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 $(g-2)$, as well as the recent anomalous upgoing ultra-high energy ANITA 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 collider. 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.
The ANITA experiment has seen anomalous Earth emergent showers of EeV energies which cannot be explained with Standard Model interactions. In addition, tests of lepton flavor universality in $ R(D^{(\ast)})$ and $R(K^{(\ast)})$ have shown significant deviations from theoretical predictions. It is known that, among single leptoquark solutions, only the chiral vector leptoquark $U_1 \sim (\mathbf{3}, \mathbf{1} , 2/3)$ can simultaneously address the discrepancies. In this paper, we show that the leptoquark motivated by flavor anomalies coupled to a sterile neutrino can also explain the ANITA Ano…
The ANITA balloon experiment has observed two EeV-energy, upgoing events originating from well below the horizon. This is puzzling, because (i) no Standard Model (SM) particle is expected to survive passage through Earth at such energies and incident angles, and (ii) no such events were reported by IceCube. In this paper, we address both these issues by invoking a beyond SM interpretation of the EeV events as due to the decay of a long-lived bino in the R-parity violating (RPV) supersymmetry. In particular, a TeV-scale slepton/squark can be resonantly produced through the interaction of the Ee…
Driven by the recent experimental hints of lepton-flavor-universality violation in the bottom-quark sector, we consider a simple extension of the Standard Model (SM) with an additional vector leptoquark $V_{\rm LQ}({\bf 3},{\bf 1},2/3)$ and a scalar diquark $S_{\rm DQ}({\bf 6},{\bf 1},4/3)$ under the SM gauge group $SU(3)_c\times SU(2)_L\times U(1)_Y$, in order to simultaneously explain the $b \to s \ell^+ \ell^-$ (with $\ell=e,μ$) and $b \to c l^- \bar ν_l$ (with $l=e,μ,τ$) flavor anomalies, as well as to generate small neutrino masses through a two-loop radiative mechanism. We perform a glob…
We study a class of DFSZ-like models for the QCD axion that can address observed anomalies in stellar cooling. Stringent constraints from SN1987A and neutron stars are avoided by suppressed couplings to nucleons, while axion couplings to electrons and photons are sizable. All axion couplings depend on few parameters that also control the extended Higgs sector, in particular lepton flavor-violating couplings of the Standard Model-like Higgs boson $h$. This allows us to correlate axion and Higgs phenomenology, and we find that that ${\rm BR}(h \to τe)$ can be as large as the current experimental…
We investigate the possibility of explaining the enhancement in semileptonic decays of $\bar B \to D^{(*)} τ\bar ν$, the anomalies induced by $b\to sμ^+μ^-$ in $\bar B\to (K, K^*, ϕ)μ^+μ^-$ and violation of lepton universality in $R_K = Br(\bar B\to K μ^+μ^-)/Br(\bar B\to K e^+e^-)$ within the framework of R-parity violating (RPV) MSSM. Exchange of down type right-handed squark coupled to quarks and leptons yield interactions which are similar to leptoquark induced interactions that have been proposed to explain the $\bar B \to D^{(*)} τ\bar ν$ by tree level interactions and $b\to s μ^+μ^-$ an…
We consider the implications of Lorentz-invariance violation (LIV) on cosmogenic neutrino observations, with particular focus on the constraints imposed on several well-developed models for ultra-high energy cosmogenic neutrino production by recent results from the Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload, and Radio Ice Cherenkov Experiment (RICE) at the South Pole. Under a scenario proposed originally by Coleman and Glashow, each lepton family may attain maximum velocities that can exceed the speed of light, leading to energy-loss through several interaction…
Taking advantage of the fact that the flavor of the neutrino in semileptonic $B$ decays $B\to D^{(*)}τν$ is not known, we show how a minimal set of higher-dimensional lepton flavor violating (LFV) operators can explain the $R(D^{(*)})$ anomalies, and as a spin-off, can give rise to the LFV decay of the Higgs boson, $h\toμτ$. We also show how none but the minimal set of operators survive the present data.
