5,249 research outputs found
Dark Scalar Doublets and Neutrino Tribimaximal Mixing from A_4 Symmetry
In the context of A_4 symmetry, neutrino tribimaximal mixing is achieved
through the breaking of A_4 to Z_3 (Z_2) in the charged-lepton (neutrino)
sector respectively. The implied vacuum misalignment of the (1,1,1) and (1,0,0)
directions in A_4 space is a difficult technical problem, and cannot be treated
without many auxiliary fields and symmetries (and perhaps extra dimensions). It
is pointed out here that an alternative scenario exists with A_4 alone and no
redundant fields, if neutrino masses are "scotogenic", i.e. radiatively induced
by dark scalar doublets as recently proposed.Comment: 8 pages, 2 figures, 1 reference and 1 paragraph adde
D4 Flavor Symmetry for Neutrino Masses and Mixing
We present the flavor symmetry, which is different from the
previous work by Grimus and Lavoura. Our model reduces to the standard model in
the low energy and there is no FCNC at the tree level. Putting the experimental
data, parameters are fixed, and then the implication of our model is discussed.
The condition to realize the tri-bimaximal mixing is presented. The possibility
for stringy realization of our model is also discussed.Comment: 10 pages, 1 figur
CM1 ADHERENCE, DISCONTINUATION, AND SWITCHING OF BIOLOGIC THERAPIES IN MEDICAID ENROLLEES WITH RHEUMATOID ARTHRITIS
Testing probability distributions underlying aggregated data
In this paper, we analyze and study a hybrid model for testing and learning
probability distributions. Here, in addition to samples, the testing algorithm
is provided with one of two different types of oracles to the unknown
distribution over . More precisely, we define both the dual and
cumulative dual access models, in which the algorithm can both sample from
and respectively, for any ,
- query the probability mass (query access); or
- get the total mass of , i.e. (cumulative
access)
These two models, by generalizing the previously studied sampling and query
oracle models, allow us to bypass the strong lower bounds established for a
number of problems in these settings, while capturing several interesting
aspects of these problems -- and providing new insight on the limitations of
the models. Finally, we show that while the testing algorithms can be in most
cases strictly more efficient, some tasks remain hard even with this additional
power
The Cabibbo Angle in a Supersymmetric D14 Model
We construct a supersymmetric model with the flavor symmetry D14 in which the
CKM matrix element |V_{ud}| can take the value |V_{ud}| =cos (pi/14) = 0.97493
implying that the Cabibbo angle theta_C is sin (theta_C) = |V_{us}| = sin
(pi/14) = 0.2225. These values are very close to those observed in experiments.
The value of |V_{ud}| (theta_C) is based on the fact that different Z2
subgroups of D14 are conserved in the up and down quark sector. In order to
achieve this, D14 is accompanied by a Z3 symmetry. The spontaneous breaking of
D14 is induced by flavons, which are scalar gauge singlets. The quark mass
hierarchy is partly due to the flavor group D14 and partly due to a
Froggatt-Nielsen symmetry U(1)_{FN} under which only the right-handed quarks
transform. The model is completely natural in the sense that the hierarchies
among the quark masses and mixing angles are generated with the help of
symmetries. The issue of the vacuum alignment of the flavons is solved up to a
small number of degeneracies, leaving four different possible values for
|V_{ud}|. Out of these, only one of them leads to a phenomenological viable
model. A study of the Z2 subgroup breaking terms shows that the results
achieved in the symmetry limit are only slightly perturbed. At the same time
they allow |V_{ud}| (theta_C) to be well inside the small experimental error
bars.Comment: 1+24 page
Higgs bosons near 125 GeV in the NMSSM with constraints at the GUT scale
We study the NMSSM with universal Susy breaking terms (besides the Higgs
sector) at the GUT scale. Within this constrained parameter space, it is not
difficult to find a Higgs boson with a mass of about 125 GeV and an enhanced
cross section in the diphoton channel. An additional lighter Higgs boson with
reduced couplings and a mass <123 GeV is potentially observable at the LHC. The
NMSSM-specific Yukawa couplings lambda and kappa are relatively large and
tan(beta) is small, such that lambda, kappa and the top Yukawa coupling are of
order 1 at the GUT scale. The lightest stop can be as light as 105 GeV, and the
fine-tuning is modest. WMAP constraints can be satisfied by a dominantly
higgsino-like LSP with substantial bino, wino and singlino admixtures and a
mass of ~60-90 GeV, which would potentially be detectable by XENON100.Comment: 20 pages, 14 figure
Direct and Indirect Detection of Dark Matter in D6 Flavor Symmetric Model
We study a fermionic dark matter in a non-supersymmetric extension of the
standard model with a family symmetry based on D6xZ2xZ2. In our model, the
final state of the dark matter annihilation is determined to be e+ e- by the
flavor symmetry, which is consistent with the PAMELA result. At first, we show
that our dark matter mass should be within the range of 230 GeV - 750 GeV in
the WMAP analysis combined with mu to e gamma constraint. Moreover we
simultaneously explain the experiments of direct and indirect detection, by
simply adding a gauge and D6 singlet real scalar field. In the direct detection
experiments, we show that the lighter dark matter mass ~ 230 GeV and the
lighter standard model Higgs boson ~ 115 GeV is in favor of the observed bounds
reported by CDMS II and XENON100. In the indirect detection experiments, we
explain the positron excess reported by PAMELA through the Breit-Wigner
enhancement mechanism. We also show that our model is consistent with no
antiproton excess suggested by PAMELA.Comment: 20 pages, 9 figures, 2 tables, accepted version for publication in
European Physical Journal
Adaptive approximate Bayesian computation for complex models
Approximate Bayesian computation (ABC) is a family of computational
techniques in Bayesian statistics. These techniques allow to fi t a model to
data without relying on the computation of the model likelihood. They instead
require to simulate a large number of times the model to be fi tted. A number
of re finements to the original rejection-based ABC scheme have been proposed,
including the sequential improvement of posterior distributions. This technique
allows to de- crease the number of model simulations required, but it still
presents several shortcomings which are particu- larly problematic for costly
to simulate complex models. We here provide a new algorithm to perform adaptive
approximate Bayesian computation, which is shown to perform better on both a
toy example and a complex social model.Comment: 14 pages, 5 figure
Swing-Leg Trajectory of Running Guinea Fowl Suggests Task-Level Priority of Force Regulation Rather than Disturbance Rejection
This study was funded by grant RGY0062/2010 of the Human Frontier Science Program (HFSP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
The Double Cover of the Icosahedral Symmetry Group and Quark Mass Textures
We investigate the idea that the double cover of the rotational icosahedral
symmetry group is the family symmetry group in the quark sector. The
icosahedral (A5) group was previously proposed as a viable family symmetry
group for the leptons. To incorporate the quarks, it is highly advantageous to
extend the group to its double cover, as in the case of tetrahedral (A4)
symmetry. We provide the basic group theoretical tools for flavor
model-building based on the binary icosahedral group I' and construct a model
of the quark masses and mixings that yields many of the successful predictions
of the well-known U(2) quark texture models.Comment: 10 pages, references added, typos in up quark mass matrix correcte
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