The anomalies in the measurements of observables involving b → sμμ decays, namely R _K , R _K*, P ₅ ^′ , and B _s ^ϕ , may be addressed by adding lepton-universality-violating new physics contributions to the effective operators $$ {\mathcal{O}}_{\mathcal{9}},{\mathcal{O}}_{10},{\mathcal{O}}_9^{\prime },{\mathcal{O}}_{10}^{\prime } $$ O 9 , O 10 , O 9 ′ , O 10 ′ . We analyze all the scenarios where the new physics contributes to a pair of these operators at a time. We perform a global fit to all relevant data in the b → s sector to estimate the corresponding new Wilson coefficients, $$ {\mathcal{O}}_9^{\mathrm{NP}},{\mathcal{O}}_{10}^{\mathrm{NP}},{\mathcal{O}}_9^{\prime },{\mathcal{O}}_{10}^{\prime } $$ O 9 N P , O 10 N P , O 9 ′ , O 10 ′ . In the light of the new data on R _K , and R _K*, presented in Moriond 2019, we find that the scenarios with new physics contributions to the $$ \left({\mathcal{O}}_9^{\mathrm{NP}},{\mathcal{O}}_9^{\prime}\right) $$ O 9 N P O 9 ′ or $$ \left({\mathcal{O}}_9^{\mathrm{NP}},{\mathcal{O}}_{10}^{\prime}\right) $$ O 9 N P O 10 ′ pair remain the most favored ones. On the other hand, though the competing scenario $$ \left({\mathcal{O}}_9^{\mathrm{NP}},{\mathcal{O}}_{10}^{\mathrm{NP}}\right) $$ O 9 N P O 10 N P remains attractive, its advantage above the SM reduces significantly due to the tension that emerges between the R _K and R _K* measurements with the new data. The movement of the R _K measurement towards unity would also result in the re-emergence of the one-parameter scenario C ₉ ^NP = − C ₉ ^′ .

The recent measurement of $R_{K^{*}}$ is yet another hint of new physics (NP) and supports the idea that it is present in $b\to s{\mu }^{+}{\mu }^{-}$ decays. We perform a combined model-independent and model-dependent analysis in order to deduce properties of this NP. Like others, we find that the NP must obey one of two scenarios: (I) $C_9^{\mu \mu }(\mathrm{NP})<0$ or (II) $C_9^{\mu \mu }(\mathrm{NP})=-C_{10}^{\mu \mu }(\mathrm{NP})<0$. A third scenario, (III) $C_9^{\mu \mu }(\mathrm{NP})=-C_9^{\prime \mu \mu }(\mathrm{NP})$, is rejected largely because it predicts $R_K=1$, in disagreement with experiment. The simplest NP models involve the tree-level exchange of a leptoquark (LQ) or a $Z^{\prime }$ boson. We show that scenario II can arise in LQ or $Z^{\prime }$ models, but scenario I is only possible with a $Z^{\prime }$. Fits to $Z^{\prime }$ models must take into account the additional constraints from $B_s^0\text{−}{\overline{B}}_s^0$ mixing and neutrino trident production. Although the LQs must be heavy, O(TeV), we find that the $Z^{\prime }$ can be light, e.g., $M_{Z^{\prime }}=10\mathrm{GeV}$ or 200 MeV.

The confirmation of excess in $R_{D^{*}}$ at the LHCb is an indication of lepton flavor nonuniversality. Various different new physics operators and their coupling strengths, which provide a good fit to $R_D$, $R_{D^{*}}$, and $q^2$ spectra, were identified previously. In this work, we try to find angular observables in $\overline{B}\to D^{*}\tau \overline{\nu }$ which enable us to distinguish between these new physics operators. We find that the $D^{*}$ polarization fraction $f_L(q^2)$ is a good discriminant of scalar and tensor new physics operators. The change in $⟨f_L(q^2)⟩$, induced by scalar and tensor operators, is about 3 times larger than the expected uncertainty in the upcoming Belle measurement.

Correlations exhibited by neutrino oscillations are studied via quantum-information theoretic quantities. We show that the strongest type of entanglement,

Neutrino oscillations provide evidence for the mode entanglement of neutrino mass eigenstates in a given flavour eigenstate. Given this mode entanglement, it is pertinent to consider the relation between the oscillation probabilities and other quantum correlations. In this work, we show that all the well-known quantum correlations, such as the Bell's inequality, are directly related to the neutrino oscillation probabilities. The results of the neutrino oscillation experiments, which measure the neutrino survival probability to be less than unity, imply Bell's inequality violation

At present, there are several measurements of $B$ decays that exhibit discrepancies with the predictions of the SM, and suggest the presence of new physics (NP) in $b\to s{\mu }^{+}{\mu }^{-}$ transitions. Many NP models have been proposed as explanations. These involve the tree-level exchange of a leptoquark (LQ) or a flavor-changing $Z^{\prime }$ boson. In this paper we examine whether it is possible to distinguish the various models via $CP$-violating effects in $B\to K^{(*)}{\mu }^{+}{\mu }^{-}$. Using fits to the data, we find the following results. Of all possible LQ models, only three can explain the data, and these are all equivalent as far as $b\to s{\mu }^{+}{\mu }^{-}$ processes are concerned. In this single LQ model, the weak phase of the coupling can be large, leading to some sizable $CP$ asymmetries in $B\to K^{(*)}{\mu }^{+}{\mu }^{-}$. There is a spectrum of $Z^{\prime }$ models; the key parameter is $g_L^{\mu \mu }$, which describes the strength of the $Z^{\prime }$ coupling to ${\mu }^{+}{\mu }^{-}$. If $g_L^{\mu \mu }$ is small (large), the constraints from $B_s^0-{\overline{B}}_s^0$ mixing are stringent (weak), leading to a small (large) value of the NP weak phase, and corresponding small (large) $CP$ asymmetries. We therefore find that the measurement of $CP$-violating asymmetries in $B\to K^{(*)}{\mu }^{+}{\mu }^{-}$ can indeed distinguish among NP $b\to s{\mu }^{+}{\mu }^{-}$ models.