E. C. F. S. Fortes, Shmuel Nussinov
The anomalously large experimentally measured ratios of the semitauonic decay $B\rightarrow D^{(*)} +τ+ν$ and the corresponding semileptonic $B\rightarrow D^{*} +ł+\barν_l$ disagree with the predictions of the standard E.W + QCD model(S.M). We briefly comment on this disagreement and on possible new physics explanations which are rather constrained and difficult to implement.
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NLO QCD corrections to inclusive semitauonic weak decays of heavy hadrons up to $1/m_b^3$
本文计算了重夸克展开中至 $1/m_b^3$ 阶的半轻子型 $B \ o X_c τ\arν_τ$ 衰变的 NLO QCD 修正，获得了包含末态质量的解析结果，并指出至 $1/m_b^2$ 阶结果可外推至 $B \ o X_u τ\arν_τ$ 衰变。
We calculate the decay width and the $τ$-lepton energy distribution as well as relevant moments for inclusive $\bar B \to X_c τ\bar ν_τ$ process including power corrections up to order $Λ_{QCD}^3/m_b^3$ and QCD corrections to the partonic level. We compare the result with the sum of the standard-model predictions of the branching fractions of the exclusive semileptonic $\bar B \to (D, D^*, D^{**}) τ\bar ν_τ$ decays as well as with the relevant experimental data. Our prediction is in agreement with the LEP measurement and is consistent with the standard-model calculation of the exclusive modes.…
The study of lepton flavor universality violation (LFUV) in semitauonic $b$-hadron decays has become increasingly important in light of longstanding anomalies in their measured branching fractions, and the very large datasets anticipated from the LHC and Belle II. In this review, we undertake a comprehensive survey of the experimental environments and methodologies for semitauonic LFUV measurements at the $B$-factories and LHCb, along with a concise overview of the theoretical foundations and predictions for a wide range of semileptonic decay observables. We proceed to examine the future prosp…
A comprehensive study of $B$, $B_s$ and $B_c$ meson semitauonic modes in potential quark model
本文基于潜在夸克模型研究B、B_s和B_c介子的半tauonic衰变模式，推导形式因子并计算分支分数，结果与标准模型一致，为未来实验和格点研究提供理论支持。
We present new precision predictions for semitauonic decays involving $ρ$ and $ω$ final state mesons. These decay channels offer an interesting orthogonal probe to study the existing B anomalies in semitauonic transitions and are accessible with the Belle II experiment. The predictions are based on combining existing light-cone sum-rule calculations for the form factors with measured experimental spectra from the BaBar and Belle collaborations. This allows us to reliably extrapolate the light-lepton form factor predictions to large values of the four-momentum transfer squared, $q^2$, and in tu…
We explore scenarios where the $R(D^{(*)})$ anomalies arise from semitauonic decays to a right-handed sterile neutrino. We perform an EFT study of all five simplified models capable of generating at tree-level the lowest dimension electroweak operators that give rise to this decay. We analyze their compatibility with current $R(D^{(*)})$ data and other relevant hadronic branching ratios, and show that one simplified model is excluded by this analysis. The remainder are compatible with collider constraints on the mediator semileptonic branching ratios, provided the mediator mass is of order TeV…
Strong anomaly of the PCAC is found in $τ\rightarrowωππν$ and $ωρν$ in the chiral limit. It originates in WZW anomaly. Theoretical result of $τ\rightarrowωππν$ agrees with data well and the measurement of $τ\rightarrowωρν$ will confirm the strong anomaly of PCAC. The strong anomaly of PCAC is studied.
We inquire if the total decay rate of neutral vector mesons can contain relevant off-shell contributions from the triangle anomaly. The answer seems to be affirmative for the case of J/Psi, and as a byproduct we get estimates of the decay width for neutral pions.
The work is devoted to the study of b-s anomaly decays. We evaluated branching fractions of $B\to K^\ast μ^+μ^-$, $B^0_s\to ϕμ^+μ^-$ and $B_s\to μ^+μ^-$ decays and compared them with available experimental data and with results from other theoretical approaches.
