Natural inflation and flavor mixing from Peccei–Quinn symmetry breaking

We propose a left–right symmetric model to simultaneously give natural inflation and flavor mixing from a Peccei–Quinn symmetry breaking at the Planck scale. Our model can be embedded into SO(10)$\mathit{SO}(10)$ grand unification theories.     

Tri-bimaximal neutrino mixing from A4 and θ13∼θC

It is a common believe that, if the tri-bimaximal mixing (TBM) pattern is explained by vacuum alignment in an $A_4$ model, only a very small reactor angle, say ${\theta }_{13}～O({\lambda }_C^2)$ being ${\lambda }_C\equiv {\theta }_C$ the Cabibbo angle, can be accommodated. This statement is based on the assumption that all the flavon fields acquire VEVs at a very similar scale and the departures from exact TBM arise at the same perturbation level. From the experimental point of view, however, a relatively large value ${\theta }_{13}～O({\lambda }_C)$ is not yet excluded by present data. In this paper, we propose a seesaw $A_4$ model in which the previous assumption can naturally be evaded. The aim is to describe a ${\theta }_{13}～O({\lambda }_C)$ without conflicting with the TBM prediction for ${\theta }_{12}$ which is rather close to the observed value (at ${\lambda }_C^2$ level). In our model the deviation of the atmospherical angle from maximal is subject to the sum-rule: ${\sin }^2{\theta }_{23}\approx 1/2+\sqrt{2}/2\cos \delta \sin {\theta }_{13}$ which is a next-to-leading order prediction of our model.     

Optical solitons with Chen–Lee–Liu equation by Lie symmetry

This paper avails of classical Lie symmetry analysis to exhibit optical solitons to Chen–Lee–Liu model. By the aid of the proposed method, we secure symmetries that transform the model to a system of ordinary differential equations which are subsequently investigated by a number of methods to recover bright, dark and singular solitons.     

Universal seesaw from left–right and Peccei–Quinn symmetry breaking

To generate the lepton and quark masses in the left–right symmetric models, we can consider a universal seesaw scenario by integrating out heavy fermion singlets which have the Yukawa couplings with the fermion and Higgs doublets. The universal seesaw scenario can also accommodate the leptogenesis with Majorana or Dirac neutrinos. We show that the fermion singlets can obtain their heavy masses from the Peccei–Quinn symmetry breaking.     

TeV gamma rays from distant BL Lacs and photon–paraphoton kinetic mixing

An effect of a proposed Beyond the Standard Model particle physics process on the energy spectra of distant astrophysical objects is presented. It is suggested that TeV gamma rays from distant BL Lacs may kinetically mix with hypothetical hidden sector paraphotons. The latter can traverse vast distances of space because of only very weak interactions with intervening objects or material. These paraphotons would then reconvert back into photons that have identical characteristics as their originators, and are detected on earth. Laser based photon regeneration experiments test this model of hidden sector physics in the range of parameters that would impact the TeV gamma ray energy spectra arriving from distant BL Lacs.     

Tensor glueball–meson mixing phenomenology

We study the Abelian Higgs model using an improved form of the action in the scalar sector. The subleading corrections are carefully analyzed and the connection between lattice and continuous parameters is worked out. The model is simulated for GeV and a remarkable improvement of the numerical performance is achieved for this value of the Higgs mass. Received: 29 December 1999 / Revised version: 3 April 2000 / Published online: 8 June 2000     

Nonzero θ13 for neutrino mixing in the context of A4 symmetry

In the original 2004 paper which first derived tribimaximal mixing in the context of A(4), i.e., the non-Abelian finite symmetry group of the tetrahedron, as its simplest application, it was also pointed out how θ(13) ≠ 0 may be accommodated. On the strength of the new T2K result that 0.03(0.04) ≤ sin(2)2θ(13) ≤ 0.28(0.34) for δ(CP) = 0 and normal (inverted) neutrino mass hierarchy, we perform a more detailed analysis of how this original idea may be realized in the context of A(4).     

Young’s double-slit interference pattern from a twisted beam

A wide range of diffractive elements have been used to evaluate the topological charge of Laguerre–Gaussian beams. Here, we show theoretically and experimentally that this charge can be simply and readily measured from the interference pattern in Young’s double-slit experiment. It can be evaluated from the twisting order of the interference. The results are confronted with previously published studies. The potentialities of the method are then compared with existing techniques.     

Interface mixing in Fe–B–Ag multilayers

Multilayers with Ag/Fe/B and Ag/B/Fe layer sequence were studied in order to reveal differences of top and bottom interfaces of Fe. The hyperfine field distribution depends on the layer sequence and the differences could be attributed to a different B concentration distribution at the top and bottom Fe–B interface.     

