The experimental prospects for precise measurements of the leptonic decays B_u -> tau nu / mu nu, B_s -> mu+ mu-, D -> mu nu and D_s -> mu nu / tau nu are very promising. Double ratios involving four of these decays can be defined in which the dependence on the values of the decay constants is essentially eliminated, thus enabling complementary measurements of the CKM matrix element V_ub with a small theoretical error. We quantify the experimental error in a possible future measurement of |V_ub| using this approach, and show that it is competitive with the anticipated precision from the conventional approaches. Moreover, it is shown that such double ratios can be more effective than the individual leptonic decays as a probe of the parameter space of supersymmetric models. We emphasize that the double ratios have the advantage of using |V_ub| as an input parameter (for which there is experimental information), while the individual decays have an uncertainty from the decay constants (e.g. f_B_s), and hence a reliance on theoretical techniques such as lattice QCD.
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.
We analyze the CP violation in the semileptonic | ΔS|=1 tau-decays in supersymmetric extensions of the standard model (SM) with R parity violating term. We show that the CP asymmetry of tau-decay is enhanced significantly and the current experimental limits obtained by CLEO collaborations can be easily accommodated. We argue that observing CP violation in semi leptonic tau-decay would be a clear evidence for R-parity violating SUSY extension of the SM.
We study the correlation between proton lifetime and leptonic CP violation in a class of renormalizable supersymmetric SO(10) grand unified theories (GUTs) with {\bf 10}, {\bf 126} and {\bf 120} Higgs fields, which provides a unified description of all fermion masses and possibly resolution of the strong CP problem. This specific model is unique in that it can readily be compatible with current proton lifetime limits for a supersymmetry (SUSY) breaking scale as low as 5 TeV due to the presence of a specific Yukawa texture. Our investigation here reveals that proton partial lifetimes predicted …
We study leptonic CP and flavor violations in supersymmetric (SUSY) grand unified theory (GUT) with right handed neutrinos, paying attention to the renormalization group effects on the slepton mass matrices due to the neutrino and GUT Yukawa interactions. In particular, we study in detail the impacts of the so-called Casas- Ibarra parameters on CP and flavor violating observables. The renormalization group effects induce CP and flavor violating elements of the SUSY breaking scalar mass squared matrices, which may result in sizable leptonic CP and flavor violating signals. Assuming seesaw formu…
We systematically analyze the correlations between the various leptonic and hadronic flavor violating processes arising in SUSY Grand Unified Theories. Using the GUT-symmetric relations between the soft SUSY breaking parameters, we assess the impact of hadronic and leptonic flavor observables on the SUSY sources of flavor violation.
Most models of weak scale supersymmetry (SUSY) predict observable rates for production of SUSY matter at the CERN LHC. The SUSY collider events are expected to be rich in jets, isolated (and non-isolated) leptons and missing E_T. After first discussing the merits of mixed axion/axino vs. neutralino cold dark matter in SUSY models, I then survey prospects for detecting SUSY matter at the LHC via leptonic signatures. In the paradigm mSUGRA model, cascade decays of gluinos and squarks should yield high rates for multi-jet plus multi-lepton events, allowing values of m_{\tg}\sim 3 (1.8) TeV to be …
We study leptonic flavor and CP violating observables in supersymmetric (SUSY) models with heavy sfermions, which is motivated by the recent results of the LHC experiments (i.e., the discovery of the Higgs-like boson with the mass of about 126 GeV and the negative searches for the superparticles). Even if the sfermion masses are of O(10-100 TeV), signals may be within the reach of future leptonic flavor- and CP-violation experiments assuming that the off-diagonal elements of the sfermion mass matrices are unsuppressed compared to the diagonal ones. We also consider the SUSY contribution to the…
In this paper we study the polarization asymmetries of the final state lepton in the radiative dileptonic decay of B meson (\bsllg) in the framework of Minimal Supersymmetric Standard Model (MSSM) and various other unified models within the framework of MSSM e.g. mSUGRA, SUGRA (where condition of universality of scalar masses is relaxed) etc. Lepton polarization, in addition of having a longitudinal component (\pl), can have two other components, \pt and \pn, lying in and perpendicular to the decay plane, which are proportional to \ml and hence are significant for final state being $μ^+ ~ μ^-$…
The non-unitarity of the leptonic mixing matrix is a generic signal of new physics aiming at the generation of the observed neutrino masses. We discuss the Minimal Unitarity Violation (MUV) scheme, an effective field theory framework which represents the class of extensions of the Standard Model (SM) by heavy neutral leptons, and discuss the present bounds on the non-unitarity parameters as well as estimates for the sensitivity of the Circular Electron Positron Collider (CEPC), based on the performance parameters from the preCDR.
