5,599 research outputs found
Leptoquarks: Neutrino masses and accelerator phenomenology
Leptoquark-Higgs interactions induce mixing between leptoquark states with
different chiralities once the electro-weak symmetry is broken. In such LQ
models Majorana neutrino masses are generated at 1-loop order. Here we
calculate the neutrino mass matrix and explore the constraints on the parameter
space enforced by the assumption that LQ-loops explain current neutrino
oscillation data. LQs will be produced at the LHC, if their masses are at or
below the TeV scale. Since the fermionic decays of LQs are governed by the same
Yukawa couplings, which are responsible for the non-trivial neutrino mass
matrix, several decay branching ratios of LQ states can be predicted from
measured neutrino data. Especially interesting is that large lepton flavour
violating rates in muon and tau final states are expected. In addition, the
model predicts that, if kinematically possible, heavier LQs decay into lighter
ones plus either a standard model Higgs boson or a gauge boson.
Thus, experiments at the LHC might be able to exclude the LQ mechanism as
explanation of neutrino data.Comment: 28 pages, 10 figure
Maximum a posteriori estimation through simulated annealing for binary asteroid orbit determination
This paper considers a new method for the binary asteroid orbit determination
problem. The method is based on the Bayesian approach with a global
optimisation algorithm. The orbital parameters to be determined are modelled
through an a posteriori distribution made of a priori and likelihood terms. The
first term constrains the parameters space and it allows the introduction of
available knowledge about the orbit. The second term is based on given
observations and it allows us to use and compare different observational error
models. Once the a posteriori model is built, the estimator of the orbital
parameters is computed using a global optimisation procedure: the simulated
annealing algorithm. The maximum a posteriori (MAP) techniques are verified
using simulated and real data. The obtained results validate the proposed
method. The new approach guarantees independence of the initial parameters
estimation and theoretical convergence towards the global optimisation
solution. It is particularly useful in these situations, whenever a good
initial orbit estimation is difficult to get, whenever observations are not
well-sampled, and whenever the statistical behaviour of the observational
errors cannot be stated Gaussian like.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Societ
On Prospects for Exploration of Supersymmetry in Double Beta Decay Experiments
We analyze constraints on the parameters of the R-parity violating
supersymmetry which can be extracted from non-observation of the neutrinoless
nuclear double beta decay () at a given half-life lower bound.
Our analysis covers a large class of phenomenologically viable R-parity
violating SUSY models. We introduce special characteristics: the SUSY
sensitivity of a decaying isotope and the SUSY reach of a
experiment. The former provides a physical criterion for a
selection of the most promising isotopes for SUSY searches and the latter gives
a measure of success for a experiment in exploring the
R-parity violating SUSY parameter space. On this basis we discuss prospects for
exploration of supersymmetry in various experiments.Comment: 11 pages, 5 Postscript figures. Modified and updated version is
printed also in Proc. of NANP97 (JINR, Dubna, July 7--11, 1997): Phys. Atom
Nucl, 1998, 61, vol. 6, p.1092--109
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