The coming flavour precision era will allow to uncover various patterns of flavour violation in different New Physics (NP) scenarios that are presently washed out by hadronic and experimental uncertainties. We illustrate this by performing the anatomy of flavour violation in the 331 models, based on the gauge group SU(3)_C X SU(3)_L X U(1)_X that are among the simplest NP scenarios with new sources of flavour and CP violation. The latter originate dominantly through the flavour violating interactions of ordinary quarks and leptons with a new heavy Z' gauge boson. After discussing first these models in some generality, we present a detailed study of Delta F=2 observables and of rare K and B meson decays in the specific beta=1/\sqrt{3} model (to be called overline{331} model) assuming significantly smaller uncertainties in CKM and hadronic parameters than presently available. The most prominent roles in our analysis play epsilon_K, Delta M_q (q=d,s), the mixing induced CP asymmetries S_{psi K_S} and S_{psi phi}, rare decays B_{s,d}-> mu^+ mu^- and in particular the CP-asymmetry S_{mu^+ mu^-}^s in B_s ->mu^+ mu^-. We identify a number of correlations between various observables that differ from those known from CMFV models. While, the Delta F=2 observables allow still for four oases in the new parameter space, we demonstrate how the inclusion of Delta F=1 observables can in the future identify the optimal oasis for this model. For 1 TeV <= M_{Z'}<= 3 TeV the overline{331} model is in good agreement with the recent data for B^+->tau^+ nu_tau, it removes the epsilon_K-S_{psi K_S} tension present in the SM and the epsilon_K-Delta M_{s,d} tension present in CMFV models. Simultaneously, while differing from the SM, it is consistent with the present data on BR(B_{s,d}->mu^+ mu^-) and S_{psi phi}. We identify the triple correlation BR(B_s->mu^+ mu^-)-S_{psi phi}-S_{mu^+ mu^-}^s.
The simplest extension of the SM that generally introduces new sources of flavour and CP violation as well as right-handed currents is the addition of a U(1) gauge symmetry to the SM gauge group. If the corresponding heavy gauge boson Z' mediates FCNC processes in the quark sector at tree-level, these new physics contributions imply a pattern of deviations from SM expectations for FCNC processes depending only on Z' couplings to fermions and on its mass. This implies stringent correlations between Delta F=2 and Delta F=1 observables which govern the landscape of the allowed parameter space for…
In many extensions of the Standard Model flavour changing neutral current processes can be mediated by tree-level heavy neutral scalars and/or pseudo-scalars H^0(A^0). This generally introduces new sources of flavour violation and CP violation as well as left-handed and right-handed scalar currents. These new physics contributions imply a pattern of deviations from SM expectations for FCNC processes that depends only on the couplings of H^0(A^0) to fermions and on their masses. In situations in which a single H^0 or A^0 dominates NP contributions stringent correlations between Delta F=2 and De…
In models with partially composite quarks, the couplings of quarks to the Z boson generically receive non-universal corrections that are not only constrained by electroweak precision tests but also lead to flavour-changing neutral currents at tree level. The impact of these flavour-changing couplings on rare K and B decays is studied in two-site models for three scenarios: an anarchic strong sector with two different choices of fermion representations both leading to a custodial protection of the Z->bb coupling, and for a strong sector invariant under a U(2)^3 flavour symmetry. In the complete…
We perform a detailed analysis of several mu-tau lepton flavour violating (LFV) processes, namely tau --> mu X (X = gamma, e+ e-, mu+ mu-, rho, pi, eta, eta'), Z --> mu tau and Higgs boson decays into mu tau. First we present a model independent operator analysis relevant to such decays, then we explicitly compute the LFV operator coefficients [and (g_μ-2)] in a general unconstrained MSSM framework, allowing slepton mass matrices to have large mu-tau entries. We systematically study the role and the interplay of dipole and non-dipole operators, showing how the rates and the mutual correlations…
These lectures give a topical review of heavy flavour physics, in particular \CP violation and rare decays, from an experimental point of view. They describe the ongoing motivation to study heavy flavour physics in the LHC era, the current status of the field emphasising key results from previous experiments, some selected topics in which new results are expected in the near future, and a brief look at future projects.
We perform an extensive study of FCNC and CP Violation within Supersymmetric (SUSY) theories with particular emphasis put on processes governed by b->s transitions and of their correlations with processes governed by b->d transitions, s->d transitions, $D^0-\bar D^0$ oscillations, lepton flavour violating decays, electric dipole moments and (g-2)_mu. We first perform a comprehensive model-independent analysis of Delta F=2 observables and we emphasize the usefulness of the R_b-gamma plane in exhibiting transparently various tensions in the present UT analyses. Secondly, we consider a number of …
The kaon sector is characterised by several processes which are under active investigation across different experiments. In this work, we present the global picture that emerges from a study of the different decay modes. We begin by revisiting the theoretical component of these decays and providing up-to-date predictions of the Standard Model as well as the corresponding uncertainties. Several new features emerge, in particular for $K_{S,L}\to μ\barμ$, and are presented in considerable detail. This offers an ideal platform for extracting the parameter space supported by the existing data. Moti…
I discuss a new Physics scenario, the 331 model, based on the gauge group $SU(3)_c \times SU(3)_L \times U(1)_X$. In particular, I elaborate on correlations between flavour observables in the $B_d$ and $B_s$ systems that can help constraining the model parameters.