Models of neutrino mass generation provide well motivated scenarios of Beyond-the-Standard-Model physics. The synergy between low energy and high energy LHC searches facilitates an effective approach to rule out, constrain or ideally pinpoint such models. In this proceedings report, we provide a brief overview of scenarios where searches at the LHC can help determine the mechanism of light neutrino masses and potentially falsify baryogenesis mechanisms.
If supersymmetry is spontaneously at a low energy scale then the resulting gravitino would be very light. The interaction strength of the longitudinal components of such a light gravitino to electron-selectron pair then becomes comparable to that of electroweak interactions. Such a light gravitino could modify the cross-section for $e^_L e^_R-->\tilde {e}_L\tilde {e}_R$ from its MSSM value. Precision measurement of this cross-section could therefore be used to probe the low energy SUSY breaking scale.
On-shell effective theory approach has been widely used in search of various supersymmetric signals, in particular, gluino/squark pairs with long cascade decay chains in which complete matrix element calculations may encounter over-20 dimensional integrations. On the other hand, leptons from polarized chargino decays may show significant boost or anti-boost effect in some scenarios and simulation without polarization information may underestimate or overestimate the lepton $p_{T}$ cut efficiencies in the first place. We study the polarization effects in supersymmetry searches of multi-jets plu…
We discuss a minimal Supersymmetric SO(10) model where B-L symmetry is broken by a {\bf 126} dimensional Higgs multiplet which also contributes to fermion masses in conjunction with a {\bf 10} dimensional superfield. This minimal Higgs choice provides a partial unification of neutrino flavor structure with that of quarks and has been shown to predict all three neutrino mixing angles and the solar mass splitting in agreement with observations, provided one uses the type II seesaw formula for neutrino masses. In this paper we generalize this analysis to include arbitrary CP phases in couplings a…
One of the main neutrino oscillation parameters whose value has not been determined very precisely is the leptonic $δ_{CP}$ phase. Since neutrinos have a tiny but finite mass they can undergo decay both visibly and invisibly. The effect of invisible decay of the third mass eigen state $ν_3$ on the sensitivity to $δ_{CP}$ is analysed here using atmospheric neutrino and anti-neutrino events. Effects of detector resolutions and systematic uncertainties are studied to identify the optimum resolutions and efficiencies required by a detector to obtain a significant sensitivity even in presence of de…
We present an overview of the indirect constraints from flavor physics on supersymmetric models. During the past few years flavor data, and in particular b -> s gamma transitions, have been extensively used in order to constrain supersymmetric parameter spaces. We will briefly illustrate here the constraints obtained by a collection of low energy observables including FCNC transitions, rare decays, leptonic and semileptonic decays of B mesons, as well as leptonic decays of K mesons. The theoretical predictions can be obtained using the computer program SuperIso.
Gaugino masses might provide useful information on the underlying scheme of supersymmetry breaking as they are least dependent on the unknown physics between the TeV scale and the high messenger scale of supersymmetry breaking. We discuss the pattern of low energy gaugino masses in various schemes of supersymmetry breaking together with the possibility to determine the gaugino masses at LHC.