In this paper, we consider a solution to explain the three discrepancies with the standard model (SM) predictions in flavor observables, i.e. anomalies in $B\rightarrow K^\astμ^+μ^-$ and $R_K=\mathcal{B}(B\rightarrow Kμ^+μ^-)/\mathcal{B}(B\rightarrow K e^+e^-)$ at the LHCb and an excess in $h\rightarrow μτ$ at the CMS in the context of R-parity violating (RPV) supersymmetry. We demonstrate that these anomalies can be explained within a unified framework: the minimal supersymmetry model (MSSM) extended with $5+\overline{5}$ vectorlike (VL) particles. The new trilinear RPV couplings involving VL…
We examine the parameter space of supersymmetric models with $R$-parity violating interactions of the form $λ' L Q D^c$ to explain the various anomalies observed in $b \rightarrow s \ell \ell$ transitions. To generate the appropriate operator in the low energy theory, we are led to a region of parameter space where loop contributions dominate. In particular, we concentrate on parameters for which diagrams involving winos, which have not been previously considered, give large contributions. Many different potentially constraining processes are analyzed, including $τ\rightarrow μμμ$, $B_s-\bar{B…
In the last few years, the ratios $R_{D^{(*)}}$ and of $R_{K^{(*)}}$ have reportedly exhibited significant deviations from the relevant Standard Model predictions, hinting towards a possible violation of Lepton Flavor Universality and a window to New Physics. We investigate to what extent the inclusion of R-parity violating couplings in the Minimal Supersymemtric Standard Model can provide a better fit to the anomalies simultaneously. We perform this analysis employing an approximate, non-abelian $\mathcal{G}_f=U(2)_q \times U(2)_\ell$ flavour symmetry, which features a natural explanation of …
In recent years, significant experimental indications that point towards Lepton Flavour Universality violating effects in B-decays, involving $b \to c τν$ and $b \to s \ell^+ \ell^-$ have been accumulated. A possible New Physics explanation can be sought within the framework of R-parity violating Supersymmetry, which contains the necessary ingredients to explain the anomalies via both leptoquark, tree-level exchange and one-loop diagrams involving purely leptonic interactions. In addition, an approximate $U(2)^2$ flavour symmetry, that respects gauge coupling unification, successfully controls…
We investigate resonance structures in CPT and Lorentz symmetry violating neutrino-antineutrino oscillations in a two generation framework. We work with four non-zero CPT-violating parameters that allow for resonant enhancements in neutrino-antineutrino oscillation phenomena in vacuo which are suitably described in terms of charge conjugation eigenstates of the system. We study the relation between the flavor, charge conjugation and mass eigenbasis of neutrino-antineutrino oscillations and examine the interplay between the available CPT-violating parameter space and possible resonance structur…
Inspired by the recent experimental results which show deviations from the standard model (SM) predictions of $b\rightarrow s \ell^+\ell^-$ transitions, we study the $R$-parity violating minimal supersymmetric standard model (RPV-MSSM) extended by the inverse seesaw mechanism. The trilinear $R$-parity violating terms, together with the chiral mixing of sneutrinos, induce the loop contributions to the $b\rightarrow s \ell^+\ell^-$ anomaly. We study the parameter space of the single-parameter scenario $C^{\rm NP}_{9,μ}=-C^{\rm NP}_{10,μ}=C_{\rm V}$ and the double-parameter scenario $(C_{\rm V},C…
We show that one can explain the neutral and charged anomalies in B-meson decays in the minimal theory for quark-lepton unification.The implications for flavor violating processes are discussed in detail. Strikingly, experimental observations suggest that the unification of quarks and leptons could be realized below the ${\cal O}(10^2)$ TeV scale.
