Higgs bosons in the left–right model

The model with the gauge group, containing one bidoublet and two triplets in the Higgs sector, is considered. The link between the constants determining the physical Higgs boson interactions and the neutrino oscillation parameters is found. It is shown that the observation of the ultrahigh-energy neutrinos with the help of the processes , gives us information on the singly charged Higgs bosons. The processes of the doubly charged Higgs bosons production, , are investigated. From the point of view of detecting the neutral Higgs bosons the process of the electron–muon recharge is studied. Received: 29 January 1999 / Revised version: 20 September 1999 / Published online: 3 February 2000     

To how many politicians should government be left?

We study opinion formation processes in small social networks. In particular we show how a group’s ability for efficient decision-making depends on its size. We adopt a threshold voter model and show that there exists a characteristic size beyond which the probability of forming internal factions-and thus absence of consensus-undergoes a qualitative change. Our work is empirically motivated by an apparent correlation between the size of a decision-making group and its performance in the particular case of national governments.     

Right handed or left handed? Forbidden x-ray diffraction reveals chirality

Enantiomers, or stereoisomers, have crystal structures that are mirror images of each other and are thus handed, like our right and left hands. The physical properties of enantiomers are identical except for optical activity, which rotates linearly polarized light by equal amounts but in opposite directions. While conventional x-ray Bragg diffraction can determine crystal structures, it does not distinguish between right- and left-handed crystals. We show resonant Bragg diffraction using circularly polarized x rays reveals the handedness of crystals by coupling x-ray helicity to a crystal screw axis. The intensity of resonantly allowed reflection of alpha-quartz is well described by an admixture of a parity-even and a parity-odd process. Our results are of general importance and demonstrate a new method to directly study chiral motifs in structures that include biomaterials, liquid crystals, magnets, multiferroics, etc.     

Minimal supersymmetric left–right model with automatic R-parity

We revisit the minimal supersymmetric left–right model with B−L=2$B-L=2$ triplet Higgs fields and show that a self-consistent picture emerges with automatic R-parity conservation even in the absence of higher-dimensional operators. By computing the effective potential for the Higgs system including heavy Majorana neutrino Yukawa couplings we show that the global minimum of the model can lie in the charge and R-parity conserving domain. The model provides natural solutions to the SUSY phase problem and the strong CP problem and makes several interesting predictions. Quark mixing angles arise only after radiative corrections from the lepton sector are taken into account. A pair of doubly charged Higgs fields remain light below TeV with one field acquiring its mass entirely via renormalization group corrections. We find this mass to be not much above the Bino mass. In the supergravity framework for SUSY breaking, we also find similar upper limits on the stau masses. Natural solutions to the μ   problem and the SUSY CP problem entails light SUL₍₂₎$\mathit{SU}{(2)}_L$ triplet Higgs fields, leading to rich collider phenomenology.     

Why PeV scale left–right symmetry is a good thing

We report the results of in-situ characterization of ⁸⁷Rb atom cloud in a quadrupole Ioffe configuration (QUIC) magnetic trap after a radio-frequency (RF) evaporative cooling of the trapped atom cloud. The in-situ absorption images of the atom cloud have shown clear bimodal optical density (OD) profiles which indicate the Bose–Einstein condensation (BEC) phase transition in the trapped gas. Also, we report here, for the first time, the measured variation in the sizes of the condensate and thermal clouds with the final frequency selected in the frequency scan of the RF-field for evaporative cooling. These results on frequency-dependent sizes of the clouds are consistent with the theoretical understanding of the BEC phenomenon in the trap.     

Direct CP violation in charm decays due to left–right mixing

Motivated by the 3.8σ   deviation from no CP violation hypothesis for the CP asymmetry (CPA) difference between D⁰→K⁺K⁻$D^0\to K^{+}{K}^{-}$ and D⁰→π⁺π⁻$D^0\to {\pi }^{+}{\pi }^{-}$, reported recently by LHCb and CDF, we investigate the CP violating effect due to the left–right (LR) mixing in the general LR symmetric model. In particular, we show that the large CPA difference could be explained in the non-manifest LR model.     

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.     

