scholarly journals Status of the Standard Model Prediction of the Muon g-2

2006 ◽  
Vol 155 (1) ◽  
pp. 365-368 ◽  
Author(s):  
M. Passera
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Standard Model Prediction ◽  
The Standard Model

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 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.

scholarly journals Effect of Systematic Uncertainty Estimation on the Muon g - 2 Anomaly

2022 ◽  
Vol 258 ◽  
pp. 09002
Author(s):  
Glen Cowan
Keyword(s):  
Standard Deviation ◽  
Standard Model ◽  
Model Prediction ◽  
Standard Model Prediction ◽  
Statistical Significance ◽  
Uncertainty Estimation ◽  
Relative Uncertainty ◽  
Systematic Uncertainties ◽  
The Standard Model ◽  
The Impact

The statistical significance that characterizes a discrepancy between a measurement and theoretical prediction is usually calculated assuming that the statistical and systematic uncertainties are known. Many types of systematic uncertainties are, however, estimated on the basis of approximate procedures and thus the values of the assigned errors are themselves uncertain. Here the impact of the uncertainty on the assigned uncertainty is investigated in the context of the muon g - 2 anomaly. The significance of the observed discrepancy between the Standard Model prediction of the muon’s anomalous magnetic moment and measured values are shown to decrease substantially if the relative uncertainty in the uncertainty assigned to the Standard Model prediction exceeds around 30%. The reduction in sensitivity increases for higher significance, so that establishing a 5σ effect will require not only small uncertainties but the uncertainties themselves must be estimated accurately to correspond to one standard deviation.

scholarly journals The Standard Model prediction for ε′/ε

2001 ◽  
Vol 617 (1-3) ◽  
pp. 441-474 ◽  
Author(s):  
E. Pallante ◽  
A. Pich ◽  
I. Scimemi
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Standard Model Prediction ◽  
The Standard Model

scholarly journals TENSION BETWEEN SCALAR/PSEUDOSCALAR NEW PHYSICS CONTRIBUTION TO Bs → μ+μ- AND B → Kμ+μ-

2010 ◽  
Vol 25 (13) ◽  
pp. 1099-1106 ◽  
Author(s):  
ASHUTOSH KUMAR ALOK ◽  
AMOL DIGHE ◽  
S. UMA SANKAR
Keyword(s):  
Standard Model ◽  
Model Prediction ◽  
Standard Model Prediction ◽  
Branching Ratio ◽  
New Physics ◽  
Strong Constraint ◽  
Maximum Value ◽  
The Standard Model ◽  
Experimental Errors ◽  
Current Bound

New physics in the form of scalar/pseudoscalar operators cannot lower the semileptonic branching ratio Br (B → K μ+μ-) below its standard model value. In addition, we show that the upper bound on the leptonic branching ratio Br (Bs → μ+μ-) sets a strong constraint on the maximum value of Br (B → K μ+μ-) in models with multiple Higgs doublets: with the current bound, Br (B → K μ+μ-) cannot exceed the standard model prediction by more than 2.5%. The conclusions hold true even if the new physics couplings are complex. However, these constraints can be used to restrict new physics couplings only if the theoretical and experimental errors in Br (B → K μ+μ-) are reduced to a few per cent. The constraints become relaxed in a general class of models with scalar/pesudoscalar operators.

scholarly journals Hadronic light-by-light scattering in the anomalous magnetic moment of the muon

2019 ◽  
Author(s):  
Nils Asmussen ◽  
Antoine Gerardin ◽  
Andreas Nyffeler ◽  
Harvey B. Meyer
Keyword(s):  
Light Scattering ◽  
Standard Model ◽  
Model Prediction ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Recent Progress ◽  
Standard Model Prediction ◽  
New Physics ◽  
The Standard Model ◽  
Discovery Potential

Hadronic light-by-light scattering in the anomalous magnetic moment of the muon a_\muaμ is one of two hadronic effects limiting the precision of the Standard Model prediction for this precision observable, and hence the new-physics discovery potential of direct experimental determinations of a_\muaμ. In this contribution, I report on recent progress in the calculation of this effect achieved both via dispersive and lattice QCD methods.

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