High-dimensional Z' phenomenology at hadron colliders

We study the phenomenology of a Z'-boson field coupled to hypercharge. The Z' propagator has a non-trivial K\"all\'en-Lehmann spectral density due to the mixing with a higher dimensional inert vector field. As a consequence detection possibilities at hadron colliders are reduced. We determine the range of parameters where this field can be studied at the Tevatron and the LHC through its production cross section via the Drell-Yan mechanism.Comment: 9 pages, 8 figures; version accepted by Phys.Rev.

Economic Efficiency of Alternative Border Carbon Adjustment Schemes: A Case Study of California Carbon Pricing and the Western North American Power Market

A local jurisdiction that regulates power plant emissions, but participates in a larger regional power market faces the issue of emissions leakage, in which local emissions decrease, but emissions associated with the imported power increase. Border carbon adjustment (BCA) schemes can be imposed on imports in an attempt to lessen leakage. This paper explores the potential cost and emission impacts of alternative BCA policies that could be implemented in the California AB32 carbon pricing system. We focus on cost and emission impacts on the power sector in California and the rest of the Western Electricity Coordinating Council (WECC) region, the latter of which provides approximately 23.5% of California’s electricity requirements. With both a simple schematic model and a detailed WECC generation-transmission expansion planning model for the year 2034 called JHSMINE, we examine the following deemed emission rate schemes for estimating and charging for emissions associated with electricity imports: no BCA, facility (import source)-specific deemed rate, a facility-neutral and constant deemed rate, and a facility-neutral and dynamic deemed rate. Our results suggest that, compared with cases with either no BCA or a BCA using facility-based deemed emission rates, facility-neutral schemes can provide efficiency gains by simultaneously lowering WECC-wide emissions and costs without raising payments by California consumers. Emissions leakage declines greatly. The precise value of the deemed rate affects these gains. One particular facility-neutral dynamic scheme in which rates are set by marginal emission rates external to California provides the greatest gain in economic efficiency. Our results also show the impact of carbon pricing and BCAs on transmission investment economics: California’s unilateral AB32 carbon pricing encourages more interstate transmission expansion because power imports are more profitable; however, BCAs that are cost-effective in lowering total regional emissions will dampen those incentives

Pseudospin symmetry in supersymmetric quantum mechanics: Schr\"odinger equations

The origin of pseudospin symmetry (PSS) and its breaking mechanism are explored by combining supersymmetry (SUSY) quantum mechanics, perturbation theory, and the similarity renormalization group (SRG) method. The Schr\"odinger equation is taken as an example, corresponding to the lowest-order approximation in transforming a Dirac equation into a diagonal form by using the SRG. It is shown that while the spin-symmetry-conserving term appears in the single-particle Hamiltonian $H$, the PSS-conserving term appears naturally in its SUSY partner Hamiltonian $\tilde{H}$. The eigenstates of Hamiltonians $H$ and $\tilde{H}$ are exactly one-to-one identical except for the so-called intruder states. In such a way, the origin of PSS deeply hidden in $H$ can be traced in its SUSY partner Hamiltonian $\tilde{H}$. The perturbative nature of PSS in the present potential without spin-orbit term is demonstrated by the perturbation calculations, and the PSS-breaking term can be regarded as a very small perturbation on the exact PSS limits. A general tendency that the pseudospin-orbit splittings become smaller with increasing single-particle energies can also be interpreted in an explicit way.Comment: 31 pages, 11 figures, 2 table

Hyperon polarization in e^-p --> e^-HK with polarized electron beams

We apply the picture proposed in a recent Letter for transverse hyperon polarization in unpolarized hadron-hadron collisions to the exclusive process e^-p --> e^-HK such as e^-p-->e^-\Lambda K^+, e^-p --> e^-\Sigma^+ K^0, or e^-p--> e^-\Sigma^0 K^+, or the similar process e^-p\to e^-n\pi^+ with longitudinally polarized electron beams. We present the predictions for the longitudinal polarizations of the hyperons or neutron in these reactions, which can be used as further tests of the picture.Comment: 15 pages, 2 figures. submitted to Phys. Rev.

Nonsaturating magnetoresistance and nontrivial band topology of type-II Weyl semimetal NbIrTe4

Weyl semimetals, characterized by nodal points in the bulk and Fermi arc states on the surface, have recently attracted extensive attention due to the potential application on low energy consumption electronic materials. In this report, the thermodynamic and transport properties of a theoretically predicted Weyl semimetal NbIrTe4 is measured in high magnetic fields up to 35 T and low temperatures down to 0.4 K. Remarkably, NbIrTe4 exhibits a nonsaturating transverse magnetoresistance which follows a power-law dependence in B. Low-field Hall measurements reveal that hole-like carriers dominate the transport for T $>$ 80 K, while the significant enhancement of electron mobilities with lowering T results in a non-negligible contribution from electron-like carriers which is responsible for the observed non-linear Hall resistivity at low T. The Shubnikov-de Haas oscillations of the Hall resistivity under high B give the light effective masses of charge carriers and the nontrivial Berry phase associated with Weyl fermions. Further first-principles calculations confirm the existence of 16 Weyl points located at kz = 0, $\pm$0.02 and $\pm$0.2 planes in the Brillouin zone.Comment: 5 figures, 1 tabl