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Ebook: CP Violation: From Quarks to Leptons
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For a long time after the discovery in 1964, by Christenson, Cronin, Fitch and Turlay, that the long-lived neutral kaon decays both into three and into two pions, which has since been taken as proof of CP violation, successive new and more precise experiments confirmed the original evidence and provided results compatible with a phenomenological description confining the CP violation to the mixing between neutral kaons and antikaons.
However the Standard Model, with three generations of quarks, linking as it does CP violation to the presence of a single non trivial phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix, implies that if CP violation exists at all, then it is a general property of weak interactions, appearing in transitions were amplitudes involving all three quark families interfere with each other, producing effects with a magnitude related to that of the CKM coefficients. This fact has stimulated an impressive amount of theoretical work leading in many cases to precise predictions. This publication reviews the field, from both the theoretical and experimental point of view, while planning for the forthcoming experimentation at LHC and considering possible new facilities for kaon, B meson and neutrino physics.
Abstracted in
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For a long time after the discovery in 1964 by Christenson, Cronin, Fitch and Turlay that the long-lived neutral kaon decays both into three and into two pions, which has since been taken as proof of CP violation, successive new and more precise experiments confirmed the original evidence and provided results compatible with a phenomenolog- ical description confining the CP violation to the mixing between neutral kaons and antikaons. However, the Standard Model, with three generations of quarks, linking as it does CP violation to the presence of a single non-trivial phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix, implies that if CP violation exists at all, then it is a general property of weak interactions, appearing in transitions where amplitudes involving all three quark families interfere with each other, producing effects with a mag- nitude related to that of the CKM coefficients.This fact has stimulated an impressive amount of theoretical work, leading in many cases to precise predictions. In parallel with the progress in the theory, more refined and much more powerful experiments have been specifically designed and performed in laboratories around the world, culminating with the construction of ad hoc accelerator facilities and detectors at Frascati, KEK and SLAC.
The first evidence for CP violation beyond the realm of kaon mixing which was intensively searched for was “direct” CP violation in the decay of neutral kaons to two pions. It took a succession of increasingly more sophisticated experiments to finally uncover it and in fact, after a first evidence in 1987 by NA31, it was firmly established only in 1999 by KTeV and NA48. In this case the theoretical complications in evaluating the effect prevent, still now, a real quantitative comparison of the experimental result with the Standard Model.
In the B meson sector, theoretical calculations are in some cases more reliable and in the last few years an extraordinary wealth of experimental results has been obtained by the BELLE and BaBar collaborations, yielding an overall impressive confirmation of the Standard Model and, at least up to now, only some possible hints of physics beyond it.
In neutrino physics, the recent discovery of flavour oscillations, with the implication that neutrinos have masses different from zero and violate lepton number conservation in their time propagation, has opened new scenarios, including the possibility of CP violation in the leptonic sector. Finally, the cosmological origin of the present unbalance between matter and antimatter in the Universe must have its roots on the violation of symmetry under CP and the explanation in terms of properties of the fundamental constituents of matter and their interactions is till today an open challenge.
Recognizing that the present was an appropriate time to review the field, from both the theoretical and experimental point of view, while planning for the forthcoming ex- perimentation at LHC and considering possible new facilities for kaon, B meson and neutrino physics, the SIF Council decided to support the proposal of devoting to CP violation the CLXIII Course of the “Enrico Fermi” International School of Physics. The task has been taken up by lecturers and seminar speakers who are leading researchers in the field. Collectively, and with the active participation of the students attending the School, a comprehensive in-depth review was critically carried out and we hope that the written version of the talks, presented in these proceedings, will serve as useful reference also for other researchers engaged or planning to enter in this exciting field of physics.
Lectures were given by H. Aihara, I. Bigi, P. Bloch, E. Blucher, A. Dolgov, J.J. Gomez-Cadenas, L. Lanceri, L. Littenberg, A. Masiero, A.I. Sanda and M.S. Sozzi, and seminars by R. Battiston, J.N. Butler, F. Costantini, A. Di Domenico, M. Giorgi, D. Hitlin, N. Ramsey and F. Bucci. We thank them all for their efforts in preparing the material for their careful and inspiring presentations, for the explanations during the discussion session and more generally for contributing to the lively atmosphere of the School. A well deserved thank is due for the timely preparation of the written text; unfortunately the written version of one of the seminars could not be included in these proceedings.
The dedicated work before, during and after the School, of the scientific secretaries Flavio Costantini and Marco Sozzi, was essential for the outcome.
Finally we thank Barbara Alzani for her invaluable help in the logistic preparation of the course and in making sure that everything went smoothly, as well as the local staff: G. Bianchi-Bazzi, R. Brigatti and L. Corengia; the help and patience of Marcella Missiroli were crucial for the completion of this volume.
Financial support to the School from INFN, the University and the Scuola Normale Superiore of Pisa is gratefully acknowledged.