In recent years, several deviations from the Standard Model predictions in semileptonic decays of $B$-meson might suggest the existence of new physics which would break the lepton-flavour universality. In this work, we have explored the possibility of using muon sneutrinos and right-handed sbottoms to solve these $B$-physics anomalies simultaneously in $R$-parity violating minimal supersymmetric standard model. We find that the photonic penguin induced by exchanging sneutrino can provide sizable lepton flavour universal contribution due to the existence of logarithmic enhancement for the first…
Recently, several $B$-physics experiments report interesting anomalies in the semi-leptonic decays of $B$-mesons, such as the excess in the $R_{D^{(\ast)}}$ measurements. These anomalies seem to suggest intriguing hints of lepton flavor non-universality, and the R-parity violating (RPV) interactions are candidates for explaining this non-universality. In this paper, we discuss the RPV interactions for resolving the $R_{D^{(\ast)}}$ anomaly with the Grand Unified Theory (GUT) assumption. To solve the $R_{D^{(\ast)}}$ anomaly, it is known that large RPV couplings and around $1~{\rm TeV}$ sfermio…
The recent experimental results including $R_{K^{(\ast)}}$, $R_{D^{(\ast)}}$, $(g-2)_μ$ and $W$ mass show deviations from the standard model (SM) predictions, implying the clues of new physics (NP). In this work, we investigate the explanations of these anomalies in the $R$-parity violating minimal supersymmetric standard model (RPV-MSSM) extended with the inverse seesaw mechanism. The non-unitarity extent $η_{ee}$ and the loop corrections from the interaction $λ'\hat L \hat Q \hat D$ are utilized to raise the prediction of $W$ mass through muon decays. We also find that the interaction $λ'\ha…
We consider fermionic UV completions of little Higgs models and their associated T-parity violating anomalous vertices. In particular, we investigate strategies to avoid such parity-violating anomalies. We show that it is unlikely a QCD-like UV completion could be used to implement a model with anomaly-free global symmetry groups. This is because the vacuum state is unlikely to achieve the necessary alignment. However, we will see that certain multi-link moose models, although anomalous, possess a modified form of T-parity that leads to a stable particle. Finally, we briefly discuss a discrimi…
We estimate contributions from Kaluza-Klein excitations of gauge bosons and physical charge scalar for the explanation of the lepton flavor universality violating excess in the ratios $\mathcal{R}(D)$ and $\mathcal{R}(D^*)$ in 5 dimensional Universal Extra Dimensional scenario with non-vanishing boundary localized terms. This model is conventionally known as non-minimal Universal Extra Dimensional model. We obtain the allowed parameter space in accordance with constraints coming from $B_c \to τν$ decay, as well as those from the electroweak precision tests.
Motivated by tensions between experimental measurements and SM predictions in $b\to s \ell^+\ell^-$ transitions, we present the first study of non-minimal flavour-violating Minimal Supersymmetric Standard Model (MSSM) scenarios contributing to the relevant Wilson coefficients to address the observed anomalies using SuperIso and MARTY. We calculate the full one-loop analytical contributions of the general MSSM to Wilson coefficients relevant for flavour anomalies, together with the anomalous muon magnetic dipole moment $(g-2)_μ$. We show that, after imposing theoretical constraints on the flavo…
Hints of violation of lepton flavor universality in semileptonic $B$ decays have prompted a renewed interest in leptoquarks at the low TeV scale. Among the different scenarios suggested, some happen to violate also lepton number, yet not much attention has been paid to the expected size of the associated lepton number violating processes. In this note we examine this issue. We find that there is a single leptoquark scenario compatible with the current size of the anomalies which also violates lepton number. In this scenario (Majorana) neutrino masses are radiatively generated. With the leptoqu…
A recent LHCb measurement of the ratio $R_{K^*}$ of $B\to K^*μ\barμ$ to $B\to K^*e\bar e$ branching fractions has produced results in mild tension with the standard model (SM). This adds to the known anomalies also induced by the $b\to s\ell\bar\ell$ transitions, resulting in a confidence level now as high as 4$σ$. We analyze whether the parameter space preferred by all the $b\to s\ell\bar\ell$ anomalies is compatible with a heavy $Z'$ boson assumed to have nonuniversal couplings to SM fermions dictated by the principle of minimal flavor violation (MFV). We deal with the MFV couplings of the $…
I review some aspects of the interplay between anomalies and chiral symmetry. The quantum anomaly that breaks the U(1) axial symmetry of massless QCD leaves behind a flavor-singlet discrete chiral invariance. When the mass is turned on this residual symmetry has a close connection with the strong CP violating parameter theta. One result is that a first order transition is usually expected when the strong CP violating angle passes through pi. This symmetry can be understood either in terms of effective chiral Lagrangians or in terms of the underlying quark fields.
B-anomalies hint towards New Physics violating Lepton Flavor Universality at the TeV scale. The way they manifest points out to very particular structures for this New Physics. In this talk I review some UV-complete models to explain the B-anomalies, and possible directions these models suggest for Physics beyond the TeV scale.
