3,199 research outputs found
Mirror World at the Large Hadron Collider
A mirror world can modify in a striking way the LHC signals of the Higgs
sector. An exact or approximate Z_2 symmetry between the mirror world and our
world allows large mixing between the Higgs bosons of these worlds, leading to
production rates and branching ratios for these states that are markedly
different from the standard model and are characteristic of a mirror world. The
constraints on these Higgs boson masses from precision electroweak data differ
from the standard model bound, so that the new physics that cancels the
quadratic divergence induced by the top quark may appear at a larger scale,
possibly beyond the reach of the LHC. However, the scale of new physics needed
to cancel the quadratic divergence induced by the Higgs boson is not
significantly changed. With small breakings of the Z_2 parity, the lightest
mirror quarks (and possibly charged mirror leptons) could be the dark matter in
the universe, forming galactic halos that are stable to cooling. A possible
signal from the relic radiation density of the mirror world is also discussed.Comment: 15 pages, 1 figur
Large-N estimates of universal amplitudes of the CP^{N-1} theory and comparison with the JQ model
We present computations of certain finite-size scaling functions and
universal amplitude ratios in the large-N limit of the CP^{N-1} field theory.
We pay particular attention to the uniform susceptibility, the spin stiffness
and the specific heat. Field theoretic arguments have shown that the
long-wavelength description of the phase transition between the Neel and
valence bond solid states in square lattice S=1/2 anti-ferromagnets is expected
to be the non-compact CP^1 field theory. We provide a detailed comparison
between our field theoretic calculations and quantum Monte Carlo data close to
the Neel -VBS transition on a S=1/2 square-lattice model with competing
four-spin interactions (the JQ model).Comment: 15 page
Grace and Courtesy in Living with Conflict in the Montessori Children’s House
The purpose of this research was to determine in what ways increased role-play lessons of grace and courtesy affected conflict resolution in an early childhood classroom. This research study was conducted at a private Montessori school in a midwestern metropolitan area. The sixweek study was completed in a classroom with 29 children, ranging in age from thirty-three months to six years old. During the study, data was collected on the number of conflicts and grace and courtesy lessons. Data was also collected on levels of cooperation and use of respectful language among children, as observed and reflected on, by the adult. Results showed that increased grace and courtesy lessons correlated to the decrease in number of conflicts during the intervention, and children were noted using grace and courtesy lesson language in their interactions. Further study could include grace and courtesy lessons directed to specific reasons for conflict per classroom
Alien Registration- Gregoire, Adonias J. (Sanford, York County)
https://digitalmaine.com/alien_docs/3592/thumbnail.jp
Ruthenium/Iridium Ratios in the Cretaceous-tertiary Boundary Clay: Implications for Global Dispersal and Fractionation Within the Ejecta Cloud
Ruthenium (Ru) and iridium (Ir) are the least mobile platinum group elements (PGE's) within the Cretaceous-Tertiary (K-T) boundary clay (BC). The Ru/Ir ratio is, therefore, the most useful PGE interelement ratio for distinguishing terrestrial and extraterrestrial contributions to the BC. The Ru/Ir ratio of marine K-T sections (1.77 +/- 0.53) is statistically different from that of the continental sections (0.93 +/- 0.28). The marine Ru/Ir ratios are chondritic (C1 = 1.48 +/- 0.09), but the continental ratios are not. We discovered an inverse correlation of shocked quartz size (or distance from the impact site) and Ru/Ir ratio. This correlation may arise from the difference in Ru and Ir vaporization temperature and/or fractionation during condensation from the ejecta cloud. Postsedimentary alteration, remobilization, or terrestrial PGE input may be responsible for the Ru/Ir ratio variations within the groups of marine and continental sites studied. The marine ratios could also be attained if approximately 15 percent of the boundary metals were contributed by Deccan Trap emissions. However, volcanic emissions could not have been the principal source of the PGE's in the BC because mantle PGE ratios and abundances are inconsistent with those measured in the clay. The Ru/Ir values for pristine Tertiary mantle xenoliths (2.6 +/- 0.48), picrites (4.1 +/- 1.8), and Deccan Trap basalt (3.42 +/- 1.96) are all statistically distinct from those measured in the K-T BC
Neutron scattering study of ferroelectric Sn2P2S6 under pressure
Ferroelectric phase transition in the semiconductor Sn2P2S6 single crystal
has been studied by means of neutron scattering in the pressure-temperature
range adjacent to the anticipated tricritical Lifshitz point (p=0.18GPa,
T=296K). The observations reveal a direct ferroelectric-paraelectric phase
transition in the whole investigated pressure range (0.18 - 0.6GPa). These
results are in a clear disagreement with phase diagrams assumed in numerous
earlier works, according to which a hypothetical intermediate incommensurate
phase extends over several or even tens of degrees in the 0.5GPa pressure
range. Temperature dependence of the anisotropic quasielastic diffuse
scattering suggests that polarization fluctuations present above TC are
strongly reduced in the ordered phase. Still, the temperature dependence of the
(200) Bragg reflection intensity at p=0.18GPa can be remarkably well modeled
assuming the order-parameter amplitude growth according to the power law with
logarithmic corrections predicted for a uniaxial ferroelectric transition at
the tricritical Lifshitz point
Beyond Mean Field Confrontation of Different Models with High Transverse Momentum Proton Spectra
Several models have been proposed to simulate heavy ion reactions beyond the
mean field level. The lack of data in phase space regions which may be
sensitive to different treatments of fluctuations made it difficult to judge
these approaches. The recently published high energy proton spectra, measured
in the reaction 94 AMeV Ar + Ta, allow for the first time for a comparison of
the models with data. We find that these spectra are reproduced by Quantum
Molecular Dynamics (QMD) and Boltzmann Uehling Uhlenbeck (BUU) calculations.
Models like Boltzmann Langevin (BL) in which additional fluctuations in
momentum space are introduced overpredict the proton yield at very high
energies. The BL approach has been successfully used to describe the recently
measured very subthreshold kaon production assuming that the fluctuations
provide the necessary energy to overcome the threshold in two body collisions.
Our new findings suggest that the very subthreshold kaon production cannot be
due to two body scattering and thus remains a open problem.Comment: 5 pages, 3 figures (eps), revte
Fusiform Rust Incidence in Loblolly and Slash Pine Plantations in East Texas
A method to predict the incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp.
fusiforme) in unthinned loblolly (Pinus taeda L.) and slash pine (Pinus elliotti Englem.) plantations located on non-oldfields in East Texas is presented. In addition, procedures are described to estimate changes in rust incidence over time as: 1. A rust-free tree remains rust free, develops stem or branch galls, or dies. 2. A tree with branch galls remains with branch galls only, develops stem galls, or dies. 3. A tree with stem galls remains with stem galls, or dies. Multinomial logistic regression models utilizing basic plantation parameters as predictors were fit to estimate current rust incidence and, then, the change in rust condition over time. South. J. Appl. For. 15(2):79-84
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