We derive constraints on the mass insertion parameters from the recent measurements of B_s - B_s bar mixing, and discuss their implications on SUSY breaking mediation mechanisms and SUSY flavor models. Some SUSY flavor models are already excluded or disfavored by B_s - B_s bar mixing. We also discuss how to test the SM and SUSY models in the future experiments, by studying other CP violating observables related to b -> s transition, such as the time-dependent CP asymmetry in B -> phi K_S and the direct CP asymmetry in B -> X_s gamma.
We present a SUSY breaking scenario based on Abelian gaugino kinetic term mixings between hidden and observable sectors. If an extra U(1) gaugino in the observable sector obtains a large mass through this mixing effect based on SUSY breaking in the hidden sector, soft SUSY breaking parameters in the MSSM may be affected by radiative effects due to this gaugino mass. New phenomenological aspects are discussed in such a SUSY breaking scenario.
We discuss a grand unified model based on SUSY SU(5) in extra dimensions and on the flavour group A4xU(1) which, besides reproducing tri-bimaximal mixing for neutrinos with the accuracy required by the data, also leads to a natural description of the observed pattern of quark masses and mixings.
We propose a SUSY scenario to explain the current electron and muon $g-2$ discrepancies without introducing lepton flavor mixings. Threshold corrections to the Yukawa couplings can enhance the electron $g-2$ and flip the sign of the SUSY contributions. The mechanism predicts a flavor-dependent slepton mass spectrum. We show that it is compatible with the Higgs mediation scenario.
This study indicates that in E6 grand unified theories (GUTs), once a hierarchical structure of up-quark-type Yukawa couplings is given as a basic structure of flavor, larger lepton mixings than the quark mixings and milder down-quark-type (and charged-lepton-type) mass hierarchies than up-quark-type mass hierarchy can generically be obtained under a few natural assumptions. The basic flavor structure is compatible with non-Abelian horizontal symmetry, which can solve the SUSY flavor problem. It is shown that in solving the SUSY flavor problem, the E6 structure, which realizes bi-large neutrin…
We address the problem of rationalizing the pattern of fermion masses and mixings by adding a nonabelian flavor symmetry in a grand unified framework. With this purpose, we include an A4 flavor symmetry into a unified renormalizable SUSY GUT SU(5) model. With the help of the "Type II Seesaw" mechanism we are able to obtain the pattern of observed neutrino mixings in a natural way, through the so called tribimaximal matrix.
We construct a realistic model based on SUSY SO(10) with U(2) flavor symmetry. A set of symmetric mass textures give rise to very good predictions; 15 masses and 6 mixing angles are predicted by 11 parameters. Both the vacuum oscillation and LOW solutions are favored for the solar neutrino problem.
We present a study of charged lepton mass matrix diagonalization in R-parity violating SUSY. The case in which the bilinear couplings $μ_i$ have large values is given special attention.
We re-examine constraints from the evidence for observation of the lifetime difference in $D^0$-${\bar D}^0$ mixing on the parameters of supersymmetric models with R-parity violation (RPV). We find that RPV SUSY can give large negative contribution to the lifetime difference. We also discuss the importance of the choice of weak or mass basis when placing the constraints on RPV-violating couplings from flavor mixing experiments.
We present a next-to-leading order determination of the gluino-mediated SUSY contributions to B_d-Bbar_d mixing and to the CP asymmetry a_{J/psi K_s} in the framework of the mass-insertion approximation. Using hadronic matrix elements recently computed on the lattice, we obtain improved constraints on the squark-mass splittings.
Motivated by the recent measurements of the B_s-\bar{B}_s mass difference from the D0 and CDF collaborations, we probe new physics effects in the B_q-\bar{B}_q mixing within the context of the supersymmetric grand unified model (SUSY GUT). We find that new physics effects in B_{s(d)}-\bar{B}_{s(d)} mixing lead to the correlated information in the branching fractions of the lepton flavor violating decays, which may serve as a test of the SUSY GUT. We also discuss the implication of such new physics effects on the quark-lepton complementarity in the neutrino mixings.
