Lepton-flavor-violating decays of light pseudoscalars, $P=π^0,η,η'\toμe$, are stringently suppressed in the Standard Model up to tiny contributions from neutrino oscillations, so that their observation would be a clear indication for physics beyond the Standard Model. However, in effective field theory such decays proceed via axial-vector, pseudoscalar, or gluonic operators, which are, at the same time, probed in spin-dependent $μ\to e$ conversion in nuclei. We derive master formulae that connect both processes in a model-independent way in terms of Wilson coefficients, and study the implications of current $μ\to e$ limits in titanium for the $P\toμe$ decays. We find that these indirect limits surpass direct ones by many orders of magnitude.
Recent evidence for a CP violating asymmetry in the semileptonic decays of B_s mesons cannot be accommodated within the Standard Model. Such an asymmetry can be explained by new physics contributions to Delta B=2 components of either the mass matrix or the decay matrix. We show that mixing with a hidden pseudoscalar meson with a mass around 5 GeV can result in a new CP violating contribution to the mixing and can resolve several anomalies in this system including the width difference, the average width and the charge asymmetry. We also discuss the effects of the hidden meson on other b physics…
We study the production processes $e^+e^-\to H^0_iZ$, $H^0_iH^0_j$ and $H^0_iν_e\overline ν_e$ in the context of the CP violating MSSM. In a given channel we show that the cross-section for all i (=1,2,3) can be above 0.1 fb provided $M_{H_{2,3}}\la 300$ GeV. This should be detectable at a Next Linear Collider and would provide evidence for scalar-pseudoscalar mixing.
Using the present upper bound on the neutron electric dipole moment, we give an estimate for the upper limit of the CP-violating couplings of the eta(eta') to the nucleon. Using this result, we then derive constraints on the CP-violating eta(eta')-pi-pi couplings, which define the two-pion CP-violating decays of the eta and eta' mesons. Our results are relevant for the running and planned measurements of rare decays of the eta and eta' mesons by the GlueX Collaboration at JLab and the LHCb Collaboration at CERN.
We analyze contributions to the electric dipole (EDM) and Schiff (SFM) moments of deuteron induced by the CP-violating three-pseudoscalar meson couplings using phenomenological Lagrangian approach involving nucleons and pseudoscalar mesons $P=π, K, η, η'$. Deuteron is considered as a proton-neutron bound state and its properties are defined by one- and two-body forces. One-body forces correspond to a picture there proton and neutron are quasi free constituents of deuteron and their contribution to the deuteron EDM (dEDM) is simply the sum of proton and neutron EDMs. Two-body forces in deuteron…
Entangled pseudoscalar neutral meson pairs have been used in studying CP violation and searching CPT violation, but almost all the previous works concern $C=-1$ entangled state. Here we consider $C=+1$ entangled state of pseudoscalar neutral mesons, which is quite different from $C=-1$ entangled state and provides complementary information on symmetry violating parameters. After developing a general formalism, we consider three kinds of decay processes, namely, semileptonic-semileptonic, hadronic-hadronic and semileptonic-hadronic processes. For each kind of processes, we calculate the integra…
A mu+ mu- collider is an appealing machine to probe resonant CP-violating transitions of a CP-even Higgs particle into the Z boson or into another CP-odd Higgs scalar. These phenomena are studied within a manifestly gauge-invariant approach implemented by the pinch technique. The CP invariance of an extended Higgs sector motivated by supersymmetric E_6 models is assumed to be broken radiatively by the presence of heavy Majorana fermions. CP violation originating from Higgs-Z mixing is found to be very modest, whereas CP-number violating transitions involving Higgs scalars only can be resonantl…
