scholarly journals Standard model matrix elements for neutralB-meson mixing and associated decay constants

2001 ◽  
Vol 64 (9) ◽  
Author(s):  
Laurent Lellouch ◽  
C.-J. David Lin
Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.


1999 ◽  
Vol 14 (14) ◽  
pp. 2173-2203 ◽  
Author(s):  
HONG-MO CHAN ◽  
SHEUNG TSUN TSOU

Based on a non-Abelian generalization of electric–magnetic duality, the Dualized Standard Model (DSM) suggests a natural explanation for exactly three generations of fermions as the "dual colour" [Formula: see text] symmetry broken in a particular manner. The resulting scheme then offers on the one hand a fermion mass hierarchy and a perturbative method for calculating the mass and mixing parameters of the Standard Model fermions, and on the other hand testable predictions for new phenomena ranging from rare meson decays to ultra-high energy cosmic rays. Calculations to one-loop order gives, at the cost of adjusting only three real parameters, values for the following quantities all (except one) in very good agreement with experiment: the quark CKM matrix elements ‖Vrs‖, the lepton CKM matrix elements ‖Urs‖, and the second generation masses mc, ms, mμ. This means, in particular, that it gives near maximal mixing Uμ3 between νμ and ντ as observed by SuperKamiokande, Kamiokande and Soudan, while keeping small the corresponding quark angles Vcb, Vts. In addition, the scheme gives (i) rough order-of-magnitude estimates for the masses of the lowest generation, (ii) predictions for low energy FCNC effects such as KL→ eμ, and (iii) a possible explanation for the long-standing puzzle of air showers beyond the GZK cut-off. All these together, however, still represent but a portion of the possible physical consequences derivable from the DSM scheme, the majority of which are yet to be explored.


2021 ◽  
Vol 81 (3) ◽  
Author(s):  
Y. Amhis ◽  
Sw. Banerjee ◽  
E. Ben-Haim ◽  
F. U. Bernlochner ◽  
M. Bona ◽  
...  

AbstractThis paper reports world averages of measurements of b-hadron, c-hadron, and $$\tau $$ τ -lepton properties obtained by the Heavy Flavour Averaging Group using results available through September 2018. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, $$C\!P$$ C P  violation parameters, parameters of semileptonic decays, and Cabibbo–Kobayashi–Maskawa matrix elements.


2015 ◽  
Author(s):  
Tomomi Ishikawa ◽  
Taku Izubuchi ◽  
Christoph Lehner ◽  
Amarjit Soni ◽  
Yasumichi Aoki

2014 ◽  
Vol 78 ◽  
pp. 03004 ◽  
Author(s):  
P. Van Isacker

1992 ◽  
Vol 07 (27) ◽  
pp. 6833-6844 ◽  
Author(s):  
V.M. BELYAEV

The amplitude of K meson mixing is calculated. Pseudo-Goldstone fields are considered as phases of γ5 transformation of quark fields. A formalism for description of K and π mesons in this approach is given. The amplitude is expressed in terms of matrix elements [Formula: see text] and [Formula: see text]. It is shown that there is a relation between [Formula: see text] and [Formula: see text]. This relation is in good agreement with known values for amplitudes. The result for the parameter of K meson mixing is [Formula: see text]. From general consideration it is shown that the correction to the vacuum factorization hypothesis must be positive.


2008 ◽  
Vol 23 (31) ◽  
pp. 4945-4958 ◽  
Author(s):  
FRANCESCA DI LODOVICO

Flavour mixing is described within the Standard Model by the Cabibbo–Kobayashi–Maskawa (CKM) matrix elements. With the increasingly higher statistics collected by many experiments, the matrix elements are measured with improved precision, allowing for more stringent tests of the Standard Model. In this paper, a review of the current status of the absolute values of the CKM matrix elements is presented, with particular attention to the latest measurements.


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