We study the effects of scalar-pseudoscalar mixing induced from quantum loop on $ε'/ε$ in SUSY models with $\tanβ\sim m_{t}/m_{b}$. We find that even the non-universal soft ${\cal A}^{d}$ term and Yukawa matrix, $Y^{d}$, are hermitian, the predicted value of $|ε'/ε|$ can be consistent with the measured results of NA48 and KTeV. And also the EDMs are compatible with experimental bounds.
We re-examine constraints from the recent evidence for observation of the lifetime difference in D^0 - \bar{D}^0 mixing on the parameters of supersymmetric models with R-parity violation (RPV). We find that RPV SUSY can give large negative contribution to the lifetime difference. We also discuss the importance of the choice of weak or mass basis when placing the constraints on RPV-violating couplings from flavor mixing experiments.
The SM predictions for CP violating effects in D meson systems are highly suppressed at the per mill level. Therefore, any experimental evidence for a sizable CP violation in D0-D0bar mixing would unambiguously point towards a New Physics (NP) signal. Within supersymmetric scenarios, the popular alignment models can naturally account for large, non-standard effects in D0-D0bar mixing. We demonstrate that, within alignment models, detectable CP violating effects in D0-D0bar mixing would unambiguously imply a lower bound for the electric dipole moment (EDM) of hadronic systems, like the neutron …
A SUSY SO(10) $\times A_4$ GUT model is constructed for fermion masses and mixing by introducing a minimal set of low dimensional Higgs representations needed to break the guage symmetry down to $SU(3)_c \times U(1)_{em}$. The hierarchy of fermion masses can be understood in the framework of $A_4$ symmetry. From the $A_4$-invariant superpotential, the "double lopsided" mass matrices for the charged leptons and the down quarks are obtained. It is shown that this structure leads to bi-large neutrino mixings simultaneously with small CKM mixing angles. An excellent fit to the masses and mixings o…
We perform a renormalisation group analysis of the SO(10) model proposed by Chang, Masiero and Murayama, which links the large atmospheric neutrino mixing angle to loop-induced transitions between right-handed b and s quarks. We compute the impact on B_s-B_s-bar mixing and find that the mass difference in the B_s system can exceed its Standard Model value by a factor of 16.
It is recently announced by the {\bf Ut}{\it fit} collaboration that the CP phase of the $B_s$ mixing amplitude, $ϕ_{B_s}$, deviates more than $3 σ$ from the standard-model prediction. In this paper we discuss how large correction to $ϕ_{B_s}$ is possible in the supersymmetric SU(5) ground unified model (SUSY SU(5) GUT) with right-handed neutrinos. Here, we assume the supergravity-like boundary condition for the SUSY-breaking terms. We found that the 95% probability region derived by the {\bf Ut}{\it fit} collaboration is marginal in this model.
In supersymmetric (SUSY) models the misalignment between fermion and sfermion families introduces unsuppressed flavor-changing processes. Even if the mass parameters are chosen to give no flavor violation, family dependent radiative corrections make this adjustment not stable. In particular, due to the observed large neutrino mixings and potentially large neutrino Yukawa couplings, sizable lepton flavor violation (LFV) is expected. After introducing the basic concepts, the framework and the main assumptions, we report on a recent study of rare leptonic decays in a class of SUSY-GUT models with…
We discuss the implications, for general flavour mixing, of the recent results regarding the new allowed range for mixing in the $B_s$ meson system, as well as the new improved bounds on $BR(\bar{B}_s\toμ^+μ^-)$. Constraints on right handed insertions, in particular, improve considerably in the large $\tanb$ regime where the contributions to $B_s$ mixing are dominated by double Higgs penguins. Similarly, the allowed regions of parameter space when varying multiple insertions also decrease significantly.
The recent analyses of the world neutrino data, including the T2K and MINOS results, point toward a statistically significant deviation of theta13 from zero. In this paper we present a SUSY SU(5) model based on the discrete S4 group which predicts a large theta13 of order lambdaC, lambdaC being the Cabibbo angle. The other mixing angles in the neutrino sector are all compatible with current experimental data. In the quark sector, the entries of the CKM mixing matrix as well as the mass hierarchies in both up and down quark sectors are well reproduced and only a small enhancement is needed to r…
This is an addendum to the previous publication, P. Ko and J.-h. Park, Phys. Rev. D80, 035019 (2009). The semileptonic charge asymmetry in B_s decays is discussed in the context of general MSSM with gluino-mediated flavor and CP violation in light of the recent measurements at the Tevatron.
