1,127 research outputs found
Entropy change at the martensitic transformation in ferromagnetic shape memory alloys Ni_{2+x}Mn_{1-x}Ga
The entropy change between the high-temperature cubic phase and
the low-temperature tetragonally-based martensitic phase of
NiMnGa () alloys was studied. The experimental
results obtained indicate that in the NiMnGa alloys
increases with the Ni excess . The increase of is presumably
accounted for by an increase of magnetic contribution to the entropy change. It
is suggested that the change in modulation of the martensitic phase of
NiMnGa results in discontinuity of the composition dependence
of .Comment: presented at MMM-47, to be published in J. Appl. Phys. (May 15, 2003
Vitamin Dietary Supplement: Changes and Challenges with the New ANVISA Regulations
In July 2018, the Brazilian National Health Surveillance Agency (AgĂȘncia Nacional de VigilĂąncia SanitĂĄria, ANVISA, in Portuguese) published new regulations for food supplements, leading to changes both in the sales denomination and labeling statements, and in the composition of these products. Among dietary supplements, those containing vitamins are the most consumed by the population. The objective of the present work is to discuss the changes in the parameters established for the products containing vitamins, mainly in relation to the required and allowed concentrations of micronutrients, and to verify the impact of these changes for the population since the publication of the new standards. Until July 2018, vitamin-based products containing between 15% and 100% of the recommended daily intake (RDI) of these micronutrients were classified as vitamin supplements; above this dosage, they were considered medicines. The new legislation changed the minimum and maximum limits allowed for vitamin food supplements. Taking into account the maximum vitamin limits established for adults, the most relevant differences were the increase in these limits in a proportion of 100, 76 and 43 times in regarding vitamins E, B6 and C respectively, when compared to those previously established. For the required minimum limits, the major difference was observed for vitamin D, with a four-fold increase in its concentration. In conclusion, changes in legislation can influence the health of the population, so the ideal amounts of vitamin in supplements and the recommendation to consume these products require extensive discussion and reflection
Development and operational experience of magnetic horn system for T2K experiment
A magnetic horn system to be operated at a pulsed current of 320 kA and to
survive high-power proton beam operation at 750 kW was developed for the T2K
experiment. The first set of T2K magnetic horns was operated for over 12
million pulses during the four years of operation from 2010 to 2013, under a
maximum beam power of 230 kW, and protons were exposed to
the production target. No significant damage was observed throughout this
period. This successful operation of the T2K magnetic horns led to the
discovery of the oscillation phenomenon in 2013 by
the T2K experiment. In this paper, details of the design, construction, and
operation experience of the T2K magnetic horns are described.Comment: 22 pages, 40 figures, also submitted to Nuclear Instrument and
Methods in Physics Research,
Search for Cosmic-Ray Antideuterons
We performed a search for cosmic-ray antideuterons using data collected
during four BESS balloon flights from 1997 to 2000. No candidate was found. We
derived, for the first time, an upper limit of 1.9E-4 (m^2 s sr
GeV/nucleon)^(-1) for the differential flux of cosmic-ray antideuterons, at the
95% confidence level, between 0.17 and 1.15 GeV/nucleon at the top of the
atmosphere.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
Constraining Supersymmetry
We review constraints on the minimal supersymmetric extension of the Standard
Model (MSSM) coming from direct searches at accelerators such as LEP, indirect
measurements such as b -> s gamma decay and the anomalous magnetic moment of
the muon. The recently corrected sign of pole light-by-light scattering
contributions to the latter is taken into account. We combine these constraints
with those due to the cosmological density of stable supersymmetric relic
particles. The possible indications on the supersymmetric mass scale provided
by fine-tuning arguments are reviewed critically. We discuss briefly the
prospects for future accelerator searches for supersymmetry.Comment: 21 LaTeX pages, 9 eps figures, Invited Contribution to the New
Journal of Physics Focus Issue on Supersymmetr
Flavor mixing in the gluino coupling and the nucleon decay
Flavor mixing in the quark-squark-gluino coupling is studied for the minimal
SU(5) SUGRA-GUT model and applied to evaluation of the nucleon lifetime. All
off-diagonal (generation mixing) elements of Yukawa coupling matrices and of
squark/slepton mass matrices are included in solving numerically one-loop
renormalization group equations for MSSM parameters, and the parameter region
consistent with the radiative electroweak symmetry breaking condition is
searched. It is shown that the flavor mixing in the gluino coupling for a large
is of the same order of magnitude as the corresponding
Kobayashi-Maskawa matrix element in both up-type and down-type sector. There
exist parameter regions where the nucleon decay amplitudes for charged lepton
modes are dominated by the gluino dressing process, while for all the examined
regions the neutrino mode amplitudes are dominated by the wino dressing over
the gluino dressing.Comment: 24 pages, LaTeX, figures are available upon request.