We give a status report on quark flavour physics in view of the latest data from the B factories and the LHC, and discuss the impact of the latest experimental results on new physics in the MFV framework. We also show some examples of the implications in supersymmetry.
We present an overview of what we learned so far from low-energy flavour observables, concerning physics beyond the Standard Model, and what we could still learn from further studies in flavour physics in the next few years.
This decade should make a significant progress towards the Theory of Flavour and the main goal of this talk is to transfer this believe to my colleagues in the particle physics community. Indeed a significant part of this decade could turn out to be the Flavour Era with participation of the LHC, Belle II, Super-Flavour-Facility and dedicated Kaon and lepton flavour violation experiments. Selected superstars of flavour physics listed below will play a prominent role in these events. In this writeup the leading role is played by the prima donna of 2010: CP violation in B_s system.
The so-called supersymmetric flavour problem does not exist in isolation to the Standard Model flavour problem. We show that a realistic flavour symmetry can simultaneously solve both problems without ad hoc modifications of the SUSY model. Furthermore, departures from the SM expectations in these models can be used to discriminate among different possibilities. In particular we present the expected values for the electron EDM in a flavour model solving the supersymmetric flavour and CP problems.
In the context of the recently measured non-leptonic decays $B_{d}\to K^{*0}\bar{K}^{*0}$ and $B_{s}\to K^{*0}\bar{K}^{*0}$ we analyse the anatomy of the $L_{VV}$ observable that compares the longitudinal components of $B_s \to VV$ and $B_d \to VV$ decays. This observable is cleaner than the longitudinal polarisation fraction as it is afflicted only at subleading order in a $1/m_b$ expansion by the theoretical uncertainties arising in the transverse components entering the polarisation fraction. Focusing on the particular case of $B_{d}\to K^{*0}\bar{K}^{*0}$ and $B_{s}\to K^{*0}\bar{K}^{*0}$,…
The experimental success of the predictions of the Standard Model in the flavour sector suggests that New Physics should possess a highly non-generic flavour structure. Different approaches to this idea of Minimal Flavour Violation have been proposed and studied during the last years. At last, the LHC provides the possibility to test these patterns from different points of view, i.e. through the direct search of New Physics at the high energy frontier, and through the indirect constraints at the intensity frontier of precision measurements.
Lectures content: (1) Flavour physics within the SM and the flavour problem; (2) B-physics phenomenology: mixing, CP violation, and rare decays; (3) Flavour physics beyond the SM: models and predictions.
A number of phenomenologically relevant processes at hadron colliders, such as Higgs and Z boson production in association with b quarks, can be conveniently described as scattering of heavy quarks in the initial state. We present a detailed analysis of this class of processes, identifying the form of the leading initial-state collinear logarithms that allow the relation of calculations performed in different flavour schemes in a simple and reliable way. This procedure makes it possible to assess the size of the logarithmically enhanced terms and the effects of their resummation via heavy-quar…
Though models with the radiative neutrino mass generation are phenomenologically attractive, the complicated relationship between the flavour structure of additional Yukawa matrices and the neutrino mass matrix sometimes is a barrier to explore the models. We introduce a simple prescription to analyze the relation in a class of models with the asymmetric Yukawa structure. We then apply the treatment to the Zee-Babu model as a concrete example of the class and discuss the phenomenological consequences of the model. The combined studies among the neutrino physics, the lepton flavour violation, a…
We comprehensively examine precision predictions for scalar leptoquark pair production at the LHC. In particular, we investigate the impact of lepton $t$-channel exchange diagrams that are potentially relevant in the context of leptoquark scenarios providing an explanation for the flavour anomalies. We also evaluate the corresponding total rates at the next-to-leading order in QCD. Moreover, we complement this calculation with the resummation of soft-gluon radiation at the next-to-next-to-leading logarithmic accuracy, hence providing the most precise predictions for leptoquark pair production …
The B^0 -> J/ψK_{S,L} channels are outstanding probes of CP violation. We have a detailed look at the associated Standard-Model uncertainties, which are related to doubly Cabibbo-suppressed penguin contributions, and point out that these usually neglected effects can actually be taken into account unambiguously through the CP asymmetries and the branching ratio of the B^0 -> J/ψpi^0 decay. Using the most recent B-factory measurements, we find a negative shift of the extracted value of beta, which softens the tension in the fits of the unitarity triangle. In addition, this strategy can be used …
We analyse three different New Physics scenarios for Delta F=2 flavour-changing neutral currents in the quark sector in the light of recent data on neutral-meson mixing. We parametrise generic New Physics contributions to B_q-Bbar_q mixing (q=d,s), in terms of one complex quantity Delta_q, while three parameters Delta_K^tt, Delta_K^ct and Delta_K^cc are needed to describe K-Kbar mixing. In Scenario I, we consider uncorrelated New Physics contributions in the B_d, B_s, and K sectors. In this scenario, it is only possible to constrain the parameters Delta_d and Delta_s whereas there are no non-t…
This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the proton and nucleus structure at high energy to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton-proton, proton-…