Recent T2K, MINOS and Double CHOOZ results, together with global fits of mixing parameters, indicate a sizeable reactor angle theta13 ~ 8 deg which, if confirmed, would rule out tri-bimaximal (TB) lepton mixing. Recently two of us studied the vacuum alignment of the Altarelli-Feruglio A4 family symmetry model including additional flavons in the 1' and 1" representations, leading to so-called "trimaximal" neutrino mixing and allowing a potentially large reactor angle. Here we show how such a model may arise from a Supersymmetric (SUSY) Grand Unified Theory (GUT) based on SU(5), leading to sum r…
We study the constraints on supersymmetric contributions to b to s transitions from the recent allowed range and measurement of Bs-Bsbar mixing obtained by the D0 and CDF collaborations at the Tevatron. We compute the upper bounds on the relevant off-diagonal squark mass terms and compare them with the bounds coming from Delta F=1 decays. We find that the constraints on chirality-flipping mass insertions are unaffected. Conversely, the measurement of Bs-Bsbar mixing is effective in constraining chirality-conserving mass insertions, and it has striking effects in the case in which left- and rig…
We study flavor-changing neutral current and CP violations in the minimal supersymmetric left-right model. We calculate the beyond-standard-model contributions to the neutral kaon mixing $ΔM_K$ and $ε$, and find possible to have a numerical cancelation between the contributions from the right-handed gauge boson and supersymmetric box diagram. With the cancelation, the right-handed $W$-boson mass scale can be lowered to about 2 TeV, well within the search limit of LHC.
In this work we re-examine the correlation between B(d,s)-anti-B(d,s) mixing and Lepton Flavour Violation in the light of recent experimental measurements in the $B_s$ system. We perform a generic SUSY analysis of the allowed down squark mass insertion parameter space. In the SUSY GUT scenario this parameter space is then used to make predictions for LFV branching ratios. We find that the recent measurement for the CP phase $ϕ_s$ excludes the lowest rates for tau --> mu + gamma and provides a lower bound of ~ 3E-9 for tan beta = 10. Future experimental improvements in the bound on tau --> mu +…
We investigate the effect of SUSY phases ($θ_A$ and $θ_μ$) on the $B^0_d - \bar{B}^0_d$ mixing in the minimal supergravity model. It is known that the complex phase $θ_A$ $=$ arg($A$) ($A$ is the universal coefficient of the trilinear scalar couplings) is essentially unconstrained by the electric dipole moment experiment, while the phase $θ_μ$ $=$ arg($μ$) ($μ$ is the supersymmetric Higgsino mass) is strongly constrained to zero. We found that $θ_A$ does not affect the phase of the $B^0_d - \bar{B}^0_d$ mixing matrix element $M_{12}(B)$ by numerical analysis of the renormalization group equati…
We present a quantitative analysis of the flavor physics of a SUSY SO(10) model proposed by Chang, Masiero, and Murayama, linking b -> s transitions to the large observed atmospheric neutrino mixing. We consider B_s-B_s-bar mixing and tau -> mu gamma and discuss their correlation paying careful attention to their different dependences on model parameters. Our analysis shows that an order-of-magnitude enhancement of the mass difference with respect to the Standard Model is possible and can be reconciled with the most stringent bounds on lepton flavor violation. The situation for various Delta B…
CP violation, fermion masses and mixing angles including that of neutrinos are studied in an SUSY SO(10)$\times Δ(48) \times$ U(1) model with small $tan β$. It is amazing that the model can provide a successful prediction on twenty three observables by only using four parameters. The renormalization group (RG) effects containing those above the GUT scale are considered. Fifteen relations among the low energy parameters are found with nine of them free from RG modifications. They could be tested directly by low energy experiments.
We study a supersymmetric extension of the Standard Model based on discrete A4xZ3xZ4 flavor symmetry. We obtain quark mixing angles as well as a realistic fermion mass spectrum and we predict tribimaximal leptonic mixing by a spontaneous breaking of A4. The top quark Yukawa interaction is present at the renormalizable level in the superpotential while all the other Yukawa interactions arise only at higher orders. We study the Higgs potential and show that it can potentially solve the so called vacuum alignment problem. The leading order predictions are not spoiled by subleading corrections.
