331-Z′ mediated FCNC effects on b → dμ+μ− transitions

2018 ◽  
Vol 33 (36) ◽  
pp. 1850225
Author(s):  
Soram Robertson Singh ◽  
Barilang MAWLONG
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Branching Ratio ◽  
Decay Modes ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current ◽  
Quark Level ◽  
Lepton Polarization ◽  
Text Model ◽  
New Formula

We study the rare semileptonic [Formula: see text] and [Formula: see text] decay modes mediated by the quark level [Formula: see text] transition in this paper. We analyze observables such as the differential branching ratio, lepton polarization asymmetry and forward–backward asymmetry within the standard model in the large hadronic recoil region. We then analyze these observables within the 331 or [Formula: see text] model in which a new heavy [Formula: see text] boson contributes. The effects of the [Formula: see text]-mediated flavor changing neutral current (FCNC) transitions on these modes are examined by varying the mass [Formula: see text] and the model parameter [Formula: see text]. The new [Formula: see text] couplings are constrained by flavor observables of [Formula: see text] mixing. For the obtained parameter space, we observe [Formula: see text] sensitivities of our observables of interest and deviations from standard model can range from moderate to large depending on the [Formula: see text] value.

Investigating the 331-Z′ mediated FCNC effects on b → sμ+μ− transitions

2018 ◽  
Vol 33 (21) ◽  
pp. 1850125 ◽  
Author(s):  
Soram Robertson Singh ◽  
Barilang Mawlong ◽  
Ritu D’cruz
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Branching Ratio ◽  
Decay Modes ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current ◽  
Lepton Polarization ◽  
Text Model ◽  
New Formula

The rare semileptonic [Formula: see text] and [Formula: see text] decay modes mediated by the [Formula: see text] transition are studied in this paper. We analyze observables such as the differential branching ratio, lepton polarization asymmetry and forward–backward asymmetry within the standard model in the low [Formula: see text] region. We then perform an analysis of the same modes within the 331 or [Formula: see text] model in which a new heavy [Formula: see text] boson contributes. The effects of the [Formula: see text]-mediated flavor-changing neutral current (FCNC) transitions on these modes are investigated by varying the mass [Formula: see text] and the model parameter [Formula: see text]. The new [Formula: see text] couplings are constrained by flavor observables of [Formula: see text] mixing and branching ratio of [Formula: see text]. We find that for some values of these couplings, the observables are quite sensitive to [Formula: see text] effects and deviations from Standard Model can be large.

scholarly journals Study of Bs0 → ℓ+ℓ−γ decays in a nonuniversal Z′ model

2019 ◽  
Vol 34 (09) ◽  
pp. 1950048 ◽  
Author(s):  
D. Banerjee ◽  
M. Kumar ◽  
P. Nayek ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Branching Ratio ◽  
Branching Ratios ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current ◽  
Coupling Parameters ◽  
Text Model ◽  
Boson Coupling

We investigate [Formula: see text] decays in a nonuniversal [Formula: see text] model derived from the extension of the Standard Model (SM). Considering the [Formula: see text]-mediated flavor-changing neutral current (FCNC) effects, we calculate the branching ratio and forward–backward asymmetry [Formula: see text] for [Formula: see text] decay processes. We compare the obtained results with predictions of the SM and discuss the sensitivity of the observables to [Formula: see text] boson coupling parameters. We find that the branching ratios are enhanced by one order from SM predictions in [Formula: see text] model scenario. We also observe that the variation of forward–backward asymmetry with the [Formula: see text] boson coupling parameters portrays discrimination between NP effects and SM results.

Impact of Z′ boson on lepton flavor violating decays

2019 ◽  
Vol 34 (12) ◽  
pp. 1950068
Author(s):  
P. Maji ◽  
P. Nayek ◽  
S. Sahoo
Keyword(s):  
B Meson ◽  
Neutral Current ◽  
Branching Ratio ◽  
Test Theory ◽  
Decay Channels ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current ◽  
Text Model ◽  
Three Body

Recently, some small hints of lepton flavor violating (LFV) decays have been probed in different colliders and accelerators. Although these processes are forbidden in the Standard Model (SM), observation of LFV decays are considered as good probes to test theory beyond the SM. In this paper, we study some LFV decays, e.g. three-body decay channels of [Formula: see text] lepton like [Formula: see text], [Formula: see text] and two-body decays of B meson and [Formula: see text] lepton like [Formula: see text] and [Formula: see text] in [Formula: see text] model. We calculate the branching ratio of the above decays considering the effect of both [Formula: see text] and [Formula: see text]-mediated flavor-changing neutral-current (FCNC).

