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 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.

scholarly journals RARE FCNC-B DECAYS AT HADRON MACHINES

1993 ◽  
Vol 08 (36) ◽  
pp. 3397-3411 ◽  
Author(s):  
DAVID B. CLINE
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Cherenkov Light ◽  
Beyond The Standard Model ◽  
B Decays ◽  
Future Prospects ◽  
Novel Technique ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current

We review the current studies and future prospects for studies of Flavor Changing Neutral Current (FCNC) processes, emphasizing rare B decays. These experiments will be very sensitive to physics beyond the standard model. A key problem in these studies is the method to trigger the detector. We discuss a novel technique that uses an optical-Cherenkov light trigger to select events with significant impact parameters.

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 Status of rare exclusive B meson decays in 2018

2018 ◽  
Vol 33 (18n19) ◽  
pp. 1830016 ◽  
Author(s):  
Johannes Albrecht ◽  
Stefanie Reichert ◽  
Danny van Dyk
Keyword(s):  
B Meson ◽  
Experimental Situation ◽  
Neutral Current ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Flavor Changing ◽  
Theoretical Status ◽  
Flavor Changing Neutral Current ◽  
B Quark

This review discusses the present experimental and theoretical status of rare flavor-changing neutral current b-quark decays at the beginning of 2018. It includes a discussion of the experimental situation and details of the currently observed anomalies in measurements of flavor observables, including lepton flavor universality. Progress on the theory side within and beyond the Standard Model theory is also discussed, together with potential New Physics interpretations of the present measurements.

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.

scholarly journals Disentangling QCD and new physics in D → πℓ+ℓ−

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
New Physics ◽  
Operator Product ◽  
Beyond The Standard Model ◽  
Spectral Functions ◽  
The Standard Model ◽  
Model Independent ◽  
Weak Annihilation

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.

scholarly journals One Loop Corrections to Decay \(\tau\rightarrow \mu\gamma\) in Economical 3-3-1 Model

2015 ◽  
Vol 25 (2) ◽  
pp. 113
Author(s):  
Truong Trong Thuc ◽  
Le Tho Hue ◽  
Dinh Phan Khoi ◽  
Nguyen Thanh Phong
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Lepton Flavor ◽  
Unitary Gauge ◽  
The Standard Model ◽  
Charged Leptons

Lepton flavor violating (cLFV) decays of charged leptons such as \(\tau\rightarrow \mu\gamma\), \(\tau\rightarrow e\gamma\), \(\mu\rightarrow e\gamma\),..., are now the subjects of experiments as signals of new Physics beyond the Standard Model (SM). In the limit of the unitary gauge, we prove that contributions from one loop corrections to the above decays are very small in the framework of the economical 3-3-1 model.

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.

Study of the semileptonic Bc → ηcτ−v̄τ decay in W′ model

2021 ◽  
Author(s):  
S. Mahata ◽  
P. Maji ◽  
S. Biswas ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Results ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Text Model

Recently, many discrepancies between the Standard Model (SM) predictions and experimental results have been found in [Formula: see text] quark transitions. Motivated by these discrepancies, we investigated the semileptonic [Formula: see text] decay in [Formula: see text] model. In this paper, we have estimated different decay observables such as branching ratio, lepton flavor universality (LFU) ratio [Formula: see text] and forward–backward asymmetry in the SM as well as in the [Formula: see text] model. In [Formula: see text] model, we find significant deviations from the SM for the observables except for the forward–backward asymmetry. This deviation gives us a possible indication of new physics (NP).

scholarly journals RADIATIVE AND ELECTROWEAK RARE B DECAYS

2004 ◽  
Vol 19 (06) ◽  
pp. 934-948 ◽  
Author(s):  
M. NAKAO
Keyword(s):  
B Meson ◽  
Dominant Role ◽  
Rare Decay ◽  
Neutral Current ◽  
New Physics ◽  
Beyond The Standard Model ◽  
B Meson Decays ◽  
Meson Decays ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current

This report summarizes the latest experimental results on radiative and electroweak rare B meson decays. These rare decay processes proceed through the Flavor-Changing-Neutral-Current processes, and thus are sensitive to the postulated new particles in the theories beyond the Standard Model. Experiments at e+e- colliders, Belle, BaBar and CLEO, have been playing the dominant role, while the CDF and D0 experiments have just started to provide new results from Tevatron Run-II. The most significant achievement is the first observation of the decay B→K*ℓ+ℓ-, which opens a new window to search for new physics in B meson decays.

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