The experimental observation of lepton-number violating processes would unambiguously indicate the Majorana nature of neutrinos. Various $ΔL$ = 2 processes for pseudoscalar meson $M_1$ decays to another pseudoscalar meson $M_2$ and two charged leptons $\ell_1$, $\ell_2$ ($M_1^+\to \ell_1^+\ell_2^+M_2^-$) have been studied extensively. Extending the existing literature on the studies of these kinds of processes, we consider the rare decays of heavy mesons to a vector meson or a pseudoscalar meson. These processes have not been searched for experimentally, while they may have sizable decay rates…
Pseudoscalar particles $ϕ$ usually couple electromagnetically by an interaction of the form $\frc14 g ϕF {\widetilde F}$, allowing them to convert to photons in the presence of magnetic fields. Notably, new low-mass pseudoscalars emitted from supernova (SN) 1987A would have been converted to $γ$-rays in the intervening magnetic field of the galaxy. Therefore, measurements by the Solar Maximum Mission (SMM) Gamma-Ray Spectrometer (GRS) can limit the inverse coupling constant to $g^{-1}>1{\times}10^{11}\,\rm GeV$, assuming the pseudoscalar is massless. This is an improvement over other astrophys…
A light pseudoscalar coupled to two photons would be copiously emitted by the core of a supernova. Part of this flux would be converted to $γ-$rays by the galactic magnetic field. Measurements on the SN1987A $γ-$ray flux by the Gamma-Ray Spectrometer on the Solar Maximum Mission satellite already imply a bound on the coupling $g < 3 \times 10^{-12}$ GeV$^{-1}$. The improved generation of satellite-borne detectors, like EGRET or the project GLAST, could be able to detect a pseudoscalar-to-photon signal from a nearby supernova, for allowed values of $g$.
A light pseudoscalar coupled to two photons would be copiously emitted by the core of a supernova and part of this flux would be converted to gamma-rays by the galactic magnetic field. Measurements on the SN1987A gamma-ray flux by the Gamma-Ray Spectrometer on the Solar Maximum Mission satellite imply stringents bounds on such process. The improved generation of satellite-borne detectors, like EGRET or the projegeneration of satellite-borne detectors, like EGRET or the project GLAST, could be able to detect a pseudoscalar-to-photon signal from a nearby supernova.
The effects of an external time-dependent magnetic field in the conversion probability of photon-to-axion-like particles are studied. Our findings show that for a certain time regime, the amplitude of the produced axion-like field can be enlarged with respect to the static case, thus, enhancing the probability of conversion.
Experiments are planned to improve the sensitivity of mu-e conversion from the current ~ 10^{-12} to 10^{-16} - 10^{-18}. If the muon (bound to the nucleus) could be polarised, a spin asymmetry of the final state electron is sensitive to CP violating phases on lepton flavour violating operators. This is similar to extracting phases from asymmetries in the final state spin and phase space distributions of mu to 3e and mu to e gamma.
Axions or similar hypothetical pseudoscalar bosons may have a small CP-violating scalar Yukawa interaction g_s(N) with nucleons, causing macroscopic monopole-dipole forces. Torsion-balance experiments constrain g_p(e) g_s(N), whereas g_p(N) g_s(N) is constrained by the depolarization rate of ultra-cold neutrons or spin-polarized nuclei. However, the pseudoscalar couplings g_p(e) and g_p(N) are strongly constrained by stellar energy-loss arguments and g_s(N) by searches for anomalous monopole-monopole forces, together providing the most restrictive limits on g_p(e) g_s(N) and g_p(N) g_s(N). The…
We review several methods for determining the Kobayashi-Maskawa phase $γ={\rm Arg} V^*_{ub}$ from rate and CP asymmetry measurements in hadronic B decays. We focus on the processes $B\to DK, B_s\to D_s K$, and on charmless decays to two light pseudoscalars and decays to a pair of a pseudoscalar and a vector meson. Theoretical uncertainties underlying these methods are discussed.
