We present a complete study of R-parity violating supersymmetric effects in thirteen exclusive and inclusive semi-leptonic $b \to (s,d) ν\barν$ decays, including $B^+_u\to K^{(*)+}ν\barν$, $B^0_d\to K^{(*)0}ν\barν$, $B^0_s\to ϕν\barν$, $B^0_d\to π^0(ρ^0)ν\barν$, $B^+_u\to π^+(ρ^+)ν\barν$, $B^0_s\to K^{(*)0}ν\barν$ and $B \to X_{s,d} ν\barν$ decay modes, and we find those thirteen modes are very sensitive to the constrained R-parity violating couplings. We derive stringent bounds on relevant R-parity violating couplings, which are based on all existent experimental upper limits of involved semi-leptonic decays. In addition, we also investigate the sensitivities of the branching ratios and di-neutrino invariant mass spectra to the survived R-parity violating coupling spaces. Since the experimental bounds would become much better soon through Super-B, we expect that future experiments will greatly strengthen our bounds.
We calculate the CP-violating effects in the top quark semi-leptonic three body decays induced by the supersymmetric CP-odd phase of the top squark trilinear soft breaking term $\arg(A_t)$. The light top squark mass is assumed to be close to the top quark mass $m_{\tilde{t}}\sim m_t$. The CP-conserving phase is provided by the $χ^+$ and $χ^0$ cut. We find that the partial rate asymmetry is in the 0.1% level. In the most favorable parameter region the decay rate asymmetr can reach up to 0.55%.
Low-energy results from measurements of leptonic dipole moments are used to derive constraints on the CP-violating phases of the dimensionful parameters of the minimal supersymmetric extension of the standard model (MSSM). We use these (known) bounds to investigate the impact of these phases on CP-even cross sections at high-energy e^+e^- and e^-e^- colliders. To that end we define two measures of the significance with which the existence of non--vanishing phases could be deduced from the measurements of these cross sections. We find that highly significant evidence for deviations from the CP-…
Semi-leptonic and leptonic decays of B-mesons are important probes for testing SM and theories beyond it because of their relative cleanliness and far less theoretical uncertainties. In semi-leptonic decays based on quark level transition $b \to s τ^+ τ^-$ apart from branching ratio one can study many other (possible) observables associated with final state leptons like, lepton pair Forward Backward asymmetry, lepton polarization asymmetries etc. But as proposed recently if we can tag the B-meson than one can measure the polarization asymmetries of both the leptons. Here we will study the pola…
We review the prospects for Central Exclusive Production (CEP) of BSM Higgs bosons at the LHC using forward proton detectors proposed to be installed at 220 m and 420 m from the ATLAS and/ or CMS. Results are presented for MSSM in standard benchmark scenarios and in scenarios compatible with the Cold Dark Matter relic abundance and other precision measurements. Following results of the LHC Higgs boson searches, we investigate a hypothesis that candidates found at a mass of 125 GeV are compatible with light CP-even MSSM Higgs bosons. We show that CEP can give a valuable information about spin-p…
The prospects for central exclusive diffractive (CED) production of MSSM Higgs bosons at the LHC are reviewed. It is shown that the CED channels, making use of forward proton detectors at the LHC installed at 220 m and 420 m distance around ATLAS and / or CMS, can provide important information on the Higgs sector of the MSSM. In particular, CED production of the neutral CP-even Higgs bosons h and H and their decays into bottom quarks has the potential to probe interesting regions of the M_A--tan_beta parameter plane of the MSSM and may give access to the bottom Yukawa couplings of the Higgs bo…
A brief report on the QCD factorization approach to exclusive B decays and its applications is presented. In an appendix a subtle issue concerning partial integration in the parameterization of infrared-sensitive power corrections is clarified.
Possibility of observing associated production of charged Higgs and W boson in the framework of MSSM at LHC is studied. Both leptonic and hadronic decays of W boson are studied while the charged Higgs boson is considered to decay to a $τ$ lepton and a neutrino. Therefore two search categories are defined based on the leptonic and hadronic final states, i.e. $\ell τ+E^{miss}_{T}$ and $jj τ+E^{miss}_{T}$ where $\ell=e$ or $μ$ and $j$ is a light jet from $W$ decay. The discovery chance of the two categories is evaluated at an integrated luminosity of 300 \invfb at LHC. It is shown that both lepto…
In this paper, the semileptonic decays of heavy mesons are treated fully relativistically. By means of an effective vertex, the effect of Fermi momentum are included both at the inclusive and at the exclusive levels, and the spin of both parent and daughter particles are taken into account. The differential decay rates with respect to the lepton energy and momentum transfer are compared with data from ARGUS and CLEO.
