Our primary interest is in generalizing the problem of Cosegmentation to a large group of images, that is, concurrent segmentation of common foreground region(s) from multiple images. We further wish for our algorithm to offer scale invariance (foregrounds may have arbitrary sizes in different images) and the running time to increase (no more than) near linearly in the number of images in the set. What makes this setting particularly challenging is that even if we ignore the scale invariance desiderata, the Cosegmentation problem, as formalized in many recent papers (except), is already hard to solve optimally in the two image case. A straightforward extension of such models to multiple images leads to loose relaxations; and unless we impose a distributional assumption on the appearance model, existing mechanisms for image-pair-wise measurement of foreground appearance variations lead to significantly large problem sizes (even for moderate number of images). This paper presents a surprisingly easy to implement algorithm which performs well, and satisfies all requirements listed above (scale invariance, low computational requirements, and viability for the multiple image setting). We present qualitative and technical analysis of the properties of this framework.

In this article, we have considered an extension of the inert Higgs doublet model with $SU(2{)}_L$ singlet vectorlike fermions. Our model is capable of addressing some interesting anomalous results in $b\to s{\ell }^{+}{\ell }^{-}$ decays [like $R(K^{(*)})$] and in muon ($g-2$). Apart from explaining these anomalies, and being consistent with other flavor data, the model satisfies relevant constraints in the dark matter sector, while remaining within the reach of ongoing direct detection experiments. The model also produces signatures at the large hadron collider (LHC) with final states comprised of dilepton, dijet and missing energy, providing signals to be probed at higher luminosity.

Belle II has reported the first evidence for $B^{+}\to K^{+}\nu \overline{\nu }$ with a branching ratio $2.7\sigma$ higher than the standard model expectation. We explain this and the MiniBooNE and muon anomalous magnetic moment anomalies in a model with a dark scalar that couples to a slightly heavier sterile Dirac neutrino and that communicates with the visible sector via a Higgs portal. We make predictions for rare kaon and other $B$ meson decays.

In this paper, we study the ensemble clustering problem, where the input is in the form of multiple clustering solutions. The goal of ensemble clustering algorithms is to aggregate the solutions into one solution that maximizes the agreement in the input ensemble. We obtain several new results for this problem. Specifically, we show that the notion of agreement under such circumstances can be better captured using a 2D string encoding rather than a voting strategy, which is common among existing approaches. Our optimization proceeds by first constructing a non-linear objective function which is then transformed into a 0-1 Semidefinite program (SDP) using novel convexification techniques. This model can be subsequently relaxed to a polynomial time solvable SDP. In addition to the theoretical contributions, our experimental results on standard machine learning and synthetic datasets show that this approach leads to improvements not only in terms of the proposed agreement measure but also the existing agreement measures based on voting strategies. In addition, we identify several new application scenarios for this problem. These include combining multiple image segmentations and generating tissue maps from multiple-channel Diffusion Tensor brain images to identify the underlying structure of the brain.

We study a generic leptophilic U(1)_X extension of the standard model with a light gauge boson. The U(1)_X charge assignments for the leptons are guided by lepton universality violating (LUV) observables in semileptonic b → sℓℓ decays, muon anomalous magnetic moment and the origin of leptonic masses and mixing. Anomaly cancellation conditions require the addition of new chiral fermions in the model, one of which acts as a dark matter (DM) candidate when it is stabilised by an additional $$ {\mathcal{Z}}_2 $$Z 2 symmetry. From our analysis, we show two different possible models with similar particle content that lead to quite contrasting neutrino mass origin and other phenomenology. The proposed models also have the potential to address the anomalous results in b → cℓν_ℓ decays like R(D), R(D^∗), electron anomalous magnetic moment and the very recent KOTO anomaly in the kaon sector. We also discuss different possible collider signatures of our models which can be tested in future.

We study flavor changing neutral current decays of B and K mesons in the dark U(1)_D model, with the dark photon/dark Z mass between 10 MeV and 2 GeV. Although the model provides an improved fit (compared to the standard model) to the differential decay distributions of B → K^(∗)ℓ⁺ℓ⁻, with ℓ = μ, e, and B_s→ ϕμ⁺μ⁻, the allowed parameter space is ruled out by measurements of atomic parity violation, K⁺→ μ⁺ + invisible decay, and $$ {B}_s-{\overline{B}}_s $$B s − B ¯ s mixing, among others. To evade constraints from low energy data, we extend the model to allow for (1) additional invisible Z_D decay, (2) a direct vector coupling of Z_D to muons, and (3) a direct coupling of Z_D to both muons and electrons, with the electron coupling fine-tuned to cancel the Z_D coupling to electrons via mixing. We find that only the latter case survives all constraints.