scholarly journals Leptoquarks in Flavour Physics

2018 ◽  
Vol 179 ◽  
pp. 01015 ◽  
Author(s):  
Dario Müller
Keyword(s):  
Standard Model ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Z Boson ◽  
New Physics ◽  
Experimental Results ◽  
The Standard Model ◽  
Z Boson Decays ◽  
Flavour Physics ◽  
Lepton Flavour

While the LHC has not directly observed any new particle so far, experimental results from LHCb, BELLE and BABAR point towards the violation of lepton flavour universality in b ⟶ sℓ+ and b ⟶ c-ℓν. In this context, also the discrepancy in the anomalous magnetic moment of the muon can be interpreted as a sign of lepton flavour universality violation. Here we discuss how these hints for new physics can also be explained by introducing leptoquarks as an extension of the Standard Model. Indeed, leptoquarks are good candidates to explain the anomaly in the anomalous magnetic moment of the muon because of an mg/mμ enhanced contribution giving correlated effects in Z boson decays which is particularly interesting in the light of future precision experiments.

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.

scholarly journals The Current Status of the Fermilab Muon g–2 Experiment

Universe ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 43
Author(s):  
Nandita Raha
Keyword(s):  
Standard Model ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
New Physics ◽  
Previous Measurement ◽  
Current Status ◽  
Future Outlook ◽  
The Standard Model ◽  
Very High

The anomalous magnetic moment of the muon can be both measured and computed to a very high precision, making it a powerful probe to test the Standard Model and search for new physics. The previous measurement by the Brookhaven E821 experiment found a discrepancy from the SM predicted value of about three standard deviations. The Muon g–2 experiment at Fermilab will improve the precision to 140 parts per billion compared to 540 parts per billion of E821 by increasing statistics and using upgraded apparatus. The first run of data taking has been accomplished in Fermilab, where the same level of statistics as E821 has already been attained. This paper, summarizes the current experimental status and briefly describes the data quality of the first run. It compares the statistics of this run with E821 and discusses the future outlook.

scholarly journals Explaining (g − 2)μ with multi-TeV sleptons

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Wolfgang Altmannshofer ◽  
Sri Aditya Gadam ◽  
Stefania Gori ◽  
Nick Hamer
Keyword(s):  
Standard Model ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
New Physics ◽  
Electroweak Symmetry Breaking ◽  
Higgs Bosons ◽  
Electroweak Symmetry ◽  
Flavor Changing ◽  
The Standard Model ◽  
Order Of Magnitude

Abstract We present a supersymmetric extension of the Standard Model in which the new physics contributions to the anomalous magnetic moment of the muon can be more than an order of magnitude larger than in the minimal supersymmetric Standard Model. The extended electroweak symmetry breaking sector of the model can consistently accommodate Higgs bosons and Higgsinos with O(1) couplings to muons. We find that sleptons with masses in the multi-TeV range can comfortably explain the recently confirmed discrepancy in the anomalous magnetic moment of the muon. We discuss additional phenomenological aspects of the model, including its effects on tau flavor changing decays.

scholarly journals Flavour Anomalies in a U(1) SUSY Extension of the SM

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Gauge Boson ◽  
New Physics ◽  
Low Energy ◽  
Effective Theory ◽  
The Standard Model ◽  
Meson Mixing ◽  
Additional Anomaly ◽  
Lepton Flavour

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.

Study of the semileptonic Bc → ηcτ−v̄τ decay in W′ model

2021 ◽  
Author(s):  
S. Mahata ◽  
P. Maji ◽  
S. Biswas ◽  
S. Sahoo
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Results ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Text Model

Recently, many discrepancies between the Standard Model (SM) predictions and experimental results have been found in [Formula: see text] quark transitions. Motivated by these discrepancies, we investigated the semileptonic [Formula: see text] decay in [Formula: see text] model. In this paper, we have estimated different decay observables such as branching ratio, lepton flavor universality (LFU) ratio [Formula: see text] and forward–backward asymmetry in the SM as well as in the [Formula: see text] model. In [Formula: see text] model, we find significant deviations from the SM for the observables except for the forward–backward asymmetry. This deviation gives us a possible indication of new physics (NP).

scholarly journals Recent Measurements of CP-Violation at the B-Factories

2003 ◽  
Vol 18 (30) ◽  
pp. 2083-2098
Author(s):  
Gabriella Sciolla
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
New Physics ◽  
Experimental Results ◽  
Time Dependent ◽  
The Standard Model ◽  
Substantial Progress ◽  
Cp Asymmetries

Recent measurements of time-dependent CP-asymmetries at the B-factories have led to substantial progress in our understanding of CP-violation. In this paper, we review some of these experimental results and discuss their implications in the Standard Model and their sensitivity to New Physics.

scholarly journals Search for Charged Lepton Flavour Violation at CMS

2018 ◽  
Vol 182 ◽  
pp. 02090
Author(s):  
Swagata Mukherjee
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Particle Physics ◽  
Charged Lepton ◽  
New Physics ◽  
Lepton Sector ◽  
Lepton Flavour Violation ◽  
The Standard Model ◽  
Flavour Violation ◽  
Lepton Flavour

Lepton flavour is a conserved quantity in the standard model of particle physics, but it does not follow from an underlying gauge symmetry. After the discovery of neutrino oscillation, it has been established that lepton flavour is not conserved in the neutral sector. Thus the lepton sector is an excellent place to look for New Physics, and in this perspective the Charged Lepton Flavour Violation is interesting. Various extensions of the standard model predict lepton flavour violating decays that can be observed at LHC. This report summarises several searches for lepton flavour violation with data collected by the CMS detector.

Supersymmetric Lepton Flavor Violation, the Muon Anomalous Magnetic Moment, and e- e- Colliders

2003 ◽  
Vol 18 (16) ◽  
pp. 2769-2778
Author(s):  
Graham D. Kribs
Keyword(s):  
Standard Model ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
International Workshop ◽  
Lepton Flavor Violation ◽  
Muon Anomalous Magnetic Moment ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Central Value ◽  
The Standard Model

I explain the theoretical connection between lepton flavor violation and muon g - 2 in supersymmetry1. Given any central value deviation of muon g - 2 from the standard model that is assumed to be due to weak scale supersymmetry, I show that stringent bounds on lepton flavor violating scalar masses can be extracted. These bounds are essentially independent of supersymmetric parameter space. I then briefly compare this indirect handle on supersymmetric lepton flavor violation with direct observation at a future lepton collider operating in the e- e- mode. This is a summary of a talk given at e- e-01: 4th International Workshop on Electron-Electron Interactions at TeV Energies.

scholarly journals Probing new physics scenarios of muon g − 2 via J/ψ decay at BESIII

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Gorazd Cvetič ◽  
C. S. Kim ◽  
Donghun Lee ◽  
Dibyakrupa Sahoo
Keyword(s):  
Model Prediction ◽  
Magnetic Moment ◽  
Experimental Measurement ◽  
Anomalous Magnetic Moment ◽  
Numerical Study ◽  
Standard Model Prediction ◽  
Vector Boson ◽  
New Physics ◽  
Muon Anomalous Magnetic Moment ◽  
The Standard Model

Abstract The disagreement between the standard model prediction and the experimental measurement of muon anomalous magnetic moment can be alleviated by invoking an additional particle which is either a vector boson (X1) or a scalar (X0). This new particle, with the mass mX ≲ 2mμ, can be searched for in the decay J/ψ → μ−μ+X, where X is missing. Our numerical study shows that the search is quite feasible at the BESIII experiment in the parameter space allowed by muon g − 2 measurements.

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