Supersymmetric left-right models: LHC-phenomenology, parameter determination and model discrimination

• Applicant: Professor Dr. Werner R. Porod
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2012 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 212523604

• Final Report Year: 2017

Final Report Abstract

The LHC-experiments at CERN have started with the exploration of the tera-electron-voltscale. With this they have entered an energy range which had not been explored before by a terrestrial experiment. The first phase culminated in the discovery of a Higgs-boson with a mass of 125 GeV. This has far reaching consequences for particle physics models beside being an extremely important discovery on its on. Despite the fact, that this completes the Standard Model of particle physics there are several hints that this model needs to be extended. The two main reasons are the observed neutrino masses as well as the need for a dark matter candidate. Supersymmetric models are among the best motived extensions of the Standard Model (SM) of particle physics. They are not only interesting for particle physics but also for cosmology as they contain for example candidates for the observed dark matter. Moreover they have the potential to explain the observed asymmetry of matter versus anti-matter in the Universe. A natural explanation of neutrino occurs in so-called left-right symmetric models, e.g. an extension of the Standard Model gauge group. The combination of these models with supersymmetry and the consequences for phenomenology have been the main foci of this project. In the course of this project we have constructed different variants of left-right symmetric models consistent with gauge coupling unification and neutrino data while predicting at the same time additional vector bosons in the TeV range. Moreover, they predict additional Higgs bosons and in several cases also additional matter states. On the one hand we have explored, which of the excesses in the ATLAS and CMS data of the first run could be explained by these models. We have also worked out which additional predictions exist in the corresponding regions of parameter space. For example one of the investigated model classes predicted in the corresponding part of parameter space the existence of a right-handed neutrino with a mass below 200 GeV and also a relatively light doubly charged Higgs boson which is detectable in the current run of LHC. A further prediction are the existence of additional light neutral Higgs bosons, which are singlets under the Standard Model gauge group. While their direct production cross section at LHC is tiny, they can be produced in the cascade decays of supersymmetric particles. We also have worked out, to which extent existing LHC analyses constrain the parameter space of such models and found cases where existing limits on certain particles are substantially modified as in complete models new decay possibilities exist which have not been considered by the experimental collaborations for the searches. These models do not only predict additional particles which are searched for in collider experiments but they predict also flavour violating decay modes of leptons which are not present in the Standard Model. For such decay modes severe experimental bounds exists. Consequently they have been taken into account in this project. We have also estimated to which extent upcoming experiments such as Mu3e or Belle 2 can constrain such models further and found that they will be able for certain models to exclude a substantial part of the possible parameter space if no signal is detected. Moreover, we have developed in the course of this project the publicly available Flavor Kit package which allows an easy evaluation of flavour observables, both in the lepton as well as in the quark sector, for extensions of the Standard Model, both supersymmetric and non-supersymmetric ones.

Publications

• Implications of the 98 GeV and 125 GeV Higgs scenarios in nondecoupling supersymmetry with updated ATLAS, CMS, and PLANCK data, Phys. Rev. D 88 (2013) no.3, 035011
  B. Bhattacherjee, M. Chakraborti, A. Chakraborty, U. Chattopadhyay, D. Das and D. K. Ghosh
  
• A Flavor Kit for BSM models, Eur. Phys. J. C 74 (2014) no.8, 2992
  W. Porod, F. Staub and A. Vicente
  
• Constrained minimal Dirac gaugino supersymmetric standard model, Phys. Rev. D 90 (2014) no.4, 045017
  K. Benakli, M. Goodsell, F. Staub and W. Porod
  
• Lepton flavor violation in low-scale seesaw models: SUSY and non-SUSY contributions, JHEP 1411 (2014) 048
  A. Abada, M. E. Krauss, W. Porod, F. Staub, A. Vicente and C. Weiland
  
• Is the CMS eejj excess a hint for light supersymmetry?, Phys. Rev. D 92 (2015) no.5, 055019
  M. E. Krauss and W. Porod
  
• A constrained supersymmetric left-right model, JHEP 1603 (2016) 009
  M. Hirsch, M. E. Krauss, T. Opferkuch, W. Porod and F. Staub