In the standard model (SM), the Cabibbo-Kobayashi-Maskawa (CKM) matrix is the only origin of flavor violations (FVs). On the other hand, in general, there are a lot of sources of the FVs in a physics beyond the SM, through the diagonalizing matrices which make Yukawa matrices diagonal. Although most of the diagonalizing matrices are unknown ones, grand unified theories (GUTs) can fix these matrices. In particular, if we consider a GUT model based on the $SO(10)$ group, these diagonalizing matrices are strongly related to each other because of the matter unification. However, this unification c…
In minimal SUSY GUT models the $R$-parity breaking terms are severely constrained by SU(5) gauge invariance. We consider the particular case where the explicit $R$-parity breaking occurs only via dimension 2 terms of the superpotential. This model possesses only three R-parity breaking parameters. We have studied the predictions of this model for the neutrino masses and mixing angles at the one-loop level within the framework of a radiatively broken unified supergravity model. We find that this model naturally yields masses and mixing angles that can explain the solar and atmospheric neutrino …
The simplest unified extension of the Minimal Supersymmetric Standard Model with bilinear R-Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino anomalies. Despite the smallness of neutrino masses R-parity violation is observable at present and future high-energy colliders, providing an unambiguous cross-check of the model.
We present a flavor model of quarks and leptons with the non-Abelian discrete symmetry $S_4$ in the framework of the SU(5) SUSY GUT. Three generations of $\bar 5$-plets in SU(5) are assigned to ${\bf 3}$ of $S_4$ while the first and second generations of 10-plets in SU(5) are assigned to ${\bf 2}$ of $S_4$, and the third generation of 10-plet is assigned to ${\bf 1}$ of $S_4$. Right-handed neutrinos are also assigned to ${\bf 2}$ for the first and second generations and ${\bf 1}'$ for the third generation. We predict the Cabibbo angle as well as the tri-bimaximal mixing of neutrino flavors. We…
We have constructed a SUSY SO(10) x SU(2)_F model in which a set of symmetric mass matrices with five texture zeros (having 11 parameters) leads to 22 measurable fermion masses, mixing angles and CP phases, all in agreement with available experimental data within one sigma. The LMA solution for solar neutrinos is obtained as well as neutrino mixing angles and absolute values of neutrino masses. We have investigated the possibility of baryogenesis resulting from soft leptogenesis. We find that, with soft SUSY masses assuming their natural values of the order of a TeV, the observed baryon asymme…
We construct a Supersymmetric (SUSY) Grand Unified Theory (GUT) of Flavour based on S4 x SU(5), together with an additional (global or local) Abelian symmetry, and study it to next-to-leading order (NLO) accuracy. The model includes a successful description of quark and lepton masses and mixing angles at leading order (LO) incorporating the Gatto-Sartori-Tonin (GST) relation and the Georgi-Jarlskog (GJ) relations. We study the vacuum alignment arising from F-terms to NLO and such corrections are shown to have a negligible effect on the results for fermion masses and mixings achieved at LO. Tri…
We report on a study of CP Violation in D0-D0bar mixing and Electric Dipole Moments in the framework of supersymmetric alignment models. Both classes of observables are strongly suppressed in the Standard Model and highly sensitive to new sources of flavor and CP violation that can be present in models of New Physics. Supersymmetric alignment models generically predict large non-standard effects in D0-D0bar mixing and we show that visible CP violation in D0-D0bar mixing implies lower bounds for the EDMs of hadronic systems, like the neutron EDM and the mercury EDM, in the reach of future exper…
The neutrino flavor mixing may induce rich flavor and CP violating phenomena in the SUSY GUTs. In this paper we discuss the hadronic EDMs and the correlation among low-energy processes induced by the mixings between second and third generations in the SUSY SU(5) GUT with the right-handed neutrinos.
We show that the like-sign di-muon anomaly reported recently by the D0 Collaboration can be explained in the supersymmetric standard model (SM) if the squarks and the sleptons in the first two generations have relatively small, but degenerate mass spectrum, and those in the third generation are larger as O(1-10)TeV. This split generation model provides large contributions to the B_s-{\bar B}_s mixing, although most of the FCNC's are suppressed due to the large masses of the third generation squarks or the GIM mechanism partially acting on the first and second generations.
