scholarly journals Update on SU(2) gauge theory with NF = 2 fundamental flavours.

2018 ◽  
Vol 175 ◽  
pp. 08020 ◽  
Author(s):  
Vincent Drach ◽  
Tadeusz Janowski ◽  
Claudio Pica
Keyword(s):  
Gauge Theory ◽  
Standard Model ◽  
Wide Class ◽  
Minimal Realization ◽  
Meson Spectrum ◽  
Chiral Extrapolation ◽  
Decay Constants ◽  
Composite Higgs ◽  
The Status

We present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. This theory provides a minimal template which is ideal for a wide class of Standard Model extensions featuring novel strong dynamics, such as a minimal realization of composite Higgs models. We present an update on the status of the meson spectrum and decay constants based on increased statistics on our existing ensembles and the inclusion of new ensembles with lighter pion masses, resulting in a more reliable chiral extrapolation. Preprint: CP3-Origins-2017-048 DNRF90

scholarly journals Gauge/gravity dual dynamics for the strongly coupled sector of composite Higgs models

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Johanna Erdmenger ◽  
Nick Evans ◽  
Werner Porod ◽  
Konstantinos S. Rigatos
Keyword(s):  
Gauge Theory ◽  
Chiral Symmetry Breaking ◽  
Quark Condensate ◽  
Strongly Coupled ◽  
Baryon Spectrum ◽  
Decay Constants ◽  
Composite Higgs ◽  
Higher Dimensional ◽  
Holographic Description ◽  
Gauge Gravity

Abstract A holographic model of chiral symmetry breaking is used to study the dynamics plus the meson and baryon spectrum of the underlying strong dynamics in composite Higgs models. The model is inspired by top-down D-brane constructions. We introduce this model by applying it to Nf = 2 QCD. We compute meson masses, decay constants and the nucleon mass. The spectrum is improved by including higher dimensional operators to reflect the UV physics of QCD. Moving to composite Higgs models, we impose perturbative running for the anomalous dimension of the quark condensate in a variety of theories with varying number of colors and flavours. We compare our results in detail to lattice simulations for the following theories: SU(2) gauge theory with two Dirac fundamentals; Sp(4) gauge theory with fundamental and sextet matter; and SU(4) gauge theory with fundamental and sextet quarks. In each case, the holographic results are encouraging since they are close to lattice results for masses and decay constants. Moreover, our models allow us to compute additional observables not yet computed on the lattice, to relax the quenched approximation and move to the precise fermion content of more realistic composite Higgs models not possible on the lattice. We also provide a new holographic description of the top partners including their masses and structure functions. With the addition of higher dimension operators, we show the top Yukawa coupling can be made of order one, to generate the observed top mass. Finally, we predict the spectrum for the full set of models with top partners proposed by Ferretti and Karateev.

scholarly journals A more natural composite Higgs model

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Hsin-Chia Cheng ◽  
Yi Chung
Keyword(s):  
Standard Model ◽  
Higgs Model ◽  
Quadratic Term ◽  
Beyond The Standard Model ◽  
Higgs Potential ◽  
Little Higgs ◽  
Composite Higgs ◽  
Partial Compositeness ◽  
Quartic Term ◽  
Natural Composite

Abstract Composite Higgs models provide an attractive solution to the hierarchy problem. However, many realistic models suffer from tuning problems in the Higgs potential. There are often large contributions from the UV dynamics of the composite resonances to the Higgs potential, and tuning between the quadratic term and the quartic term is required to separate the electroweak breaking scale and the compositeness scale. We consider a composite Higgs model based on the SU(6)/Sp(6) coset, where an enhanced symmetry on the fermion resonances can minimize the Higgs quadratic term. Moreover, a Higgs quartic term from the collective symmetry breaking of the little Higgs mechanism can be realized by the partial compositeness couplings between elementary Standard Model fermions and the composite operators, without introducing new elementary fields beyond the Standard Model and the composite sector. The model contains two Higgs doublets, as well as several additional pseudo-Nambu-Goldstone bosons. To avoid tuning, the extra Higgs bosons are expected to be relatively light and may be probed in the future LHC runs. The deviations of the Higgs couplings and the weak gauge boson couplings also provide important tests as they are expected to be close to the current limits in this model.

scholarly journals Testing the mechanism of lepton compositeness

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Vincenzo Afferrante ◽  
Axel Maas ◽  
René Sondenheimer ◽  
Pascal Törek
Keyword(s):  
Gauge Theory ◽  
Standard Model ◽  
Gauge Invariance ◽  
Bound States ◽  
Lattice Gauge Theory ◽  
Higgs Field ◽  
Left Handed ◽  
Lattice Gauge ◽  
The Standard Model ◽  
Weyl Fermions

Strict gauge invariance requires that physical left-handed leptons are actually bound states of the elementary left-handed lepton doublet and the Higgs field within the standard model. That they nonetheless behave almost like pure elementary particles is explained by the Fr"ohlich-Morchio-Strocchi mechanism. Using lattice gauge theory, we test and confirm this mechanism for fermions. Though, due to the current inaccessibility of non-Abelian gauged Weyl fermions on the lattice, a model which contains vectorial leptons but which obeys all other relevant symmetries has been simulated.

