Lecture

B-physics anomalies: data, EFT analyses, and model-building

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Description

This lecture by the instructor delves into the B-physics anomalies observed in recent data, focusing on Lepton Flavor Universality violations in semi-leptonic decays of the b quark. The anomalies are analyzed through a general Effective Field Theory (EFT) approach, leading to model-building considerations. The lecture explores the implications of the anomalies, the need for EFT Lagrangian, and the importance of FCNC and four-quark operators. The discussion also covers the LFU ratios, the role of Leptoquarks in generating effective operators, and the multi-scale picture involving flavor symmetries. The instructor concludes by highlighting the significance of the anomalies and the potential for new non-standard effects to emerge.

Official source

Ontological neighbourhood

Physics

Particle physics: Standard Model

Quantum field theory: Topics in quantum field theory

Related concepts (32)

Flavour (particle physics)

In particle physics, flavour or flavor refers to the species of an elementary particle. The Standard Model counts six flavours of quarks and six flavours of leptons. They are conventionally parameterized with flavour quantum numbers that are assigned to all subatomic particles. They can also be described by some of the family symmetries proposed for the quark-lepton generations. In classical mechanics, a force acting on a point-like particle can only alter the particle's dynamical state, i.e.

Color confinement

In quantum chromodynamics (QCD), color confinement, often simply called confinement, is the phenomenon that color-charged particles (such as quarks and gluons) cannot be isolated, and therefore cannot be directly observed in normal conditions below the Hagedorn temperature of approximately 2 terakelvin (corresponding to energies of approximately 130–140 MeV per particle). Quarks and gluons must clump together to form hadrons. The two main types of hadron are the mesons (one quark, one antiquark) and the baryons (three quarks).

Effective field theory

In physics, an effective field theory is a type of approximation, or effective theory, for an underlying physical theory, such as a quantum field theory or a statistical mechanics model. An effective field theory includes the appropriate degrees of freedom to describe physical phenomena occurring at a chosen length scale or energy scale, while ignoring substructure and degrees of freedom at shorter distances (or, equivalently, at higher energies).

Gluon field

In theoretical particle physics, the gluon field is a four-vector field characterizing the propagation of gluons in the strong interaction between quarks. It plays the same role in quantum chromodynamics as the electromagnetic four-potential in quantum electrodynamics - the gluon field constructs the gluon field strength tensor. Throughout this article, Latin indices take values 1, 2, ..., 8 for the eight gluon color charges, while Greek indices take values 0 for timelike components and 1, 2, 3 for spacelike components of four-dimensional vectors and tensors in spacetime.

Chiral symmetry breaking

In particle physics, chiral symmetry breaking is the spontaneous symmetry breaking of a chiral symmetry – usually by a gauge theory such as quantum chromodynamics, the quantum field theory of the strong interaction. Yoichiro Nambu was awarded the 2008 Nobel prize in physics for describing this phenomenon ("for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics").

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