We study hadronic and leptonic flavor physics in a SUSY SO(10) model proposed by Chang, Masiero, and Murayama, which links b -> s transitions to the observed large atmospheric neutrino mixing angle. We find large effects in B_s-B_s-bar mixing and BR(tau -> mu gamma) and comment on B_d -> phi K_S.
SUSY effects on various flavor changing neutral current processes are discussed in the minimal supergravity model and the SU(5) grand unified theory with right-handed neutrino supermultiplets. In particular, in the latter case the neutrino Yukawa coupling constants can be a source of the flavor mixing in the right-handed-down-type-squark sector. It is shown that due to this mixing the time-dependent CP asymmetry of radiative B decay can be as large as 30% and the ratio of $B_s$-$\bar{B}_s$ mixing and $B_d$-$\bar{B}_d$ mixing deviates from the prediction in the standard model and the minimal su…
Following the recent results from Daya Bay and RENO, which measure the lepton mixing angle theta^l_13 ~ 0.15, we revisit a supersymmetric S4 x SU(5) model, which predicts tri-bimaximal (TB) mixing in the neutrino sector with theta^l_13 being too small in its original version. We show that introducing one additional S4 singlet flavon into the model gives rise to a sizable theta^l_13 via an operator which leads to the breaking of one of the two Z2 symmetries preserved in the neutrino sector at leading order. The results of the original model for fermion masses, quark mixing and the solar mixing …
We present a global $χ^2$ analysis of electroweak data, including fermion masses and mixing angles, in SO(10) SUSY GUTs. Just as precision electroweak data is used to test the Standard Model, the well determined Standard Model parameters are the precision electroweak data for testing theories beyond the Standard Model. In this talk we use the latest experimentally measured values for these parameters. We study several models discussed in the literature. One of these models provides an excellent fit to the low energy data with $χ^2 \sim 1$ for 3 degrees of freedom. We present our predictions fo…
We construct a simple SO(10) SUSY GUT with $D_3$ family symmetry and low energy R parity. The model describes fermion mass matrices with 14 parameters and gives excellent fits to 20 observable masses and mixing angles in both quark and lepton sectors, giving 6 predictions. Bi-large neutrino mixing is obtained with hierarchical quark and lepton Yukawa matrices; thus avoiding the possibility of large lepton flavor violation. The model naturally predicts small 1-3 neutrino mixing, $\sin θ_{13} \simeq 0.05$, and a CP violating phase $δ$ close to $π/2$. Among other interesting predictions is a tiny…
We revisit the effect of the large stop mixing on the decay and production of the lightest SUSY Higgs at the LHC. We stress that whenever the inclusive 2-photon signature is substantially reduced, associated production, $Wh$ and $t\bar t h$, with the subsequent decay of the Higgs into photons is enhanced and becomes an even more important discovery channel. We also point out that these reductions in the inclusive channel do not occur for the smallest Higgs mass where the significance is known to be lowest. We show that in such scenarios the Higgs can be produced in the decay of the heaviest st…
While SUSY particles, if they exist at the TeV-scale, will be discovered at the Tevatron or the LHC, the determination of the SUSY-breaking scenario and its free parameters will require additional information, e.g. from a future International Linear Collider. We point out that such information, in particular on SUSY-particle mixing and the associated soft SUSY-breaking parameters, can also be obtained from measurements at existing or future polarized hadron colliders, since the polarization of initial-state quarks, transmitted through weak gauge bosons or squarks, can be strongly correlated wi…
Neutrino oscillation experiments suggest existence of new flavor-violating interactions in high energy scale. It may be possible to probe them by the flavor- and CP-violating processes in leptons and hadrons in the supersymmetric (SUSY) models. In this article the third-generation flavor violation is reviewed in the SUSY seesaw model and SUSY SU(5) GUT with the right-handed neutrinos.