We discuss a connection between axial anomaly and polarized radiative processes. By comparison with the corresponding unpolarized cases, we consider some physical outputs for the $π^+$ and $Z^0$ polarized radiative decays. We analyse in detail the pattern of mass singularity cancellation.
We extend the approach of Dolgov and Zakharov to the axial anomaly to study polarized radiative decays. We analyse the pattern of mass singularity cancellation in the corresponding decay rates. We compare polarized and unpolarized cases. The cancellation of the infrared and collinear singularities is verified to all powers of the lepton mass for the $π^+$ and $Z^0$ polarized radiative decays.
In this proceedings, we discuss a light (17 MeV) $Z'$ solution to the anomaly observed in the decay of Beryllium-8 by the Atomki collaboration. We detail an anomaly free model with minimal particle content which can satisfy all other experimental constraints with gauge couplings $\mathcal{O}(10^{-4})$.
We use our lattice QCD computation of the $B_c\rightarrow J/ψ$ form factors to determine the differential decay rate for the semitauonic decay channel and construct the ratio of branching fractions $R(J/ψ) = \mathcal{B}(B_c^- \rightarrow J/ψτ^-\barν_τ)/\mathcal{B}(B_c^- \rightarrow J/ψμ^-\barν_μ)$. We find $R(J/ψ) = 0.2582(38)$ and give an error budget. We also extend the relevant angular observables, which were recently suggested for the study of lepton flavor universality violating effects in $B\rightarrow D^*\ellν$, to $B_c \rightarrow J/ψ\ellν$ and make predictions for their values under d…
We propose to measure the Wess-Zumino anomaly contribution by considering angular distributions in the decays $τ\toν_τηπ^{-}π^{0}$, $τ\toν_τK^- π^{-} K^+ $ and $τ\toν_τK^- π^- π^+$. Radial excitations of the $K^*$, which cannot be seen in $e^++e^-$, should be observed in the $ K^- π^+ π^-$ decay channel.
The largest global symmetry that can be made local in the Standard Model + 3$ν_R$ while being compatible with Pati-Salam unification is $SU(3)_H\times U(1)_{B-L}$. The gauge bosons of this theory would induce flavour effects involving both quarks and leptons, and are a potential candidate to explain the recent reports of lepton universality violation in rare B meson decays. In this letter we characterise this type of models and show how they can accommodate the data and naturally be within reach of direct searches.
We report on a confined quark model calculation of the transition form factors for the radiative decays of η(η')->γl^+l^- and η(η')->γπ^+π^-. The η-η' mixing angle θ_P is determined from the set of data on the electromagnetic η(η') decays. It is found that θ_P\sim -16.5. The analysis of the dipionic mass distribution in the decay η'->γπ^+π^- confirms the existence of a non-resonant contribution which is the box anomaly.
Recent experimental results from the LHCb, BaBar and Belle collaborations on the semitauonic decays of $B$ meson, $\bar{B}\rightarrow D^{(\ast)}τ\barν$, showing a significant deviation from the Standard Model (SM), hint towards a new physics scenario beyond the SM. In this work, we show that these enhanced decay rates can be explained within the framework of $E_{6}$ motivated Alternative Left-Right Symmetric Model (ALRSM), which has been successful in explaining the recent CMS excesses and has the feature of accommodating high scale leptogenesis. The R-parity conserving couplings in ALRSM can …
The QCD anomaly coupling of $η'-g-g$ is treated as the axial vector current triangle anomaly. By assuming the divergent axial vector coupling of the $η'$ meson with the quark line in the triangle diagram, we calculate the QCD anomaly of $η'-g-g$ as well as the QED anomaly of $η'-γ-γ$ with only one common parameter $κ_{η'}$. We obtain consistent results of the branching ratios for $B\toη' X_s, J/ψ\toη'γ$ and $η'\to γγ$ when comparing with experimental data.
