1,564 research outputs found
Contribution of Type Ia and Type II Supernovae for Intra-Cluster Medium Enrichment
The origin of the chemical composition of the intracluster medium (ICM) is
discussed in this paper. In particular, the contribution from Type Ia
supernovae (SNe Ia) to the ICM enrichment is shown to exist by adopting the
fitting formulas which have been used in the analysis of the solar system
abundances. Our analysis means that we can use the frequency of SNe Ia relative
to SNe II as the better measure than for
estimating the contribution of SNe Ia. Moreover, the chemical compositions of
ICMs are shown to be similar to that of the solar system abundances. We can
also reproduce the sulfur/iron abundance ratio within a factor of 2, which
means that the abundance problem of sulfur needs not to be emphasized too
strongly. We need more precise observations to conclude whether ICMs really
suffer the shortage problem of sulfur or not.Comment: 20 pages, LaTeX text and 15 postscript figures. Accepted for
publication in Astrophysical Journa
Variations on Supersymmetry Breaking and Neutrino Spectra
The problem of generating light neutrinos within supersymmetric models is
discussed. It is shown that the hierarchy of scales induced by supersymmetry
breaking can give rise to suppression factors of the correct order of magnitude
to produce experimentally allowed neutrino spectra.Comment: 18 pages, LaTeX, Contribution to "Neutrino Workshop", Fuji-Yoshida,
Japan, August 200
Higgs potential in S_3 invariant model for quark/lepton mass and mixing
We analyzed the S_3 invariant Higgs potential with S_3 singlet and doublet
Higgs. We obtained a relation (|v_1|/|v_2|)^2=-sin2phi_2/sin2phi_1 from this
S_3 invariant Higgs potential, where v_1, v_2 and phi_1, phi_2 are vacuum
pectation values and phases of S_3 doublet Higgs, respectively. This relation
could be satisfied exactly by the results |v_1|/ |v_2|=0.207, phi_1=-74.9deg
and phi_2=0.74deg obtained from the previous our work analyzing the
quark/lepton mass and mixing in S_3 invariant Yukawa interaction. Furthermore,
the relation v_S ~ v_D=sqrt{|v_1|^2+|v_2|^2}=174GeV is obtained and then the
coupling strength of Higgs to top quark g_{H_Stt}=m_t/v_S is altered as by a
factor sqrt{2} from the standard value. Introduced the S_3 doublet Higgs, FCNC
are produced in tree level. Predicted branching ratios for rare decays mu^- to
e^-e^+e^-, K^0_L to mu^+\mu^- etc., induced by the FCNC are sufficiently below
the present experimental upper bounds.Comment: 16 pages, 3 figure
R-invariant New Inflation Model vs Supersymmetric Standard Model
We revisit the implications of the R-invariant New Inflation model to the
supersymmetric standard model in light of recent discussion of gravitino
production processes by the decay of the inflaton or the supersymmetry breaking
field. We show that the models with supergravity mediation do not go well with
the R-invariant New Inflation model, where the gravitino abundance produced by
the decay of the inflaton or the supersymmetry breaking field significantly
exceeds the bounds from cosmological observations without fine-tuning. We also
show that the models with gauge mediation can go together with R-invariant New
Inflation model, where the dark matter and the baryon asymmetry are
consistently explained without severe fine-tuning.Comment: 19 pages, 3 figure
Inverted Hybrid Inflation as a solution to gravitino problems in Gravity Mediation
It was recently found that the decay of inflaton and the SUSY breaking field
produces many gravitinos in the gravity mediation scenario. These discoveries
led to an exclusion of many inflation models such as chaotic, (smooth) hybrid,
topological and new inflation models. Under these circumstances we searched for
a successful inflation model and found that the ``inverted'' hybrid inflation
models can solve the gravitino overproduction problem by their distinctive
shape of the potential. Furthermore, we found that this inflation model
simultaneously can explain the observed baryon asymmetry through the
non-thermal leptogenesis and is consistent with the WMAP results, that is,
and the negligible tensor to scalar ratio.Comment: 23 pages, 2 figures in
Minimal Supergravity, Inflation, and All That
We consider an inflationary model in the hidden-sector broken supergravity
with an effectively large cutoff. The inflaton decay into right-handed
neutrinos naturally causes the observed baryon asymmetry of the universe with a
reheating temperature low enough to avoid the gravitino overproduction. We
emphasize that all the phenomenological requirements from cosmology and
particle physics are satisfied in the large-cutoff theory.Comment: 15pages, 4figures, text and refs. adde
On Myosin II dynamics in the presence of external loads
We address the controversial hot question concerning the validity of the
loose coupling versus the lever-arm theories in the actomyosin dynamics by
re-interpreting and extending the phenomenological washboard potential model
proposed by some of us in a previous paper. In this new model a Brownian motion
harnessing thermal energy is assumed to co-exist with the deterministic swing
of the lever-arm, to yield an excellent fit of the set of data obtained by some
of us on the sliding of Myosin II heads on immobilized actin filaments under
various load conditions. Our theoretical arguments are complemented by accurate
numerical simulations, and the robustness of the model is tested via different
choices of parameters and potential profiles.Comment: 6 figures, 8 tables, to appear on Biosystem
Gauged Discrete Symmetries and Proton Stability
We discuss the results of a search for anomaly free Abelian Z_N discrete
symmetries that lead to automatic R-parity conservation and prevents dangerous
higher-dimensional proton decay operators in simple extensions of the minimal
supersymmetric extension of the standard model (MSSM) based on the left-right
symmetric group, the Pati-Salam group and SO(10). We require that the
superpotential for the models have enough structures to be able to give correct
symmetry breaking to MSSM and potentially realistic fermion masses. We find
viable models in each of the extensions and for all the cases, anomaly freedom
of the discrete symmetry restricts the number of generations.Comment: 8 pages, 2 figures; v2 : typos fixed, references adde
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