We study CP asymmetries in two-body decays of top squarks into neutralinos and sleptons at the LHC. These asymmetries are used to probe the CP phases possibly present in the stop and neutralino sector of the Minimal Supersymmetric Standard Model. Taking into account bounds from experimental electric dipole moment searches, we identify areas in the mSUGRA parameter space where CP asymmetries can be sizeable and discuss the feasibility of their observation at the LHC. As a result, potentially detectable CP asymmetries in stop decays at the LHC are found, motivating further detailed experimental …
We analyze constraints on low-energy flavour-changing sfermion mass terms, coming from FCNC and CP violating processes, in the model-independent framework of the mass insertion method. We discuss the relevance of these constraints as tests of supersymmetric extensions of the standard model; in particular, we consider grand-unified models and models with non-universal soft breaking terms.
We probe the high scale SUSY at 10-50 TeV in the CP violations of K, B0 and Bs mesons. In order to estimate the contribution of the squark flavor mixing to these CP violations, we discuss the squark mass spectrum, which is consistent with the recent Higgs discovery. Taking the universal soft parameters at the SUSY breaking scale, we obtain the squark mass spectrum at 10 TeV and 50 TeV, where the SM emerges. Then, the 6times6 mixing matrix between down-squarks and down-quarks is discussed by input of the experimental data of K, B0 and Bs mesons.It is found that epsilon_K is most sensitive to th…
In the minimal supersymmetric standard model (MSSM), the μ-parameter and the trilinear coupling A_t may be generically complex and can affect various observables at B factories. Imposing the edm constraints, we find that there is no new large phase shift in the B^0 - \bar{B^0} mixing, CP violating dilepton asymmetry is smaller than 0.1 %, and the direct CP violation in B\to X_s γcan be as large as \sim \pm 16 %.
With the primary motivation of probing the quark substructure of scalar mesons, a generalized linear sigma model for the lowest and the next-to-lowest scalar and pseudoscalar mesons is employed to investigate several semi-leptonic decays of $D$ mesons. The free parameters of the model (in its leading approximation) have been previously determined from fits to mass spectra and various low-energy parameters. With these fixed parameters, the model has already given encouraging predictions for different low-energy decays and scattering, as well as for semileptonic decay channels of $D_s^+$ that in…
We discuss the prospects of observing double parton scattering (DPS) processes with purely leptonic final states at the LHC. We first study same-sign W pair production, which is particularly suited for studying momentum and valence number conservation effects, followed by discussions on double Drell-Yan and production of J/psi pairs. The effects of initial state and intrinsic transverse momentum smearing on pair-wise transverse momentum balance characteristic to DPS are studied quantitatively. We also present a new technique, based on rapidity differences, to extract the DPS component from a d…
Cascade decays of Supersymmetric (SUSY) particles are likely to be prolific sources of Higgs bosons at the Large Hadron Collider (LHC). In this work, we explore, with the help of detailed simulation, the role of non-universal gaugino masses in the production of the Higgs bosons under SUSY cascades. The analysis is carried out by choosing an appropriate set of benchmark points with non-universal gaugino masses in the relevant SUSY parameter space and then contrasting the resulting observations with the corresponding cases having universal relationship among the same. It is shown that even of da…
We study CP violation in semi-leptonic $τ$ decays and we determine the conditions necessary to be able to define a observable CP asymmetry. We apply these conditions in both models, the standard model for the electroweak interactions and its supersymmetric extensions. In the first case, the leading order contribution to the direct CP asymmetry in $τ^{\pm} \to K^{\pm}π^0 ν_τ$ decay rates is evaluated. In the second case,we compute the SUSY effective hamiltonian that describes the $|ΔS|=1$ semileptonic decays of tau leptons. We show that SUSY contributions may enhance the CP asymmetry of $τ\to K…
Supersymmetric (SUSY) Grand Unified theories (GUTs) generally predict FCNC and CP violating processes to occur both in the leptonic and hadronic sectors. Assuming an underlying SU(5) group plus right-handed neutrinos (RN), we perform an extensive study of FCNC and CP violation, analyzing the correlations between leptonic and hadronic processes like mu-> e gamma and K-Kbar mixing, tau->mu gamma and b -> s transitions such as B_d -> phi K_s and Bs-Bsbar mixing. Moreover, we examine the impact of the considered scenario on the UT analyses, monitoring the low energy consequences implied by possibl…
Rare leptonic kaon and pion decays $K^+(π^+) \to μ^+\, ν_μ\, e^+ e^-$ can be used to probe a dark photon of mass ${\cal O}(10)$~MeV, with the background coming from the mediation of a virtual photon. This is most relevant for the 16.7-MeV dark photon proposed to explain a 6.8$σ$ anomaly recently observed in $^8$Be transitions by the Atomki Collaboration. We evaluate the reach of future experiments for different scenarios of how the dark photon couples with the standard model particles, and show that a great portion of the preferred 16.7-MeV dark photon parameter space can be decisively probed.…
We study a CP and T violating triple (spin) correlation in the muon to electron conversion in nuclei in the context of the seesaw mechanism. After concluding that the results are negative for all three seesaw types, we turn to the left-right symmetric theories as the original source of seesaw. We find that in general this correlation is of order one which offers a hope of observing CP violation in lepton flavor violating processes for a L-R scale below around 10-30 TeV. We discuss the conditions that could render to (unlikely) conspiracies as to suppress the CP violating effects.