We present a QCD-based calculation of the exclusive semileptonic decay Lambda_b -> p l nu-bar. Using the ideas of Heavy Quark Effective Theory, we discuss the factorization of the amplitude. Further, resummed Sudakov effects are put in to ensure a consistent perturbative expansion.
We investigate the prospects for Central Exclusive Production (CEP) of MSSM Higgs bosons at the LHC using forward proton detectors proposed to be installed at 220 m and 420 m distance around ATLAS and / or CMS. We summarize the situation after the first and very successful data taking period of the LHC. The discovery of a Higgs boson and results from searches for additional MSSM Higgs bosons from both the ATLAS and CMS experiments, based on data samples each corresponding to about 25 fb-1, have recently led to a proposal of new low-energy MSSM benchmark scenarios. The CEP signal cross section …
We study a subset of electroweak-precision observables consisting of $M_W$, $\sin^2θ_{\tiny eff}^τ$, $BR(Z\toτ^+τ^-)$ and $Γ(Z\toτ^+τ^-)/Γ(Z\to e^+e^-)-1$ (characterizing leptonic $Z$-decays) in the context of the NMSSM. After a brief review of common MSSM-NMSSM effects, e.g. for $Γ(Z\toτ^+τ^-)/Γ(Z\to e^+e^-)-1$, which has been little discussed, even in the MSSM), specific NMSSM scenarios are studied, with the result that the NMSSM, considering existing constraints on its spectrum, is essentially consistent with available measurements, given the current accuracy.
We investigate the possibility of testing factorization hypothesis in non-leptonic exclusive decays of B-meson. In particular, we considered the non factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+} (π^-, ρ^-) known as well-factorizable modes. By taking the ratios BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(π^-,ρ^-)), we found that under the present theoretical and experimental uncertainties there's no evidence for the breakdown of factorization description to heavy-heavy decays of the B meson.
The relatively clean theoretical probes of the Standard Model (SM), and the various theories beyond the SM, provided by radiative, semi-leptonic and (purely) leptonic decays of B-mesons have become increasingly important. Due to the large number of possible distributions in the semi-leptonic decays based on the quark level transition $b \to s \ell^+ \ell^-$ (not just the branching ratio), these transitions have become very useful. A study of the Forward-Backward asymmetries for the inclusive decay ($B \to X_s \ell^+ \ell^-$) is carried out in this paper. This study shall be performed in the SM…
Exclusive, non-leptonic, two-body decays of B mesons simplify greatly in the heavy quark limit. In this talk I discuss the factorized structure that holds in this limit and some of its consequences: (a) naive factorization is recovered in a certain limit; (b) `non-factorizable' effects are hard and can be calculated; (c) strong interaction phases vanish in the heavy quark limit (and can be calculated as well). As an illustration, I compute the penguin contribution to the decay $B_d\toπ^+π^-$ and its effect on the determination of $\sin 2α$.
The spectra and form factors of exclusive semi-leptonic decays of B-meson are analyzed, taking account of confined effects of quarks by the Covariant Oscillator Quark Model. The predicted B --> (D*,D)l nubar_l spectra with the conventional value of V_cb are fit well to the high-precision experiment. It is also shown the values of V_cb and V_ub obtained through decay widths for the B --> (D,D*,rho)l nubar_l processes are consistent with the presently accepted ones.