We investigate the pattern of CP violation in K, B_d and B_s mixing in a symmetrical SU(2)_R x SU(2)_L x U(1) model with spontaneous CP violation. We calculate the phases of the left and right quark mixing matrices beyond the small phase approximation and perform a careful analysis of all relevant restrictions on the model's parameters from Delta m_K, Delta m_B, epsilon, epsilon'/epsilon and the CP asymmetry in B->J/psi K_S. We find that, with current experimental data, the mass of the right-handed charged gauge boson, M2, is restricted to be in the range 2.75 to 13 TeV and the mass of the fla…
The coming flavour precision era will allow to uncover various patterns of flavour violation in different New Physics scenarios. We discuss different classes of them. A simple extension of the Standard Model that generally introduces new sources of flavour and CP violation as well as right-handed currents is the addition of a U(1) gauge symmetry to the SM gauge group. In such Z' models correlations between various flavour observables emerge that could test and distinguish different Z' scenarios. A concrete model with flavour violating Z' couplings is the 331 model based on the gauge group SU(3…
The interplay of flavour and collider physics is entering a new era with the start-up of the LHC. During the past few years rare B decays and in particular b -> s gamma transitions have been extensively used and provided exciting opportunities for mapping possible routes beyond the SM. Flavour constraints play in this manner a complementary role to the direct searches. Here we present an overview of the existing flavour constraints on various models and show examples of comparison with the LHC discovery potentials. The SuperIso program which is dedicated to flavour physics observable calculati…
We present the invited lectures given at the second Asia-Europe-Pacific School of High-Energy Physics (AEPSHEP), which took place in Puri, India in November 2014. The series of lectures aimed at graduate students in particle experiment/theory, covering the very basics of flavor physics and CP violation, some useful theoretical methods such as OPE and effective field theories, and some selected topics of flavour physics in the era of LHC.
The recent successes of the SM do not weaken the arguments in favour of New Physics residing at the TeV scale. Finding and identifying it represents the prime challenge for a generation of high energy physicists. To differentiate between different scenarios of New Physics we need to analyze their impact on flavour dynamics. A continuing comprehensive program of heavy flavour studies instrumentalizing the high sensitivity of \cp analyses is intrinsically connected to LHC's core mission. In B decays we can typically expect no more than moderate deviations from SM predictions. $B_s$ transitions p…
The meV frontier of neutrinoless double beta decay in the JUNO era
INFN Sezione di Roma Tre（罗马第三大学INFN分部）；SISSA/INFN（的里雅斯特国际高等研究学校/意大利国家核物理研究所）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学 Kavli宇宙粒子与天体物理前沿研究中心（WPI））；Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences（保加利亚科学院核研究与核能研究所）
The Littlest Higgs Model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. We present a new analysis of quark observables in the LHT model in view of the oncoming flavour precision era. We use all available information on the CKM parameters, lattice QCD input and experimental data on quark flavour observables and corresponding theoretical calculations, taking into account new lower bounds on the symmetry breaking scale and the mirror quark masses from the LHC. We investigate by how much the branching ratios for a number of rare $K$ …
The measurements carried out at LEP and SLC projected us into the precision era of electroweak physics. This has also been relevant in the theoretical interpretation of LHCb and Belle measurements of rare $B$ semileptonic decays, paving the road for new physics with the inference of lepton universality violation in $R_{K^{(*)}}$ ratios. The simplest explanation of these flavour anomalies -- sizeable one-loop contributions respecting Minimal Flavour Violation -- is currently disfavoured by electroweak precision data. In this work, we discuss how to completely relieve the present tension between…
This chapter of the report of the ``Flavour in the era of the LHC'' Workshop discusses the theoretical, phenomenological and experimental issues related to flavour phenomena in the charged lepton sector and in flavour-conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavour structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the Standard Model, presenting benchmarks for the discovery potential of forthcoming measurements both at t…
Neutrino physics in the early Universe is key to our understanding of later cosmological stages, such as primordial nucleosynthesis (BBN) or the formation of large-scale structures. The coming decade promises new experimental results to explore and constrain cosmological models even more precisely - which requires robust theoretical predictions. This PhD thesis presents a study of the evolution of neutrinos in the first seconds after the Big Bang, more precisely when the temperature of the Universe is of the order of one mega-electronvolt. This evolution is obtained numerically by solving kine…
Symmetries in the Physical Laws of Nature lead to observable effects. Beyond regularities and conserved magnitudes, the last decades in Particle Physics have seen the identification of symmetries, and their well defined breaking, as the guiding principle for the elementary constituents of matter and their interactions. Flavour SU(3) symmetry of hadrons led to the Quark Model and the antisymmetry requirement under exchange of identical fermions led to the colour degree of freedom, the charge for the interactions of quarks and gluons in the SU(3) local gauge symmetry. Parity Violation in weak in…