We compute the generic one-loop contribution involving scalar leptoquarks (LQ) to the $W$ and $Z$ leptonic decay widths. In our computation we include for the first time the finite terms and the corrections due to the external momenta of the electroweak bosons, which is a step beyond the leading-logarithmic approximation considered in the literature so far. We show that the terms we include can be numerically quite significant. They amount to about $20\%$ for scalar LQ masses below $1.5$~TeV, as currently allowed by the direct searches at the LHC. To further illustrate the relevance of our res…
In the context of SUSY grand unification a link is established between the hadronic and leptonic soft breaking sectors. Such relation is here exploited in particular for FCNC processes in B physics. It is shown how bounds on leptonic FCNC involving the third generation translate into constraints on FC B decays. In the second part of the contribution we show that tests of lepton universality in K and B decays can represent an interesting handle to obtain relevant information on the amount of FCNC in the second and third fermion generation.
The most recent measurements of the observables $R_{D^{(*)}}$ are in tension with the Standard Model offering hints of New Physics in $b\rightarrow c \ell \barν_{\ell}$ transitions. Motivated by these results, in this work we present an analysis on their $b\rightarrow u \ell \barν_{\ell}$ counterparts (for $\ell=e, ~μ, ~τ$). Our study has three main objectives. Firstly, using ratios of branching fractions, we assess the effects of beyond the Standard Model scalar and pseudoscalar particles in leptonic and semileptonic $B$ decays ($B^-\rightarrow \ell^- \barν_{\ell}$, $\bar{B}\rightarrow π\ell …
A low energy non-unitary leptonic mixing matrix is a generic feature of many extensions of the Standard Model. In such a case, the task of future precision neutrino oscillation experiments is more ambitious than measuring the three mixing angles and the leptonic (Dirac) CP-phase, i.e., the accessible parameters of a unitary leptonic mixing matrix. A non-unitary mixing matrix has 13 parameters that affect neutrino oscillations, out of which four are CP-violating. In the scheme of Minimal Unitarity Violation (MUV) we analyse the potential of a Neutrino Factory for determining or constraining the…
We study supersymmetric (SUSY) models in which the muon $g-2$ discrepancy and the dark matter relic abundance are simultaneously explained. The muon $g-2$ discrepancy, or a 3$σ$ deviation between the experimental and theoretical results of the muon anomalous magnetic moment, can be resolved by SUSY models, which implies at least three SUSY multiplets have masses of $\mathop{\mathcal{O}}(100)\, \mathrm{GeV}$. In particular, models with the bino, higgsino and slepton having $\mathop{\mathcal{O}}(100)\, \mathrm{GeV}$ masses are not only capable to explain the muon $g-2$ discrepancy but naturally …
Current attempts to understand supersymmetry (susy) breaking are focused on the idea that we are not in the ground state of the universe but, instead, in a metastable state that will ultimately decay to an exactly susy ground state. It is interesting to ask how experiments at the Large Hadron Collider (LHC) will shed light on the properties of this future supersymmetric universe. In particular we ask how we can determine whether this final state has the possibility of supporting atoms and molecules in a susy background.