If the inflaton is a pseudoscalar, then it naturally interacts with gauge fields via an axion-like coupling to $F_{μν} \tilde{F}^{μν}$. Through this coupling, the rolling inflaton produces quanta of the gauge field, that in their turn source the tensor components of the metric perturbations. Due to the parity-violating nature of the system, the right- and the left-handed tensor modes have different amplitudes. Such an asymmetry manifests itself in the form of non-vanishing TB and EB correlation functions in the Cosmic Microwave Background (CMB). We compute the amplitude of the parity-violating…
The pieces of the hypernuclear strangeness violating potential due to the pseudoscalar meson exchanges are derived using methods which were successfully applied to hyperon nonleptonic decays. The estimates are tested by comparison with measured hyperon nonleptonic decay amplitudes. All isospin changes $ΔI=1/2$ and $ΔI=3/2$ are included in the derived potential. All calculational methods used are reviewed and described in detail.
We study an extension of QED involving a light pseudoscalar (an axion-like particle), together with a very massive fermion which has Lorentz-violating interactions with the photon and the pseudoscalar, including a nonminimal Lorentz-violating coupling. We investigate the low energy effective action for this model, after integration over the fermion field, and show that interesting results are obtained, such as the generation of a correction to the standard coupling between the axion-like particle and the photon, as well as Lorentz-violating effects in the interaction energy involving electroma…
We entertain the idea that a suitable background of cold (very low momentum) pseudoscalar particles or condensate, may trigger a background that effectively generates Lorentz-invariance violation. This aether-like background induces a Chern-Simons modification of QED. Physics is different in different frames and, in the rest frame of the pseudoscalar background, high momentum photons can decay into pairs. The threshold for such decay depends quadratically on the rest mass of the particles. This mechanism could explain in a natural way why antiprotons are absent in recent cosmic ray measurement…
The measurement of CP asymmetries in charged B meson decays might provide the first demonstration of CP violation outside the K system. Among the usual three CP-odd phases $α$, $β$ and $γ$, the phase $γ$ seems to be the most difficult to explore experimentally. In this talk I would like to report on a recent analysis of the CP asymmetry in the partial widths for the non-leptonic decays $B^{\pm} \to M {\bar M} π^{\pm}$ ($ M = π^+, K ^+, π^0, η$), which results from the interference of the non-resonant decay amplitude with the resonant amplitude for $B^{\pm} \to χ_{c0} π^{\pm} $ followed by the …
The flavor violating $μ^--e^-$ conversion in nuclei is studied within the minimal supersymmetric standard model. We focus on the R-parity violating contributions at tree level including the trilinear and the bilinear terms in the superpotential as well as in the soft supersymmetry breaking sector. The nucleon and nuclear structure have consistently been taken into account in the expression of the $μ^--e^-$ conversion branching ratio constructed in this framework. We have found that the contribution of the strange quark sea of the nucleon is comparable with that of the valence quarks. From the …
An observation of any lepton number violating process will undoubtedly point towards the existence of new physics and indirectly to the clear Majorana nature of the exchanged fermion. In this work, we explore the potential of a minimal extension of the Standard Model via heavy sterile fermions with masses in the $[ 0.1 - 10]$ GeV range concerning an extensive array of "neutrinoless" meson and tau decay processes. We assume that the Majorana neutrinos are produced on-shell, and focus on three-body decays. We conduct an update on the bounds on the active-sterile mixing elements, $|U_{\ell_α4} U_…
Recently Csaki, Kaloper and Terning (hep-ph/0111311) suggested that the observed dimming of distant type Ia supernovae may be a consequence of mixing of the photons with very light axions. We point out that the effect of the plasma, in which the photons are propagating, must be taken into account. This effect changes the oscillation probability and renders the dimming frequency-dependent, contrary to observations. One may hope to accommodate the data by averaging the oscillations over many different coherence domains. We estimate the effect of coherence loss, either due to the inhomogeneities …
