1,328 research outputs found
Production and decays of supersymmetric Higgs bosons in spontaneously broken R-parity
We study the mass spectra, production and decay properties of the lightest
supersymmetric CP-even and CP-odd Higgs bosons in models with spontaneously
broken R-parity (SBRP). We compare the resulting mass spectra with expectations
of the Minimal Supersymmetric Standard Model (MSSM), stressing that the model
obeys the upper bound on the lightest CP-even Higgs boson mass. We discuss how
the presence of the additional scalar singlet states affects the Higgs
production cross sections, both for the Bjorken process and the "associated
production". The main phenomenological novelty with respect to the MSSM comes
from the fact that the spontaneous breaking of lepton number leads to the
existence of the majoron, denoted J, which opens new decay channels for
supersymmetric Higgs bosons. We find that the invisible decays of CP-even
Higgses can be dominant, while those of the CP-odd bosons may also be sizeable.Comment: 21 pages, 8 figures; minor changes, final version for publicatio
Minimal supergravity radiative effects on the tri-bimaximal neutrino mixing pattern
We study the stability of the Harrison-Perkins-Scott (HPS) mixing pattern,
assumed to hold at some high energy scale, against supersymmetric radiative
corrections. We work in the framework of a reference minimal supergravity model
(mSUGRA) where supersymmetry breaking is universal and flavor-blind at
unification. The radiative corrections considered include both RGE running as
well as threshold effects. We find that in this case the solar mixing angle can
only increase with respect to the HPS reference value, while the atmospheric
and reactor mixing angles remain essentially stable. Deviations from the solar
angle HPS prediction towards lower values would signal novel contributions from
physics beyond the simplest mSUGRA model.Comment: 13 pages, 3 figures; added reference; final version for publicatio
On the Stability and the Approximation of Branching Distribution Flows, with Applications to Nonlinear Multiple Target Filtering
We analyse the exponential stability properties of a class of measure-valued
equations arising in nonlinear multi-target filtering problems. We also prove
the uniform convergence properties w.r.t. the time parameter of a rather
general class of stochastic filtering algorithms, including sequential Monte
Carlo type models and mean eld particle interpretation models. We illustrate
these results in the context of the Bernoulli and the Probability Hypothesis
Density filter, yielding what seems to be the first results of this kind in
this subject
Predicting Neutrinoless Double Beta Decay
We give predictions for the neutrinoless double beta decay rate in a simple
variant of the A_4 family symmetry model. We show that there is a lower bound
for the neutrinoless double beta decay amplitude even in the case of normal
hierarchical neutrino masses, corresponding to an effective mass parameter
|m_{ee}| >= 0.17 \sqrt{\Delta m^2_{ATM}}. This result holds both for the CP
conserving and CP violating cases. In the latter case we show explicitly that
the lower bound on |m_{ee}| is sensitive to the value of the Majorana phase. We
conclude therefore that in our scheme, neutrinoless double beta decay may be
accessible to the next generation of high sensitivity experiments.Comment: 4 pages, 5 figures, 1 tabl
Invisible Higgs Boson Decays in Spontaneously Broken R-Parity
The Higgs boson may decay mainly to an invisible mode characterized by
missing energy, instead of the Standard Model channels. This is a generic
feature of many models where neutrino masses arise from the spontaneous
breaking of ungauged lepton number at relatively low scales, such as
spontaneously broken R-parity models. Taking these models as framework, we
reanalyze this striking suggestion in view of the recent data on neutrino
oscillations that indicate non-zero neutrino masses. We show that, despite the
smallness of neutrino masses, the Higgs boson can decay mainly to the invisible
Goldstone boson associated to the spontaneous breaking of lepton number. This
requires a gauge singlet superfield coupling to the electroweak doublet
Higgses, as in the Next to Minimal Supersymmetric Standard Model (NMSSM)
scenario for solving the -problem. The search for invisibly decaying Higgs
bosons should be taken into account in the planning of future accelerators,
such as the Large Hadron Collider and the Next Linear Collider.Comment: 24 pages, 10 figures; typos corrected, published versio
Delineation of management zones using mobile measurements of soil apparent electrical conductivity and multivariate geostatistical techniques
Site-specific management promotes the identification and management of areas within the field, which represent subfield regions with homogeneous characteristics (management zones). However,
determination of subfield areas is difficult because of the complex combination of factors which could affect crop yield. One possibility to capture yield variability is the use of soil physical properties to define
the management zones as they are related to plant available water.
With the aim of characterizing the spatial variability of the main soil physical variables and using this information to determine potential management zones, soil samples were taken from 70 locations in a
33-ha field in Badajoz, southwestern Spain. Firstly, accurate spatial distribution maps of the soil attributes were generated by using regression kriging as the most suitable algorithm in which exhaustive secondary information on soil apparent electrical conductivity (ECa) was incorporated. ECa
measurements were carried out with a Veris 3100 operating in both shallow (0–30 cm), ECs, and deep (0–90 cm), ECd,mode. Clay, coarse sand and fine sand were the soil physical properties which exhibited
higher correlation with ECa (positively correlated with the finer texture component, clay, and negatively correlated with the coarser ones, coarse and fine sands), particularly with ECs. Thus, this was the
secondary variable used to obtain the kriged maps. Later, principal component analysis and fuzzy cluster
classification were performed to delineate management zones, resulting in two subfields to be managed separately. This number of subfields was determined using the fuzzy performance index and normalized
classification entropy as the way to optimize the classification algorithm
- …