Higgs bosons of a supersymmetric E6E_6 model at the Large Hadron Collider

It is found that CP symmetry may be explicitly broken in the Higgs sector of a supersymmetric $E_6$ model with two extra neutral gauge bosons at the one-loop level. The phenomenology of the model, the Higgs sector in particular, is studied for a reasonable parameter space of the model, in the presence of explicit CP violation at the one-loop level. At least one of the neutral Higgs bosons of the model might be produced via the $WW$ fusion process at the Large Hadron Collider.Comment: 23 pages, 5 figures, JHE

Explicit CP violation in a MSSM with an extra U(1)′U(1)'

We study that a minimal supersymmetric standard model with an extra $U(1)'$ gauge symmetry may accommodate the explicit CP violation at the one-loop level through radiative corrections. This model is CP conserving at the tree level and cannot realize the spontaneous CP violation for a wide parameter space at the one-loop level. In explicit CP violation scenario, we calculate the Higgs boson masses and the magnitude of the scalar-pseudoscalar mixings in this model at the one-loop level by taking into account the contributions of top quarks, bottom quarks, exotic quarks, and their superpartners. In particular, we investigate how the exotic quarks and squarks would affect the scalar-pseudoscalar mixings. It is observed that the size of the mixing between the heaviest scalar and pseudoscalar Higgs bosons is changed up to 20 % by a complex phase originated from the exotic quark sector of this model.Comment: 19 pages, 3 figure

Higgs bosons of a supersymmetric U(1)′U(1)' model at the ILC

We study the scalar Higgs sector of the next-to-minimal supersymmetric standard model with an extra U(1), which has two Higgs doublets and a Higgs singlet, in the light leptophobic $Z'$ scenario where the extra neutral gauge boson $Z'$ does not couple to charged leptons. In this model, we find that the sum of the squared coupling coefficients of the three neutral scalar Higgs bosons to $ZZ$, normalized by the corresponding SM coupling coefficient is noticeably smaller than unity, due to the effect of the extra U(1), for a reasonable parameter space of the model, whereas it is unity in the next-to-minimal supersymmetric standard model. Thus, these two models may be distinguished if the coupling coefficients of neutral scalar Higgs bosons to $ZZ$ are measured at the future International Linear Collider by producing them via the Higgs-strahlung, $ZZ$ fusion, and $WW$ fusion processes.Comment: 12 pages, 2 figures, 1 table, PR

A Market-Oriented Analysis of the \u27Terminating Access Monopoly\u27 Concept

Policymakers have long invoked the concept of a “terminating access monopoly” to inform communications policy. Roughly speaking, the concept holds that a consumer-facing network provider, no matter how small or how subject to retail competition, generally possesses monopoly power vis-à-vis third-party senders of communications traffic to its customers. Regulators and advocates have routinely cited that concern to justify regulatory intervention in a variety of contexts where the regulated party may or may not have possessed market power in any relevant retail market. Despite the centrality of the terminating access monopoly to modern communications policy, there is surprisingly little academic literature on that concept as it applies to current regulatory debates. This paper seeks to fill that gap by exploring the various settings in which the concept does, or does not, help explain market dynamics in the communications sector. We conclude that the terminating access monopoly phenomenon, strictly understood, does not itself generally threaten market failures except in very limited circumstances. As the paper explains, the phenomenon could threaten inefficient outcomes only where, because of the underlying market context, the interconnecting provider or its customer has a particularized need to reach the customer set of the terminating access provider, and even then, market forces might correct any problem without regulatory intervention

A Market-Oriented Analysis of the \u27Terminating Access Monopoly\u27 Concept

Policymakers have long invoked the concept of a “terminating access monopoly” to inform communications policy. Roughly speaking, the concept holds that a consumer-facing network provider, no matter how small or how subject to retail competition, generally possesses monopoly power vis-à-vis third-party senders of communications traffic to its customers. Regulators and advocates have routinely cited that concern to justify regulatory intervention in a variety of contexts where the regulated party may or may not have possessed market power in any relevant retail market. Despite the centrality of the terminating access monopoly to modern communications policy, there is surprisingly little academic literature on that concept as it applies to current regulatory debates. This paper seeks to fill that gap by exploring the various settings in which the concept does, or does not, help explain market dynamics in the communications sector. We conclude that the terminating access monopoly phenomenon, strictly understood, does not itself generally threaten market failures except in very limited circumstances. As the paper explains, the phenomenon could threaten inefficient outcomes only where, because of the underlying market context, the interconnecting provider or its customer has a particularized need to reach the customer set of the terminating access provider, and even then, market forces might correct any problem without regulatory intervention

Electroweak phase transition in a nonminimal supersymmetric model

The Higgs potential of the minimal nonminimal supersymmetric standard model (MNMSSM) is investigated within the context of electroweak phase transition. We investigate the allowed parameter space yielding correct electroweak phase transitoin employing a high temperature approximation. We devote to phenomenological consequences for the Higgs sector of the MNMSSM for electron-positron colliders. It is observed that a future $e^+ e^-$ linear collider with $\sqrt{s} = 1000$ GeV will be able to test the model with regard to electroweak baryogenesis.Comment: 28 pages, 5 tables, 12 figure

The influence of position in overlap joints of Mg and Al alloys on microstructure and hardness of laser welds

Structure and properties of laser beam welding zone of dissimilar materials, AZ31 magnesium alloy and A5754 Aluminum alloy, are investigated. The microstructure and quality of the Mg/Al weld were studied by metallography, microhardness and optical microscopy. Differences in physical and mechanical properties of both materials, magnesium and aluminum, affect weldability and resistance of this combination, and lead to the formation of intermetallic compounds in the welded metal

Superconductivity and Lattice Instability in Compressed Lithium from Fermi Surface Hot Spots

The highest superconducting temperature T$_c$ observed in any elemental metal (Li with T$_c$ ~ 20 K at pressure P ~ 40 GPa) is shown to arise from critical (formally divergent) electron-phonon coupling to the transverse T$_1$ phonon branch along intersections of Kohn anomaly surfaces with the Fermi surface. First principles linear response calculations of the phonon spectrum and spectral function $\alpha^2 F(\omega)$ reveal (harmonic) instability already at 25 GPa. Our results imply that the fcc phase is anharmonically stabilized in the 25-38 GPa range.Comment: 4 pages, 3 embedded figure

Quasinormal Ringing for Acoustic Black Holes at Low Temperature

We investigate a condensed matter ``black hole'' analogue, taking the Gross-Pitaevskii (GP) equation as a starting point. The linearized GP equation corresponds to a wave equation on a black hole background, giving quasinormal modes under some appropriate conditions. We suggest that we can know the detailed characters and corresponding geometrical information about the acoustic black hole by observing quasinormal ringdown waves in the low temperature condensed matters.Comment: 9 pages, 3 figures, PRD accepted versio