We consider an Abelian model with a CP-conserving Higgs potential spanned by two complex Higgs fields. The CP invariance of the Higgs potential is then broken explicitly beyond the Born approximation by introducing soft-CP-violating Yukawa interactions. Based on the non-renormalization theorem, we derive the consistency conditions under which a CP-odd counterterm exists and, at the same time, renders the one-loop-induced mixing of a CP-even Higgs boson with a CP-odd Higgs scalar ultra-violet finite. The novel CP-odd tadpole renormalization may then be determined from the minimization constrain…
The coherent muon-electron conversion rates in various nuclei are calculated for general lepton flavor violating interactions. We solve the Dirac equations numerically for the initial state muon and the final state electron in the Coulomb force, and perform the overlap integrals between the wave functions and the nucleon densities. The results indicate that the conversion branching ratio increases for a light nucleus up to the atomic number Z ~ 30, is largest for Z = 30 -- 60, and becomes smaller for a heavy nucleus with Z > (~ 60). We also discuss the uncertainty from the input proton and neu…
There is no guarantee that the violation of lepton number, assuming it exists, will primarily manifest itself in neutrinoless double beta decay ($0νββ$). Lepton-number violation and lepton-flavor violation may be related, and much-needed information regarding the physics that violates lepton number can be learned by exploring observables that violate lepton flavors other than electron flavor. One of the most promising observables is $μ^- \rightarrow e^+$ conversion, which can be explored by experiments that are specifically designed to search for $μ^- \rightarrow e^-$ conversion. We survey lep…
We present a new class of constraints to the lepton-family number and R-parity violating couplings from muonium conversion, $μ^{-} + {_{22}^{48}} Ti \to e^{-} + {_{22}^{48}} Ti$, a class of tau decays, $τ\to l +$ (light meson) with $l= μor e$, and $J/ψ$ and $π^0$ decays into a lepton pair. We find that $μ^{-} + {_{22}^{48}} Ti \to e^- + {_{22}^{48}} Ti$ provides one of the strongest constraints along with $Δm_{K}, Δm_{B}$, $μ\to e γ$ and the neutrinoless double $β$ decay. Search for these lepton-family number violating (LFNV) decays forbidden in the standard model is clearly warranted in vario…
In general, attempts to extend the standard model will include extra gauge structure. We parameterize string and technicolor models for a Z' boson with primitive lepton flavor violating interactions. Calculations for its muon conversion rate (mu N -> e N) on Titanium are made and used to show the potential of forthcoming experiments MECO at Brookhaven National Laboratory and PRIME at the Japan Hadron Facility (to be renamed). For reasonable choices of parameters, such U(1) bosons with masses the order 10 TeV and mu-e Z' charge as low as ~10^-5 are demonstrated to be accessible for MECO and PRI…
We study flavor violating processes in the production or decay of a neutral pseudoscalar meson $P^0$ in the framework of a general two Higgs Doublet Model type III (2HDM-III). We use a version of the model where Yukawa interactions of neutral Higgs bosons allow for flavor change at the tree-level, but conserves CP symmetry. We focus on all possible $τ^{\pm} \to l^{\pm}P^0 $ and $P^0 \to l^+l'^-$ decay channels, where $l,l'$ are charged leptons. We find that these processes provide complementary information on quark and lepton FCNC Yukawa couplings. In particular flavor violating parameters in …
We deduce the mass of the pseudoscalar glueball $G$ from an $η$-$η'$-$G$ mixing formalism based on the anomalous Ward identity for transition matrix elements. With the inputs from the recent KLOE experiment, we find a solution for the pseudoscalar glueball mass around $(1.4\pm 0.1)$ GeV, which is fairly insensitive to a range of inputs with or without Okubo-Zweig-Iizuka-rule violating effects. This affirms that $η(1405)$, having a large production rate in the radiative $J/Ψ$ decay and not seen in $γγ$ reactions, is indeed a leading candidate for the pseudoscalar glueball. Other relevant quanti…
We carry out a $U$-spin symmetry analysis for CP violation in $B^- $ decays into three light $π^-π^-π^+$, $π^- K^-K^+$, $K^-K^-K^+$ and $K^- π^-π^+$ mesons. We clarify some subtle points in constructing decay amplitudes with $U=0$ formed by the two negatively charged light mesons in the final states. $U$-spin conserving momentum independent and momentum dependent decay amplitudes, and $U$-spin violating decay amplitudes due to quark mass difference are constructed.