We show that the $ηγZ$ anomaly can be measured by analysing parity-violating effects in the $η-->γμ+μ-$ decay. In this sense, we find that the longitudinal polarization of the outgoing $μ^+$ is an appropriate observable to be considered in future high-statistics $η$ factories. The effect is expected to lie in the range $10^{-5}-10^{-6}$ in the Standard Model.
The cosmic ray data of PAMELA/ATIC may be explained by dark matter decay with a decay rate $τ_{DM}^{-1}\sim 10^{-26}{sec}^{-1} \sim 10^{-45}{eV}$, an energy scale which could not be understood within the framework of the standard model or its simple supersymmetric extension. We propose anomaly induced dark matter decay to exponentially suppress the decay rate, and apply to a supersymmetric extension of the Ma's inert Higgs model of the radiative seesaw mechanism for neutrino masses. In this model the lightest right-handed neutrino $ψ_N$ and the lightest neutralino $χ$ can fill the observed nec…
We examine the contribution of W boson loops to the amplitude of the process H --> γγwithin the dispersion relation approach, taking up an issue raised in this context recently. We show that the non-vanishing limit of the relevant formfactor for mW --> 0 is due to a finite subtraction induced by the value of the corresponding trace anomaly. The argument can be truned around and one thus arrives at a dispersive ("infrared") derivation of the trace anomaly.
In the framework of the "current scheme" of $η- η'$ mixing we calculate the amplitude of the decay $η' \to π^+ π^- γ$ in the soft limit and compare our results with recently reported values of the phenomenological additive terms to the $ρ$--meson background.
$Z \to γγ$ decay amplitude is considered and proven to be zero due to properties of polarization vectors and Bose statistics. Triangular diagrams for a pseudoscalar $\to γγ$ and $Z \to γγ$ processes with massive fermions in the loop are explicitely calculated. In the Standard Model axial anomaly vanishes in the sum of these diagrams as Z boson is mixed with one of the Goldstone bosons.
It is shown that the rates of the decays Upsilon(1^3D_1) -> eta Upsilon(1S) and Upsilon(1^3D_2) -> eta Upsilon(1S) should be comparable to and likely exceed that of the recently discussed in the literature two-pion transition Upsilon(1D) -> pi pi Upsilon(1S). The reason for this behavior is that the discussed eta transitions are enhanced by the contribution of the anomaly in the flavor singlet axial current in QCD.
An investigation is performed of all non-leptonic kaon decays sensitive to the chiral anomaly. Within the framework of chiral perturbation theory, there are two classes of anomalous amplitudes at $O(p^4)$: reducible and direct contributions. Only radiative transitions are affected by the anomaly. The phenomenology of the decays $K_L \to π^+ π^- γ$ and $K^+ \to π^+ π^0 γ$ is studied in detail. Including the dominant contributions of $O(p^6)$, the experimentally observed dependence of the direct emission amplitude for $K_L \to π^+ π^- γ$ on the photon energy can be understood. A survey is made o…
We calculate the $O(p^6)$ corrections to the anomalous form factors appearing in $π^+$, $K^+ \to e^+ νγ,\ μ^+νγ$ and $K_{l4}$ decays in Chiral Perturbation Theory. The relevant dimension $6$ terms of the lagrangian are evaluated assuming their saturation by the vector meson contribution.
The anomaly in the vacuum expectation value of the product of axial and two vector currents (AVV) in QCD is investigated. The goal is to determine from its value the $π^0 \to 2 γ$ decay width with high precision. The sum rule for AVV formfactor is studied. The difference $f_{π^0} - f_{π^+}$ caused by strong interaction is calculated and appears to be small. The $π^0 - η$ mixing is accounted. The $π^0 \to 2 γ$ decay width determined theoretically from the axial anomaly is found to be $Γ(π^0 \to 2 γ) = 7.93 eV$ with an error $\sim 1.5%$. The measurement of the $π^0 \to 2 γ$ decay width at the sa…
A proposed solution of the anomalous behavior of the electron spectrum near the endpoint of tritium $β$-decay is offered. It is based on a new theory of mass in which mass becomes a dynamical variable, and the electron in the tritium $β$-decay has a narrow mass distribution. The predicted Kurie plots explain the main feature (``$m_ν^2 < 0 $'') of this anomalous behavior.