ICRR-Report-317-94-1
Effect of an RRRR dimension 5 operator on the proton decay in the minimal SU(5) SUGRA GUT model
We reanalyze the proton decay in the minimal SU(5) SUGRA GUT model. Unlike
previous analyses, we take into account a Higgsino dressing diagram of
dimension 5 operator with right-handed matter fields ( operator). It is
shown that this diagram gives a dominant contribution for over that from operator, and decay rate of this mode
can be comparable with that of which is dominated by
the contribution. It is found that we cannot reduce both the decay rate
of and that of simultaneously
by adjusting relative phases between Yukawa couplings at colored Higgs
interactions. Constraints on the colored Higgs mass and a typical squark
and slepton mass from Super-Kamiokande limit become
considerably stronger due to the Higgsino dressing diagram of the
operator: M_C > 6.5 \times 10^{16}\gev for m_{\tilde{f}} < 1 \tev, and
m_{\tilde{f}} > 2.5 \tev for M_C < 2.5 \times 10^{16} \gev.Comment: 32 pages, 5 figures, an appendix added, a reference adde
Novel Approach to Confront Electroweak Data and Theory
A novel approach to study electroweak physics at one-loop level in generic
theories is introduced. It separates the 1-loop
corrections into two pieces: process specific ones from vertex and box
contributions, and universal ones from contributions to the gauge boson
propagators. The latter are parametrized in terms of four effective form
factors , , and corresponding to the , , and
propagators. Under the assumption that only the Standard Model contributes to
the process specific corrections, the magnitudes of the four form factors are
determined at and at q^2=\mmz by fitting to all available precision
experiments. These values are then compared systematically with predictions of
theories. In all fits \alpha_s(\mz) and
\bar{\alpha}(\mmz) are treated as external parameters in order to keep the
interpretation as flexible as possible. The treatment of the electroweak data
is presented in detail together with the relevant theoretical formulae used to
interpret the data. No deviation from the Standard Model has been identified.
Ranges of the top quark and Higgs boson masses are derived as functions of
\alpha_s(\mz) and \bar{\alpha}(\mmz). Also discussed are consequences of
the recent precision measurement of the left-right asymmetry at SLC as well as
the impact of a top quark mass and an improved mass measurement.Comment: 123 pages, LaTeX (33 figures available via anonymous ftp),
KEK-TH-375, KEK preprint 93-159, KANAZAWA-94-19, DESY 94-002, YUMS 94-22,
SNUTP 94-82, to be published in Z.Phys.
Charmless Hadronic Two-Body B Meson Decays
We report the results of a study of two-body B meson decays to the complete
set of K pi, pi pi, and K K final states. The study is performed on a data
sample of 31.7 +/- 0.3 million B B-bar events recorded on the Upsilon(4S)
resonance by the Belle experiment at KEKB. We observe significant signals in
all K pi final states and in the pi+ pi- and pi+ pi0 final states. We set
limits on the pi0 pi0 and K K final states. A search is performed for
partial-rate asymmetries between conjugate states for flavor-specific final
states.Comment: Submitted to PR
Improved Measurement of the Partial-Rate CP Asymmetry in B+ -> K0pi+ and B- -> K0bar pi- Decays
We report an improved measurement of the partial-rate CP asymmetry in B+ =>
K0pi+ and B- => K0bar pi- decays. The analysis is based on a data sample of 85
million BBbar pairs collected at the Upsilon(4S) resonance with the Belle
detector at the KEKB e+ e- storage ring. We measure Acp(K0pi+-) = 0.07^{+0.09
+0.01}_{-0.08 -0.03}, where the first and second errors are statistical and
systematic, respectively; the corresponding 90% confidence-level interval is
-0.10 < Acp(K0pi+-) < 0.22 .Comment: 7 pages, 8 figures, submitted to Phys. Rev.
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