We investigate the size of potential higher pseudoscalar resonance contaminations of the estimates of isospin-conserving and isospin-violating $πNN$ couplings obtained using the 3-point function method in QCD sum rules. For the isospin-conserving case it is shown that conventional models of the isovector pseudoscalar spectral function imply resonance decay constants large enough to create significant contaminations, and that assuming these models are incorrect, and that the decay constants are actually much smaller, implies physically implausible values for the flavor-breaking quark condensate…
I study indirect CP violation for neutral kaons, and extend it to large values of the CP-violating parameter (taken to be real). I show how and at which condition there can exist a continuous set of basis in which the kinetic and mass terms in the Lagrangian can be diagonalized simultaneously. An ambiguity results for the mass spectrum, which then depends on the basis. In particular, for fixed (positive) (mass)^2 of the CP eigenstates K^0_1, K^0_2, and for certain ranges of values of the CP-violating parameter, a negative (mass)^2 can arise in the CP-violating basis. Under certain conditions, …
We consider the scalar-tensor theories of gravity extended by the pseudoscalar couplings to matter and gauge fields and derive constraints on the CP-odd combinations of scalar and pseudoscalar couplings from laboratory spin precession experiments and from the evolution of photon polarization over cosmological distances. We show the complimentary character of local and cosmological constraints, and derive novel bounds on the pseudoscalar couplings to photons from the laboratory experiments. It is also shown that the more accurate treatment of the spin content of nuclei used in the spin precessi…
A search for lepton flavor violating decays of the $τ$ lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb$^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy near 10.58 GeV by the BaBar detector at the SLAC PEP-II storage ring. No evidence of signal has been found, and upper limits on the branching fractions are set at $10^{-7}$ level.
We have studied lepton flavor violation processes $μ\to eγ$ and $μ-e$ conversion in nuclei induced by unparticle. Both ${\rm Br}(μ\to eγ)$ and $μ-e$ conversion rate ${\rm CR}(μ-e,{\rm Nuclei})$ strongly depend on the scale dimension $d_{\cal U}$ and the unparticle coupling $λ^{ff'}_{\rm K}$(K=V, A, S, P). Present experimental upper bounds on ${\rm Br}(μ\to eγ)$, ${\rm CR}(μ-e,{\rm Ti})$ and ${\rm CR}(μ-e,{\rm Au})$ put stringent constraints on the parameters of unaprticle physics. The scale dimensions $d_{\cal U}$ around 2 are favored for the unparticle scale $Λ_{\cal U}$ of ${\cal O}(10 {\rm …
We calculate the threshold $T$ matrices of the light pseudoscalar meson and heavy meson scattering to fourth order in heavy meson chiral perturbation theory. We determine the low-energy constants by fitting to the lattice QCD data points through both the perturbative and iterated methods and obtain the physical scattering lengths in both formalisms. The values of the scattering lengths tend to be convergent at fourth order for most of the channels in the perturbative method. The value of the scattering length for the channel $DK (I=0)$, which involves the bound state $D_{s0}^{*}(2317)$, is obt…
We present a general model-independent formalism of measuring CP and CPT violating parameters through time-ordered integrated rates of correlated decays of $C=\pm 1$ entangled states of neutral pseudoscalar mesons. We give the general formulae of CP and CPT violating parameters in terms of four measurable asymmetries defined for the time-ordered integrated rates, applicable to all kinds of decay product. Two special cases which are often realized in experiments are discussed specifically.