M. GIORGI, I. MANNELLI AND A. I. SANDA
1. Motivation
2. Symmetries in classical physics
3. Symmetries in quantum mechanics
4. T-violating observables
5. Krammer's degeneracy
6. Some comments about symmetries in particle physics
7. Arrival of K mesons
8. Regeneration
9. Discovery of CP violation
10. Where does CP violation come from?
11. How can we detect other CP violation?
12. Watson's theorem
13. Other T-odd correlations
14. My personal recollection towards the discovery of large CP violation in B decays
1. Lecture I: Introduction of the SM*: Renormalizability, neutral currents, mass generation, GIM mechanism, CP violation à la CKM
2. Lecture II: CKM phenomenology
3. Lecture III: CP violation in B decays: The “expected” triumph of a peculiar theory
4. Lecture IV: Adding high accuracy to high sensitivity
5. Lecture V: Searching for a new paradigm in 2005 and beyond following Samuel Beckett's dictum
1. Introduction
2. Theoretical reasons for new physics
3. “Observational” reasons for new physics
4. Flavour, CP and new physics
5. MSSM and phases
6. Electric-dipole moments in the MSSM
7. Flavour-dependent CP violation
8. Phenomenology of CP violation in the MSSM
9. Solutions to the CP and SUSY flavour problems
10. Conclusions
1. Introduction
2. Kaon basics
3. CP violation
4. Measuring CP violation in the K system
5. Measuring direct CP violation
6. “Relatives” of 2π decays
7. CP violation in ks decays
8. The Bell-Steinberger relation
9. CP violation in charged K decays
10. Outlook
11. Further reading
1. Introduction
2. Lecture I: The semileptonic charge asymmetry
3. Lecture II: CPT invariance and the neutral-kaon system
4. Summary
1. Introduction and historical perspective
2. CP violation in the Standard Model
3. Time evolution of B mesons
4. Observables
5. Experimental facilities and methods
6. Searches for CP violation in B mixing
7. Direct CP violation in B decays
8. Measurements of β(π1)
9. Measurements of α(π2)
10. Measurements of γ(π3)
11. Global CKM fits
12. Bs mixing at the Tevatron
13. Conclusions and outlook
1. Introduction
2. Beyond the Standard Model
3. One-loop decays
4. Conclusions
1. Introduction
2. Radiative penguin decays: b → sγ and b → dγ
3. Electroweak penguin decays: b → sℓ+ℓ−
4. B−→τ−$\bar{\nu}$ and B−→ K−ν$\bar{\nu}$
5. Radiative leptonic decays B → ℓνγ
6. Bs0 → μ+μ− and Bd0 → μ+μ− decays
7. Conclusion
1. Introduction
2. Neutrino oscillations
3. CP violation in neutrino oscillations
4. The next generation of neutrino oscillation experiments
5. Future neutrino facilities based on a megaton water detector
6. The neutrino factory
7. Physics reach of the neutrino factory
8. Conclusions
1. Introduction
2. Dynamical or accidental?
3. Three Sakharov's conditions: discussion
4. Baryon asymmetry with broken CPT and validity of standard equilibrium distributions in CPT or T violating theories
5. General features of cosmological baryon asymmetry
6. Cosmological CP violation
7. Electroweak baryogenesis in the minimal standard model [37]
8. Baryogenesis through heavy-particle decays
9. Some more models of baryogenesis
10. Conclusion
1. Introduction
2. CPT symmetry
3. Phenomenology of the neutral-kaon system
4. The CPLEAR experiment
5. Global CPT tests in the neutral-kaon system
6. Search for T and CPT violation in B decays
7. Searches for T-odd terms in weak decays
8. Searches for Electric Dipole Moments (EDM)
9. Conclusions
1. Introduction
2. Neutron beam experiments
3. Trapped-neutron experiments
4. Atomic and molecular electric-dipole moment experiments
5. Theoretical implications
1. Prelude
2. Lento, quasi una fantasia: the early '90s
3. Andante maestoso: the new experiments
4. Coda
1. Introduction
2. Kaon interferometry ay a phi-factory
3. EPR and Bell's test with kaons
4. Decoherence and CPT violation
5. The KLOE experiment at DAΦNE
6. Measurement of the π → KSKL → π+π−π+π− decay
7. KS physics
8. Some considerations on possible backgrounds
9. Conclusions
1. Introduction
2. Analysis
3. Results
4. Conclusions
1. Introduction
2. Physics motivation
3. Why do we need more than the e+e− asymmetric B factories?
4. B physics at hadron colliders
5. Requirements for B physics experiments at hadron colliders
6. Central region vs. forward region detectors
7. B physics at general-purpose detectors at the tevatron: triggering
8. B physics at the LHC
9. Outlook
1. Introduction
2. The opportunity
3. The landscape
4. Twenty-two e+e− B factory concepts
5. Symmetric storage rings
6. Asymmetric storage rings
7. Linac-ring colliders
8. Recirculating linear colliders
9. Super B factories
10. Conclusions and outlook
1. Introduction
2. B factories measurements situation in 2005
3. Super B factory