142 research outputs found
Energy Spectra and Energy Correlations in the Decay
It is shown that in the sequential decay , the energy distribution of the final state particles provides
a simple and powerful test of the vertex. For a standard Higgs boson, the
energy spectrum of any final fermion, in the rest frame of , is predicted to
be , with
and . By contrast, the spectrum for a
pseudoscalar Higgs is . There are
characteristic energy correlations between and and between
and . These considerations are applied to the ``gold--plated''
reaction , including possible effects of
CP--violation in the coupling. Our formalism also yields the energy
spectra and correlations of leptons in the decay .Comment: 14 pages + 4 figure
Leptogenesis in Theories with Large Extra Dimensions
We study the scenario of baryogenesis through leptogenesis in
higher-dimensional theories, in which the scale of quantum gravity is many
orders of magnitude smaller than the usual Planck mass. The minimal realization
of these theories includes an isosinglet neutrino which feels the presence of
large compact dimensions, whereas all the SM particles are localized on a
-dimensional subspace. In the formulation of minimal leptogenesis
models, we pay particular attention to the existence of Majorana spinors in
higher dimensions. After compactification of the extra dimensions, we obtain a
tower of Majorana Kaluza-Klein excitations which act as an infinite series of
CP-violating resonators, and derive the necessary conditions for their
constructive interference. Based on this CP-violating mechanism, we find that
the decays of the heavy Majorana excitations can produce a leptonic asymmetry
which is reprocessed into the observed baryonic asymmetry of the Universe by
means of out-of-equilibrium sphaleron interactions, provided the reheat
temperature is above 5 GeV.Comment: 34 pages, minor rewordings, to appear in Physical Review
Associations of airway inflammation and responsiveness markers in non asthmatic subjects at start of apprenticeship
<p>Abstract</p> <p>Background</p> <p>Bronchial Hyperresponsiveness (BHR) is considered a hallmark of asthma. Other methods are helpful in epidemiological respiratory health studies including Fractional Exhaled Nitric Oxide (FENO) and Eosinophils Percentage (EP) in nasal lavage fluid measuring markers for airway inflammation along with the Forced Oscillatory Technique measuring Airway resistance (AR). Can their outcomes discriminate profiles of respiratory health in healthy subjects starting apprenticeship in occupations with a risk of asthma?</p> <p>Methods</p> <p>Rhinoconjunctivitis, asthma-like symptoms, FEV1 and AR post-Methacholine Bronchial Challenge (MBC) test results, FENO measurements and EP were all investigated in apprentice bakers, pastry-makers and hairdressers not suffering from asthma. Multiple Correspondence Analysis (MCA) was simultaneously conducted in relation to these groups and this generated a synthetic partition (EI). Associations between groups of subjects based on BHR and EI respectively, as well as risk factors, symptoms and investigations were also assessed.</p> <p>Results</p> <p>Among the 441 apprentice subjects, 45 (10%) declared rhinoconjunctivitis-like symptoms, 18 (4%) declared asthma-like symptoms and 26 (6%) suffered from BHR. The mean increase in AR post-MBC test was 21% (sd = 20.8%). The median of FENO values was 12.6 ppb (2.6-132 range). Twenty-six subjects (6.7%) had EP exceeding 14%. BHR was associated with atopy (p < 0.01) and highest FENO values (p = 0.09). EI identified 39 subjects with eosinophilic inflammation (highest values of FENO and eosinophils), which was associated with BHR and atopy.</p> <p>Conclusions</p> <p>Are any of the identified markers predictive of increased inflammatory responsiveness or of development of symptoms caused by occupational exposures? Analysis of population follow-up will attempt to answer this question.</p
Fundamental CP-violating quantities in a SU(2)U(1) model with many Higgs doublets
We consider a SU(2)U(1) gauge theory with many scalar doublets,
but without fermions. We devise a systematic method of constructing quantities
which are invariant under changes of basis of the scalar fields, but acquire a
minus sign under a general CP transformation. Those quantities provide a
basis-independent way of checking for the existence of CP violation.Comment: (Latex file, 9 pages). CMU-preprin
Statistical Mechanics of Glass Formation in Molecular Liquids with OTP as an Example
We extend our statistical mechanical theory of the glass transition from
examples consisting of point particles to molecular liquids with internal
degrees of freedom. As before, the fundamental assertion is that super-cooled
liquids are ergodic, although becoming very viscous at lower temperatures, and
are therefore describable in principle by statistical mechanics. The theory is
based on analyzing the local neighborhoods of each molecule, and a statistical
mechanical weight is assigned to every possible local organization. This
results in an approximate theory that is in very good agreement with
simulations regarding both thermodynamical and dynamical properties
Model-independent analysis of Higgs spin and CP properties in the process
In this paper we investigate methods to study the Higgs coupling.
The spin and CP properties of a Higgs boson are analysed in a model-independent
way in its associated production with a pair in high-energy
collisions. We study the prospects of establishing the CP quantum numbers of
the Higgs boson in the CP-conserving case as well as those of determining the
CP-mixing if CP is violated. We explore in this analysis the combined use of
the total cross section and its energy dependence, the polarisation asymmetry
of the top quark and the up-down asymmetry of the antitop with respect to the
top-electron plane. We find that combining all three observables remarkably
reduces the error on the determination of the CP properties of the Higgs Yukawa
coupling. Furthermore, the top polarisation asymmetry and the ratio of cross
sections at different collider energies are shown to be sensitive to the spin
of the particle produced in association with the top quark pair
Probing Higgs Sector CP Violation with Top Quarks at a Photon Linear Collider
We investigate for two-Higgs doublet models with intrinsic CP violation in
the scalar potential CP-nonconserving effects in unpolarized for a range of neutral Higgs boson masses which
includes resonant production and the subsequent decay of . The importance of taking into account, even in the
resonant case, the interference with the nonresonant background is shown.
Further, we propose and calculate three asymmetries which efficiently trace
CP-violating effects in using
semileptonic decays.Comment: 13 pages, plain TeX; 6 figures available upon request from
[email protected]
Mangafodipir Protects against Hepatic Ischemia-Reperfusion Injury in Mice
Mangafodipir is a contrast agent used in magnetic resonance imaging that concentrates in the liver and displays pleiotropic antioxidant properties. Since reactive oxygen species are involved in ischemia-reperfusion damages, we hypothesized that the use of mangafodipir could prevent liver lesions in a mouse model of hepatic ischemia reperfusion injury. Mangafodipir (MnDPDP) was compared to ischemic preconditioning and intermittent inflow occlusion for the prevention of hepatic ischemia-reperfusion injury in the mouse.Mice were subjected to 70% hepatic ischemia (continuous ischemia) for 90 min. Thirty minutes before the ischemic period, either mangafodipir (10 mg/kg) or saline was injected intraperitoneally. Those experimental groups were compared with one group of mice preconditioned by 10 minutes' ischemia followed by 15 minutes' reperfusion, and one group with intermittent inflow occlusion. Hepatic ischemia-reperfusion injury was evaluated by measurement of serum levels of aspartate aminotransferase (ASAT) activity, histologic analysis of the livers, and determination of hepatocyte apoptosis (cytochrome c release, caspase 3 activity). The effect of mangafodipir on the survival rate of mice was studied in a model of total hepatic ischemia.<0.01), and by higher rates of survival in treated than in untreated animals (P<0.001). The level of protection by mangafodipir was similar to that observed following intermittent inflow occlusion and higher than after ischemic preconditioning.Mangafodipir is a potential new preventive treatment for hepatic ischemia-reperfusion injury
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