1,437 research outputs found
Lepton Mixing from Delta (3 n^2) and Delta (6 n^2) and CP
We perform a detailed study of lepton mixing patterns arising from a scenario
with three Majorana neutrinos in which a discrete flavor group Gf=Delta (3 n^2)
or Gf=Delta(6 n^2) and a CP symmetry are broken to residual symmetries Ge=Z3
and Gnu=Z2 x CP in the charged lepton and neutrino sectors, respectively. While
we consider all possible Z3 and Z2 generating elements, we focus on a certain
set of CP transformations. The resulting lepton mixing depends on group
theoretical indices and one continuous parameter. In order to study the mixing
patterns comprehensively for all admitted Ge and Gnu, it is sufficient to
discuss only three types of combinations. One of them requires as flavor group
Delta (6 n^2). Two types of combinations lead to mixing patterns with a
trimaximal column, while the third one allows for a much richer structure. For
the first type of combinations the Dirac as well as one Majorana phase are
trivial, whereas the other two ones predict in general all CP phases to be
non-trivial and also non-maximal. Already for small values of the index n of
the group, n <= 11, experimental data on lepton mixing can be accommodated well
for particular choices of the parameters of the theory. We also comment on the
relation of the used CP transformations to the automorphisms of Delta (3 n^2)
and Delta (6 n^2).Comment: 60 pages, 12 tables and 10 figures. v2: typos corrected, references
updated, some minor improvement of the text, matches version accepted for
publication in Nuclear Physics
Quenched lattice calculation of the B --> D l nu decay rate
We calculate, in the continuum limit of quenched lattice QCD, the form factor
that enters in the decay rate of the semileptonic decay B --> D l nu. Making
use of the step scaling method (SSM), previously introduced to handle two scale
problems in lattice QCD, and of flavour twisted boundary conditions we extract
G(w) at finite momentum transfer and at the physical values of the heavy quark
masses. Our results can be used in order to extract the CKM matrix element Vcb
by the experimental decay rate without model dependent extrapolations.Comment: 5 pages, 4 figures, accepted for publication on Phys. Lett. B,
corrected one typ
A Case of Subdominant/Suppressed "High Energy" Contribution to the Baryon Asymmetry of the Universe in Flavoured Leptogenesis
The CP-violation necessary for the generation of the baryon asymmetry of the
Universe in the "flavoured" leptogenesis scenario can arise from the "low
energy" PMNS neutrino mixing matrix and/or from the "high energy" part of
neutrino Yukawa couplings, which can mediate CP-violating phenomena only at
some high energy scale. The possible interplay between these two types of
CP-violation is analysed. The type I see-saw model with three heavy
right-handed Majorana neutrinos having hierarchical spectrum is considered. We
show that in the case of inverted hierarchical light neutrino mass spectrum,
there exist regions in the corresponding leptogenesis parameter space where the
relevant "high energy" phases have large CP-violating values, but the purely
"high energy" contribution in plays a subdominant role in the production
of baryon asymmetry compatible with the observations. In some of these regions
the purely "high energy" contribution in is so strongly suppressed that
one can have successful leptogenesis only if the requisite CP-violation is
provided by the Majorana phase(s) in the neutrino mixing matrix.Comment: Version accepted for publication in Phys. Lett. B; Addendum, in which
the numerical analysis is extended to the case of complex R_{13} element, and
one figure adde
Complexity of Approximate Query Answering under Inconsistency in Datalog+/-
This is the author accepted manuscript. The final version is available from the publisher via the link in this recordSeveral semantics have been proposed to query inconsistent ontological
knowledge bases, including the intersection of repairs and the intersection of closed
repairs as two approximate inconsistency-tolerant semantics. In this paper, we
analyze the complexity of conjunctive query answering under these two semantics
for a wide range of Datalog± languages. We consider both the standard setting,
where errors may only be in the database, and the generalized setting, where also
the rules of a Datalog± knowledge base may be erroneous.This work was supported by The Alan Turing Institute under the
UK EPSRC grant EP/N510129/1, and by the EPSRC grants EP/R013667/1, EP/L012138/1,
and EP/M025268/1
Complexity of Approximate Query Answering under Inconsistency in Datalog+/-
This is the author accepted manuscript. The final version is freely available from IJCAI via the link in this recordSeveral semantics have been proposed to query inconsistent
ontological knowledge bases, including
the intersection of repairs and the intersection of
closed repairs as two approximate inconsistencytolerant
semantics. In this paper, we analyze the
complexity of conjunctive query answering under
these two semantics for a wide range of Datalog±
languages. We consider both the standard setting,
where errors may only be in the database, and the
generalized setting, where also the rules of a Datalog±
knowledge base may be erroneous.This work was supported by The Alan Turing Institute under
the UK EPSRC grant EP/N510129/1, and by the EPSRC
grants EP/R013667/1, EP/L012138/1, and EP/M025268/1
TeV Scale See-Saw Mechanisms of Neutrino Mass Generation, the Majorana Nature of the Heavy Singlet Neutrinos and \betabeta-Decay
It is shown that the Majorana nature of the heavy neutrinos having
masses in the range of GeV and present in the TeV scale
type I and inverse see-saw scenarios of neutrino mass generation, is unlikely
to be observable in the currently operating and future planned accelerator
experiments (including LHC) due to the existence of very strong constraints on
the parameters and couplings responsible for the corresponding
processes, being the total lepton charge. If the heavy Majorana neutrinos
are observed and they are associated only with the type I or inverse
see-saw mechanisms and no additional TeV scale "new physics", they will behave
like Dirac fermions to a relatively high level of precision, being actually
pseudo-Dirac particles. The observation of effects proving the Majorana nature
of would imply that these heavy neutrinos have additional relatively
strong couplings to the Standard Model particles (as, e.g. in the type III
see-saw scenario), or that light neutrino masses compatible with the
observations are generated by a mechanism other than see-saw (e.g., radiatively
at one or two loop level) in which the heavy Majorana neutrinos are
nevertheless involved.Comment: 22 page
Full, hybrid and platform complementarity: Exploring the industry 4.0 technology-performance link
Literature has increasingly recognized that manufacturing companies should implement a synergic bundle of solutions to fully exploit the potential of Industry 4.0 (I4.0), rather than opting for a scattered technological adoption. Enabling I4.0 technologies, such as cloud computing, artificial intelligence, and additive manufacturing, can be implemented through various combinations to achieve different impacts on a company's performance. But what are the possible ways of combining I4.0 technologies into bundles, and do these ways actually help to achieve a performance that outperforms the adoption of single technologies? This study aims to identify the potential patterns of the technological complementary of I4.0 by considering enabled applications and performance outcomes. We interviewed 13 Italian experts in the I4.0 field, and then combined the obtained information with secondary data collected from more than 150 I4.0 use cases, as well as from websites, reports and press releases. By adopting a systems theory lens, the results of the analysis have allowed us to identify the specific performance effects of both scattered and joint technological adoptions in different application areas. Interestingly, specific examples of I4.0 complementarities emerged, namely full, hybrid and platform complementarity. This study contributes to the growing research on I4.0 outcomes by extending the concept of technological complementary within the I4.0 context. Results show that bundles of technologies have a broader effect on performance than when the same technologies are adopted in isolation, but also that single technologies can impact specific applications and the overall performance of a firm via a systematic I4.0 transformation path
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