scholarly journals Tests of the Standard Model and constraints on new physics from measurements of fermion-pair production at 183 GeV at LEP

1999 ◽  
Vol 6 (1) ◽  
pp. 1-18 ◽  
Author(s):  
G. Abbiendi et al. ◽  
2006 ◽  
Vol 49 (2) ◽  
pp. 411-437 ◽  
Author(s):  
S. Schael ◽  
◽  
R. Barate ◽  
R. Brunelière ◽  
I. De Bonis ◽  
...  

2016 ◽  
Vol 40 ◽  
pp. 1660078
Author(s):  
Torben Ferber

The Standard Model predicts interference effects between [Formula: see text] and [Formula: see text] boson exchange in fermion pair production which cause a forward–backward asymmetry [Formula: see text] even for energies well below the [Formula: see text]–pole. This energy–dependent asymmetry ([Formula: see text] at 10.58[Formula: see text]GeV) is proportional to the SM [Formula: see text] parameter and can be measured at the Belle and Belle[Formula: see text]II experiments. The sensitivity to New Physics as well as theoretical and experimental challenges are described.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Jason Aebischer ◽  
Benjamín Grinstein

Abstract Applying an operator product expansion approach we update the Standard Model prediction of the Bc lifetime from over 20 years ago. The non-perturbative velocity expansion is carried out up to third order in the relative velocity of the heavy quarks. The scheme dependence is studied using three different mass schemes for the $$ \overline{b} $$ b ¯ and c quarks, resulting in three different values consistent with each other and with experiment. Special focus has been laid on renormalon cancellation in the computation. Uncertainties resulting from scale dependence, neglecting the strange quark mass, non-perturbative matrix elements and parametric uncertainties are discussed in detail. The resulting uncertainties are still rather large compared to the experimental ones, and therefore do not allow for clear-cut conclusions concerning New Physics effects in the Bc decay.


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