Within renormalizable theories the triangle diagram correctly reproduces the lifetime of the neutral pion $π^0$. However, effective relativistic quark models which contain a second scale besides the quark mass seem unable to give the correct value for this quantity. In the Instanton Liquid Model this second scale is the mean instanton radius, in the NJL model it is the cutoff. The role of the cutoff within a path integral derivation of the chiral anomaly is clarified and the importance of higher order terms contributing to the $π^0$ decay width and other anomalous processes is pointed out.
Using flavor basis we relate flavor axial anomalies to the mass matrix of pseudoscalar isoscalar fields in the context of a Linear Sigma Model which includes U_A(1) symmetry breaking. We incorporate additional contributions to these anomalies due to external electromagnetic fields invoking 't Hooft's argument on anomaly matching and work out the predictions of this formalism for eta to gamma gamma and eta' to gamma gamma decays. We show that the only effect of the U_A(1) anomaly in these processes is in the formation of the eta and eta' systems. From experimental data on their two photon decay…
Using the formula of chiral anomaly, we discuss the pair production of quarks under color electric field $\vec{E}$ without addressing explicit formula of quark's wavefunctions. The production is assumed to occur under the effect of color magnetic field $\vec{B}$ as well as the color electric field. We obtain the life time $t_c$ of the color electric field in the limit of $B\gg E$. Applying it to the glasma in high-energy heavy-ion collisions, we find that $t_c\simeq 10Q_s^{-1}$ with saturation momentum $Q_s$.
We propose an extension of the standard model with an extra U(1)' abelian symmetry, three Higgs doublets and one Higgs singlet, where the new U(1)' charges are flavour non-universal. As a result, the model introduces an enlarger particle spectrum in the TeV scale with large new physics possibilities. The model reproduces the mixing angles and mass structures of the quarks, charged and neutral leptons. We found that the observed anomaly of the $B^{+}\rightarrow K^+ \ell \ell$ decay can be explained due to the existence of couplings with new extra fermions at the TeV scale.
We examine the possible resolution of the recently observed polarization anomaly in B0(bar{B}0) -> phi K*0(bar{K}*0) decay within R-parity violating (RPV) SUSY. We show that a combination of the superpotential trilinear (RPV)-interactions, with the couplings lambda', and the soft SUSY breaking bilinear RPV, sneutrino-Higgs mixing, proportional to tilde{mu}**2, can potentially generate the effective operators with the chirality structure necessary to account for this anomaly. However, we demonstrate that the existing experimental data on Bs -> mu+ mu- decay lead to stringent upper limits on the…
An anomaly in time distribution of neutrinos from the ISIS pulsed beam stop source observed by the KARMEN collaboration is discussed. We show that the anomaly can be interpreted as a superposition of two exponentials, both having time constants consistent with the $μ^{+}$ lifetime of 2.2 $μs$. % and, therefore, It is assumed that they both originate from muon decays at rest. One of them describes the time distribution of the prompt neutrino events, while the other describes the time distribution of events from delayed decays of slowly moving ($β\simeq 0.02$) particles in the KARMEN calorimeter…
$\cal T$-parity in the Little Higgs model could be violated by anomalies that allow the lightest $\cal T$-odd $A_H$ to decay into $ZZ$ and $W^+W^-$. We analyze these anomaly induced decays and the two-particle and the three-particle decay modes of other heavy quarks and bosons in this model which yield unique Large Hadron Collider (LHC) signals with fully reconstructable events. $\cal T$-odd quarks in the Little Higgs model are nearly degenerate in mass and they decay by almost identical processes; however, members of the heavy Higgs triplet follow distinct decay modes. The branching fractions…
We present sensitivities for the MiniBooNE experiment to a rare exotic pion decay producing a massive particle, Q^0. This type of decay represents one possible explanation for the timing anomaly reported by the KARMEN collaboration. MiniBooNE will be able to explore an area of the KARMEN signal that has not yet been investigated.
