CP ASYMMETRIES IN B0DECAYS BEYOND THE STANDARD MODEL

1991 ◽  
Vol 06 (08) ◽  
pp. 1253-1266 ◽  
Author(s):  
CLAUDIO O. DIB ◽  
DAVID LONDON ◽  
YOSEF NIR

Of the many ingredients of the Standard Model that are relevant to the analysis of CP asymmetries in B0 decays, some are likely to hold even beyond the Standard Model while others are sensitive to new physics. Consequently, certain predictions are maintained while others may show dramatic deviations from the Standard Model. Many classes of models may show clear signatures when the asymmetries are measured: four quark generations, Z-mediated flavor-changing neutral currents, supersymmetry and “real superweak” models. On the other hand, models of left-right symmetry and multi-Higgs sectors with natural flavor conservation are unlikely to modify the Standard Model predictions.

2009 ◽  
Vol 24 (32) ◽  
pp. 6223-6235 ◽  
Author(s):  
S. SAHOO ◽  
C. K. DAS ◽  
L. MAHARANA

We study the effect of both Z and Z′ mediated flavor-changing neutral currents (FCNCs) on the Λb→Λℓ+ℓ-(ℓ = μ, τ) rare decay. We find the branching ratio is reasonably enhanced from its Standard Model value due to the effect of both Z and Z′ mediated FCNCs, and gives the possibility of new physics beyond the Standard Model. The contribution of Z′ boson depends upon the precise value of MZ′.


2011 ◽  
Vol 26 (20) ◽  
pp. 3347-3356 ◽  
Author(s):  
S. SAHOO ◽  
C. K. DAS ◽  
L. MAHARANA

[Formula: see text] mixing offers a profound probe into the effects of new physics beyond the Standard Model. In this paper, [Formula: see text] and [Formula: see text] mass differences are considered taking the effect of both Z- and Z′-mediated flavor-changing neutral currents in the [Formula: see text] mixing (q = d, s). Our estimated mass of Z′ boson is accessible at the experiments LHC and B-factories in near future.


2019 ◽  
Vol 222 ◽  
pp. 01007 ◽  
Author(s):  
Dmitri Melikhov

Rare B-decays induced by flavour-changing neutral currents (FCNC) is one of the promising candidates for probing physics beyond the Standard model. However, for identifying potential new physics from the data, reliable control over QCD contributions is necessary. We focus on one of such QCD contributions – the charming loops – that potentially can lead to difficulties in disentangling new physics effects from the observable and discuss the possibility to gain control over theoretical predictions for charming loops.


1990 ◽  
Vol 05 (05) ◽  
pp. 337-347
Author(s):  
DAVID LONDON

The standard model predictions for CP violating hadronic decay asymmetries are presented in the form of probability distributions. From these distributions, it can be easily seen what the most likely values of these quantities are, which measurements would clearly be signs of new physics, and which values of the CP asymmetries would most constrain the parameters of the standard model.


2001 ◽  
Vol 16 (28) ◽  
pp. 4547-4565 ◽  
Author(s):  
YUE-LIANG WU ◽  
YU-FENG ZHOU

The measurement of sin 2β is discussed within and beyond the standard model. In the presence of new physics, the angle β extracted from the global fit (denoted by [Formula: see text]) and the one extracted from B→J/ψKS(denoted by βJ/ψ) are in general all different from the "true" angle β which is the weak phase of CKM matrix element [Formula: see text]. Possible new physics effects on the ratio [Formula: see text] is studied and parametrized in a most general form. It is shown that the ratio Rβmay provide a useful tool in probing new physics. The experimental value of Rβis obtained through an update of the global fit of the unitarity triangle with the latest data and found to be less than unity at 1σ level. The new physics effects on Rβfrom the models with minimum flavor violation (MFV) and the standard model with two-Higgs-doublet (S2HDM) are studied in detail. It is found that the MFV models seem to give a relative large value Rβ≥1. With the current data, this may indicate that this kind of new physics may be disfavored and alternative new physics with additional phases appears more relevant. As an illustration for models with additional phase beyond CKM phase, the S2HDM effects on Rβare studied and found to be easily coincide with the data due to the flavor changing neutral Higgs interaction.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Nanako Shitara ◽  
Nodoka Yamanaka ◽  
Bijaya Kumar Sahoo ◽  
Toshio Watanabe ◽  
Bhanu Pratap Das

