Flavor Beyond Standard Model G.G. Devidze High Energy Physics Institute of Tbilisi State University 1.Introduction 2.Flavor beyond the standard model 3.Heavy quarks and leptons rare decays 4. Conclusion 5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze Nanouniverse m Femtouniverse m Attouniverse m m Zeptouniverse m 2GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze Exciting time is for fundamental physics, after the LHC experiments announced about discovery of neutral Higgs particle on July the 4 th. Many in the community expect a new paradigm to emerge around the TeV scale, be it some variant of SUSY or of Technicolour or something even more radical, like extra (space) dimensions. Those novel structures can manifest themselves directly through the production of new quanta or the topology of events or indirectly by inducing forces that modify rare weak decays. Such indirect searches are not a luxury. We consider it likely that to differentiate between different scenarios of New Physics, one needs to analyze their impact on flavor dynamics. 3GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze Processes, which are highly suppressed in the Standard Model (SM), such as decays mediated by flavour changing neutral currents (FCNC) allow stringent tests of our current understanding of particle physics. These transitions are forbidden at tree level in the SM, as all electrically neutral particles have only diagonal couplings in the flavor space. FCNC processes are therefore only allowed through loop contributions and probe the underlying fundamental theory at the quantum level, where they are sensitive to masses much higher than that of the b-quark. Historically, many observations have first been indicated by FCNC processes, examples include the existence of the charm quark or the high top quark mass. Enhancements of the decay rates of these FCNC decays are predicted in a variety of different New Physics models. 4GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze The fundamental Lagrangian of the SM consists of four pieces LSM = Lgauge+Lfermion+LHiggs+LYukawa, What is the dynamical origin of the observed electroweak symmetry breaking, of related fermion masses and the reason for their hierarchy and hierarchy of their flavour-changing interactions? Will the dynamics of electroweak symmetry breaking be driven by an elementary Higgs and be calculable within perturbation theory? Will these dynamics be related to a new strong force with a composite Higgs or without Higgs at all? Could these dynamics help us to explain the amount of matter-antimatter asymmetry and the amount of dark matter observed in the universe? Will these dynamics help us to explain various anomalies observed recently in the flavour data? 5GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze What is the fundamental dynamics behind the electroweak symmetry breaking that very likely plays also an important role in flavour physics? Are there any new flavour symmetries that could help us to understand the existing hierarchies of fermion masses and the hierarchies in the quark and lepton flavour violating interactions? Are they local or global? Are they continuous or discrete? Are there any flavour violating interactions that are not governed by the SM Yukawa couplings? In other words, is the Minimal Flavour Violation (MFV) the whole story? Are there any additional flavour violating and CP-violating (CPV) phases that could explain certain anomalies present in the flavour data and simultaneously play a role in the explanation of the observed baryon-antibaryon asymmetry in the universe (BAU)? Are there any flavour conserving CPV phases that could also help in explaining the flavour anomalies in question and would be signalled in this decade through enhanced electric dipole moments (EDMs) of the neutron, the electron and of other particles? 6GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze Are there any new sequential heavy quarks and leptons of the 4th generation and/or new fermions with exotic quantum numbers like vector-like fermions? Are there any elementary neutral and charged scalar particles with masses below 1 TeV and having a significant impact on flavour physics? Are there any new heavy gauge bosons representing an enlarged gauge symmetry group? Are there any relevant right-handed (RH) weak currents that would help us to make our fundamental theory parity conserving at short distance scales well below those explored by the LHC? 7GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze In order to identify new physics through flavour physics and generally through high precision experiments we need: Many high precision measurements of many observables and precise theory, Identification of patterns of flavour violation in various NP models, in particular correlations between many flavour observables that could distinguish between various NP scenarios, Identification of correlations between low energy flavour observables and observables measured in high energy collisions. 8GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze Heavy quarks rare decays. Lepton flavour violating decays like μ →e ,  →e ,  → , decays with three leptons in the final state and  −e conversion in nuclei. Electric dipole moments of the neutron, the electron, atoms and leptons. Anomalous magnetic moment of the muon Having experimental results on these decays and observables with sufficient precision accompanied by improved theoretical calculations will exclude several presently studied models reducing thereby our exploration of short distance scales to a few avenues. 9GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze Heavy quarks rare decays. Br(t →cg)=5 ∙10 -11, Br(t →c  )=5 ∙10 -13, Br(t →cZ)=1.3 ∙10 -11, Br(t →ch)= , Even single experimental observation for any top rare processes could be breakthrough beyond the SM physics. Lepton flavour violating decays like μ →e ,  →e ,  → , decays with three leptons in the final state and  −e conversion in nuclei. Br(μ →e  ) SM < , Br(μ →e  ) exp < GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze COMET (COherent Muon to Electron Transition), to search for coherent neutrino-less conversion of muons to electrons (μ−−e− conversion), in the presence of a nucleus, μ− + N(A,Z) → e− + N(A,Z), with a single event sensitivity B(μ−N → e−N) < 10−16. Currently, the search for possible flavor violation of the muon is considered to be a powerful and the most sensitive tool to reveal or restrict a new physics beyond the SM. μ− + N(A,Z) → e − + N(A,Z), The muon system is considered to be the best system in which to study cLFV experiments because of following reasons: Intense muon beam can be obtained at meson factories Muon life time is rather long. Final states are very simple and can be precisely measured. Observation of cLFV would indicate a clear signal of physics beyond the SM. Search cLFV is especially promising to probe the Tev-scale physics.  -e conversion at level The big challenge and great discovery petential! 11GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze We have studied manifestation of NP in rare processes. Our attention was devoted to lepton flavour violation processes, top quark and neutral B-meson rare decays. Numerical estimates show that in case of B-meson double radiative decays we can get a difference from SM-result as much as ~40%. We have estimated lepton flavour violation processes rates and concluded that three body decays and  −e conversion seem more favourable then radiative decays. 12GGSWBS, Tbilisi 2012, August 6

5 th Georgian –German School and Workshop in Basic Science, Tbilisi 2012 G.G. Devidze We are at the beginning of a new era which certainly will bring us first more detailed insights into the physics at short distance scales. The interplay of high energy collider results with the flavour precision experiments will allow us to make important steps towards a New Standard Model. 13GGSWBS, Tbilisi 2012, August 6