We analyze the role of the left-left squark mixing in the rare $K^+ \rightarrow π^+ν\barν$ decay within the minimal supersymmetry with a large $\tanβ$. A Higgs boson mass of 125 GeV has been taken into account leading to correlation between stop masses and trilinear soft supersymmetry breaking coupling $A_{\tilde{t}}$. We find that measurable effects, similar to that of the well known $LR$ squark mixing terms, are possible for large $A_{\tilde{t}}$ combined with the off-diagonal $LL$-insertions. Precise measurements of the decay rate are expected from the ongoing NA62 experiment at CERN. We em…
We consider a Mass Varying Neutrinos (MaVaNs) model in supersymmetric theory. The model includes effects of supersymmetry breaking transmitted by the gravitational interaction from the hidden sector, in which supersymmetry was broken, to the dark energy sector. Then evolutions of the neutrino mass and the equation of state parameter of the dark energy are presented in the model. It is remarked that only the mass of a sterile neutrino is variable in the case of the vanishing mixing between the left-handed and a sterile neutrino on cosmological time scale. The finite mixing makes the mass of the…
We present a general analysis of B_{s,d}-> l^+ l^- and K_L -> l^+ l^- decays in supersymmetric models with non-minimal sources of flavour mixing. In spite of the existing constraints on off-diagonal squark mass terms, these modes could still receive sizeable corrections, mainly because of Higgs-mediated FCNCs arising at large tan(beta). The severe limits on scenarios with large tan(beta) and non-negligible {tilde d}^i_{R(L)}-{d-tilde}^j_{R(L)} mixing imposed by the present experimental bounds on these modes and Delta B=2 observables are discussed in detail. In particular, we show that scalar-c…
We construct a supersymmetric (SUSY) $SU(5)$ model with the flavor symmetry $S_4\times Z_3\times Z_4$. Three generations of adjoint matter fields are introduced to generate the neutrino masses via the combined type I and type III see-saw mechanism. The first two generations of the the $\mathbf{10}$ dimensional representation in $SU(5)$ are assigned to be a doublet of $S_4$, the second family $\mathbf{10}$ is chose as the first component of the doublet, and the first family as the second component. Tri-bimaximal mixing in the neutrino sector is predicted exactly at leading order, charged lepton…
We propose a mechanism to generate the neutrino mixing matrix from supersymmetric threshold corrections. Flavor violating soft breaking terms induce flavor changing self-energies that give a finite renormalization to the mixing matrix. The described threshold corrections get enhanced in case of quasi-degenerate neutrino masses. In this scenario, we adjust potentially arbitrary soft breaking parameters in a way to reproduce the observed neutrino mixing at one loop working with non-minimal flavor violating soft parameters. To incorporate small neutrino masses already at tree-level via a type I s…
In this talk I discuss the qualitative features of an SO(10) SUSY GUT with an SU(2)x U(1)$^n$ family symmetry. I then describe the global fit of this theory to precision electroweak data [including charged fermion masses and mixing angles]. Finally, the predictions of the model for neutrino masses and mixing are discussed. The most predictive version of the model naturally fits atmospheric neutrino data with maximal $ν_μ\longrightarrow ν_τ$ oscillations and solar neutrino data with small mixing angle MSW $ν_e \longrightarrow ν_{sterile}$ oscillations.
We propose a supersymmetric (SUSY) SU(5) Grand Unified Theory (GUT) including a single right-handed neutrino singlet and an adjoint matter representation below the GUT scale and extend this model to include an A4 family symmetry and a gauged anomaly-free Abelian group. In our approach hierarchical neutrino masses result from a combined type I and type III seesaw mechanism, and the A4 symmetry leads to tri-bimaximal mixing which arises indirectly. The mixing between the single right-handed neutrino and the matter in the adjoint is forbidden by excluding an adjoint Higgs, leading to a diagonal h…
We survey the lepton flavor violation branching ratios Br(mu->e,gamma), Br(tau->mu,gamma), and Br(tau->e,gamma) in mSUGRA for a broad class of lepton mass matrix textures that give nearly tribimaximal lepton mixing. Small neutrino masses are generated by the type-I seesaw mechanism with non-degenerate right-handed neutrino masses. The textures exhibit a hierarchical mass pattern and can be understood from flavor models giving rise to large leptonic mixing. We study the branching ratios for the most general CP-violating forms of the textures. It is demonstrated that the branching ratios can be …