On neutrinoless double beta decay in the minimal left–right symmetric model

We analyze the general phenomenology of neutrinoless double beta decay in the minimal left–right symmetric model. We study under which conditions a New Physics dominated neutrinoless double beta decay signal can be expected in the future experiments. We show that the correlation among the different contributions to the process, which arises from the neutrino mass generation mechanism, can play a crucial role. We have found that, if no fine tuned cancelation is involved in the light–active neutrino contribution, a New Physics signal can be expected mainly from the $W_R$ – $W_R$ channel. An interesting exception is the $W_L$ – $W_R$ channel which can give a dominant contribution to the process if the right-handed neutrino spectrum is hierarchical with $M_1\lesssim $  MeV and $M_2,M_3\gtrsim $  GeV. We also discuss if a New Physics signal in neutrinoless double beta decay experiments is compatible with the existence of a successful Dark Matter candidate in the left–right symmetric models. It turns out that, although it is not a generic feature of the theory, it is still possible to accommodate such a signal with a KeV sterile neutrino as dark matter.     

Type I and new seesaw in left–right symmetric theories

We extend the Type I seesaw and suggest a new   seesaw mechanism to generate neutrino masses within the left–right symmetric theories where parity is spontaneously broken. We construct a next to minimal left–right symmetric model where neutrino masses are determined irrespective of the B−L$B-L$ breaking scale and call it the new   seesaw mechanism. In this scenario B−L$B-L$ scale can be very low. This makes B−L$B-L$ gauge boson and the quasi-Dirac heavy leptons very light. These TeV scale particles could have large impact on lepton flavor and CP violating processes. We also shed light on the phenomenological aspects of the model within the reach of the LHC.     

Neutrino mixing and masses in a left–right model with mirror fermions

In the framework of a left–right model containing mirror fermions with gauge group SU(3) _C ⊗SU(2) _L ⊗SU(2) _R ⊗U(1) _Y′, we estimate the neutrino masses, which are found to be consistent with their experimental bounds and hierarchy. We evaluate the decay rates of the Lepton Flavor Violation (LFV) processes μ→eγ, τ→μγ and τ→eγ. We obtain upper limits for the flavor-changing branching ratios in agreement with their present experimental bounds. We also estimate the decay rates of heavy Majorana neutrinos in the channels N→W ^± l ^∓, N→Zν _l and N→Hν _l , which are roughly equal for large values of the heavy neutrino mass. Starting from the most general Majorana neutrino mass matrix, the smallness of active neutrino masses turns out from the interplay of the hierarchy of the involved scales and the double application of seesaw mechanism. An appropriate parameterization on the structure of the neutrino mass matrix imposing a symmetric mixing of electron neutrino with muon and tau neutrinos leads to tri-bimaximal mixing matrix for light neutrinos.     

Electroweak chiral Lagrangian for left–right symmetric models: The matter sector

The matter sector of electroweak chiral Lagrangian up to dimension four operators for left–right symmetric models with a neutral light Higgs is provided. The connection of these operators to Yukawa couplings, anomalous gauge couplings and parameters in the matter sector of conventional electroweak chiral Lagrangian is made. It is shown that there exists proper parameter space to loosen constraint for the mass of right handed gauge boson from the mass difference of neutral K meson.     

Nematics with quenched disorder: what is left when long range order Is disrupted?

It is now generally accepted that even low amounts of quenched disorder disrupt long-range order in anisotropic systems with continuous symmetry. However, very little is known on the key item of the nature of the residual order, if any, and particularly if this has quasi-long-range or truly-short-range character. Here we address this problem both experimentally for the nematic 6CB in dilute aerosils and with computer simulations. We find that the residual order is short ranged and scales with disorder density in agreement with the Imry-Ma argument.     

Linear collider test of a neutrinoless double beta decay mechanism in left–right symmetric theories

There are various diagrams leading to neutrinoless double beta decay in left?Cright symmetric theories based on the gauge group SU(2) _L ×SU(2) _R . All can in principle be tested at a linear collider running in electron?Celectron mode. We argue that the so-called ??-diagram is the most promising one. Taking the current limit on this diagram from double beta decay experiments, we evaluate the relevant cross section $e^{-} e^{-} \to W^{-}_{L} W^{-}_{R}$ , where $W^{-}_{L}$ is the Standard Model W-boson and $W^{-}_{R}$ the one from SU(2) _R . It is observable if the life-time of double beta decay and the mass of the W _R are close to current limits. Beam polarization effects and the high-energy behaviour of the cross section are also analyzed.     

