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 Physics , 1993, DOI: 10.1103/PhysRevD.49.3741 Abstract: Grand unified theories with fermions transforming as irreducible representations of a discrete nonabelian flavor symmetry can lead to realistic fermion masses, without requiring very small fundamental parameters. We construct a specific example of a supersymmetric GUT based on the flavor symmetry $\Delta(75)$ --- a subgroup of $SU(3)$ --- which can explain the observed quark and lepton masses and mixing angles. The model predicts $\tan\beta \simeq 2-5$ and gives a $\tau$ neutrino mass $m_\nu\simeq M_p/G_F M_{GUT}^2 = 10$ eV, with other neutrino masses much lighter. Combined constraints of light quark masses and perturbative unification place flavor symmetry breaking near the GUT scale; it may be possible to probe these extremely high energies by continuing the search for flavor changing neutral currents.
 Physics , 1999, Abstract: One way to suppress flavor changing neutral currents or CP violating processes in supersymmetry is to make at least some of the first two generations' scalars superheavy (above ~20 TeV). We summarize the motivations and challenges, theoretically and phenomenologically, for superheavy supersymmetry. We then argue for more viable alternatives on the superheavy theme and are led to models where the heavy spectrum follows a pattern of masses similar to what arises from gauge-mediation or with a "hybrid" spectrum of light and heavy masses based on each particle's transformation under a global SU(5). In the end, despite the differences between the competing ideas, a self-consistent natural theory with superheavy masses seems to prefer low-energy supersymmetry breaking with possible correlations among the light sparticle masses. The resulting light gravitino and its couplings to matter could also impact the discovery capabilities and analyses of these models at colliders. In addition, we comment on how the presence of superheavy states may influence the light spectrum, and how this may help efforts to distinguish between theories post-discovery.
 Physics , 1993, DOI: 10.1006/aphy.1993.1079 Abstract: We show how generic nonabelian gauge fields can be induced in baryons when a hierarchy of fast degrees of freedom is integrated out. We identify them with nonabelian Berry potentials and discuss their role in transmuting quantum numbers in bag and soliton models of baryons. The resulting baryonic spectra for both light and heavy quark systems are generic and resemble closely the excitation spectrum of diatomic molecules. The symmetry restoration in the system, i.e., the electronic rotational invariance in diatomic molecules, the heavy-quark symmetry in heavy baryons etc. is interpreted in terms of the vanishing of nonabelian Berry potentials that otherwise govern the hyperfine splitting.
 Harald Fritzsch Physics , 1998, Abstract: In view of the observed strong hierarchy of the quark and lepton masses and of the flavor mixing angles it is argued that the description of flavor mixing must take this into account. One particular interesting way to describe the flavor mixing, which, however, is not the one used today, emerges, which is best suited for models of quark mass matrices based on flavor symmetries. We conclude that the unitarity triangle important for $B$ physics should be close to or identical to a rectangular triangle. CP violation is maximal in this sense.
 Physics , 2009, DOI: 10.1016/j.physletb.2009.08.029 Abstract: A nonabelian finite flavor group $G \subset SO(3)$ can have double covering $G^{'} \subset SU(2)$ such that $G \not\subset G^{'}$. This situation is not contradictory, but quite natural, and we give explicit examples such as $G=D_n, G^{'}=Q_{2n}$ and $G=T, G^{'}=T^{'}$. This observation can be crucial in particle theory model building.
 Kanehisa Takasaki Physics , 1993, DOI: 10.1016/0393-0440(94)90040-X Abstract: A higher dimensional analogue of the KP hierarchy is presented. Fundamental constituents of the theory are pseudo-differential operators with Moyal algebraic coefficients. The new hierarchy can be interpreted as large-$N$ limit of multi-component ($\gl(N)$ symmetric) KP hierarchies. Actually, two different hierarchies are constructed. The first hierarchy consists of commuting flows and may be thought of as a straightforward extension of the ordinary and multi-component KP hierarchies. The second one is a hierarchy of noncommuting flows, and related to Moyal algebraic deformations of selfdual gravity. Both hierarchies turn out to possess quasi-classical limit, replacing Moyal algebraic structures by Poisson algebraic structures. The language of W-infinity algebras provides a unified point of view to these results.
 High Energy Physics - Phenomenology , 2007, DOI: 10.1016/j.physletb.2007.11.083 Abstract: We address two fundamental aspects of flavor physics: the mass hierarchy and the large lepton mixing angles. On one side, left-right flavor symmetry realizes the democratic mass matrix patterns and explains why one family is much heavier than the others. On the other side, discrete flavor symmetry such as A4 leads to the observed tribimaximal mixing for the leptons. We show that, by explicitly breaking the left-right flavor symmetry into the diagonal A4, it is possible to explain both the observed charged fermion mass hierarchies and quark and lepton mixing angles. In particular we predict a heavy 3rd family, the tribimaximal mixing for the leptons, and we suggest a possible origin of the Cabibbo and other mixing angles for the quarks.
 Gia Dvali Physics , 1999, DOI: 10.1016/S0370-2693(99)00726-1 Abstract: In theories with TeV scale quantum gravity the standard model particles live on a brane propagating in large extra dimensions. Branes may be stabilized at large (sub-millimeter) distances from each other, either due to weak Van der Waals type interactions, or due to an infrared analog of Witten's inverse hierarchy scenario. In particular, this infrared stabilization may be responsible for a large size of extra dimensions. In either case, thermal effects can drive a brief period of the late inflation necessary to avoid the problems with high reheating temperature and the stable unwanted relics. The main reason is that the branes which repel each other at zero temperature can be temporarily glued together by thermal effects. It is crucial that the temperature needed to stabilize branes on top of each other can be much smaller than the potential energy of the bound-state, which drives inflation. After 10-15 $e$-foldings bound-states cool below the critical temperature and decay ending inflation. The parallel brane worlds get separated at this stage and superstrings (of a sub-millimeter size) get stretched between them. These strings can have the right density in order to serve as a superheavy dark matter.
 Physics , 2014, Abstract: The observation of high-energy extraterrestrial neutrinos at IceCube represents the beginning of the era of neutrino astronomy. In this paper, we study the cosmic neutrino flavor ratios against the Dirac CP-violating phase at neutrino telescopes, taking into account the charged-current and neutral-current interactions at the detectors. We then demonstrate how to probe mass hierarchy at future neutrino telescopes by the precise measurements of the cosmic neutrino flavor ratios. We show that the sensitivity of our scheme is independent of the undetermined values of the Dirac CP-violating phase. We also explore the possible effects of active-sterile mixing, neutrino decay and pseudo-Dirac nature of neutrinos.
 Physics , 2013, DOI: 10.1103/PhysRevLett.111.202302 Abstract: We present possible indications for flavor separation during the QCD crossover transition based on continuum extrapolated lattice QCD calculations of higher order susceptibilities. We base our findings on flavor specific quantities in the light and strange quark sector. We propose a possible experimental verification of our prediction, based on the measurement of higher order moments of identified particle multiplicities. Since all our calculations are performed at zero baryochemical potential, these results are of particular relevance for the heavy ion program at the LHC.
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