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.

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.

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.

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).

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.

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.

scholarly journals Search for rare leptonic B decays at the Tevatron

2005 ◽  
Vol 20 (16) ◽  
pp. 3631-3635
Author(s):  
Ralf Bernhard
Keyword(s):  
Neutral Current ◽  
Branching Ratio ◽  
B Decays ◽  
Tevatron Collider ◽  
Current Decay ◽  
Flavor Changing ◽  
Upper Limits ◽  
Flavor Changing Neutral Current ◽  
Stringent Limit ◽  
Neutral Current Decay

Results of a search for the Flavor-Changing Neutral Current decay [Formula: see text] using [Formula: see text] collision data at [Formula: see text] collected at Fermilab Tevatron collider by the CDF and DØ detectors are presented. CDF reports upper limits on [Formula: see text] and [Formula: see text] at the 95% C.L. using 171 pb-1. The DØ Collaboration used 240 pb-1 to set an even more stringent limit on the branching ratio for [Formula: see text] of 5.0 · 10-7 at the 95% C.L.

scholarly journals Lepton Flavor Violating $h\to\tau\mu$ decay induced by leptoquarks

2021 ◽  
Vol 67 (4 Jul-Aug) ◽  
pp. 040801
Author(s):  
M. A. Arroyo-Ureña ◽  
R. Gaitán ◽  
J. H. Montes de Oca ◽  
R. Sánchez-Vélez
Keyword(s):  
Neutral Current ◽  
Branching Ratio ◽  
Current Decay ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Scalar Leptoquark ◽  
Flavor Changing Neutral Current ◽  
Neutral Current Decay ◽  
The One ◽  
Analytical Expressions

The flavor changing neutral current decay $h\to\tau\mu$ is studied in a renormalizable scalar leptoquark model with no proton decay. Analytical expressions for the one-loop level contributions of a scalar leptoquark to the decay width of the process $h\to\tau\mu$ are presented. We find a viable model parameter space via the current constraints on the muon ($g-2$), the decay $\tau\to\mu\gamma$, the LHC Higgs boson data and the direct leptoquark searches at the LHC. Then, we evaluate branching ratio of the decay $h\to\tau\mu$induced by leptoquarks; we find that it is of the order of $10^{-8}-10^{-7}$ ($10^{-8}$; $10^{-9}-10^{-8}$)for a scalar leptoquark mass equal to $m_{\Omega_{5/3}}=1$ TeV ($m_{\Omega_{5/3}}=2$; $m_{\Omega_{5/3}}=10$ TeV). Finally, we evaluate the number of events produced at future hadron colliders from both the $h\to\tau\mu$ decay and the potential Standard Model background finding a potentialevidence for the $h\to\tau\mu$ decay.

scholarly journals SEMILEPTONIC $\Lambda_b\to\Lambda\nu\bar\nu$ DECAY IN THE LEPTOPHOBIC Z′ MODEL

2008 ◽  
Vol 23 (05) ◽  
pp. 347-358 ◽  
Author(s):  
B. B. ŞIRVANLI
Keyword(s):  
Z Boson ◽  
Neutral Current ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Measurements ◽  
Beyond The Standard Model ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current ◽  
Charged Leptons

We study the exclusive flavor changing neutral current process [Formula: see text] in the leptophobic Z′ model, where charged leptons do not couple to the extra Z′ boson. The branching ratio, as well as, the longitudinal, transversal and normal polarizations are calculated. It has been shown that all these physical observables are very sensitive to the existence of new physics beyond the standard model and their experimental measurements can give valuable information about it.

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