The Hierarchy Problem and New Physics Scenarios

Play an AI-generated podcast conversation about this lesson

Who originally wrote the presentation of the Standard Model in Chapters 2, 3, and 4?

Guido Altarelli

What does Chapter 2 of the book present?

The architecture of the Standard Model, the way symmetries are realized, and the way this can is described at the quantum level.

How long has the structure of the Standard Model been well-established?

Half a century or so.

What aspect of the presentation in Chapter 2 requires minimal updating?

The numerical values given for parameters, such as the Fermi coupling constant $G_F$. Signup and view all the answers

Where can the most recent and accurate values of the parameters be found?

The most recent edition of the Particle Data Book (PDG). Signup and view all the answers

Who is the author that is deceased at the time of publication?

G. Altarelli Signup and view all the answers

Where is G. Altarelli affiliated with?

University of Rome 3, Rome, Italy Signup and view all the answers

What is the main topic of Chapter 3 in the PDG?

Electroweak sector of the Standard Model Signup and view all the answers

What was the main experimental tool used to establish the success of the electroweak theory?

LEP electron-positron collider of CERN Signup and view all the answers

What is the CKM mechanism?

Mass mixing mechanism in the electroweak theory Signup and view all the answers

What was the only significant addition to the minimal version of the electroweak theory?

Neutrino mixing and non-vanishing neutrino masses Signup and view all the answers

What is the main development from the experimental point of view since the writing of the chapter?

Successful completion of the first two runs of the LHC Signup and view all the answers

What is the main surprise from the theoretical point of view in the Higgs sector of the Standard Model?

Extreme closeness of the measured Higgs mass to the critical value required for vacuum stability Signup and view all the answers

What has been the general trend in the last several years regarding the agreement between Standard Model predictions and data?

Gradual disappearance of all anomalies Signup and view all the answers

What is the hierarchy problem in physics?

The hierarchy problem refers to the question of why the Higgs boson mass is so much lighter than the Planck scale, leading to the fine-tuning of parameters in the Standard Model. Signup and view all the answers

What is the significance of the naturalness issue?

The naturalness issue suggests that the parameters in a physical theory should not require excessive fine-tuning to explain observed phenomena. Signup and view all the answers

What is the current status of new physics scenarios in supersymmetric models?

Recent updates on possible new physics scenarios in supersymmetric models can be found in Ref. Signup and view all the answers

What is the current status of new physics scenarios in non-supersymmetric models?

Recent updates on possible new physics scenarios in non-supersymmetric models can be found in Ref. Signup and view all the answers

What is the focus of Chapter 4 in the text?

Chapter 4 is devoted to the theory of strong interactions, Quantum Chromodynamics (QCD). Signup and view all the answers

What has changed over the years in the experimental status of QCD?

The experimental status of QCD has evolved from a qualitatively established theory to one that is now firmly established experimentally, although not yet tested to the same precision as the electroweak theory. Signup and view all the answers

What is the LHC?

The LHC is a hadron collider where every physical process necessarily involves the strong interaction, as it collides protons (or nuclei) and aims to study the Standard Model and search for new physics signals. Signup and view all the answers

What is one remarkable consequence of the developments discussed in the text?

It is now possible to understand in detail the structure of pure strong interaction events, in which jets of hadrons are produced in the final state, by looking inside these events and tracing their structure in terms of the fundamental fields of QCD— quarks and gluons. Signup and view all the answers

What topic has not seen much improvement in the determination of the strong coupling?

The determination of the strong coupling itself. Signup and view all the answers

Where can updated discussions on the determination of the strong coupling be found?

Updated discussions can be found in the QCD review of the PDG, as well as in Ref. Signup and view all the answers

What is likely to contribute to progress in the determination of the strong coupling?

Future, more accurate LHC data, as well as non-perturbative calculations soon expected to become competitive. Signup and view all the answers

What has been the impact of the developments discussed in the text on the Standard Model?

The developments have seen a full vindication of the Standard Model as a correct and accurate theory. Signup and view all the answers

What has been stimulated by the developments discussed in the text?

The developments have stimulated a vast number of highly sophisticated experimental and theoretical results. Signup and view all the answers

What is the structure of pure strong interaction events?

Jets of hadrons are produced in the final state. Signup and view all the answers

What are the fundamental fields of QCD?

Quarks and gluons. Signup and view all the answers

What is the accuracy on the determination of the strong coupling?

The accuracy on the determination of the strong coupling itself has not improved much. Signup and view all the answers