Model-independent analysis of tri-bimaximal mixing: A softly-broken hidden or an accidental symmetry?

To address the issue of whether tri-bimaximal mixing (TBM) is a softly-broken hidden or an accidental symmetry, we adopt a model-independent analysis in which we perturb a neutrino mass matrix leading to TBM in the most general way but leave the three texture zeros of the diagonal charged lepton mass matrix unperturbed. We compare predictions for the perturbed neutrino TBM parameters with those obtained from typical SO(10) grand unified theories with a variety of flavor symmetries. Whereas SO(10) GUTs almost always predict a normal mass hierarchy for the light neutrinos, TBM has a priori no preference for neutrino masses. We find, in particular for the latter, that the value of |U_e3| is very sensitive to the neutrino mass scale and ordering. Observation of |U_e3|²>0.001 to 0.01 within the next few years would be incompatible with softly-broken TBM and a normal mass hierarchy and would suggest that the apparent TBM symmetry is an accidental symmetry instead. No such conclusions can be drawn for the inverted and quasi-degenerate hierarchy spectra.     

Newton–Hooke-type symmetry of anisotropic oscillators

Rotation-less Newton–Hooke-type symmetry, found recently in the Hill problem, and instrumental for explaining the center-of-mass decomposition, is generalized to an arbitrary anisotropic oscillator in the plane. Conversely, the latter system is shown, by the orbit method, to be the most general one with such a symmetry. Full Newton–Hooke symmetry is recovered in the isotropic case. Star escape from a galaxy is studied as an application.     

BRST symmetry for Regge–Teitelboim-based minisuperspace models

The Einstein–Hilbert action in the context of higher derivative theories is considered for finding their BRST symmetries. Being a constraint system, the model is transformed in the minisuperspace language with the FRLW background and the gauge symmetries are explored. Exploiting the first order formalism developed by Banerjee et al. the diffeomorphism symmetry is extracted. From the general form of the gauge transformations of the field, the analogous BRST transformations are calculated. The effective Lagrangian is constructed by considering two gauge-fixing conditions. Further, the BRST (conserved) charge is computed, which plays an important role in defining the physical states from the total Hilbert space of states. The finite field-dependent BRST formulation is also studied in this context where the Jacobian for the functional measure is illustrated specifically.     

Noether symmetry for Gauss–Bonnet dilatonic gravity

Noether symmetry for Gauss–Bonnet Dilatonic interaction exists for a constant dilatonic scalar potential and a linear functional dependence of the coupling parameter on the scalar field. The symmetry with the same form of the potential and coupling parameter exists all in the vacuum, radiation and matter dominated era. The late time acceleration is driven by the effective cosmological constant rather than the Gauss–Bonnet term, while the later compensates for the large value of the effective cosmological constant giving a plausible answer to the well-known coincidence problem.     

The Lee–Wick fields out of gravity

We study the Maxwell–Einstein theory in the framework of effective field theories. We show that the modified one-loop renormalizable Lagrangian due to quantum gravitational effects contains a Lee–Wick vector field as an extra degree of freedom in the theory. Thus gravity provides a natural mechanism for the emergence of this exotic particle.     

Neutrino mixing and the axion–gluon vertex

We present detailed arguments and calculations in support of our recent proposal to identify the axion arising in the solution of the strong CP problem with the Majoron, the (pseudo-)Goldstone boson of spontaneously broken lepton number symmetry. At low energies, the associated U_(1)L$U{(1)}_L$ becomes, via electroweak parity violation and neutrino mediation, indistinguishable from an axial Peccei–Quinn symmetry in relation to the strong interactions. The axionic couplings are then fully computable in terms of known SM parameters and the Majorana mass scales. The determination of these couplings involves certain three-loop diagrams, with a UV finite neutrino triangle taking over the role of the usual triangle anomaly. A main novelty of our proposal is thus to solve the strong CP problem by a non-local term that produces an anomaly-like term in the IR limit.     

Charge independence breaking and charge symmetry breaking in the nucleon–nucleon interaction from effective field theory

We discuss charge symmetry and charge independence breaking in an effective field theory approach for few-nucleon systems. We systematically introduce strong isospin-violating and electromagnetic operators in the theory. The charge dependence observed in the nucleon–nucleon scattering lengths is due to one-pion exchange and one electromagnetic four-nucleon contact term. This gives a parameter free expression for the charge dependence of the corresponding effective ranges, which is in agreement with the rather small and uncertain empirical determinations. We also compare the low energy phase shifts of the nn and the np system. We present a classification scheme for corrections to the leading order results and show that power counting explains previously made phenomenological observations.