THE EFFECT OF Z′-MEDIATED FLAVOR-CHANGING NEUTRAL CURRENT ON Bd→ℓ+ℓ- DECAY

2007 ◽  
Vol 22 (21) ◽  
pp. 1591-1599 ◽  
Author(s):  
S. SAHOO ◽  
L. MAHARANA
Keyword(s):  
Standard Model ◽  
Z Boson ◽  
Rare Decay ◽  
Neutral Current ◽  
Branching Ratio ◽  
New Physics ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current

We study the effect of both Z and Z′-mediated flavor-changing neutral current (FCNC) on the Bd→ℓ+ℓ-, (ℓ = μ, τ) rare decay. We find that the branching ratio can be larger by order two from its Standard Model (SM) value due to the effect of both Z and Z′-mediated FCNC, though the major contribution comes from Z boson and provides signals for new physics beyond the SM.

Lepton flavor violating decays in model

2019 ◽  
Vol 97 (12) ◽  
pp. 1270-1276
Author(s):  
P. Nayek ◽  
P. Maji ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Branching Ratios ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current ◽  
Text Model

Motivated by the hints of lepton flavor violating (LFV) decays, we study Bd,s → μτ, Bs,d → τe, and τ– → e– + e+ + e– decays in [Formula: see text] model. These LFV decays present interesting patterns that may reveal the shape of new physics beyond the standard model. Considering the effect of both Z- and [Formula: see text]-mediated flavor-changing neutral current we calculate the branching ratios for these decays. We find the branching ratios [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text].

scholarly journals PREDICTIONS FOR $B \to \tau \bar{\mu} + \mu \bar{\tau}$

2013 ◽  
Vol 28 (31) ◽  
pp. 1350153 ◽  
Author(s):  
DRIS BOUBAA ◽  
ALAKABHA DATTA ◽  
MURUGESWARAN DURAISAMY ◽  
SHAABAN KHALIL
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Neutral Current ◽  
Higgs Sector ◽  
New Physics ◽  
Flavor Changing ◽  
Clear Sign ◽  
Flavor Changing Neutral Current ◽  
Extended Higgs Sector

The observation of [Formula: see text] at present experiments would be a clear sign of new physics. In this paper, we calculate this process in an extended Higgs sector framework where the decay is mediated by the exchange of spin zero particle with flavor changing neutral current couplings. If we identify the scalar with the newly discovered state at LHC with a mass ~125 GeV then we find that, after imposing all experimental constraints, the [Formula: see text] can be as high as ~10-6 and [Formula: see text] can be as high as ~10-7. We also calculate this process in the minimal supersymmetric standard model and find the [Formula: see text] is typically of the order ~10-8.

scholarly journals FLAVOR VIOLATION IN A MINIMAL SO(10)×A4 SUSY GUT

2012 ◽  
Vol 27 (01) ◽  
pp. 1250005 ◽  
Author(s):  
ABDELHAMID ALBAID
Keyword(s):  
Neutral Current ◽  
Branching Ratio ◽  
Flavor Violation ◽  
Flavor Changing ◽  
Fermion Masses ◽  
Fermion Fields ◽  
Experimental Constraint ◽  
Flavor Changing Neutral Current ◽  
High Degree ◽  
Light Fermion

Flavor violating processes in the quark and lepton sectors are investigated within a realistic supersymmetric SO(10)×A4 grand unification model. By employing exotic heavy fermion fields, this model successfully describes various features of the fermion masses and mixings including large neutrino mixings accompanied by small quark mixings. In this model the flavor violation is induced at GUT scale, at which A4 flavor symmetry is broken, as a consequence of the large mixings of the light fermion fields with these exotic heavy fields. The stringent experimental constraint from μ→eγ decay rate necessitates a high degree of degeneracy of the supersymmetry breaking soft scalar masses of the exotic heavy fields and supersymmetric scalar partners of the light fermion fields. The choice of slepton masses of order 1 TeV is found to be consistent with the constraints from branching ratio of μ→eγ and with all other flavor changing neutral current processes being sufficiently suppressed.