A long-lived very light pseudoscalar boson would favor lepton flavor violating transitions of charged leptons. Its implications on the l_i --> l_j γγ, and l_i --> l_j e^+ e^- transitions are investigated. Assuming 2 m_e < m_ϕ<m_μ, it is found that the inequality B(l_i --> l_j γγ)<B(l_i --> l_j e^+ e^-) is hold. The experimental constraints on the decays l_i --> l_j γ, l_i --> l_j l_k l_k, and l_i --> l_j γγare used to bound the ϕl_i l_j couplings.
We compare two most relevant loop induced muon number violating processes, μ--> e γand μ-e conversion in nuclei, in constraining new physics. Because of much richer structure of the latter process it may be enhanced with respect to μ--> e γby a large $\ln(m^2_μ/Λ^2),$ where $Λ$ is the scale of the new physics. After model-independent considerations we present two examples constraining the R-parity violating couplings of MSSM and the off-diagonal couplings of the doubly charged Higgs bosons from the non-observation of μ-e conversion.
We study the fermionic dark matter (DM) particle interacting with Standard Model quarks via a light pseudoscalar mediator. We consider separately the scenarios for which the DM-pseudoscalar coupling is $CP$ conserving or $CP$ violating. We show that taking a contact interaction is not suitable, even when the mediator has a mass of the same order of magnitude as the typical momentum transfer at the direct-detection experiments, such that the allowed DAMA region is excluded or considerably modified by the correct relic density requirement. The DAMA result seems to indicate that the $CP$-violatin…
The form factor of the vector meson V conversion transition into the pseudoscalar meson P and the lepton pair l+l- is presented for V=rho0,omega,phi and P=pi0,eta. Our approach is based on the chiral effective field theory with resonances. The normalized form factor for omega -> pi gamma* transition was fitted to the recent NA 60 data by varying the only free parameter sigma_V. The results are compared to the available data and to the predictions of other models.
We consider the case that $μ$-$e$ conversion signal is discovered but other charged lepton flavor violating (cLFV) processes will never be found. In such a case, we need other approaches to confirm the $μ$-$e$ conversion and its underlying physics without conventional cLFV searches. We study R-parity violating (RPV) SUSY models as a benchmark. We briefly review that our interesting case is realized in RPV SUSY models with reasonable settings according to current theoretical/experimental status. We focus on the exotic collider signatures at the LHC ($pp \to μ^- e^+$ and $pp \to jj$) as the othe…
The strong coupling constants of the $π$ and $K$ mesons with negative parity octet baryons are estimated within the light cone QCD sum rules. It is observed that all strong coupling constants, similar to the case for the positive parity baryons, can be described in terms of three invariant functions, where two of them correspond to the well known $F$ and $D$ couplings in the $SU(3)_f$ symmetry, and the third function describes the $SU(3)_f$ symmetry violating effects. We compare our predictions on the strong coupling constants of pseudoscalar mesons of negative parity baryons with those corres…
We consider spontaneous CP violation in the Next to Minimal Supersymmetric Standard Model, without the usual $Z_3$ discrete symmetry. CP violation can occur at tree level, raising a potential conflict with the experimental bounds on the electric dipole moments of the electron and neutron. One escape from this is to demand that the CP violating angles are small, but we find that this entails a light neutral Higgs particle. This is almost pseudoscalar, can have a high singlet content, and will be hard to detect experimentally.
The present experimental status of searches for lepton flavor violating decays of the $τ$ lepton to a lighter mass lepton and a photon or a pseudoscalar meson is presented. The results obtained are from $e^+e^-$ annihilation data collected at a center-of-mass energy near 10.58 GeV by the \babar and the Belle detectors. In order to benefit from larger available datasets, the first $\babar-$Belle combinations of upper limits on the branching fractions of lepton flavor violating $τ$-decays are obtained.
