60,452 research outputs found
Probing the Origin of the Large-angle CMB Anomalies
It has been argued that the large-angle cosmic microwave background
anisotropy has anomalies at 3-sigma level. We review various proposed ideas to
explain the origin of the anomalies and discuss how we can constrain the
proposed models using future observational data.Comment: 5 page
Towards Visually Explaining Variational Autoencoders
Recent advances in Convolutional Neural Network (CNN) model interpretability
have led to impressive progress in visualizing and understanding model
predictions. In particular, gradient-based visual attention methods have driven
much recent effort in using visual attention maps as a means for visual
explanations. A key problem, however, is these methods are designed for
classification and categorization tasks, and their extension to explaining
generative models, e.g. variational autoencoders (VAE) is not trivial. In this
work, we take a step towards bridging this crucial gap, proposing the first
technique to visually explain VAEs by means of gradient-based attention. We
present methods to generate visual attention from the learned latent space, and
also demonstrate such attention explanations serve more than just explaining
VAE predictions. We show how these attention maps can be used to localize
anomalies in images, demonstrating state-of-the-art performance on the MVTec-AD
dataset. We also show how they can be infused into model training, helping
bootstrap the VAE into learning improved latent space disentanglement,
demonstrated on the Dsprites dataset
Contributions to Anomalies from -Parity Violating Interactions
We examine the parameter space of supersymmetric models with -parity
violating interactions of the form to explain the various
anomalies observed in transitions. To generate the
appropriate operator in the low energy theory, we are led to a region of
parameter space where loop contributions dominate. In particular, we
concentrate on parameters for which diagrams involving winos, which have not
been previously considered, give large contributions. Many different
potentially constraining processes are analyzed, including , mixing, ,
decays to charged leptons, and direct LHC searches. We find that it is
possible to explain the anomalies, but it requires large values of ,
which lead to relatively low Landau poles.Comment: 30 pages, 7 figures, references added, matched to journal versio
Recent Physics Anomalies - a First Hint for Compositeness?
We scrutinize the recently further strengthened hints for new physics in
semileptonic -meson decays, focusing on the 'clean' ratios of branching
fractions and and examining to which pattern of new effects
they point to. We explore in particular the hardly considered, yet fully
viable, option of new physics in the right-handed electron sector and
demonstrate how a recently proposed framework of leptons in composite Higgs
setups naturally solves both the and anomalies via a
peculiar structure of new physics effects, predicted by minimality of the model
and the scale of neutrino masses. Finally, we also take into account further
observables, such as , , and
angular observables in decays, to arrive at a
comprehensive picture of the model concerning (semileptonic) decays. We
conclude that -- since it is in good agreement with the experimental situation
in flavor physics and also allows to avoid ultra-light top partners -- the
model furnishes a very promising scenarios of Higgs compositeness in the light
of LHC data.Comment: 21 pages, 6 figure
Detecting and Explaining Conflicts in Attributed Feature Models
Product configuration systems are often based on a variability model. The
development of a variability model is a time consuming and error-prone process.
Considering the ongoing development of products, the variability model has to
be adapted frequently. These changes often lead to mistakes, such that some
products cannot be derived from the model anymore, that undesired products are
derivable or that there are contradictions in the variability model. In this
paper, we propose an approach to discover and to explain contradictions in
attributed feature models efficiently in order to assist the developer with the
correction of mistakes. We use extended feature models with attributes and
arithmetic constraints, translate them into a constraint satisfaction problem
and explore those for contradictions. When a contradiction is found, the
constraints are searched for a set of contradicting relations by the
QuickXplain algorithm.Comment: In Proceedings FMSPLE 2015, arXiv:1504.0301
Reconsidering the One Leptoquark solution: flavor anomalies and neutrino mass
We reconsider a model introducing a scalar leptoquark to explain recent deviations from the standard model in
semileptonic decays. The leptoquark can accommodate the persistent tension
in the decays as long as its mass is
lower than approximately , and we show that a sizeable Yukawa
coupling to the right-chiral tau lepton is necessary for an acceptable
explanation. Agreement with the measured rates is mildly compromised for parameter choices addressing the
tensions in , where the model can significantly reduce the
discrepancies in angular observables, branching ratios and the
lepton-flavor-universality observables and . The leptoquark can
also reconcile the predicted and measured value of the anomalous magnetic
moment of the muon and appears naturally in models of radiative neutrino mass
derived from lepton-number violating effective operators. As a representative
example, we incorporate the particle into an existing two-loop neutrino mass
scenario derived from a dimension-nine operator. In this specific model, the
structure of the neutrino mass matrix provides enough freedom to explain the
small masses of the neutrinos in the region of parameter space dictated by
agreement with the anomalies in , but
not the transition. This is achieved without excessive fine-tuning in
the parameters important for neutrino mass.Comment: 43 pages, 17 figures, 3 tables; corrected fit contours in fig. 1
Linear flavour violation and anomalies in B physics
We propose renormalizable models of new physics that can explain various
anomalies observed in decays of B-mesons to electron and muon pairs. The new
physics states couple to linear combinations of Standard Model fermions,
yielding a pattern of flavour violation that gives a consistent fit to the
gamut of flavour data. Accidental symmetries prevent contributions to baryon-
and lepton-number-violating processes, as well as enforcing a loop suppression
of new physics contributions to flavour violating processes. Data require that
the new flavour-breaking couplings are largely aligned with the Yukawa
couplings of the SM and so we also explore patterns of flavour symmetry
breaking giving rise to this structure.Comment: v2: 28 pages, 10 figures. Added two appendices to make the SU(2)
structure of the model clearer, and to discuss Z/photon penguin
contributions. Updated a bound on Bs mixing, and added references.
Conclusions unchanged. Version to appear in JHE
Pati-Salam explanations of the B-meson anomalies
We provide a combined explanation of the increasingly tantalizing -meson
anomalies, both in and , in the Pati-Salam model
with minimal matter content. This well-known model, based on the gauge group
, naturally contains a variety of
scalar leptoquarks with related and restricted couplings. In particular we show
that the seesaw-motivated scalar leptoquark within the representation
and its right-handed parity partner can solve both anomalies while making testable predictions for related
observables such as and . The solution of the
anomaly alone can be related to a type-II seesaw neutrino mass
structure. Explaining also requires the existence of a light
right-handed neutrino, which constrains the UV structure of the model.Comment: 26 pages, includes discussion of RGEs; to appear in JHE
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