A search for A b′ quark with flavor changing neutral current decay modes at TRISTAN

1990 ◽  
Vol 234 (1-2) ◽  
pp. 197-201 ◽  
Author(s):  
I. Adachi ◽  
H. Aihara ◽  
M. Doser ◽  
R. Enomoto ◽  
H. Fujii ◽  
...  
Keyword(s):  
Neutral Current ◽  
Decay Modes ◽  
Current Decay ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current ◽  
Neutral Current Decay ◽  
B Quark

Study of Λb → Λℓ+ℓ− (ℓ = e,μ,τ) decays in the G(221) model

2016 ◽  
Vol 31 (36) ◽  
pp. 1650197
Author(s):  
Shuai-Wei Wang
Keyword(s):  
Sum Rules ◽  
Branching Ratio ◽  
Form Factors ◽  
New Physics ◽  
Tree Level ◽  
Decay Channels ◽  
Flavor Changing ◽  
The Standard Model ◽  
Lepton Polarization ◽  
Text Model

We study respectively the baryonic semilepton decays [Formula: see text][Formula: see text] in the [Formula: see text] model, which includes the tree-level flavor-changing-neutral-currents (FCNCs) induced by [Formula: see text] and [Formula: see text] bosons and modifies the Wilson coefficients [Formula: see text] and [Formula: see text]. For the form factors, we use the results of QCD light-cone sum rules (LCSR) in the low [Formula: see text] region and lattice QCD in the high [Formula: see text] region, respectively. We consider the effects of this new physics (NP) model on some measured physical observables, like the differential branching ratio, the longitudinal polarization of the dilepton system, the lepton-side forward–backward asymmetry and the baryon-side forward–backward asymmetry, and find, obvious differences occur in some observables between the Standard Model (SM) and this NP model. Meanwhile, we also discuss the double lepton polarization asymmetries of these decay channels, and find, [Formula: see text], [Formula: see text] and [Formula: see text] of these decay channels are sensitive to the contribution of this NP model.

scholarly journals Lepton flavor violating decays of B and K mesons in models with extended gauge group

2018 ◽  
Vol 33 (14n15) ◽  
pp. 1850087 ◽  
Author(s):  
Fayyazuddin ◽  
Muhammad Jamil Aslam ◽  
Cai-Dian Lu
Keyword(s):  
Gauge Group ◽  
Particle Physics ◽  
Neutral Current ◽  
Representation Formula ◽  
Decay Modes ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Effective Lagrangian ◽  
Flavor Changing Neutral Current ◽  
Promising Area

Lepton flavor violating (LFV) decays are forbidden in the Standard Model (SM) and to explore them one has to go beyond it. The flavor changing neutral current induced lepton flavor conserving and LFV decays of [Formula: see text] and [Formula: see text] mesons is discussed in the gauge group [Formula: see text]. The lepto-quark [Formula: see text] corresponding to gauge group [Formula: see text] allows the quark–lepton transitions and hence giving a framework to construct the effective Lagrangian for the LFV decays. The mass of lepto-quark [Formula: see text] provides a scale at which the gauge group [Formula: see text] is broken to the SM gauge group. Using the most stringent experimental limit [Formula: see text], the upper bound on the effective coupling constant [Formula: see text] is obtained for certain pairing of lepton and quark generations in the representation [Formula: see text] of the group [Formula: see text]. Later, the effective Lagrangian for the LFV meson decays for the gauge group [Formula: see text] is constructed. Using [Formula: see text], the bound on the ratio of effective couplings is obtained to be [Formula: see text]. A number of decay modes are discussed which provide a promising area to test this model in the current and future particle physics experiments.

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