We present an analysis of non-leptonic B decays in the minimally flavour-violating MSSM with large tan(beta). We relate the Wilson coefficients of the relevant hadronic scalar operators to leptonic observables, showing that the present limits on the Bs->mu+ mu- and B+->tau nu_tau branching fractions exclude any visible effect in hadronic decays. We study the transverse helicity amplitudes of B->VV decays, which exhibit an enhanced sensitivity to the scalar operators, showing that even though an order one modification relative to the SM is not excluded in some of these amplitudes, they are too …
We present a phenomenology study on central exclusive production of $W^+W^-$ boson pairs in proton-proton collisions at the Large Hadron Collider at 14 TeV using the forward proton detectors, such as the ATLAS Forward Proton or the CMS-TOTEM Precision Proton Spectrometer detectors. Final states where at least one of the $W$ bosons decay hadronically in a large-radius jet are considered. The latter extends previous efforts that consider solely leptonic final states. A measurement of exclusive $W^+W^-$ also allows us to further constrain anomalous quartic gauge boson interactions between photons…
We consider the possibility of violations of the selection rule $ΔS=ΔQ$ at an appreciable level in {\it exclusive} semi-leptonic decays of Kaons. At $Φ$-Factories, intense Kaon beams will be available and will probe among others, the semi-leptonic decays $K_{l4}$ and $K_{l3γ}$ in addition to $K_{l3}$ and could provide novel testing grounds for the $ΔS=ΔQ$ rule. In particular, the branching ratio of $K_{l3γ}$ is non-negligible and could be used to probe new phenomena associated with the violation of this selection rule. Furthermore, we modify certain di-lepton event rate ratios and asymmetries …
The Cabibbo-Kobayashi-Maskawa matrix element |V_ub| can be extracted from the rate for the semi-leptonic decay B -> pi + l + antineutrino_l, with little theoretical uncertainty, provided the hadronic form factor for the B -> pi transition can be measured from some other B decay. In here, we suggest using the decay B -> pi Jψ. This is a color suppressed decay, and it cannot be properly described within the usual factorization approximation; we use instead a simple and very general phenomenological model for the b d Jψvertex. In order to relate the hadronic form factors in the B -> pi Jψand B ->…
We investigate the prospects for Central Exclusive Diffractive (CED) production of MSSM Higgs bosons at the LHC using forward proton detectors (FPD) proposed to be installed 220 m and 420 m from ATLAS and CMS detectors. We summarize the situation after the first and very successful data taking period of the LHC. The discovery of a Higgs boson and results from searches for additional MSSM Higgs bosons from the ATLAS and CMS, have recently led to a proposal of new low-energy MSSM benchmark scenarios. The CED signal cross section for the process H -> bb and its backgrounds are estimated in these …
We study the exclusive $b \to u \ell^- \barν_{\ell} (\ell=τ,μ,e)$ decays in the MSSM with and without R-parity violation. From the experimental measurements of branching ratios $\mathcal{B}(B^-_u \to τ^- \barν_τ)$, $\mathcal{B}(B^-_u \to M'^0 \ell'^- \barν_{\ell'})$ and $\mathcal{B}(\bar{B}^0_d \to M'^+ \ell'^- \barν_{\ell'})$ $(\ell'=μ,e, M'=π,ρ)$, we derive new upper bounds on the relevant new physics parameters within the decays. Using the constrained new physics parameter spaces, we predict the charged Higgs effects and the R-parity violating effects on the branching ratios, the normalized…
We address a number of theoretical and phenomenological issues in two-body charmless non-leptonic B decays in the context of a factorization model. A classification of the exclusive decays involving tree and penguin amplitudes is reviewed. The role of QCD anomaly in exclusive decays involving an $η$ or $η'$ is elucidated and comparison is made with the existing data. We argue that the factorization approach accounts for most of the observed two-body B decays.
We provide a rigorous basis for factorization for a large class of non-leptonic two-body $B$-meson decays in the heavy-quark limit. The factorization formula incorporates elements of the naive factorization approach and the hard-scattering approach, but allows us to compute systematically radiative (``non-factorizable'') corrections to naive factorization for decays such as $B\to Dπ$ and $B\to ππ$. We discuss the factorization formula for a general final state from a general point of view. We then consider factorization for decays into heavy-light final states (such as $B\to Dπ$) in more detai…
We consider the leptonic and semileptonic (SL) lepton flavour violating (LFV) decays of the charged leptons in the minimal supersymmetric standard model (MSSM). The formalism for evaluation of branching fractions for the SL LFV charged-lepton decays with one or two pseudoscalar mesons, or one vector meson in the final state, is given. Previous amplitudes for the SL LFV charged-lepton decays in MSSM are improved, for instance the $γ$-penguin amplitude is corrected to assure the gauge invariance. The decays are studied not only in the model-independent formulation of the theory in the frame of M…
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 $μ^+ ~ μ^-$…
I briefly describe recent developments in the theoretical analysis of non leptonic and semileptonic B decays. For non leptonic transitions, I focus on factorization, from the naive formulation to the most recent achievements. As for semileptonic decays, I mainly consider B transitions to excited charmed states.
We study vertex corrections to the leptonic electroweak observables in the general MSSM at tan(beta) < 35. In particular, we address the question of whether supersymmetry can be responsible for the observed 2 sigma deviation from the Standard Model prediction in the invisible width of the Z. We find that the presence of a light (around 100 GeV) chargino and sleptons hinted by the muon g-2 measurements makes the agreement with experiment slightly better and improves the electroweak fit.
