In light of the very recent updates on the $$R_K$$
 and $$R_{K^*}$$
 measurements from the LHCb and Belle collaborations, we systematically explore here imprints of New Physics in $$b \rightarrow s \ell ^+ \ell ^- $$
 transitions using the language of effective field theories. We focus on effects that violate Lepton Flavour Universality both in the Weak Effective Theory and in the Standard Model Effective Field Theory. In the Weak Effective Theory we find a preference for scenarios with the simultaneous presence of two operators, a left-handed quark current with vector muon coupling and a right-handed quark current with axial muon coupling, irrespective of the treatment of hadronic uncertainties. In the Standard Model Effective Field Theory we select different scenarios according to the treatment of hadronic effects: while an aggressive estimate of hadronic uncertainties points to the simultaneous presence of two operators, one with left-handed quark and muon couplings and one with left-handed quark and right-handed muon couplings, a more conservative treatment of hadronic matrix elements leaves room for a broader set of scenarios, including the one involving only the purely left-handed operator with muon coupling.

/pdf/new-physics-in-b-to-s-ell-ell-confronts-new-data-on-lepton-4hu9x78xpe.pdf

New Physics in $b \to s \ell^+ \ell^-$ confronts new data on Lepton Universality

Motivated by the success of the flavour physics programme carried out over the last decade at the Large Hadron Collider (LHC), we characterize in detail the physics potential of its High-Luminosity and High-Energy upgrades in this domain of physics. We document the extraordinary breadth of the HL/HE-LHC programme enabled by a putative Upgrade II of the dedicated flavour physics experiment LHCb and the evolution of the established flavour physics role of the ATLAS and CMS general purpose experiments. We connect the dedicated flavour physics programme to studies of the top quark, Higgs boson, and direct high-$p_T$ searches for new particles and force carriers. We discuss the complementarity of their discovery potential for physics beyond the Standard Model, affirming the necessity to fully exploit the LHC's flavour physics potential throughout its upgrade eras.

Opportunities in Flavour Physics at the HL-LHC and HE-LHC

Lepton flavor universality violating $B\ensuremath{\rightarrow}K\ensuremath{\ell}\ensuremath{\ell}$ and ${K}^{*}\ensuremath{\ell}\ensuremath{\ell}$ decays tentatively observed by LHCb can be explained by leptoquark exchange. We explore a simple model for the $B$ anomalies with a composite leptoquark from new strong dynamics at the TeV scale, a confining SU(${N}_{HC}$) hypercolor interaction. The new matter fields, fundamentals under $\mathrm{SU}({N}_{HC})$, are heavy vectorlike fermions $\mathrm{\ensuremath{\Psi}}$, $S$, and an inert scalar doublet $\ensuremath{\phi}$. $\mathrm{\ensuremath{\Psi}}$ is colored under QCD while $S$ is neutral, and the hyperbaryon ${S}^{N}$ is an asymmetric dark matter candidate. The model is tightly constrained by meson-antimeson oscillations, lepton flavor violation, and LHC searches for resonant production of the exotic bound states. The dark matter may be detectable through its magnetic dipole moment. If ${m}_{S}$ is sufficiently small, composite leptoquarks and heavy lepton partners can be pair-produced at an observable level at LHC.

B decay anomalies and dark matter from vectorlike confinement

We analyze the recent hints of lepton flavor universality violation in both charged-current and neutral-current rare decays of $B$ mesons in an $R$-parity-violating supersymmetric scenario. Motivated by simplicity and minimality, we had earlier postulated the third-generation superpartners to be the lightest (calling the scenario ``RPV3'') and explicitly showed that it preserves gauge coupling unification and of course has the usual attribute of naturally addressing the Higgs radiative stability. Here we show that both ${R}_{{D}^{(*)}}$ and ${R}_{{K}^{(*)}}$ flavor anomalies can be addressed in this RPV3 framework. Interestingly, this scenario may also be able to accommodate two other seemingly disparate anomalies, namely, the longstanding discrepancy in the muon ($g\ensuremath{-}2$), as well as the recent anomalous upgoing ultrahigh-energy Antarctic Impulsive Transient Antenna events. Based on symmetry arguments, we consider three different benchmark points for the relevant RPV3 couplings and carve out the regions of parameter space where all (or some) of these anomalies can be simultaneously explained. We find it remarkable that such overlap regions exist, given the plethora of precision low-energy and high-energy experimental constraints on the minimal model parameter space. The third-generation superpartners needed in this theoretical construction are all in the 1--10 TeV range, accessible at the LHC and/or next-generation hadron colliders. We also discuss some testable predictions for the lepton-flavor-violating decays of the tau lepton and $B$ mesons for the current and future $B$-physics experiments, such as LHCb and Belle II. Complementary tests of the flavor anomalies in the high-${p}_{T}$ regime in collider experiments such as the LHC are also discussed.

Addressing R D ( * ) , R K ( * ) , muon g − 2 and ANITA anomalies in a minimal R -parity violating supersymmetric framework

Dark matter contribution to b → sμ+μ− anomaly in local U(1)Lμ−Lτ model

The LHCb has measured the ratios of $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ to $B\ensuremath{\rightarrow}{K}^{*}{e}^{+}{e}^{\ensuremath{-}}$ branching fractions in two dilepton invariant mass squared bins, which deviate from the standard model predictions by approximately $25\ensuremath{\sigma}$ These new measurements strengthen the hint of lepton flavor universality breaking which was observed earlier in $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ decays In this work we explore the possibility of explaining these anomalies within the framework of $R$-parity violating interactions In this framework, $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ transitions are generated through tree and one loop diagrams involving exchange of down-type right-handed squarks, up-type left-handed squarks and left-handed sneutrinos We find that the tree level contributions are not enough to explain the anomalies, but at one loop, simultaneous explanation of the deviations in $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ and $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ is feasible for a parameter space of the Yukawa couplings that is consistent with the bounds coming from $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ and ${D}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ decays and ${B}_{s}\ensuremath{-}{\overline{B}}_{s}$ mixing

Scrutinizing R -parity violating interactions in light of R K ( * ) data

We show that the anomalies observed in the measurements of the B decays $B \rightarrow D^{(*)}\tau \bar{\nu }$ and $B \rightarrow K \ell ^+\ell ^-$ as well as the anomalous magnetic moment of the muon $(g-2)_\mu $ can be simultaneously explained in a $E_6$ motivated left-right model which naturally accommodates leptoquarks, while satisfying the constraints from flavor processes like $B^0 - \bar{B}^0$ mixing, $D^0 - \bar{D}^0$, and (semi) leptonic decays of B and D mesons.

Girish Kumar

Papers

Scrutinizing R -parity violating interactions in light of R K ( * ) data

Explainin g R( D$$^{(*)}$$), RK and ( g – 2)$$_{\mu }$$ in a E6 Motivated Left- Ri ght Model