Theory and Phenomenology of New Particles in the Standard Model and Beyond

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The landmark discovery of the Higgs boson by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC) are accompanied by exciting hadronic physics discoveries by LHCb on the charmonium-like XYZ hadronic states (e.g., the recent confirmation of the charged Z(4430) state). These LHC experimental collaborations illustrate the main two themes of my research program: theoretical studies of the Higgs sector and exotic hadrons. ***In electroweak symmetry breaking mechanisms with classically scale-invariant Higgs sectors, the Higgs mechanism emerges from the quantum corrections to the effective potential (i.e. the Coleman-Weinberg mechanism). In this approach, the experimentally observed 125 GeV Higgs mass can be accommodated in these scale-invariant models by a large Higgs self-coupling solution, and the small mass scale of the Higgs boson is attributed to a custodial classical scale-invariance symmetry.  With the inclusion of a Higgs portal interaction, extensions of this mechanism beyond the Standard Model  provides a natural scenario for cosmologically-stable dark matter. ***My proposed research includes exploration of classically scale-invariant extensions of the Higgs sector to two-doublet models, and to hidden sector dark-matter models with Higgs portal interactions. The purpose of this program is to provide predictions from these scenarios that can help interpret future experimental results emerging from the LHC, new Higgs experimental programs, and dark matter searches. The eventual measurement of the Higgs self-coupling will be particularly important, because it is one of the striking signals of the scale-invariant Higgs mechanism.***Another exciting area in particle physics are the intriguing observations of the charmonium-like XYZ mesons that challenge our concepts of conventional quark-antiquark models of mesons. The Zc(3900) observed by BESIII and Belle along with the Zc(4430) observed by Belle and confirmed by LHCb are the most striking examples, because their minimal quark content requires a tetraquark configuration. ***My proposed research includes study of QCD exotica; states that go beyond conventional quark-antiquark  models of mesons.  QCD sum-rule methods will be used to study the mass spectrum  and decay decay modes of the Zc states, with a goal of distinguishing between competing interpretations for these states.  A comprehensive QCD sum-rule study of the spin-zero and spin-one light and heavy-light hybrids (states composed of a quark, antiquark, and gluonic excitation) with conventional and exotic JPC will be conducted, with a goal of identifying overall supermultiplet patterns and  mass hierarchies to aid in the interpretation of the upcoming GlueX and PANDA experiments.*** Thus my research program will advance knowledge of new particles in the Standard Model (Higgs, exotic hadronic states) and  beyond the Standard Model (dark matter).*****