scholarly journals RARE DECAYS AND CP VIOLATION BEYOND THE STANDARD MODEL

2006 ◽  
Vol 21 (08n09) ◽  
pp. 1738-1749 ◽  
Author(s):  
LUCA SILVESTRINI
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Rare Decays ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Unitarity Triangle ◽  
Minimal Flavour Violation ◽  
The Standard Model ◽  
The Status ◽  
Flavour Violation

We review the status of rare decays and CP violation in extensions of the Standard Model. We analyze the determination of the unitarity triangle and the model-independent constraints on new physics that can be derived from this analysis. We find stringent bounds on new contributions to [Formula: see text] and [Formula: see text] mixing, pointing either to models of minimal flavour violation or to models with new sources of flavour and CP violation in b → s transitions. We discuss the status of the universal unitarity triangle in minimal flavour violation, and study rare decays in this class of models. We then turn to supersymmetric models with nontrivial mixing between second and third generation squarks, discuss the present constraints on this mixing and analyze the possible effects on CP violation in b → s nonleptonic decays and on [Formula: see text] mixing. We conclude presenting an outlook on Lepton-Photon 2009.

scholarly journals Lattice gauge theory for physics beyond the Standard Model

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
Richard C. Brower ◽  
◽  
Anna Hasenfratz ◽  
Ethan T. Neil ◽  
Simon Catterall ◽  
...  
Keyword(s):  
Gauge Theory ◽  
Standard Model ◽  
Lattice Gauge Theory ◽  
Beyond The Standard Model ◽  
Lattice Gauge ◽  
The Standard Model

scholarly journals The Belle II Experiment at the SuperKEKB

2019 ◽  
Vol 218 ◽  
pp. 07003
Author(s):  
Chang-Zheng Yuan
Keyword(s):  
Standard Model ◽  
Precision Measurement ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Heavy Flavor ◽  
High Precision Measurement ◽  
The Standard Model ◽  
The Status ◽  
Belle Ii ◽  
Belle Experiment

Belle II experiment at the SuperKEKB collider is a major upgrade of the Belle experiment at the KEKB asymmetric e+e− collider at the KEK. The experiment will focus on the search for new physics beyond the standard model via high precision measurement of heavy flavor decays and search for rare signals. In this talk, we present the status of the SuperKEKB collider and the Belle II detector.

scholarly journals Leptonic Decays of Heavy Quarks on the Lattice

1997 ◽  
Vol 12 (25) ◽  
pp. 4477-4538 ◽  
Author(s):  
Hartmut Wittig
Keyword(s):  
Cp Violation ◽  
Continuum Limit ◽  
Systematic Errors ◽  
Decay Constants ◽  
Leptonic Decays ◽  
The Standard Model ◽  
Lattice Calculations ◽  
The Status ◽  
Lattice Approach ◽  
The Continuum

The status of lattice calculations of heavy-light decay constants and of the B parameter BB is reviewed. After describing the lattice approach to heavy quark systems, the main results are discussed, with special emphasis on the systematic errors in present lattice calculations. A detailed analysis of the continuum limit for decay constants is performed. The implications of lattice results on studies of CP violation in the Standard Model are discussed.

scholarly journals Meson Spectrum from the Bethe-Salpeter Equation

1997 ◽  
Vol 50 (1) ◽  
pp. 95 ◽  
Author(s):  
C. J. Burden ◽  
L. Qian ◽  
C. D. Roberts ◽  
P. C. Tandy ◽  
M. J. Thomson
Keyword(s):  
Mass Spectrum ◽  
Pseudoscalar Meson ◽  
Phenomenological Model ◽  
Light Quark ◽  
Meson Spectrum ◽  
Decay Constants ◽  
Model Based ◽  
Meson Octet

We present details of a model for calculating the mass spectrum of light-quark mesons and decay constants of the pseudoscalar meson octet from a phenomenological model based on Dyson–Schwinger and Bethe–Salpeter equations. In this model the Bethe-Salpeter kernel is approximated by a separable ansatz obtained from input quark propagators.

scholarly journals Flattening the inflaton potential beyond minimal gravity

2018 ◽  
Vol 168 ◽  
pp. 06001 ◽  
Author(s):  
Hyun Min Lee
Keyword(s):  
Standard Model ◽  
Higgs Field ◽  
Gravity Models ◽  
Induced Gravity ◽  
Consistent Description ◽  
The Standard Model ◽  
Self Consistent ◽  
The Status

We review the status of the Starobinsky-like models for inflation beyond minimal gravity and discuss the unitarity problem due to the presence of a large non-minimal gravity coupling. We show that the induced gravity models allow for a self-consistent description of inflation and discuss the implications of the inflaton couplings to the Higgs field in the Standard Model.

Sign in / Sign up

Export Citation Format

Share Document