We propose a strategy for distinguishing the Dirac / Majorana character of heavy neutrinos with masses below the $W$ boson mass, using purely leptonic decays at the LHC. The strategy makes use of a forward-backward asymmetry of the opposite charge lepton in the $W^{+}\rightarrow l^{+}l^{+}l^{'-}ν$ decay. In order to check the experimental feasibility of the model, we show, through a numerical analysis, that in the decay $W^{+}\rightarrow e^{+}e^{+}μ^{-}ν$ the two positrons in the final state can be distinguished for different ranges of the heavy neutrino masses. Finally, we estimated the numbe…
We study orbifold compactifications of the type IIB superstring on AdS_5 x S^5/Gamma, where Gamma is the abelian group Z_8, which can lead to non-SUSY three and four family models based on quartification. In particular, we focus on two models, one fully quartified model and one a model with two trinification families and one quartification family, which reduces to the standard model with a minimal leptonic color sector.
We study a purely leptonic signature of the Randall-Sundrum scenario with Standard Model fields in the bulk at LHC: the contribution from the exchange of Kaluza-Klein (KK) excitations of gauge bosons to the clear Drell-Yan reaction. We show that this contribution is detectable (even with the low luminosities of the LHC initial regime) for KK masses around the TeV scale and for sufficiently large lepton couplings to KK gauge bosons. Such large couplings can be compatible with ElectroWeak precision data on the Zff coupling in the framework of the custodial O(3) symmetry recently proposed, for sp…
A bilinear R-Parity breaking SUSY model for neutrino mass and mixing predicts the lightest superparticle to decay mainly into a pair of tau leptons or b quarks along with a neutrino for relatively light SUSY spectra. This leads to a distinctive triple bang signature of SUSY events at ultrahigh energy neutrino telescopes like IceCube or Antares. While the expected signal size is only marginal at IceCube, it will be promising for a future multi-km^3 size neutrino telescope.
We discuss the production at $e^+e^-$ colliders of Higgs bosons in association with both the scalar leptons and the lightest neutralinos in the Minimal Supersymmetric extension of the Standard Model. While the rates for associated Higgs production with neutralinos and first/second generation sleptons are rather tiny, the cross section for the production of the lightest Higgs boson $h$ with scalar $τ$ lepton pairs can reach the femtobarn level at c.m. energies at and above 500 GeV in favorable regions of the parameter space, making this process potentially detectable at a high-luminosity $\ee$ …
We examine the ATLAS and CMS 7 & 8 TeV multijet supersymmetry (SUSY) searches requiring the incidence of a single lepton in the framework of the supersymmetric grand unified model No-Scale Flipped SU(5) with extra vector-like flippon multiplets derived from F-Theory, or F-SU(5) for short. Investigated are five multijet+lepton SUSY searches: 4.7/fb ATLAS 7 TeV gluino and light stop searches, as well as 13/fb ATLAS and 9.7/fb CMS 8 TeV light stop searches. Most significantly, all five leptonic SUSY searches represent statistically independent data samples. Findings show that all five orthogonal …
The SU(5) GUT model extended with fermions in the adjoint $24_F$ representation predicts triplet fermions in the 100 GeV mass range, opening up the possibility of testing seesaw at LHC. However, once the model is supersymmerized, the triplet fermion mass is constrained to be close to the GUT scale for the gauge couplings to unify. We propose an extension of the SUSY SU(5) model where type II seesaw can be tested at LHC. In this model we add a matter chiral field in the adjoint $\hat{24}_F$ representation and Higgs chiral superfields in the symmetric $\hat{15}_H$ and $\hat{\bar{15}}_H$ represen…
We perform realistic simulations of the current and future long baseline experiments such as T2K, NO$ν$A, DUNE and T2HK in order to determine their ultimate potential in probing neutrino oscillation parameters. We quantify the potential of these experiments to underpin the octant of the atmospheric angle $θ_{23}$ as well as the value and sign of the CP phase $δ_{CP}$.