High Luminosity upgrades of the KEK-B collider are being discussed. We consider the role of the purely leptonic decays B^\pm -> l^\pm nu and B^0 -> l+l- in motivating such an upgrade. These decays are very sensitive to R parity violating extensions of the MSSM, and we show that future runs of the KEK-B factory can be competitive with high energy colliders for probing such models.
We make predictions for the exclusive semileptonic and the non-leptonic decay widths of the B_c meson. We evaluate the B_c semileptonic form factors for different decay channels in a relativistic model, and use factorization to obtain the non-leptonic decay widths.
We show that the use of forward proton detectors at the LHC installed at 220 m and 420 m distance around ATLAS and / or CMS can provide important information on the Higgs sector of the MSSM. We analyse central exclusive production of the neutral CP-even Higgs bosons h and H and their decays into bottom quarks, tau leptons and W bosons in different MSSM benchmark scenarios. Using plausible estimates for the achievable experimental efficiencies and the relevant background processes, we find that the prospective sensitivity of the diffractive Higgs production will allow to probe interesting regio…
We summarize the status of semileptonic and leptonic $B$ decays, including $|V_{cb}|$ and $|V_{ub}|$ exclusive and inclusive determinations, decays to excited states of the charm meson spectrum and decays into $τ$ leptons.
We study the associated production of selectrons and neutralinos with subsequent leptonic decay of the selectron in eγscattering within the framework of MSSM and NMSSM. Due to the weak couplings of singlino dominated neutralinos, associated neutralino production e^+ + e^- -> neutralino_1 + neutralino_2 at a linear collider can be strongly suppressed in some regions of the parameter space. Then the process e + gamma -> selectron_{L/R} + neutralino_{1/2} -> e + neutralino_{1/2} + neutralino_1 can give additional informations on the underlying theory and the character of neutralino_1 and neutrali…
We present SUSY_FLAVOR -- a Fortran 77 program that calculates important leptonic and semi-leptonic low-energy observables in the general R-parity conserving MSSM. For a set of input MSSM parameters, the code gives predictions for the K0-bar K0, D-bar D, B_d-bar B_d and B_s-bar B_s mixing parameters; B to X_s gamma, B_{s,d} to l+ l-, K0_L to pi nu-bar nu and K+ to pi+ nu-bar nu decay branching ratios; and the electric dipole moments of the leptons and the neutron. All these quantities are calculated at one-loop level (with some higher-order QCD corrections included) in the exact sfermion mass …
We investigate the prospects for Central Exclusive Diffractive (CED) production of BSM Higgs bosons at the LHC using forward proton detectors installed at 220 m and 420 m distance around ATLAS and / or CMS. We update a previous analysis for the MSSM taking into account improvements in the theoretical calculations and the most recent exclusion bounds from the Tevatron. We extend the MSSM analysis to new benchmark scenarios that are in agreement with the cold dark matter relic abundance and other precision measurements. We analyse the exclusive production of Higgs bosons in a model with a fourth…
Exclusive non-leptonic two-body decays are discussed on the basis of a generalized factorization approach which also includes non-factorizeable contributions. Numerous decay processes can be described satisfactorily. The success of the method makes possible the determination of decay constants from non-leptonic decays. In particular, we obtain f_{D_s}=(234+-25) MeV and f_{D^*_s}=(271+-33) MeV. The observed constructive and destructive interference pattern in charged B- and D-decays, respectively, can be understood in terms of the different alpha_s-values governing the interaction among the qua…
We present the calculation of multiphoton radiation effects in leptonic W-boson decays in the framework of the Yennie-Frautschi-Suura exclusive exponentiation. This calculation is implemented in the Monte Carlo event generator WINHAC for single W-boson production in hadronic collisions at the parton level. Some numerical results obtained with the help of this program are also presented.
The definitions and properties of elastic and inelastic Isgur-Wise form factors are reviewed. The nature of the "missing" exclusive semi-leptonic decay fraction is identified. The role that completeness sum rules play in relating form factors, spectroscopy, and model building is outlined.