In this work we study the short-range contributions that induce effective lepton number violating (LNV) interactions. We obtain a full set of constraints on the effective short-range couplings from a large variety of low-energy $|ΔL|= 2$ processes of pseudoscalar mesons $K, D, D_s, B$, and $τ$-lepton. These constraints provide complementary and additional information to the one obtained from the neutrinoless double-$β$ ($0νββ$) decay. As expected, the bounds on electron-electron short-range couplings are the only ones that are strongly constrained by the $0νββ$ decay. Although weaker, LNV effe…
A pseudo-scalar inflaton field can have interesting phenomenological signatures associated with parity violation. The existing analyses of these signatures typically assume statistical isotropy. In the present work we instead investigate the possibility that a pseudo-scalar inflaton is coupled to a vector field carrying a small but non-negligible vacuum expectation value (vev) coherent over our Hubble patch. We show that, in such case, correlators involving the primordial curvature perturbations and gravitational waves violate both statistical isotropy and parity symmetry. We compute the Cosmi…
We consider neutral pseudoscalar mesons in an entangled or Einstein-Podolsky-Rosen state with $C=-1$. Due to quantum entanglement and antisymmetry of this state, the rates of the joint decays of the meson pair display various interesting features, as is well known. As functions of CP and CPT violating parameters, here we obtain some exact results about the joint decay rates and their asymmetries for a given time difference defined for joint decays to flavor eigenstates, as well as those for joint decays to CP eigenstates. The entanglement allows a meaningful and useful definition of the transi…
We analyze the lepton flavor violating process $μ-e$ conversion in the framework of the minimal R-symmetric supersymmetric standard model. The theoretical predictions are determined by considering the experimental constraint on parameter $δ^{12}$ from the lepton flavor violating decay $μ\rightarrow e γ$. The numerical results show that $γ$ penguins and Z penguins dominate the predictions on CR($μ-e$,Nucleus), and the contributions from Higgs penguins and box diagrams are insignificant. The theoretical predictions on conversion rate CR($μ-e$,Nucleus) in a Al or Ti target can be enhanced close t…
A detailed study of the muonic analogue of neutrinoless double beta decay, (muon^-,muon^+) conversion, has been carried out for the A=44 nuclear system. We studied several lepton number violating (LNV) mechanisms potentially triggering this process: exchange by light and heavy Majorana neutrinos as well as exchange by supersymmetric particles participating in R-parity violating interactions. The nuclear structure has been taken into account within the renormalized Quasiparticle Random Phase Approximation method. To our knowledge, this is the first realistic treatment of nuclear structure aspec…
A lepton-flavor violating (LFV) Z' boson may mimic some of the phenomena usually attributed to supersymmetric theories. Using a conservative model of LFV Z' bosons, the recent BNL E821 muon g-2 deviation allows for a LFV Z' interpretation with a boson mass up to 4.8 TeV while staying within limits set by muon conversion, mu -> e gamma, and mu -> eee. This model is immediately testable as one to twenty e^+e^- -> mu tau events are predicted for an analysis of the LEP II data. Future muon conversion experiments, MECO and PRIME, are demonstrated to have potential to probe very high boson masses wi…
We re-examine resonant massless-neutrino conversions in a dense medium induced by flavour changing neutral current (FCNC) interactions. We show how the observed $\barν_e$ energy spectra from SN1987a and the supernova $r$-process nucleosynthesis provide constraints on supersymmetric models with $R$ parity violation, which are much more stringent than those obtained from the laboratory. We also suggest that resonant massless-neutrino conversions may play a positive role in supernova shock reheating. Finally, we examine the constraints on explicit $R$-parity-violating FCNCs in the presence of non…
Neutrinoless hadron Lepton Number Violating (LNV) decays can be induced by virtual Majorana neutrino, which in turn indubitably show the Majorana nature of neutrinos. Many three-body LNV processes and Lepton Flavour Violating (LFV) processes have been studied extensively in theory and by experiment. As a supplement, we here study 75 four-body LNV (LFV) processes from heavy pseudoscalar $B$ and $D$ decays. Most of these processes have not been studied in theory and searched for in experiment, while they may have sizable decay rates. Since the four-body decay modes have the same vertexes and mix…
