeV scale. It is also shown that a proposed n-n experiment at the European Spallation Source has a sensitivity to a mass scale for new physics that goes beyond all other experiments and up to the PeV scale for certain regions of parameter space.
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| 2. |
- Calibbi, Lorenzo, et al.
(författare)
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Selectron NLSP in gauge mediation
- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 2014:9, s. Article no. 133 -
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Tidskriftsartikel (refereegranskat)abstract
- We discuss gauge mediation models in which the smuon and the selectron are mass-degenerate co-NLSP, which we, for brevity, refer to as selectron NLSP. In these models, the stau, as well as the other superpartners, are parametrically heavier than the NLSP. We start by taking a bottom-up perspective and investigate the conditions under which selectron NLSP spectra can be realized in the MSSM. We then give a complete characterization of gauge mediation models realizing such spectra at low energies. The splitting between the slepton families is induced radiatively by the usual hierarchies in the Standard Model Yukawa couplings and hence, no new sources of flavour misalignment are introduced. We construct explicit weakly coupled messenger models which give rise to selectron NLSP, while accommodating a 126 GeV MSSM Higgs mass, both within the framework of General Gauge Mediation and in extensions where direct couplings between the messengers and the Higgs fields are present. In the latter class of models, large A-terms and relatively light stops can be achieved. The collider signatures of these models typically involve multilepton final states. We discuss the relevant LHC bounds and provide examples of models where the decay of the NLSP selectron is prompt, displaced or long-lived. The prompt case can be viewed as an ultraviolet completion of a simplified model recently considered by the CMS collaboration.
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| 3. |
- Ferretti, Gabriele, 1963, et al.
(författare)
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Baryon number violation in supersymmetry: n - (n)over-bar oscillations as a probe beyond the LHC
- 2016
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 5:5, s. Art. no. 144-
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Tidskriftsartikel (refereegranskat)abstract
- We summarize the current status of baryon number violation in supersymmetry and provide prospects for going beyond the present reach by means of a new search for neutron-antineutron oscillations. The main motivation is the recently proposed neutron-antineutron oscillation experiment at the European Spallation Source in Lund, Sweden, which is projected to be able to improve the current bound on the transition probability in the quasi-free regime by three orders of magnitude. We consider various processes involving superpartners that give rise to neutron-antineutron oscillations and extract the corresponding simplified models, including only the most relevant superpartners and couplings. In terms of these models we recast and determine the exclusion limits from LHC searches as well as from searches for flavor transitions, CP violation and di-nucleon decays. We find that, for certain regions of the parameter space, the proposed neutron-antineutron experiment has a reach that goes beyond all other experiments, as it can probe gluino and squark masses in the multi-TeV range.
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