Abstract We report theoretical results of the electric dipole moment (EDM) of 210Fr which arises from the interaction of the EDM of an electron with the internal electric field in an atom and the scalar-pseudoscalar electron-nucleus interaction; the two dominant sources of CP violation in this atom. Employing the relativistic coupled-cluster theory, we evaluate the enhancement factors for these two CP violating interactions to an accuracy of about 3% and analyze the contributions of the many-body effects. These two quantities in combination with the projected sensitivity of the 210Fr EDM experiment provide constraints on new physics beyond the Standard Model. Particularly, we demonstrate that their precise values are necessary to account for the effect of the bottom quark in models in which the Higgs sector is augmented by nonstandard Yukawa interactions such as the two-Higgs doublet model.


2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Damir Bečirević ◽  
Svjetlana Fajfer ◽  
Nejc Košnik ◽  
Aleks Smolkovič

AbstractWe show that the current values of $$R_K^\mathrm {exp}$$ R K exp and $$R_{K^*}^\mathrm {exp}$$ R K ∗ exp can be accommodated by allowing a nonzero New Physics coupling $$\delta C_9^{\mu \mu }$$ δ C 9 μ μ to be complex, both in the scenario in which only $$\delta C_9^{\mu \mu }$$ δ C 9 μ μ is affected, and in the scenario with complex $$\delta C_{9,10}^{\mu \mu }$$ δ C 9 , 10 μ μ satisfying $$\delta C_{9}^{\mu \mu }=-\delta C_{10}^{\mu \mu }$$ δ C 9 μ μ = - δ C 10 μ μ . A presence of the weak CP-violating phase can then be tested by measuring the CP-asymmetry, $$\mathcal {A}_\mathrm {CP}$$ A CP . We show that this asymmetry is enhanced around the peak of each $$c\bar{c}$$ c c ¯ -resonance, and in fact more pronounced in the close vicinity of $$J/\psi $$ J / ψ and $$\psi (2S)$$ ψ ( 2 S ) . Therefore, measuring $$\mathcal {A}_\mathrm {CP}$$ A CP before and after the resonances’ peak could be revelatory of the CP-violation that originates from beyond the Standard Model, or to be a significant constrain when building a realistic scenario of New Physics.


2018 ◽  
Vol 175 ◽  
pp. 01004
Author(s):  
Arantza Oyanguren

The LHCb collaboration has provided a plethora of precise measurements of flavour observables in the last years. In the B meson sector some of these results show consistent deviations from Standard Model predictions with a clear tendency to specific New Physics scenarios. B decay anomalies are found in particular related to lepton flavour universality tests and angular observables in Flavour-Changing-Neutral-Current transitions. I review here the LHCb measurements and their experimental caveats. Results from Lattice are crucial in the coming years to verify if these anomalies are explained by QCD effects or if they are unambiguous hints of physics beyond the Standard Model.


2004 ◽  
Vol 19 (06) ◽  
pp. 907-917 ◽  
Author(s):  
Y. GROSSMAN

In the first part of the talk the flavor physics input to models beyond the Standard Model is described. One specific example of such a new physics model is given: a model with bulk fermions in one non-factorizable extra dimension. In the second part of the talk we discuss several observables that are sensitive to new physics. We explain what type of new physics can produce deviations from the Standard Model predictions in each of these observables.


1990 ◽  
Vol 05 (24) ◽  
pp. 1947-1949 ◽  
Author(s):  
ROBERT FOOT

In extended gauge models with gauge group G, electric charge quantization is not always an automatic consequence of the consistency of the theory. Exotic fermions which have SU (3) ⊗ SU (2) L ⊗ U (1) invariant mass terms can provide a simple method for preserving the charge quantization feature of the standard model. This procedure is applied to the segregated isospin model.This approach indicates that precision measurements of the τ-lepton life-time and rare flavor-changing neutral processes may provide the first indications of new physics beyond the standard model.


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