scholarly journals Updated Standard Model Prediction for $K \to \pi \nu \bar{\nu}$ and $\epsilon_K$

2021 ◽  
Author(s):  
Martin Gorbahn ◽  
Joachim Brod ◽  
Emmanuel Stamou
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Standard Model Prediction

scholarly journals Standard Model prediction of the Bc lifetime

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Jason Aebischer ◽  
Benjamín Grinstein
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Strange Quark ◽  
Standard Model Prediction ◽  
New Physics ◽  
Operator Product ◽  
Special Focus ◽  
Third Order ◽  
Clear Cut ◽  
The Standard Model

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.

scholarly journals Standard Model Prediction for DirectCPViolation inK→ππDecay

2015 ◽  
Vol 115 (21) ◽  
Author(s):  
Z. Bai ◽  
T. Blum ◽  
P. A. Boyle ◽  
N. H. Christ ◽  
J. Frison ◽  
...  
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Standard Model Prediction

scholarly journals Update on the hadronic vacuum polarisation contributions to muon g − 2 and α(mZ2)

2019 ◽  
Vol 218 ◽  
pp. 01002
Author(s):  
Zhiqing Zhang
Keyword(s):  
Standard Model ◽  
Magnetic Anomaly ◽  
Cross Section ◽  
Model Prediction ◽  
Standard Model Prediction ◽  
Boson Mass ◽  
Cross Section Data ◽  
Section Data ◽  
Hadronic Contribution ◽  
Vacuum Polarisation

An update of the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic couplings constant at the Z-boson mass is presented. Newest e+e−→ hadrons cross-section data mainly from the BABAR and VEPP-2000 experiments have been included. For the muon (g−2)/2, the lowest-order hadronic contribution is evaluated to be (693.1 ± 3.4) · 10−10, improving the precision of our previous evaluation by 21%. The full Standard Model prediction differs by 3.5 σ from the experimental value. The five-quark hadronic contribution to $ \alpha (\mathop m\nolimits_z^2 ) $ is evaluated to be (276.0 ± 0.9) · 10−4.

scholarly journals Possible bilepton resonances in like-sign pairs

2019 ◽  
Vol 34 (10) ◽  
pp. 1950076 ◽  
Author(s):  
Claudio Corianò ◽  
Paul H. Frampton
Keyword(s):  
Standard Model ◽  
Pair Production ◽  
Model Prediction ◽  
Standard Model Prediction ◽  
Mass Range ◽  
Entire Mass Range ◽  
Large Ratio ◽  
The Standard Model ◽  
Integrated Luminosity

We consider pair production of bileptons Y[Formula: see text]Y[Formula: see text] at the LHC for the presently accumulated integrated luminosity of 150/fb. It is shown that the entire mass range 800 GeV [Formula: see text]M(Y) [Formula: see text] 2000 GeV can be successfully searched. A bilepton resonance will have an exceptionally large ratio of signal to background because the Standard Model prediction is so infinitesimal. A 5[Formula: see text] discovery is quite feasible.

scholarly journals Form Factor Measurements at BESIII for an Improved Standard Model Prediction of the Muon g-2

2018 ◽  
Vol 46 ◽  
pp. 1860026
Author(s):  
Marco Destefanis
Keyword(s):  
Form Factor ◽  
Standard Model ◽  
Model Prediction ◽  
Particle Physics ◽  
Standard Model Prediction ◽  
Final States ◽  
Direct Measurements ◽  
The Standard Model ◽  
Data Driven Approach

The anomalous part of the magnetic moment of the muon, (g-2)[Formula: see text], allows for one of the most precise tests of the Standard Model of particle physics. We report on recent results by the BESIII Collaboration of exclusive hadronic cross section channels, such as the 2[Formula: see text], 3[Formula: see text], and 4[Formula: see text] final states. These measurements are of utmost importance for an improved calculation of the hadronic vacuum polarization contribution of (g-2)[Formula: see text], which currenty is limiting the overall Standard Model prediction of this quantity. BESIII has furthermore also intiatated a programme of spacelike transition form factor measurements, which can be used for a determination of the hadronic light-by-light contribution of (g-2)[Formula: see text] in a data-driven approach. These results are of relevance in view of the new and direct measurements of (g-2)[Formula: see text] as foreseen at Fermilab/USA and J-PARC/Japan.

scholarly journals THEORY OF THE τ LEPTON ANOMALOUS MAGNETIC MOMENT

2007 ◽  
Vol 22 (03) ◽  
pp. 159-179 ◽  
Author(s):  
S. EIDELMAN ◽  
M. PASSERA
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Standard Model Prediction ◽  
Low Energy ◽  
Leading Order ◽  
The Standard Model

This paper reviews and updates the Standard Model prediction of the τ lepton g-2. Updated QED and electroweak contributions are presented, together with new values of the leading-order hadronic term, based on the recent low energy e+ e- data from BaBar, CMD-2, KLOE and SND, and hadronic light-by-light contribution. The total prediction is confronted to the available experimental bounds on the τ lepton anomaly, and prospects for its future measurements are briefly discussed.

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