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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Colorless top partners, a 125 GeV Higgs boson, and the limits on naturalness

Theories of physics beyond the Standard Model that address the hierarchy problem generally involve top partners, new particles that cancel the quadratic divergences associated with the Yukawa coupling of the Higgs to the top quark. With extensions of the Standard Model that involve new colored particles coming under strain from collider searches, scenarios in which the top partners carry no charge under the strong interactions have become increasingly compelling. Although elusive for direct searches, these theories predict modified couplings of the Higgs boson to the Standard Model particles. This results in corrections to the Higgs production and decay rates that can be detected at the Large Hadron Collider (LHC) provided the top partners are sufficiently light, and the theory correspondingly natural. In this paper we consider three theories that address the little hierarchy problem and involve colorless top partners, specifically the Mirror Twin Higgs, Folded Supersymmetry, and the Quirky Little Higgs. For each model we investigate the current and future bounds on the top partners, and the corresponding limits on naturalness, that can be obtained from the Higgs program at the LHC. Here, we conclude that the LHC will not be able to strongly disfavor naturalness, with mild tuning at the level of about one part in ten remaining allowed even with 3000 fb$^{-1}$ of data at 14 TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurement of muon plus proton final states in ν μ interactions on hydrocarbon at < E ν > = 4.2 GeV

A study of charged-current muon neutrino scattering on hydrocarbon in which the final state includes a muon, at least one proton, and no pions is presented. Although this signature has the topology of neutrino quasielastic scattering from neutrons, the event sample contains contributions from quasielastic and inelastic processes where pions are absorbed in the nucleus. The analysis accepts events with muon production angles up to 70° and proton kinetic energies greater than 110 MeV. The cross section, when based completely on hadronic kinematics, is well described by a relativistic Fermi gas nuclear model including the neutrino event generator modeling for inelastic processes and particle transportation through the nucleus. This is in contrast to the quasielastic cross section based on muon kinematics, which is best described by an extended model that incorporates multinucleon correlations. As a result, this measurement guides the formulation of a complete description of neutrino-nucleus interactions that encompasses the hadronic as well as the leptonic aspects of this process.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