B anomalies with unparticles

2021 ◽  
Vol 36 (30) ◽  
Author(s):  
Jong-Phil Lee
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
The Standard Model ◽  
Model Predictions ◽  
Best Fit

We analyze the [Formula: see text] anomalies associated with the [Formula: see text] decays in the unparticle model. The fraction of the branching ratios [Formula: see text] and other parameters related to the polarization are fitted to the experimental data by minimizing [Formula: see text]. The best-fit values are [Formula: see text] and [Formula: see text] which are still larger than the standard model predictions. We find that our results safely render the branching ratio [Formula: see text] below [Formula: see text].

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.

Unparticle effects on B → D(∗)τν

2019 ◽  
Vol 34 (19) ◽  
pp. 1950149
Author(s):  
Jong-Phil Lee
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Results ◽  
The Standard Model ◽  
Best Fit

We examine the possible unparticle effects on [Formula: see text] associated with [Formula: see text] decays by minimum-[Formula: see text] fitting. Recent measurements from Belle and LHCb are included in this analysis. While it is true that the new experimental results of [Formula: see text] get closer to the Standard Model (SM) predictions, there is still room for new physics and unparticles are also one possibility. Our best-fit values are [Formula: see text] and [Formula: see text], which are still far from the SM values by more than [Formula: see text] or almost [Formula: see text] [Formula: see text]. We also find that the unparticle effects are quite safe to render the branching ratio [Formula: see text] less than 10%.

scholarly journals A COMPARATIVE STUDY ON B →K*ℓ+ ℓ- AND $B \to K_0^\ast (1430) \ell^+ \ell^-$ DECAYS IN THE SUPERSYMMETRIC MODELS

2011 ◽  
Vol 26 (12) ◽  
pp. 901-911 ◽  
Author(s):  
V. BASHIRY ◽  
M. BAYAR ◽  
K. AZIZI
Keyword(s):  
Standard Model ◽  
Comparative Study ◽  
Scalar Meson ◽  
Branching Ratio ◽  
Mass Region ◽  
P Wave ◽  
Muon Channel ◽  
The Standard Model ◽  
Model Predictions ◽  
Supersymmetric Models

In this paper, we compare the branching ratio and rate difference of electron channel to muon channel of [Formula: see text] and B →K*ℓ+ℓ- decays, where [Formula: see text] is the p-wave scalar meson, in the supersymmetric models. MSSM with R parity is considered since considerable deviation from the standard model predictions can be obtained in B→Xs ℓ-ℓ+. Taking CQ1 and CQ2 about one which is consistent with the B→K*μ+μ- rate at low dileptonic invariant mass region (1 ≤ q2 ≤ 6 GeV 2). It is found that, firstly, the [Formula: see text] decay is measurable at LHC, secondly, in comparison with B →K*ℓ+ ℓ- decay a greater deviation in the [Formula: see text] decay can be seen. Measurement of these observables for the semileptonic rare [Formula: see text], in particular, at low q2 region can give valuable information about the nature of interactions within Standard Model or beyond.

scholarly journals Impact of Scalar Leptoquarks on Heavy Baryonic Decays

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
K. Azizi ◽  
A. T. Olgun ◽  
Z. Tavukoğlu
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Lattice Qcd ◽  
Light Cone ◽  
Branching Ratio ◽  
Form Factors ◽  
Full Theory ◽  
The Standard Model ◽  
The Impact ◽  
Scalar Leptoquarks

We present a study on the impact of scalar leptoquarks on the semileptonic decays of Λb, Σb, and Ξb. To this end, we calculate the differential branching ratio and lepton forward-backward asymmetry defining the processes Λb→Λl+l-, Σb→Σl+l-, and Ξb→Ξl+l-, with l being μ or τ, using the form factors calculated via light cone QCD in full theory. In calculations, the errors of form factors are taken into account. We compare the results obtained in leptoquark model with those of the standard model as well as the existing lattice QCD predictions and experimental data.