The recent NA48/2 improvement on R_K=Gamma(K->e nu_e)/Gamma(K->mu nu_mu) emphasizes the role of K_l2 decays in probing the mu-e universality. Supersymmetric (SUSY) extensions of the Standard Model can exhibit mu-e non-universal contributions. Their origin is twofold: those deriving from lepton flavor conserving couplings are subdominant with respect to those arising from lepton flavor violating (LFV) sources. We show that mu-e non-universality in K_l2 is quite effective in constraining relevant regions of SUSY models with LFV (for instance, supergravities with a see-saw mechanism for neutrino …
The favoured R-parity violating SUSY scenarios for the anomalous HERA events correspond to top and charm squark production via the $λ'_{131}$ and $λ'_{121}$ couplings. In both cases the corresponding electronic branching fractions of the squarks are expected to be $\ll 1$. Consequently the canonical leptoquark signature is incapable of probing these scenarios at the Tevatron collider over most of the MSSM parameter space. We suggest alternative signatures for probing them at Tevatron, which seem to be viable over the entire range of MSSM parameters.
We explore a Z' boson with family-nonuniversal couplings to charged leptons. The general effect of Z-Z' mixing, of both kinetic and mass types, is included in the analysis. Adopting a model-independent approach, we perform a comprehensive study of constraints on the leptonic Z' couplings from currently available experimental data on a number of flavor-conserving and flavor-changing transitions. Detailed comparisons are made to extract the most stringent bounds on the leptonic couplings. Such information is fed into predictions of various processes that may be experimentally probed in the near …
We discuss the possibility to probe leptonic mixing parameters at high-energy neutrino telescopes in a model-independent way, using astrophysical neutron and pion sources. In particular we show how the octant of the 2-3 mixing angle might be determined independently of prior knowledge of the source, even when current uncertainties on the other mixing parameters are included. We also argue that non-trivial neutrino oscillation effects should be taken into account when using high-energy flavor ratios for astrophysical diagnostics.
We explore supersymmetric contributions to the decay $K_S^0\rightarrowμ^+μ^-$, in light of current experimental data. The Standard Model (SM) predicts $\mathcal{B}(K_S^0\rightarrowμ^+μ^-)\approx5\times 10^{-12}$. We find that contributions arising from flavour violating Higgs penguins can enhance the branching fraction up to $\approx 35\times 10^{-12}$ within different scenarios of the Minimal Supersymmetric Standard Model (MSSM), as well as suppress it down to $\approx 0.78\times 10^{-12}$. Regions with fine-tuned parameters can bring the branching fraction up to the current experimental uppe…
Collider search for dark matter production has been performed over the years based on high pT standard model signatures balanced by large missing transverse energy. The mono-Z boson production with leptonic decay has a clean signature with the advantage that the decaying electrons and muons can be precisely measured. This signature not only enables reconstruction of the Z boson rest frame, but also makes possible recovery of the underlying production dynamics through the decaying lepton angular distribution. In this work, we exploit full information carried by the leptonic Z boson decays to se…
In this work we study the phenomenological consequences of the existence of long-range forces coupled to lepton flavour numbers in solar neutrino oscillations. We study electronic forces mediated by scalar, vector or tensor neutral bosons and analyze their effect on the propagation of solar neutrinos as a function of the force strength and range. Under the assumption of one mass scale dominance, we perform a global analysis of solar and KamLAND neutrino data which depends on the two standard oscillation parameters, Δm^2_{21} and \tan^2θ_{12}, the force coupling constant, its range and, for the…
The discovery of leptonic CP violation is one of the primary goals of next-generation neutrino oscillation experiments, which is feasible due to the recent measurement of a relatively large leptonic mixing angle θ_{13}. We suggest two new working observables ΔA^{\rm m}_{αβ} \equiv \max[A^{\rm CP}_{αβ}(δ)] - \min[A^{\rm CP}_{αβ}(δ)] and ΔA^{\rm CP}_{αβ}(δ) \equiv A^{\rm CP}_{αβ}(δ) - A^{\rm CP}_{αβ}(0) to describe the CP-violating effects in long-baseline and atmospheric neutrino oscillation experiments. The former signifies the experimental sensitivity to the leptonic Dirac CP-violating phase …
The purely leptonic decays D -> e nu and Ds -> e nu, for which no experimental limits exist, are highly suppressed in the Standard Model. Mere observation of these decays at the B factories BELLE/BaBar or forthcoming CLEO-c would be a clear signal of physics beyond the SM. We show that R parity violating slepton contributions can give rise to spectacular enhancements of the decay rates, resulting in branching ratios as large as 5 x 10^-3, which strongly motivates a search in these channels.