The experimental hint of large $B\to η^\prime + X_s$ is linked to the $b\to s$ penguins via the gluon anomaly. Using running $α_s$ in the $η^\prime$-$g$-$g$ coupling, the standard $b\to sg^*$ penguin alone seems insufficient, calling for the need of dipole $b\to sg$ at 10% level from new physics, which could also resolve the ${\cal B}_{s.l.}$ and charm counting problems. The intereference of standard and new physics contributions may result in direct CP asymmetries at 10% level, which could be observed soon at B Factories.
The charm content in $η'$ is estimated using the QCD U(1) axial anomaly applied to $b\to s g g \to η' s$. We find $f_{η'}^{(c)} \approx - 3.1$ MeV for $m_c = 1.3$ GeV. Our estimate agrees with other independent methods by Feldmann and Kroll, and Araki, Musakhanov and Toki. The resulting branching ratios for $B \to η' K$ in the generalized factorization model are marginally consistent with the CLEO data, although they are lower than the data by $\sim 2$.
The hadronic decay of radially and orbitally excited charmonium above charm threshold by $^3 P_{0}$ pair creation and chromoelectric flux--tube breaking is discussed in an harmonic oscillator approximation. We find independent evidence from a study of widths for a 2S admixture in the predominantly 1D state $ψ(3770)$, and explore the possibility of metastable radially excited $2 \; ^{3}P_{0,1,2}$ states being a source of the anomalously large production of $ψ^{'}$ at the Tevatron. At least one of them is expected to be narrow as a consequence of the existence of nodes in the radial wave functio…
We compute the decay rates for the exclusive decays $B^{\pm} \to (η^{\prime},η) (K^{\pm}, K^{*\pm})$ and $B^{0}\to (η^{\prime},η) (K^{0}, K^{*0})$ in a QCD-improved factorization framework by including the contribution from the process $b\to sgg \to s (η^{\prime}, η)$ through the QCD anomaly. This method provides an alternative estimate of the contribution $b \to s c\bar{c} \to s(η,η^\prime)$ to these decays as compared to the one using the intrinsic charm content of the $η^{\prime}$ and $η$ mesons determined through the decays $J/ψ\to (η,η^\prime ,η_c) γ$. The resulting branching ratios are c…
The recently observed diphoton anomaly at the LHC appears to suggest the presence of a rather broad resonance. In this note, it is pointed out that this does not hold if the two photons are produced along with an extra state. Specifically, the diphoton invariant mass arising from various $A \to Bγγ$ processes, with $A,B$ being scalars, fermions, or vectors, though peaked at a rather large value, would naturally be broad and could fit rather well the observed deviations. This interpretation has a number of advantages over the two-photon resonance hypothesis, for example with respect to the comp…
Chiral anomaly in the $η^{(\prime)}\toπ^+π^-γ$ and $η^{(\prime)}\toπ^+π^-l^+l^-$ decays
研究手性异常在η(′)→π+π−γ和η(′)→π+π−l+ l−衰变中的影响，通过表面项修正VAAA型异常，估计低能常数α(′)，并与实验数据一致。
Motivated by the $R_K$ and $R_{K^*}$ anomalies from B decays, we extend the minimal supersymmetric model with a non-universal anomaly-free $U(1)^\prime$ gauge symmetry, coupling non-universally to the lepton sector as well as the quark sector. In particular, only the third generation quarks are charged under this $U(1)^\prime$, which can easily evade the dilepton bound from the LHC searches. An extra singlet is introduced to break this $U(1)^\prime$ symmetry allowing for the $μ$-term to be generated dynamically. The relevant constraints of $B_s-\bar{B}_s$ mixing, $D^0-\bar{D}^0$ mixing and the…
Dark matter implications of the neutron anomaly
本文受中子衰变异常启发，重新研究中子衰变模型 $n \ ightarrow χχχ$ 并精确计算相关反应速率，发现需引入 $χ$ 粒子的两个“世代”才能在满足所有约束下拟合该异常。
We build the electromagnetic trace anomaly effective term for a generalized linear sigma model with two chiral nonets, one with a quark-antiquark structure, the other one with a four quark content. In the leading order of this framework, we study the decays into two photons of the lowest isosinglet scalar mesons. We find that the direct inclusion of underlying mixing among two- and four-quark components in the trace anomaly term is essential in order for the model prediction to agree with the available experimental data on decay width of $f_0(980)$ to two photons. Consequently, this sets a low…