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 BARYONIC DECAYS Λb → Λl+l- IN THE TTM MODEL

2013 ◽  
Vol 28 (17) ◽  
pp. 1350075 ◽  
Author(s):  
YAN-LI WEN ◽  
CHONG-XING YUE ◽  
JIAO ZHANG
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Rare Decays ◽  
Form Factors ◽  
Branching Ratios ◽  
Wide Range ◽  
The Standard Model ◽  
Model Predictions ◽  
Order Of Magnitude ◽  
Transversal Polarization

In the framework of the top triangle moose model, we analyze the rare decays Λb → Λl+l-(l = e, μ, τ) by using the form factors calculated in full QCD. We calculate the contributions of the new particles predicted by this model to observables, such as the branching ratios, forward–backward asymmetry (A FB ) and polarizations related these decay processes. We find that, in wide range of the parameter space, the values of the branching ratios are enhanced by one order of magnitude comparing to the standard model predictions. This model can also produce significant corrections to A FB , normal polarization PN and transversal polarization PT.

NON-STANDARD HIGGS BOSON AND THE DECAY KL→π0l+l−

1988 ◽  
Vol 03 (17) ◽  
pp. 1677-1682 ◽  
Author(s):  
M.I. DOBROLIUBOV ◽  
A. YU. IGNATIEV
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
Upper Bounds ◽  
The Standard Model

We investigate various mechanisms of enhancement of the branching ratios of the decay KL→π0l+l− as compared to the predictions of the Standard Model. We propose a model with several Higgs doublets, which contains a Higgs boson with nearly equal couplings to e+e− and µ+µ− pairs. In this model, the branching ratio BR (KL→π0e+e−, π0µ+µ−) can be close to the present experimental upper bounds.

scholarly journals Relativistic calculations of R(D(∗)), R(Ds(∗)), R(ηc) and R(J/ψ)

2020 ◽  
Vol 35 (17) ◽  
pp. 2050076
Author(s):  
Tian Zhou ◽  
Tianhong Wang ◽  
Yue Jiang ◽  
Xiao-Ze Tan ◽  
Geng Li ◽  
...  
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Relativistic Correction ◽  
New Physics ◽  
Decay Rates ◽  
The Standard Model ◽  
Model Predictions

Recently, the deviation of the ratios [Formula: see text], [Formula: see text] and [Formula: see text] have been found between experimental data and the Standard Model predictions, which may be the hint of new physics. In this work, we calculate these ratios within the Standard Model by using the improved instantaneous Bethe–Salpeter method. The emphasis is pad to the relativistic correction of the form factors. The results are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], which are consistent with predictions of other models and the experimental data. The semileptonic decay rates and corresponding form factors at zero recoil are also given.

scholarly journals Alleviating the B̄ → Dτντ and B̄ → D∗τντ puzzle in the MSSM

2019 ◽  
Vol 34 (32) ◽  
pp. 1950209
Author(s):  
Dris Boubaa ◽  
Shaaban Khalil ◽  
Stefano Moretti
Keyword(s):  
Standard Model ◽  
Branching Ratios ◽  
Current Data ◽  
The Standard Model ◽  
Model Predictions ◽  
Theoretical Predictions ◽  
Sneutrino Mass ◽  
Sizeable Increase

We show that Supersymmetric effects driven by penguin contributions to the [Formula: see text] transition are able to account simultaneously for a sizeable increase of both branching ratios of [Formula: see text] and [Formula: see text] with respect to the Standard Model predictions, thereby approaching their experimentally measured values. We emphasize that a light chargino and neutralino, with masses less than 300 GeV, in addition to a large stau/sneutrino mass and a large [Formula: see text], are essential for enhancing the effect of the lepton penguin [Formula: see text], which is responsible for the improved theoretical predictions with respect to current data.

scholarly journals Study of the rare decays Bs,d∗→ l+l− in Z′ model

2017 ◽  
Vol 32 (14) ◽  
pp. 1750075 ◽  
Author(s):  
Debika Banerjee ◽  
Priya Maji ◽  
Sukadev Sahoo
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Rare Decays ◽  
Branching Ratio ◽  
Branching Ratios ◽  
New Physics ◽  
Leptonic Decays ◽  
The Standard Model ◽  
Text Model ◽  
Vector Formula

The rare decays [Formula: see text] are important to probe the flavor sector of the standard model and to search new physics beyond the SM. Unlike pseudoscalar [Formula: see text] meson, the leptonic decays of vector [Formula: see text] mesons are not chirally suppressed which compensates for their short lifetimes, and results in significant branching ratios. In this paper, we estimate the branching ratios of [Formula: see text][Formula: see text] rare decays in [Formula: see text] model which is an extension of the SM with an extra [Formula: see text] gauge symmetry. We find that the branching ratios are increased from their corresponding standard model values and vary with the mass of [Formula: see text] boson. The lower the mass of [Formula: see text] boson, the higher is the branching ratio.

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