Unitarity Constraints on Higgs Portals

Dark matter that was once in thermal equilibrium with the Standard Model is generally prohibited from obtaining all of its mass from the electroweak phase transition. This implies a new scale of physics and mediator particles to facilitate dark matter annihilation. In this work, we focus on dark matter that annihilates through a generic Higgs portal. We show how partial wave unitarity places an upper bound on the mass of the mediator (or dark) Higgs when its mass is increased to be the largest scale in the effective theory. For models where the dark matter annihilates via fermion exchange, an upper bound is generated when unitarity breaks down around 8.5 TeV. Models where the dark matter annihilates via fermion and higgs boson exchange push the bound to 45.5 TeV. We also show that if dark matter obtains all of its mass from a new symmetry breaking scale that scale is also constrained. We improve these constraints by requiring perturbativity in the Higgs sector up to each unitarity bound. In this limit, the bounds on the dark symmetry breaking vev and the dark Higgs mass are now 2.4 and 3 TeV, respectively, when the dark matter annihilates via fermion exchange. When dark matter annihilates via fermion and higgs boson exchange, the bounds are now 12 and 14.2 TeV, respectively. The available parameter space for Higgs portal dark matter annihilation is outlined. We also show how the bounds are improved if Higgs portal dark matter is only a fraction of the observed relic abundance. Finally, we discuss how to apply these arguments to other dark matter scenarios and discuss prospects for direct detection and future collider searches. If the Higgs portal is responsible for dark matter annihilation, planned direct detection experiments will cover almost all the parameter space. The ILC and/or VLHC, however, is needed to establish the Higgs portal mechanism

Measurement of the 1/E Dependence of the 7-Li(p,n)7-Be Total Reaction Cross Section

This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

Roentgen cephalometric analysis of ridge resorption and changes in jaw and occlusal relationships in immediate complete denture wearers

In eighteen subjects assigned for immediate complete upper and lower dentures, roentgen cephalometric recordings were made before extraction of the residual anterior dentition and 3 weeks, 3 months, 6 months and 1 year after denture insertion. The cephalometric analysis was based on electronic measurements of linear and angular morphological variables and computer head plots generated from 177 reference points (Walker, 1967), derived for each subject for each of the five observation stages. The reduction of the alveolar ridges was most rapid during the first 3 months of denture wear and particularly during the post-extraction period of 3 weeks. The reduction in anterior height of the lower ridge was on average twice as great as that of the upper ridge. The ridge resorption and the accompanying settling of the dentures on the basal seats, measured from lead shots inserted in the dentures, brought about an upward rotation of the mandible with a resulting decrease in occlusal vertical dimension and reduction in overjet of the dentures. In accordance with the amount of ridge reduction, these changes showed great individual variation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73577/1/j.1365-2842.1980.tb01466.x.pd

Excitation of High-Spin States by Inelastic Proton Scattering

This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit

Excitation of High-Spin States by Inelastic Proton Scattering

This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit

Supermodels for early LHC

We investigate what new physics signatures the LHC can discover in the 2009-2010 run, beyond the expected sensitivity of the Tevatron data by 2010. We construct "supermodels", for which the LHC sensitivity even with only 10 inverse picobarn is greater than that of the Tevatron with 10 inverse femtobarn. The simplest supermodels involve s-channel resonances in the quark-antiquark and especially in the quark-quark channels. We concentrate on easily visible final states with small standard model backgrounds, and find that there are simple searches, besides those for Z' states, which could discover new physics in early LHC data. Many of these are well-suited to test searches for "more conventional" models, often discussed for multi-inverse femtobarn data sets.Comment: 11 pages, 6 figures; v2, references adde

Order parameter symmetry in ferromagnetic superconductors

We analyze the symmetry and the nodal structure of the superconducting order parameter in a cubic ferromagnet, such as ZrZn$_2$. We demonstrate how the order parameter symmetry evolves when the electromagnetic interaction of the conduction electrons with the internal magnetic induction and the spin-orbit coupling are taken into account. These interactions break the cubic symmetry and lift the degeneracy of the order parameter. It is shown that the order parameter which appears immediately below the critical temperature has two components, and its symmetry is described by {\em co-representations} of the magnetic point groups. This allows us to make predictions about the location of the gap nodes.Comment: 12 pages, ReVTeX, submitted to PR

Possible symmetries of the superconducting order parameter in a hexagonal ferromagnet

We study the order parameter symmetry in a hexagonal crystal with co-existing superconductivity and ferromagnetism. An experimental example is provided by carbon-based materials, such as graphite-sulfur composites, in which an evidence of such co-existence has been recently discovered. The presence of a non-zero magnetization in the normal phase brings about considerable changes in the symmetry classification of superconducting states, compared to the non-magnetic case.Comment: 4 pages, REVTe

Recombinant antibodies derived from laser captured single plasma cells of multiple sclerosis brain identified phage peptides which may be used as tools for characterizing intrathecal IgG response

Oligoclonal bands and increased IgG antibody levels can be detected in the cerebrospinal fluid in vast majority of patients with Multiple Sclerosis (MS). However, the antigenic specificity of oligoclonal IgG has yet to be determined. Using laser capture microdissection, we isolated single CD38+ plasma cells from lesion areas in two autopsy MS brains, and generated three recombinant antibodies (rAbs) from clonally expanded plasma cells. Panning phage-displayed random peptide libraries was carried out to determine peptide antigen specificities of these MS brain rAbs. We identified 25 high affinity phage peptides from which 5 peptides are unique. Database searches revealed that they shared sequence homologies with Epstein-Barr nuclear antigens 4 and 6, as well as with other viral proteins. Significantly, these peptides were recognized by intrathecal IgG and oligoclonal IgG bands in other MS patients. Our results demonstrate that functional recombinant antibodies can be generated from clonally expanded plasma cells in MS brain lesions by laser capture microdissection, and that these MS brain rAbs have the potential for determining the targets of intrathecal IgG and oligoclonal bands