It has been recently suggested that the anomalous excess of low-energy electron-like events observed by the MiniBooNE experiment, could be explained by the radiative decay of a heavy sterile neutrino nu_h of the mass around 500 MeV with a muonic mixing strength in the range |U_{μh}|^2 \simeq (1-4)\times 10^{-3}. If such nu_h exists its admixtures in the decay Ds -> mu+nu would result in the decay Ds -> mu+nu_h with the branching fraction \simeq (1.2-5.5)\times 10^{-4}, which is in the experimentally accessible range. Interestingly, the existence of the Ds -> mu+nu_h decay at this level may als…
The experimental observation of sizable transverse components for B-> phi K^* decay is in strong contrast to all other VV modes, and poses a challenge to our understanding of B decay dynamics. Observing that the gluon emitted from b-> sg^{(*)} chromodipole transition is transverse, we give a heuristic model where the transverse phi descends from the emitted gluon, hence similar phenomena should occur for B-> omega K^* but not for B-> rho^0 K^*. New physics in bsg chromodipole coupling, perhaps needed for the \bar B -> phi K_S CP violation anomaly, may lead to different patterns of CP and T vio…
In this paper, we consider the Standard Model (SM) with one family of vector-like (VL) leptons, which couple to all three families of the SM leptons. We study the constraints on this model coming from the heavy charged lepton mass bound, electroweak precision data, the muon anomalous magnetic moment, lepton flavor violation, Higgs decay constraints and a recently measured lepton non-universality observable, $R_{K^{*0}}$. We find that the strongest constraints are coming from the muon $g-2, \ R_{μμ}=Γ(h\toμμ)/Γ(h\toμμ)_\text{SM}, \ R_{γγ}$ and $\text{BR}(μ\to eγ)$. Although VL leptons couple to…
Visible and Invisible Pseudoscalar Meson Decays from Anomaly Sum Rules
研究利用异常求和规则分析伪标量介子衰变，发现胶球可能存在，并提升介子衰变分支比。
The effects of the anomalous contact terms are taken into account in tau to eta(eta')2pi nu decay. tau to 3pi nu is computed. Theoretical result agrees with data. It is the first time the anomalous vertex eta aa is tested. An a_{1} resonance is predicted in the final state. The decay rate of tau to eta'3pi nu is predicted.
The decay width of $N(1535)\rightarrow Nη$ is as large as that of $N(1535)\rightarrow Nπ$. This is in evident conflict with simple expectations based on flavor symmetry and phase space. Similarly, the decay width of $Λ(1670) \rightarrow Λ(1116) η$ is larger than predicted by flavor symmetry. In this work, we propose that the axial $U(1)_{A}$ anomaly is responsible for an enhanced coupling of (some) excited baryons to the $η$ meson. We test this idea by including a new, chirally symmetric but $U(1)_{A}$ anomalous, term in an effective hadronic model decribing baryons and their chiral partners i…
The ground-state (lightest) hybrid nonet with exotic quantum numbers $J^{PC}=1^{-+}$ and the nonet of their chiral partners with $J^{PC}=1^{+-}$ build a homochiral multiplet involving left- and right-handed currents, which under chiral transformation change just as (axial-)vector mesons. Masses and interactions of hybrids can be obtained in the context of the extended Linear Sigma Model. Here, we concentrate on the decays oh hybrids into two pseudoscalar mesons, such as $ηπ$ and $η^{\prime}π$ modes. Indeed, $π_{1}(1400)\rightarrowπη$ and $π_{1}(1600)\rightarrowπη^{\prime}$ have been seen in ex…
We point out the necessity to consider $β$-decay observables in resolutions of the $W$-boson anomaly in the Standard Model Effective Field Theory that go beyond pure oblique corrections. We demonstrate that present global analyses that explain the $W$-boson mass anomaly predict a large, percent-level, violation of first-row CKM unitarity. We investigate what solutions to the $W$-boson mass anomaly survive after including $β$-decay constraints.