We investigate the associated production of charged Higgs bosons (H^\pm) and W bosons at the CERN Large Hadron Collider, using the leptonic decay H^+ -> tau^+ nu_tau and hadronic W decay, within different scenarios of the Minimal Supersymmetric Standard Model (MSSM) with both real and complex parameters. Performing a parton level study we show how the irreducible Standard Model background from W + 2 jets can be controlled by applying appropriate cuts. In the standard m_h^max scenario we find a viable signal for large tan beta and intermediate H^\pm masses (~ m_t). In MSSM scenarios with large …
We apply HQET to semi-leptonic $B$ meson decays into a variety of excited charm states. Using three realistic meson models with fermionic light degrees of freedom, we examine the extent that the sum of exclusive single charmed states account for the inclusive semi-leptonic $B$ decay rate. The consistency of form factors with the Bjorken and Voloshin sum rules is also investigated.
We compute supersymmetric contributions to pion leptonic (π_{l2}) decays in the Minimal Supersymmetric Standard Model (MSSM). When R-parity is conserved, the largest contributions to the ratio R_{e/μ} = Γ[ π^+ \to e^+ ν_e(γ)]/Γ[ π^+ \to μ^+ ν_μ(γ)] arise from one-loop (V-A)x(V-A) corrections. These contributions can be potentially as large as the sensitivities of upcoming experiments; if measured, they would imply significant bounds on the chargino and slepton sectors complementary to current collider limits. We also analyze R-parity violating interactions, which may produce a detectable devia…
We investigate the viability of observing charged Higgs bosons (H^\pm) produced in association with W bosons at the CERN Large Hadron Collider, using the leptonic decay H^+ -> tau^+ nu_tau and hadronic W decay, within the Minimal Supersymmetric Standard Model. Performing a parton level study we show how the irreducible Standard Model background from W + 2 jets can be controlled by applying appropriate cuts. In the standard m_h^max scenario we find a viable signal for large tan beta and intermediate H^\pm masses (~ m_t).
We study lifetimes of heavy mesons in the 't Hooft model, a large-$N_c$ theory of strong interaction in two-dimensional spacetime. Since this model is solvable, one can evaluate the total decay widths through hadronic amplitudes that are determined unambiguously within the formalism. We investigate quark-hadron duality by numerically comparing the exclusive result and one from the heavy quark expansion, with the contribution of Pauli interference being consistently incorporated. Within certain numerical accuracy, we find that the maximal difference between inclusive and exclusive rates for $τ[…
In this paper we analyze the process $B_s \to \ell^+ \ell^-$ in a model II 2HDM and MSSM. All the leading terms of Wilson coefficients relevant to the process are given in the large tan$β$ limit. It is shown that the decay width for $B_s \to \ell^+ \ell^-$ depends on all parameters except $m_{A^0}$ in the 2HDM. The branching ratio of $B_s \to μ^+ μ^-$ can reach its experimental bound in some large tan$β$ regions of the parameter space in MSSM because the amplitude increases like tan$^3β$ in the regions. For l=$τ$, the branching ratio can even reach $10^{-4}$ in the regions. Therefore, the expe…
In this letter we investigate the proper normalization for the B meson eikonal valence wave function used in exclusive B decays. The normalization appropriate for a hard scattering process renormalized at the scale $μ$ is determined by calculating the short distance contribution to the purely leptonic decay.
We present a calculation of the rare decay modes D^0 -> e^+ e^- gamma and D^0 -> mu^+ mu^- gamma in the framework of Standard Model. For the short distance part, we have derived QCD corrections to the Wilson coefficients involved, including C_9. The latter is found to be strongly suppressed by the corrections, leading to diminished values for the c -> u l^+l^- branching ratios in the 10^(-10) range. Within SM the exclusive decays are dominated by long distance effects. Nonresonant contributions are estimated using heavy quark and chiral symmetries to be at the level of 10%, compared to the con…
We derive bounds on leptonic double mass insertions of the type $δ^{l}_{i4} δ^{l}_{4j}$ in four generational MSSM, using the present limits on $l_i \to l_j + γ$. Two main features distinguish the rates of these processes in MSSM4 from MSSM3 : (a) tan$β$ is restricted to be very small $\lesssim 3 $ and (b) the large masses for the fourth generation leptons. In spite of small $\tanβ$, there is an enhancement in amplitudes with $llrr$($δ_{i4}^{ll}δ_{4j}^{rr}$) type insertions which pick up the mass of the fourth generation lepton, $m_{τ'}$. We find these bounds to be at least two orders of magnit…
Assuming that the axion mechanism of solving the strong CP problem does not exist and the vanishing of theta at tree level is achieved by some model-building means, we study the naturalness of having large CP-violating sources in the leptonic sector. We consider the radiative mechanisms which transfer a possibly large CP-violating phase in the leptonic sector to the theta parameter. It is found that large theta cannot be induced in the models with one Higgs doublet as at least three loops are required in this case. In the models with two or more Higgs doublets the dominant source of theta is t…
We present a method to compute, by numerical simulations of lattice QCD, the light-cone wave functions which enter exclusive processes at large momentum transfer, such as electromagnetic elastic scatterings, or exclusive semi-leptonic decays as B -> pi (B -> rho) and radiative decays as B -> K* gamma. The method is based on first principles and does not require any model assumption.