Vector leptoquarks can address the lepton flavor universality anomalies in decays associated with the $b \to c \ell ν$ and $b \to s \ell \ell$ transitions, as observed in recent years. Generically, these leptoquarks yield new sources of CP violation. In this paper, we explore constraints and discovery potential for electric dipole moments (EDMs) in leptonic and hadronic systems. We provide the most generic expressions for dipole moments induced by vector leptoquarks at one loop. We find that $O(1)$ CP-violating phases in tau and muon couplings can lead to corresponding EDMs within reach of nex…
Neutrino oscillations are solidly established, with a hint of CP violation just emerging. Similarly, there are hints of lepton universality violation in $b \to s$ transitions at the level of $2.6 σ$. By assuming that the unitary transformation between weak and mass charged leptons equals the leptonic mixing matrix measured in neutrino oscillation experiments, we predict several lepton flavor violating (LFV) B meson decays. We are led to the tantalizing possibility that some LFV branching ratios for B decays correlate with the leptonic CP phase $δ$ characterizing neutrino oscillations. Moreover…
We address the presently reported significant flavor anomalies in the $K$ and $B$ meson systems such as the CP violating Kaon decay ($ε'/ε$) and lepton-flavor universality violation in $B$ meson decays ($R_{K^{(*)}},$ and also commenting ${R_{D^{(*)}}}$), by proposing flavorful and chiral vector bosons as the new physics constitution at $\sim 1\,\mathrm{TeV}$. Interestingly, if the new (composite) vector bosons are quite heavier than $\sim 1\,\mathrm{TeV}$, we face a difficulty in addressing the anomaly in $ε'/ε$ consistently with the constraint from the $K^0$-$\overline{K^0}$ mixing. Both of …
We propose renormalizable models of new physics that can explain various anomalies observed in decays of B-mesons to electron and muon pairs. The new physics states couple to linear combinations of Standard Model fermions, yielding a pattern of flavour violation that gives a consistent fit to the gamut of flavour data. Accidental symmetries prevent contributions to baryon- and lepton-number-violating processes, as well as enforcing a loop suppression of new physics contributions to flavour violating processes. Data require that the new flavour-breaking couplings are largely aligned with the Yu…
Motivated by the recent experimental progress on the $R_{D^{(\ast)}}$ and $R_{K^{(\ast)}}$ anomalies in $B$-decays, we consider an extension of the Standard Model by a single vector leptoquark field. We study how one can achieve the required lepton flavour non-universality, starting from a priori universal gauge couplings. While the unitary coupling flavour structure, induced by the mass misalignment of quarks and leptons after $SU(2)_L$ breaking, does not allow to comply with stringent bounds from lepton flavour violating processes, we find that effectively non-unitary couplings, due to mixin…
Motivated by the recent measurement of the lepton flavour nonuniversality ratio $R_{K^*}$ by the LHCb Collaboration, we study the implications of vector leptoquarks on the observed anomalies associated with the $\bar B \to \bar K^* l^+ l^-$ decay processes. The leptoquark couplings are constrained from the measured branching ratios of $B_s \to l^+ l^-$, $K_L \to l^+ l^-$ and $B_s \to μ^\mp e^\pm$ processes. Using these constrained couplings, we estimate the branching ratios, forward-backward and lepton polarization asymmetries and also the form factor independent optimized observables ($P_{i}^…
The formalism for neutrino flavor change induced by lepton family number violating interactions is developed for the three-neutrino case, and used to derive the corresponding flavor change probabilities in matter. Applied to the solar and atmospheric neutrino fluxes, it is argued that the observed anomalies, including the zenith dependence for the atmospheric case, could be due to such interactions.