We pursue a possibility that a pseudo-Nambu-Goldstone boson is lurking around or below the intermediate scale. To this end we consider an anomaly-free global flavor symmetry, and construct models where the pseudo-Nambu-Goldstone boson is coupled preferentially to leptons. The experimental and astrophysical bounds derived from couplings to photons and nucleons are significantly relaxed. If sufficiently light, the pseudo-Nambu-Goldstone boson contributes to dark matter, and interestingly, it generally decays into photons through couplings arising from threshold corrections. We show that the rece…
Muon $g-2$ Anomaly from Vector-like Leptons in a 2-Higgs-doublet + Scalar Singlet Model
鉴于 Fermilab 新结果，本文重新审视了包含类矢量带电费米子、标量双重态和单态的经济模型，以解释 Muon $g-2$ 反常，并详细探讨了其对轻子味普适性、Higgs 衰变及带电轻子味破坏衰变的现象学影响。
One of the main motivations to look beyond the SM is the discrepancy between the theoretical prediction and observation of anomalous magnetic moment of muon. Alleviating this tension between theory and experiment and satisfying the bounds from lepton flavor violation data simultaneously is a challenging task. In this paper, we consider generalised Two Higgs Doublet Model, with a Yukawa structure as a perturbation of Type X Two Higgs Doublet Model. In view of this model, we explore muon anomaly and lepton flavor violation along with constraints coming from B-physics, theoretical constraints, el…
The most general, renormalizable Lagrangian that includes massive neutrinos contains ``right-handed neutrino'' Majorana masses of order M. While there are prejudices in favor of M much larger than the weak scale, virtually nothing is known about the magnitude of M. I argue that the LSND anomaly provides, currently, the only experimental hint: M around 1 eV. If this is the case, the LSND mixing angles are functions of the active neutrino masses and mixing and, remarkably, adequate fits to all data can be naturally obtained. I also discuss consequences of this ``eV-seesaw'' for supernova neutrin…
We discuss the Type-X (lepton-specific) two Higgs doublet model as a solution of the anomaly of the muon $g-2$. We consider various experimental constraints on the parameter space such as direct searches for extra Higgs bosons at the LEP II and the LHC Run-I, electroweak precision observables, the decay of $B_s \to μ^+μ^-$, and the leptonic decay of the tau lepton. We find that the measurement of the tau decay provides the most important constraint, which excludes the parameter region that can explain the muon $g-2$ anomaly at the 1$σ$ level. We then discuss the phenomenology of extra Higgs bo…
We examine the large branching ratio for the process $B\to η^{\prime} K$ from the standpoint of R parity violating supersymmetry. We have given all possible $R_p$ violating contributions to $B\to η^{\prime} K$ amplitudes. We find that only two pairs of $λ^{\prime}$-type $R_p$ violating couplings can solve this problem after satisfying all other experimental bounds. We also analyze those modes where these couplings can appear, {\em e.g.}, $B^\pm \to π^{\pm}K^0$, $B^{\pm,0} \to K^{*\pm,0} η^{(\prime)}$, $B^{\pm} \toϕK^{\pm}$ etc., and predict their branching ratios. Further, one of these two pai…
We point out that right-handed neutrinos can resolve the tension between the latest CDF II measurement of the $W$-boson mass, $M_W$, and the standard model. Integrating out the new states yields a single $d=6$ operator, which induces a deviation from unitarity in the PMNS matrix. This alters the extraction of the Fermi constant from muon decay and increases the prediction for $M_W$, in line with the CDF II result. Non-unitarity of the PMNS matrix would also affect beta, meson, and tau decays. We find that the CDF II value for $M_W$ can be explained without conflicting with lepton flavour unive…
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