60,452 research outputs found

    Probing the Origin of the Large-angle CMB Anomalies

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    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

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    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 b→sℓℓ{b \rightarrow s \ell \ell} Anomalies from R{R}-Parity Violating Interactions

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    We examine the parameter space of supersymmetric models with RR-parity violating interactions of the form λ′LQDc\lambda' L Q D^c to explain the various anomalies observed in b→sℓℓb \rightarrow s \ell \ell 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 τ→μμμ\tau \rightarrow \mu \mu \mu, Bs−BˉsB_s-\bar{B}_s mixing, B→K(∗)ννˉB \rightarrow K^{(*)} \nu \bar{\nu}, ZZ decays to charged leptons, and direct LHC searches. We find that it is possible to explain the anomalies, but it requires large values of λ′\lambda', which lead to relatively low Landau poles.Comment: 30 pages, 7 figures, references added, matched to journal versio

    Recent B\boldsymbol{B} Physics Anomalies - a First Hint for Compositeness?

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    We scrutinize the recently further strengthened hints for new physics in semileptonic BB-meson decays, focusing on the 'clean' ratios of branching fractions RKR_K and RK∗R_{K^\ast} 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 RKR_K and RK∗R_{K^\ast} 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 B(Bs→μ+μ−){\cal B}(B_s \to \mu^+\mu^-), ΔMBs\Delta M_{B_s}, and angular observables in B→K∗μ+μ−B \to K^{\ast} \mu^+ \mu^- decays, to arrive at a comprehensive picture of the model concerning (semileptonic) BB 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

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    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

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    We reconsider a model introducing a scalar leptoquark ϕ∼(3,1,−1/3)\phi \sim (\mathbf{3}, \mathbf{1}, -1/3) to explain recent deviations from the standard model in semileptonic BB decays. The leptoquark can accommodate the persistent tension in the decays Bˉ→D(∗)τνˉ\bar{B}\rightarrow D^{(*)}\tau \bar{\nu} as long as its mass is lower than approximately 10 TeV10 \text{ TeV}, and we show that a sizeable Yukawa coupling to the right-chiral tau lepton is necessary for an acceptable explanation. Agreement with the measured Bˉ→D(∗)τνˉ\bar{B}\rightarrow D^{(*)}\tau \bar{\nu} rates is mildly compromised for parameter choices addressing the tensions in b→sμμb \to s \mu \mu, where the model can significantly reduce the discrepancies in angular observables, branching ratios and the lepton-flavor-universality observables RKR_K and RK∗R_{K^*}. 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 Bˉ→D(∗)τνˉ\bar{B}\rightarrow D^{(*)}\tau \bar{\nu}, but not the b→sb \to s 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

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    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

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    We provide a combined explanation of the increasingly tantalizing BB-meson anomalies, both in RK(∗)R_{K^{(*)}} and RD(∗)R_{D^{(*)}}, in the Pati-Salam model with minimal matter content. This well-known model, based on the gauge group SU(4)LC×SU(2)L×SU(2)RSU(4)_{LC} \times SU(2)_L \times SU(2)_R, 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 (10‾,3,1)(\overline{10}, 3, 1) and its right-handed parity partner (10‾,1,3)(\overline{10}, 1, 3) can solve both anomalies while making testable predictions for related observables such as B→KννB \to K\nu\nu and B→KμτB \to K \mu\tau. The solution of the RK(∗)R_{K^{(*)}} anomaly alone can be related to a type-II seesaw neutrino mass structure. Explaining also RD(∗)R_{D^{(*)}} 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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