The muon $g-2$ anomaly is a long-standing discrepancy from its standard model prediction. The recent improved measurement of the fine structure constant makes the electron $g-2$ anomaly very interesting for both sign and magnitude in comparison to the muon $g-2$ anomaly. In order to explain both muon and electron $g-2$ anomalies, we introduce flavor violation in the minimal supersymmetric standard model (MSSM) as a low energy theory. The lepton flavor violating process $τ\to eγ$ is one the major constraints to explain both $g-2$ anomalies simultaneously emerging from flavor violating terms. We…
We show how cosmic gamma rays can be used to constrain models of asymmetric Dark Matter decaying into lepton pairs by violating flavor. First of all we require the models to explain the anomalies in the charged cosmic rays measured by PAMELA, FERMI and HESS; performing combined fits we determine the allowed values of the Dark Matter mass and lifetime. For these models, we then determine the constraints coming from the measurement of the isotropic gamma-ray background by FERMI for a complete set of lepton flavor violating primary modes and over a range of DM masses from 100 GeV to 10 TeV. We fi…
LHCb found hints for physics beyond the standard model in $B\to K^*μ^+μ^-$, $B\to K^*μ^+μ^-/B\to K^*e^+e^-$ and $B_s\toϕμ^+μ^-$. In addition, the BABAR results for $B\to D^{(*)}τν$ and the CMS excess in $h\toτ^\pmμ^\mp$ also point towards lepton flavour (universality) violating new physics. While $B\to D^{(*)}τν$ and $h\toτ^\pmμ^\mp$ can be naturally explained by an extended Higgs sector, the probably most promising explanation for the $b\to sμμ$ anomalies is a $Z'$ boson. Furthermore, combining a 2HDM with a gauged $L_μ-L_τ$ symmetry allows for explaining the $b\to sμ^+μ^-$ anomalies and $h\t…
We consider several hints for new physics involving CP-asymmetries in B-decays and interpret them in terms of generic contributions to effective Wilson coefficients. The effects we focus on are: the differences in the fitted value of sin(2 beta) versus the ones directly measured via the time dependent CP asymmetries in B -> J/psi K or via B -> (phi,eta') K; the difference between the direct CP asymmetries in B- -> K- pi0 and B0 -> K- pi+ and the ~2.2 sigma indications for the CP-asymmetry in Bs -> J/psi phi. To alleviate concerns regarding the disagreement between inclusive and exclusive Vub, …
The measurements carried out at LEP and SLC projected us into the precision era of electroweak physics. This has also been relevant in the theoretical interpretation of LHCb and Belle measurements of rare $B$ semileptonic decays, paving the road for new physics with the inference of lepton universality violation in $R_{K^{(*)}}$ ratios. The simplest explanation of these flavour anomalies -- sizeable one-loop contributions respecting Minimal Flavour Violation -- is currently disfavoured by electroweak precision data. In this work, we discuss how to completely relieve the present tension between…
We construct an extension of the Standard Model with a scalar leptoquark $ϕ\sim (3,1,-\tfrac13)$ and the discrete flavour symmetry $G_f=D_{17}\times Z_{17}$ to explain anomalies observed in charged-current semi-leptonic $B$ meson decays and in the muon anomalous magnetic moment, together with the charged fermion masses and quark mixing. The symmetry $Z_{17}^{\rm diag}$, contained in $G_f$, remains preserved by the leptoquark couplings, at leading order, and efficiently suppresses couplings of the leptoquark to the first generation of quarks and/or electrons, thus avoiding many stringent experi…
We compute the parity violating part of the time-dependent gravitational response function of an ideal gas of Weyl fermions up to third order in the derivative expansion and give its full tensorial structure. Our main results are two functions that parametrize the energy-momentum tensor in terms of gauge-invariant combinations of vector and tensor metric perturbations. The zero frequency limit of these functions is related with the anomalous constitutive relations and with the full anomalous partition function in the presence of gauge and mixed anomalies. In particular, our results imply the e…
Indirect searches have the potential to probe scales beyond the realm of direct searches. In this letter we consider the implications of two parity violating experiments: weak charge of proton $Q_W^p$ and the Caesium atom $Q_W^{Cs}$ on the solutions to lepton flavour non-universality violations (LFUV) in the decay of $B$ mesons. Working in a generic implementation of a minimal $Z^\prime$ model, we assume the primary contribution being due to the electron to facilitate comparison with the low $q^2$ parity violating experiments. We demonstrate that the conclusion is characterized by different li…
In order to simultaneously account for both $R_{D^{(\ast)}}$ and $R_{K^{(\ast)}}$ anomalies in $B$-decays, we consider an extension of the Standard Model by a single vector leptoquark field, and study how one can achieve the required lepton flavour non-universality, starting from a priori universal gauge couplings. While the unitary quark-lepton mixing induced by $SU(2)_L$ breaking is insufficient, we find that effectively nonunitary mixings hold the key to simultaneously address the $R_{K^{(\ast)}}$ and $R_{D^{(\ast)}}$ anomalies. As an intermediate step towards various UV-complete models, we…
We discuss an optimal $R$-parity breaking SUSY solution to the $R_b$ excess as well as the ALEPH 4-jet anomaly. The latter arises from the pair production of stop via chargino decay at LEP1.5, followed by its $R$--violating decay into a light quark pair. The model satisfies top quark and $Z$--boson decay constraints along with gaugino mass unification.
