Wormholes in R2R^2-gravity within the f(R,T)f(R,T) formalism

We propose, as a novelty in the literature, the modelling of wormholes within the particular case of the $f(R,T)$ gravity, namely $f(R,T)=R+\alpha R^{2}+\lambda T$, with $R$ and $T$ being the Ricci scalar and trace of the energy-momentum tensor, respectively, while $\alpha$ and $\lambda$ are constants. Although such a functional form application can be found in the literature, those concern to compact astrophysical objects, such that no wormhole analysis has been done so far. The quadratic geometric and linear material corrections of this theory make the matter content of the wormhole to remarkably be able to obey the energy conditions.Comment: Published versio

Probing new physics in B→Dℓ+ℓ−B \to D \ell^+ \ell^- decays by using angular asymmetries

We present the fully general, model independent study of a few rare semileptonic $B$ decays that get dominant contributions from $W$-annihilation and $W$-exchange diagrams, in particular $B^0 \to \bar{D}^0 \ell^+\ell^-$, where $\ell = e,\mu$. We consider the most general Lagrangian for the decay, and define three angular asymmetries in the Gottfried-Jackson frame, which are sensitive to new physics. We show how these angular asymmetries can be easily extracted from the distribution of events in the Dalitz plot for $B \to D \ell^+ \ell^-$ decays. Especially a non-zero forward-backward asymmetry within the frame would give the very first hint of possible new physics. These observations are also true for related decay modes, such as $B^+ \to D^+ \ell^+ \ell^-$ and $B^0 \to D^0 \ell^+ \ell^-$. Moreover, these asymmetry signatures are not affected by either $B^0$-$\bar{B}^0$ or $D^0$-$\bar{D}^0$ mixings. Then, this implies that both $B^0 \to \bar{D}^0 \ell^+ \ell^-$ and $B^0 \to D^0 \ell^+ \ell^-$ as well as their CP conjugate modes can all be considered together in our search for signature of new physics. Hence, it would be of great importance to look for and study these decays in the laboratory, LHCb and Belle II in particular.Comment: 5 pages, 2 figure