Related Experiment Video
Updated: Mar 8, 2026
07:46
Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
9.0K
Revisiting Lepton Flavor Universality in B Decays
Ferruccio Feruglio1,2, Paride Paradisi1,2, Andrea Pattori1,3
1Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, I-35100 Padova, Italy.
Physical Review Letters
|January 21, 2017
Summary
Quantum effects significantly impact lepton flavor universality (LFU) in B decays. This study reveals new LFU-breaking effects in Z and tau decays, and lepton flavor violation, by incorporating previously neglected quantum corrections.
Area of Science:
- High Energy Physics
- Particle Physics
- Quantum Field Theory
Background:
- Lepton flavor universality (LFU) is a key principle in the Standard Model of particle physics.
- Previous studies on LFU in B decays have often neglected important quantum effects.
- Understanding deviations from LFU could indicate new physics beyond the Standard Model.
Purpose of the Study:
- To revisit Lepton Flavor Universality (LFU) in B decays by incorporating quantum effects.
- To investigate the impact of quantum corrections on electroweak symmetry breaking and low-energy effective Lagrangians.
- To explore potential LFU-breaking and lepton flavor-violating phenomena induced by these quantum effects.
Main Methods:
- Construction of a low-energy effective Lagrangian starting from a high energy scale Λ.
- Application of one-loop renormalization group equations (RGEs) for running effects from Λ down to the electroweak scale (v).
- Inclusion of Quantum Electrodynamics (QED) RGEs from the electroweak scale down to 1 GeV.
Main Results:
- Quantum effects significantly modify the leptonic couplings of the Z boson.
- A purely leptonic effective Lagrangian is generated due to these quantum effects.
- Large LFU-breaking effects are predicted in Z and tau decays.
- Visible lepton flavor violating effects are induced in various tau decay processes.
Conclusions:
- Quantum effects play a crucial role in B decays and lepton flavor universality.
- The study predicts observable deviations from LFU and lepton flavor violation.
- These findings provide new avenues for searching for new physics at the energy frontier.
More Related Videos
11:33All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
10.3K
05:45Capillary Electrophoresis-based Hydrogen/Deuterium Exchange for Conformational Characterization of Proteins with Top-down Mass Spectrometry
Published on: June 8, 2021
3.9K
Related Concept Videos
03:23Types of Radioactivity
20.4K
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
20.4K
01:09Electron Behavior
13.9K
Electrons are negatively charged subatomic particles attracted to and orbit around the positively-charged nucleus of an atom. They reside in spaces associated with energy levels called shells and are further organized into subshells and orbitals within each shell.
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the nucleus have less energy,...
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the nucleus have less energy,...
13.9K
00:54Electron Behavior
110.5K
Overview
Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside in locations that are associated with energy levels called shells and are further organized into sub-shells and orbitals within each shell.
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the...
Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside in locations that are associated with energy levels called shells and are further organized into sub-shells and orbitals within each shell.
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the...
110.5K
03:26Electron Configuration of Multielectron Atoms
65.9K
The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the 3s orbital, giving a 1s22s22p63s1 configuration. The electrons occupying the outermost shell orbital(s) (highest value of n) are called valence electrons, and those occupying the inner shell orbitals are called core electrons. Since the core electron shells correspond to noble gas electron configurations, we can abbreviate electron...
65.9K
01:27π Electron Effects on Chemical Shift: Overview
1.8K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.8K
01:19Thomson's e/m Experiment
7.3K
In a beam of charged particles created by a heated cathode, the particles move at different speeds. However, many applications need a beam with uniform particle speeds. An arrangement known as a velocity selector uses electric and magnetic fields to pick particles with a particular speed from the beam.
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The magnetic...
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The magnetic...
7.3K