scholarly journals Flavour violating effects of Yukawa running in SMEFT

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Jason Aebischer ◽  
Jacky Kumar
Keyword(s):  
Renormalization Group ◽  
Standard Model ◽  
Low Energy ◽  
Effective Theory ◽  
Rotation Effect ◽  
High Scale ◽  
The Standard Model ◽  
Flavour Violation ◽  
Precision Observables ◽  
Electroweak Precision

Abstract We study Yukawa Renormalization Group (RG) running effects in the context of the Standard Model Effective Theory (SMEFT). The Yukawa running being flavour dependent leads to RG-induced off-diagonal entries, so that initially diagonal Yukawa matrices at the high scale have to be rediagonalized at the electroweak (EW) scale. Performing such flavour rotations can lead to flavour violating operators which differ from the ones obtained through SMEFT RG evolution. We show, that these flavour rotations can have a large impact on low-energy phenomenology. In order to demonstrate this effect, we com- pare the two sources of flavour violation numerically as well as analytically and study their influence on several examples of down-type flavour transitions. For this purpose we con- sider $$ {B}_s-{\overline{B}}_s $$ B s − B ¯ s mixing, b → sγ, b → sℓℓ as well as electroweak precision observables. We show that the rotation effect can be comparable or even larger than the contribution from pure RGE evolution of the Wilson coefficients.

scholarly journals EFFECTIVE THEORIES AND ELECTROWEAK PRECISION CONSTRAINTS

2008 ◽  
Vol 23 (18) ◽  
pp. 2653-2685 ◽  
Author(s):  
ZHENYU HAN
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Effective Theory ◽  
Theory Method ◽  
The Standard Model ◽  
Precision Observables ◽  
Electroweak Precision ◽  
Effective Theories ◽  
Effective Operators

This is a pedagogical and self-contained review on obtaining electroweak precision constraints on TeV scale new physics using the effective theory method. We identify a set of relevant effective operators in the Standard Model and calculate from them corrections to all major electroweak precision observables. The corrections are compared with data to put constraints on the effective operators. Various approaches and applications in the literature are reviewed.

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.

scholarly journals Theory requirements for SM Higgs and EW precision physics at the FCC-ee

2021 ◽  
Vol 136 (9) ◽  
Author(s):  
S. Heinemeyer ◽  
S. Jadach ◽  
J. Reuter
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
High Precision ◽  
Boson Mass ◽  
Experimental Measurements ◽  
Mixing Angle ◽  
The Standard Model ◽  
The Status ◽  
Precision Observables ◽  
Electroweak Precision

AbstractHigh-precision experimental measurements of the properties of the Higgs boson at $$\sim 125$$ ∼ 125  GeV as well as electroweak precision observables such as the W-boson mass or the effective weak leptonic mixing angle are expected at future $$e^+e^-$$ e + e - colliders such as the FCC-ee. This high anticipated precision has to be matched with theory predictions for the measured quantities at the same level of accuracy. We briefly summarize the status of these predictions within the standard model and of the tools that are used for their determination. We outline how the theory predictions will have to be improved in order to reach the required accuracy, and also comment on the simulation frameworks for the Higgs and EW precision program.

scholarly journals Global fits of third family hypercharge models to neutral current B-anomalies and electroweak precision observables

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
B. C. Allanach ◽  
J. Eliel Camargo-Molina ◽  
Joe Davighi
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
Data Set ◽  
The Standard Model ◽  
Precision Observables ◽  
Electroweak Precision ◽  
Combined Data

AbstractWhile it is known that third family hypercharge models can explain the neutral current B-anomalies, it was hitherto unclear whether the $$Z-Z^\prime $$ Z - Z ′ mixing predicted by such models could simultaneously fit electroweak precision observables. Here, we perform global fits of several third family hypercharge models to a combination of electroweak data and those data pertinent to the neutral current B-anomalies. While the Standard Model is in tension with this combined data set with a p-value of .0007, simple versions of the models (fitting two additional parameters each) provide much improved fits. The original Third Family Hypercharge Model, for example, has a p-value of $${.065}$$ . 065 , with $$\sqrt{\Delta \chi ^2}=6.5\sigma $$ Δ χ 2 = 6.5 σ .

scholarly journals The black hole interior and the type II Weyl fermions

2018 ◽  
Vol 33 (07n08) ◽  
pp. 1850047 ◽  
Author(s):  
M. A. Zubkov
Keyword(s):  
Black Hole ◽  
Standard Model ◽  
Fermi Surface ◽  
Momentum Space ◽  
Low Energy ◽  
Effective Theory ◽  
Type Ii ◽  
The Standard Model ◽  
Weyl Semimetals ◽  
Black Hole Interior

It was proposed recently that the black hole may undergo a transition to the state, where inside the horizon the Fermi surface is formed that reveals an analogy with the recently discovered type II Weyl semimetals. In this scenario, the low energy effective theory outside of the horizon is the Standard Model, which describes excitations that reside near a certain point [Formula: see text] in momentum space of the hypothetical unified theory. Inside the horizon the low energy physics is due to the excitations that reside at the points in momentum space close to the Fermi surface. We argue that those points may be essentially distant from [Formula: see text] and, therefore, inside the black hole the quantum states are involved in the low energy dynamics that are not described by the Standard Model. We analyze the consequences of this observation for the physics of the black holes and present the model based on the direct analogy with the type II Weyl semimetals, which illustrates this pattern.

scholarly journals Semileptonic τ decays: powerful probes of non-standard charged current weak interactions

2019 ◽  
Vol 212 ◽  
pp. 08002 ◽  
Author(s):  
Pablo Roig
Keyword(s):  
Weak Interactions ◽  
High Energy ◽  
New Physics ◽  
Effective Field ◽  
Low Energy ◽  
Effective Theory ◽  
Tau Decays ◽  
The Standard Model ◽  
Precision Observables ◽  
Hadronic Tau

When looking for heavy (O(few TeV)) New Physics, the most efficient way to bene?t from both high and low-energy measurements simultaneously is the use of the Standard Model Effective Field Theory (SMEFT). In this talk I highlight the importance of semileptonic τ decays in complementing, in this respect, the traditional low-energy precision observables and high-energy measurements. This is yet another reason for considering hadronic tau decays as golden channels at Belle-II beyond the unquestionable interest of the CP violation anomaly in τ → KS πντ decays, that I also discuss within the effective theory. A couple of new results for τ−→ K− ντ decays are also included.

Sign in / Sign up

Export Citation Format

Share Document