We have computed the branching ratios of the exclusive pseudoscalar (vector) + tensor modes that are allowed in the decays of the B_c meson. The dominant spectator and annihilation contributions in those decays are evaluated using the factorization hypothesis. We find that some of these decay channels, such as B_c --> (ρ^-, D_s^{*-}, D_s^{-})χ_{c2} and B_c^ -->π^- \bar{B_{s2}^{*0}}, have branching ratios of the order of 10^{-4}, which seems to be at the reach of forthcoming experiments at the LHC. The inclusive branching fraction of the two-body B_c decays involving tensor particles is approxi…
In this paper we argue that having available higher order fully exclusive Monte Carlo generator for Higgs boson production from heavy quark fusion will be mandatory for data analysis at LHC. The H to tau tau channel, a key for early discovery of the Higgs boson in the MSSM scenario, is discussed. With simplified example and for mH = 120 GeV we show, that depending on choice among presently available approaches, used for simulation of Higgs boson production from b bbar H Yukawa coupling, final acceptance for the signal events being reconstructed inside mass window may differ by a factor of 3. T…
The principal difficulty in deducing weak interaction properties from experimental measurements of $B$-decays lies in controlling the strong interaction effects. In this talk I review the status of theoretical calculations of the amplitudes for exclusive leptonic and semileptonic decays, in the latter case with special emphasis on the extraction of the $V_{cb}$ and $V_{ub}$ matrix elements.
We discuss factorization in exclusive radiative leptonic B->γeνdecays using the soft-collinear effective theory. The form factors describing these decays can be expanded in a power series in Lambda/E_γwith E_γthe photon energy. We write down the most general operators in the effective theory which contribute to the form factors at leading order in Lambda_QCD/E_γ, proving their factorization into hard, jet and soft contributions, to all orders in alpha_s.
We perform an analysis of two-body non leptonic decays of $B$ and $B_s$ mesons in the factorization approximation. We make use of the semileptonic decay amplitudes previously calculated on the basis of an effective lagrangian satisfying chiral and heavy quark symmetries and including spin 1 resonances. Exclusive semileptonic $D$-decay data are used as experimental input. Our results compare favorably with data, whenever they are available and indicate a positive value for the ratio of non leptonic coefficients $a_2/a_1$, similarly to previous studies.
We study the exclusive decays of $B\to K^{(*)}l^+l^-$ within the framework of the PQCD. We obtain the form factors for the $B\to K^{(*)}$ transitions in all allowed values of $q^2$, which agree with the lattice results. We find that our distributions of the decay rates and leptonic asymmetries are consistent with that given in the other QCD models in the literature.
We consider a scenario of Minimal Supersymmetric Standard Model (MSSM) with $R$-parity violation, where the lightest supersymmetric particle (LSP) is the lighter sbottom $(\tilde b_1)$. We study the production of a sbottom pair at the LHC and their subsequent decays through the baryon number violating $(U D D)$ operators leading to a top pair with two light quarks. Looking for both semi-leptonic and fully hadronic (no leptons) final states, we perform cut-based as well as multivariate analyses (MVA) to estimate the signal significance at the 13 TeV run of the LHC. We find that a cut-based anal…
The weak decays of $Λ_b \to Λl^{+} l^{-}$ ($l=e, μ$) are investigated in Minimal Supersymmetric Standard Model (MSSM) and also in Supersymmetric (SUSY) SO(10) Grand Unified Models. In MSSM the special attention is paid to the Neutral Higgs Bosons (NHBs) as they make quite a large contribution in exclusive $B \to X_{s} l^{+} l^{-}$ decays at large $\tanβ$ regions of parameter space of SUSY models, since part of SUSY contributions is proportional to $\tan^{3}β$. The analysis of decay rate, forward-backward asymmetries, lepton polarization asymmetries and the polarization asymmetries of $Λ$ baryo…