The vertex H^+_αW^-h^0_β, involving the gauge boson W^+- and the charged (H^+-_α) and neutral Higgs bosons (h^0_β), arises within the context of many extensions of the SM, and it can be used to probe the quantum numbers of the Higgs multiplet. After presenting a general discusion for the expected form of this vertex with arbitrary Higgs representations, we discuss its strength for several specific models, which include: i) the Two-Higgs Doublet Model (THDM), both the generic and the SUSY case, and ii) models with additional Higgs triplets, including both SUSY and non-SUSY cases. We find that i…
We investigate a strategy to search for light, nearly degenerate higgsinos within the natural MSSM at the LHC. We demonstrate that the higgsino mass range $μ$ in $100-150$ GeV, which is preferred by the naturalness, can be probed at $2σ$ significance through the monojet search at 14 TeV HL-LHC with 3000 fb$^{-1}$ luminosity. The proposed method can also probe certain region in the parameter space for the lightest neutralino with a high higgsino purity, that cannot be reached by planned direct detection experiments at XENON-1T(2017).
We study whether the individual violation of the lepton numbers L_{e,mu,tau} in the charged sector can lead to measurable rates for BR(mu->e gamma) and BR(tau->mu gamma). We consider three different scenarios, the fist one corresponds to the Minimal Supersymmetric Standard Model with non-universal soft terms. In the other two cases the violation of flavor in the leptonic charged sector is associated to the neutrino problem in models with a see-saw mechanism and with R-parity violation respectively.
The implications of the latest measurement of the branching fraction of B($ b\rightarrow s γ$) of b hadrons, which is another signature of New Physics beyond Standard Model is presented here. The quark transitions $ b \rightarrow s $, $ b \rightarrow d $ do not happen at tree level in the Standard Model as the Z boson does not couple to quarks of different flavour. In this work the present bounds on the quark transition $ b \rightarrow s $ within the constrained minimal supersymmetric extension of the Standard Model (CMSSM), in which there are three independent soft SUSY breaking parameters $ …
We report on an extensive analysis of FCNC and CPV effects in SUSY theories. We present results for Delta F=2 and Delta F=1 processes governed by b --> s transitions both in the low and high tanbeta regime, focussing in particular on S_psi_phi, the phase of Bs mixing. We emphasize that while the MFV framework is not suited to explain potentially large effects in S_psi_phi as indicated by recent data from CDF and D0, models with large right-right mass insertions in the 32 sector provide natural frameworks to account for such effects. Exemplarily we consider two SUSY models based on an abelian a…
In supersymmetric models where the magnitude of the GUT scale gaugino mass parameter M_3 is suppressed relative to M_1 and M_2, the lightest neutralino can be a mixed higgsino-bino state with a thermal relic abundance in agreement with the WMAP central value for Ω_{\rm CDM} h^2 and consistent with all other phenomenological constraints. In these models, the gluino can be as light as 200 GeV without conflicting with the LEP2 bounds on the chargino mass. Thus, gluino pair production can be accessible at the Fermilab Tevatron at high rates. In this framework, gluinos decay radiatively with a larg…
It is known that after Affleck-Dine baryogenesis, spatial inhomogeneities of Affleck-Dine field grow into non-topological solitons called Q-balls. In gauge mediated SUSY breaking models, sufficiently large Q-balls with baryon charge are stable while Q-balls with lepton charge can always decay into leptons. For a Q-ball that carries nonzero $B$ and $L$ charges, the difference between the baryonic component and the leptonic component in decay rate may induce nonzero electric charge on the Q-ball. This implies that charged Q-ball, also called gauged Q-ball, may emerge in our universe. In this pap…