Leptoquarks are ubiquitous in several extensions of the Standard Model and seem to be able to accommodate the universality-violation-driven $B$-meson-decay anomalies and the $(g-2)_μ$ discrepancy interpreted as deviations from the Standard Model predictions. In addition, the search for lepton-flavour violation in the charged sector is, at present, a major research program that could also be facilitated by the dynamics generated by leptoquarks. In this article, we consider a rather wide framework of both scalar and vector leptoquarks as the generators of lepton-flavour violation in processes in…
Recently, it was pointed out that the mixing phase in the Bs-Bsbar system is large, contrary to the expectations in the Standard Model as well as in minimal flavour violation models. The leptonic decay widths of the D_s meson are also found to be larger than expected. We show how a minimal set of four R-parity violating lambda-prime type couplings can explain both these anomalies. We also point out other phenomenological implications of such new physics.
The recent results from the Fermilab muon $g-2$ experiment, as well as the persisting hints of lepton flavor universality violation in $B$-meson decays, present a very strong case for flavor-nonuniversal new physics beyond the Standard Model. We assert that a minimal $R$-parity violating supersymmetric scenario with relatively light third-generation sfermions (dubbed as 'RPV3') provides a natural, well-motivated framework for the simultaneous explanation of all flavor anomalies, while being consistent with a multitude of low-energy flavor constraints, as well as with limits from high-energy co…
The LHCb has measured the ratios of $B\to K^\astμ^+μ^-$ to $B\to K^\ast e^+ e^-$ branching fractions in two dilepton invariant mass squared bins, which deviate from the Standard Model predictions by approximately $2.5σ$. These new measurements strengthen the hint of lepton flavor universality breaking which was observed earlier in $B\to K\ell^+\ell^-$ decays. In this work we explore the possibility of explaining these anomalies within the framework of $R$-parity violating interactions. In this framework, $b\to s\ell^+\ell^-$ transitions are generated through tree and one loop diagrams involvin…
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 $b \to s\ell\ell$ 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 $\mathcal{Z}_2$ symmetry. From our analysis, we show two different possible models with simila…
Motivated by an explanation of the $R_{K^{(*)}}$ anomalies, we propose a Standard Model extension via two scalar SU(2)$_L$ triplet leptoquarks and three generations of triplet Majorana fermions. The gauge group is reinforced by a $Z_2$ symmetry, ensuring the stability of the lightest $Z_2$-odd particle, which is a potentially viable dark matter candidate. Neutrino mass generation occurs radiatively (at the three-loop level), and leads to important constraints on the leptoquark couplings to leptons. We consider very generic textures for the flavour structure of the $h_1$ leptoquark Yukawa coupl…
We consider the U(1)$_X$ model, which can induce the flavor violating couplings through vectorlike fermions and address the observed rare $B$-meson decay anomalies. To be consistent with all the other observations, both the associated gauge boson mass and the vectorlike lepton mass are bounded from above. We argue that the search for new vectorlike leptons is promising and provides a complement to the $Z'$ search. A detailed collider analysis shows that the model with the vectorlike lepton mass up to 1000 GeV could be tested at the future LHC.
The existing anomalies appearing in decays of the form $b\to s \ell^+ \ell^-$ constitute a possible hint for new physics. We point out that modifications to the SM results due to heavy neutrinos could account for the observed deviations while satisfying existing constraints from lepton flavor violating processes. The required mixing angle, however, is an order of magnitude larger than suggested by recent global fits to lepton flavor conserving processes. We frame our discussion in terms of a Type-I seesaw model, but it can be made more general.
