We present a self-consistent
χ
2 analysis of several supersymmetric (SUSY) grand unified theories recently discussed in the literature. We obtain global fits to low energy data, including gauge ...couplings, fermion masses and mixing angles, gauge boson masses and
BR(
b →
sγ). One of the models studied provides an excellent fit to the low energy data with
χ
2 ∼ 1 for 3 degrees of freedom, in a large region of the experimentally allowed SUSY parameter space. We also discuss the consequences of our work for a general MSSM analysis at the Z scale.
In gauge-mediated SUSY breaking models, messengers transmit SUSY breaking from a partially hidden sector to the standard model sector via common standard model gauge interactions. The minimal set of ...messengers has quantum numbers of a
5+
5
̄
of SU(5); identical to the quantum numbers of the minimal Higgs sector of an SU(5) GUT. We show in a simple model with messenger masses of order the GUT scale that Higgs - messenger mixing quite naturally leads to a low energy MSSM with gluinos as the lightest supersymmetric particles LSP. We study the phenomenological consequences of such a model.
A small gain-length product as high as 5.5 is demonstrated in a diode-pumped core-doped ceramic Nd:YAG amplifier. This module allows one to realize a self-adaptive laser resonator operating at 100 Hz ...and delivering single longitudinal mode, 20 ns and 100 mJ laser pulses.
Tens of thousands of people die from dog-mediated rabies annually. Deaths can be prevented through post-exposure prophylaxis for people who have been bitten, and the disease eliminated through dog ...vaccination. Current post-exposure prophylaxis use saves many lives, but availability remains poor in many rabies-endemic countries due to high costs, poor access, and supply.
We developed epidemiological and economic models to investigate the effect of an investment in post-exposure prophylaxis by Gavi, the Vaccine Alliance. We modelled post-exposure prophylaxis use according to the status quo, with improved access using WHO-recommended intradermal vaccination, with and without rabies immunoglobulin, and with and without dog vaccination. We took the health provider perspective, including only direct costs.
We predict more than 1 million deaths will occur in the 67 rabies-endemic countries considered from 2020 to 2035, under the status quo. Current post-exposure prophylaxis use prevents approximately 56 000 deaths annually. Expanded access to, and free provision of, post-exposure prophylaxis would prevent an additional 489 000 deaths between 2020 and 2035. Under this switch to efficient intradermal post-exposure prophylaxis regimens, total projected vaccine needs remain similar (about 73 million vials) yet 17·4 million more people are vaccinated, making this an extremely cost-effective method, with costs of US$635 per death averted and $33 per disability-adjusted life-years averted. Scaling up dog vaccination programmes could eliminate dog-mediated rabies over this time period; improved post-exposure prophylaxis access remains cost-effective under this scenario, especially in combination with patient risk assessments to reduce unnecessary post-exposure prophylaxis use.
Investing in post-exposure vaccines would be an extremely cost-effective intervention that could substantially reduce disease burden and catalyse dog vaccination efforts to eliminate dog-mediated rabies.
World Health Organization.
Yukawa unification in SO(10)
Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields,
06/2002
Journal Article
A general operator expansion is presented for quark and lepton mass matrices in unified theories based on a U(2) flavor symmetry, with breaking parameter of order
V
cb
≈
m
s
/
m
b
≈ √
m
c
/
m
t
. ...While solving the supersymmetric flavor-changing problem, a general form for the Yukawa couplings follows, leading to nine relations among the fermion masses and mixings, five of which are precise. The combination of grand unified and U(2) symmetries provides a symmetry understanding for the anomalously small values of
m
u
/
m
c
and
m
c
/
m
t
. A fit to the fermion mass data leads to a prediction for the angles of the CKM unitarity triangle, which will allow a significant test of these unified U(2) theories. A particular SO(10) model provides a simple realization of the general operator expansion. The lighter generation masses and the non-trivial structure of the CKM matrix are generated from the exchange of a single U(2) doublet of heavy vector generations. This model suggests that
CP is spontaneously broken at the unification scale—in which case there is a further reduction in the number of free parameters.
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