Wider frequency domain for negative refraction index in a quantized composite right–left handed transmission line

The refraction index of the quantized lossy composite right-left handed transmission line(CRLH-TL) is deduced in the thermal coherence state. The results show that the negative refraction index(herein the left-handedness) can be implemented by the electric circuit dissipative factors(i.e., the resistances R and conductances G) in a higher frequency band(1.446 GHz≤ω≤ 15 GHz), and flexibly adjusted by the left-handed circuit components(Cl, Ll) and the right-handed circuit components(Cr, Lr) at a lower frequency(ω = 0.995 GHz). The flexible adjustment for left-handedness in a wider bandwidth will be significant for the microscale circuit design of the CRLH-TL and may make the theoretical preparation for its compact applications.     

Experimental behaviour of the P-wave isovector ππ phase shift and the pion form factor left hand cut contribution

By using the experimental data on the P-wave isovector phase shift ₁ ¹ the importance of the pion form factor left hand cut contribution of the second Riemann sheet is investigated. Starting with the pion form factor phase representation, finding the suitable parametrization of the phase shift ₁ ¹ and calculating the corresponding integral in the pion c.m. momentum plane, one zero and two poles are found on the negative imaginary axis. The appearance of these poles and zero reveals that the contribution of the left hand cut of the second Riemann sheet to the pion form factor behaviour at the elastic region is nonnegligible.Dedicated to Academician Václav Votruba on the occasion of his seventieth birthday.Discussions with Professor M.Blaek and Professor J.Fischer are acknowledged.     

New exact solutions of the Tzitzéica type equations arising in nonlinear optics using a modified version of the improved $$\tan \left( {\varPhi \left( \xi \right)/2} \right)$$-expansion method

The paper deals with the Tzitzéica type nonlinear evolution equations arising in nonlinear optics and their new exact solutions. First, through the use of the Painlevé transformation and Lie symmetry method, the Tzitzéica, Dodd–Bullough–Mikhailov, and Tzitzéica–Dodd–Bullough equations are converted to nonlinear ordinary differential equations (NODEs), and then, a modified version of the improved \(\tan \left( {\varPhi \left( \xi \right)/2} \right)\)-expansion method, proposed by the authors, is adopted to generate new exact solutions of the reduced equations. The method truly recommends a reliable and capable technique to produce new exact solutions of a variety of nonlinear partial differential equations (NPDEs).     

Exact solutions of perturbed nonlinear Schrödinger’s equation with Kerr law nonlinearity by improved $${\textbf{tan}} \left( {\frac{{\boldsymbol{\phi}} \left( {\boldsymbol{\xi}} \right)}{{\textbf{2}}}} \right)$$-expansion method

This paper carries out exact solutions of the perturbed nonlinear Schödinger’s equation withy Kerr law nonlinearity by using the improved tan\(\left( {\frac{\phi \left( \xi \right)}{2}} \right)\)-expansion method. The exact solutions contain four types: hyperbolic function solution, trigonometric function solution, exponential solution, and rational solution. The method appears to be easier and faster by means of symbolic computational system and can be applied to the other nonlinear evolution equations in mathematical physics.     

How does anticommutator\left\{ {Q_\alpha \bar Q_\beta } \right\} realize energy-momentumP μ in quantum supergravity?

It is investigated to what extent the well-known algebra \(\left\{ {Q^S ,\bar Q^S } \right\} = \gamma ^\mu P_\mu \) in the rigid supersymmetry theory holds in quantum supergravity: The anti-commutator \(\left\{ {Q_\alpha ^S ,\bar Q_\beta ^S } \right\} = \gamma ^m \tilde P_m \) defines an “internal” translation generator \(\tilde P_m \) , quite another from the “external” translation generatorP _μ. It is, however, shown that those two operators give the same matrix elements between any two physical states aside from a proportional factor. Such a “miracle” is caused by some particular properties of global gauge transformation charge universal in gauge theories. These properties are fully clarified in a general manner.