We present a first update on the constraints on general MSSM scenarios with non-minimal sources of flavour violation (NMFV). Using the public code SuperIso, we present an up-to-date computation of the relevant Wilson coefficients related to $b\to s ll$ transitions which manifest tensions with the SM predictions. We present benchmark scenarios compatible with the most recent fits to the Wilson coefficients. We finally discuss the possibility for such scenarios to completely explain the recent flavour anomalies.
We derive effective actions for parity-violating fluids in both $(3+1)$ and $(2+1)$ dimensions, including those with anomalies. As a corollary we confirm the most general constitutive relations for such systems derived previously using other methods. We discuss in detail connections between parity-odd transport and underlying discrete symmetries. In (3+1) dimensions we elucidate connections between anomalous transport coefficients and global anomalies, and clarify a previous puzzle concerning transports and local gravitational anomalies.
We discuss two independent issues about the baryon asymmetry of the universe. First, assuming that it is generated by an unspecified source at high temperatures, we study the effects of non-perturbative $SU(2)_W$ dynamics above the electroweak scale, in the context of supersymmetric models. We find that there is a substantial difference with the nonsupersymmetric case with the net effect of relaxing previous bounds on B and L violating interactions. In particular supersymmetry allows neutrino masses as large as 10 eV (preferred by solar neutrino and COBE data and measurable at future neutrino …
We study the Standard Model and the new physics predictions for the lepton-flavour-universality violating (LFUV) ratios in various $b\to s \ell^+\ell^-$ channels with scalar, pseudoscalar, vector, axial-vector, and $Λ$ baryon final states, considering both unpolarized and polarized final state hadrons. In order to formulate physical observables, we use the model independent effective Hamiltonian approach and employ the helicity formalism. We provide the explicit expressions of the helicity amplitudes in terms of the Wilson coefficients and the hadronic form factors by using the same kinematica…
We examine current constraints on and the future sensitivity to the strength of couplings between quarks and neutrinos in the presence of a form factor generated from loop effects of hidden sector particles that interact with quarks via new interactions. We consider models associated with either vector or scalar interactions of quarks and leptons generated by hidden sector dynamics. We study constraints on these models using data from coherent elastic neutrino-nucleus scattering and solar neutrino experiments and demonstrate how these new interactions may be discovered by utilizing the recoil …
We address the presently reported significant flavor anomalies in the Kaon and $B$ meson systems such as the CP violating Kaon decay ($ε'/ε$) and lepton-flavor universality violation in $B$ meson decays ($R_{K^{(*)}},{R_{D^{(*)}}}$), by proposing flavorful and chiral vector bosons as the new physics constitution at around TeV scale. The chiral-flavorful vectors (CFVs) are introduced as a 63-plet of the global $SU(8)$ symmetry, identified as the one-family symmetry for left-handed quarks and leptons in the standard model (SM) forming the 8-dimensional vector. Thus the CFVs include massive gluon…
Motivated by recent $R_D$, $R_{D^*}$ and $R_{J/ψ}$ anomalies in $B\to D\ell^- \barν_{\ell}$, $B\to D^*\ell^- \barν_{\ell}$ and $B_c\to J/ψ\ell^- \barν_{\ell}$ decays, respectively, we study possible R-parity violating supersymmetric effects in $B_c\to J/ψ\ell^- \barν_{\ell},η_c\ell^- \barν_{\ell}$ and $Λ_b \to Λ_c \ell^- \barν_{\ell}$ decays, which are also induced by $b\to c \ell^- \barν_{\ell}$ at quark level. We find that (I) the constrained slepton exchange couplings $λ_{i33}\tildeλ'^*_{i23}$ involving in $b\to c τ^- \barν_τ$ transition from relevant latest experimental data still have qui…
In recent years, several observables associated to semileptonic $b \to s$ processes have been found to depart from their predicted values in the Standard Model, including a few tantalizing hints of lepton flavor universality violation. In this work we consider an existing model with a massive $Z^\prime$ boson that addresses the anomalies in $b \to s$ transitions and extend it with a non-trivial embedding of neutrino masses. We analyze lepton flavor violating effects, induced by the non-universal interaction associated to the $b \to s$ anomalies and by the new physics associated to the neutrino…
