Dark Z' Search and (Un)Natural Supersymmetric Models

[摘要] The Standard Model (SM) of particle physics is the most successful theory of particles and fundamental laws of nature. It has been tested numerous times for over forty years. Yet, it is considered to be incomplete. It does not incorporate gravity and does not explain dark matter or dark energy. The parameters in the SM are ad-hoc in nature and the Higgs mass is unstable to quantum corrections. The SM covers only ~ 5% of the energy-matter content of the cosmos.Dark matter (DM) has been indirectly observed via its gravitational effects on ordinary matter. Currently, there are no acceptable results from terrestrial experiments that can explain the particle properties of the DM. We consider several production models for a dark gauge boson, Z;; that mediates a dark force. We find that by introducing new cuts, we can optimize dilepton resonance and MET searches at the Large Hadron Collider that can efficiently look for the Z;; of mass of O(100 GeV). Supersymmetry (SUSY) is the most widely used framework for beyond the SM framework. It provides a good DM candidate and can achieve better gauge coupling unfication compared to the SM. For it to solve the hierarchy problem in a natural way, SUSY is expected to show itself at a scale of a few hundred GeVs. We present a model that combines two different SUSY breaking mechanisms allowing gaugino masses of O(TeV) and yet preserving naturalness in the theory. For this purpose, we introduce messenger fields resulting in a compressed gaugino spectrum. This more compressed spectrum is less constrained by LHC searches and allows for lighter gluinos. In addition to the model, we present gaugino pole mass equations that differ from (and correct) the original literature.We also consider the case where SUSY is not associated with the weak scale and solves the hierarchy problem by fine-tuning while retaining its other appealing features. A Mini-Split SUSY model is presented with SUSY scalars, msc in the mass range of 100 - 1000 TeV. Higgsino masses, if not at the Planck scale, should generically appear at the same scale. The gaugino mass contributions from anomaly mediation, with the heavy Higgsino threshold, generally leads to a more compressed spectrum than standard anomaly mediation, while the presence of extra vector-like matter near msc typically leads to an even more compressed spectrum. Heavy Higgsinos improve gauge coupling unification relative to the MSSM. This model achieves the experimentally observed mass of Higgs and has a DM candidate.

[发布机构] Johns Hopkins University

[效力级别] Dilepton Resonance

[关键词] Non-minimal Dark Matter;Dilepton Resonance;Gaugomaly Mediation;Mini-Split Supersymmetry;Physics