On Flavourful Easter eggs for New Physics hunger and Lepton Flavour Universality violation

Within the standard approach of effective field theory of weak interactions for $\Delta B = 1$ transitions, we look for possibly unexpected subtle New Physics effects, here dubbed "flavourful Easter eggs". We perform a Bayesian global fit using the publicly available HEPfit package, taking into account state-of-the-art experimental information concerning these processes, including the suggestive measurements from LHCb of $R_{K}$ and $R_{K^{*}}$, the latter available only very recently. We parametrize New Physics contributions to $b \to s$ transitions in terms of shifts of Wilson coefficients of the electromagnetic dipole and semi-leptonic operators, assuming CP-conserving effects, but allowing in general for violation of lepton flavour universality. We show how optimistic/conservative hadronic estimates can impact quantitatively the size of New Physics extracted from the fit. With a conservative approach to hadronic uncertainties we find nonzero New Physics contributions to Wilson coefficients at the level of $\sim 3\sigma$, depending on the model chosen. Furthermore, given the interplay between hadronic contributions and New Physics effects in the leptonic vector current, a scenario with nonstandard leptonic axial currents is comparable to the more widely advocated one with New Physics in the leptonic vector current.Comment: 27 pages, 6 figures and 5 tables. v2: numerical results and plots replaced with higher statistics MC runs, references added. v3: final version to appear in EPJ

Synergy between Hund-Driven Correlations and Boson-Mediated Superconductivity

Multiorbital systems such as the iron-based superconductors provide a new avenue to attack the long-standing problem of superconductivity in strongly correlated systems. In this work we study the superconductivity driven by a generic bosonic mechanism in a multiorbital model including the full dynamical electronic correlations induced by the Hubbard U and the Hund's coupling. We show that superconductivity survives much more in a Hund's metal than in an ordinary correlated metal with the same degree of correlation. The redistribution of spectral weight characteristic of the Hund's metal reflects also in the enhancement of the orbital-selective character of the superconducting gaps, in agreement with experiments in iron-based superconductors

Interplay between destructive quantum interference and symmetry-breaking phenomena in graphene quantum junctions

We study the role of electronic spin and valley symmetry in the quantum interference (QI) patterns of the transmission function in graphene quantum junctions. In particular, we link it to the position of the destructive QI antiresonances. When the spin or valley symmetry is preserved, electrons with opposite spin or valley display the same interference pattern. On the other hand, when a symmetry is lifted, the antiresonances are split, with a consequent dramatic differentiation of the transport properties in the respective channel. We demonstrate rigorously this link in terms of the analytical structure of the electronic Green function, which follows from the symmetries of the microscopic model, and we confirm the result with numerical calculations for graphene nanoflakes. We argue that this is a generic and robust feature that can be exploited in different ways for the realization of nanoelectronic QI devices, generalizing the recent proposal of a QI-assisted spin-filtering effect [A. Valli et al., Nano Lett. 18, 2158 (2018)10.1021/acs.nanolett.8b00453]

Soybean meal-dependent intestinal inflammation induces different patterns of bone-loss in adult zebrafish scale

Inflammatory bowel disease have been linked to several health issues, including high risk of low bone mineral density. Danio rerio (zebrafish) is a good model to verify the effects of intestinal inflammation, since its gastrointestinal and immune systems are closely related to that of mammalians. Zebrafish is also a powerful model to study bone metabolism using the scale as the read-out model. Food strongly impacts zebrafish gut physiology, and it is well known that soybean meal induces intestinal inflammation. Adult zebrafish fed with defatted soybean meal (SBM) exhibited an intestinal inflammation evidenced by morphological alterations, inflammatory infiltrate, and increased mRNA expression of inflammatory cytokines (IL-1\u3b2, IL-6, IL-8, IL-10, TGF\u3b2, TNF-\u3b1). The peak of acute intestinal inflammation, spanning between week 2 and 3, correlates with a transitory osteoporosis-like phenotype in the scale border. Later, a chronic inflammatory condition, associated with persistent IL-8 expression, correlates with the progression of resorption lacunae in the scale center. Both types of resorption lacunae were associated with intense osteoclastic tartrate-resistant acid phosphatase (TRAP) activity. After 3 weeks of SBM treatment, osteoclast activity decreased in the scale border but not in the center. At the same time, alkaline phosphatase (ALP) is activated in the border to repair the bone matrix. This model can contribute to elucidate in vivo the molecular mechanisms that links intestinal inflammation and bone metabolism in IBD