Search results for "Homogeneous space"
showing 10 items of 142 documents
Symmetries and similarities for spin orientation parameters in at SM thresholds
2011
Abstract We consider the spin orientation of the final Z bosons for the processes in the Standard Model. We demonstrate that at the threshold energies of these processes the analytical expressions for the Z boson polarization vectors and alignment tensors coincide ( e + e − → Z H , Z γ ) or are very similar ( e + e − → Z Z ). In addition, we present interesting symmetry properties for the spin orientation parameters.
Do p annihilations at rest choose the Eightfold way?
1993
Dynamical selection rules observed in pp annihilation at rest are linked to relations between SU(3) invariant amplitudes. The ϱπ puzzle, the KK suppression in P wave, and the unexplained production rates of πa2 (1320) are shown to be manifestions of one SU(3) amplitude ratio. The dynamical selection rules observed in the production of strange mesons lead to symmetries in SU(3) amplitudes. We conjecture that these symmetries reflect the underlying quark-gluon dynamic. It is shown that the contribution of annihilation diagrams to important annihilation channels like ϱ0π0 or ηω is small or vanishes. Hence rearrangement must play an important role. The use of SU(3) relations in the context of N…
Gauge fields, hidden local symmetries, and meson exchange currents
1997
Abstract The model dependence of the electromagnetic isovector meson exchange current (MEC) operator at higher momentums transfer is studied. For this purpose, the MEC operator constructed from a Lagrangian of the πϱa 1 system obtained within the framework of the hidden local symmetries (HLS) approach is compared with the analogous operator derived earlier from a minimal Yang-Mills (YM) Lagrangian. Numerical results for the deuteron disintegration near threshold show that the model dependent part of the exchange current modifies the tail of the cross section sensibly and that the presence of the a 1 meson both in the MEC and in the nuclear interaction provides a consistent description of th…
Masses, mixings, Yukawa couplings and their symmetries
1993
We present a method to find the number of real and imaginary observable parameters coming from the Yukawa sector in an arbitrary gauge theory. The method leads naturally to a classification of Yukawa couplings according to their symmetries and suggests a new parametrization of masses and mixings that is useful to study the behaviour of Yukawa couplings under the renormalization group. We apply it to some examples based on the Standard Model with Yukawa couplings obeying various chiral symmetries. We also show how our method of parameter counting can be used in some models with an enlarged leptonic sector.
Absolute neutrino mass scale from flavor symmetries
2013
Abstract The 2012 has been an important year for neutrino physics, current data are reviewed and compared with 2011 global fit. Models based on discrete flavor symmetries predict neutrino mass mass sum-rule (MSR), which is useful to reduce the number of independent model parameters. We found that only four classes of MSR are possible. Such neutrino MSRs constrain the absolute neutrino mass scale. We study the implications of these mass relations for the lightest neutrino mass and for the lower bound of the effective mass m e e of the neutrinoless double beta decay.
Topological structure of dense hadronic matter
2007
8 pages, 4 figures.-- ISI Article Identifier: 000244425500052.
Yukawa sector of multi-Higgs-doublet models in the presence of Abelian symmetries
2013
A general method for classifying the possible quark models of a multi-Higgs-doublet model, in the presence of Abelian symmetries, is presented. All the possible sets of textures that can be present in a given sector are shown, thus turning the determination of the flavor models into a combinatorial problem. Several symmetry implementations are studied for two and three Higgs doublet models. Some models' implementations are explored in great detail, with a particular emphasis on models known as Branco-Grimus-Lavoura and nearest-neighbor-interaction. Several considerations on the flavor changing neutral currents of multi-Higgs models are also given.
On the classification of accidental symmetries of the two Higgs doublet model potential
2011
Recently, it has been shown [arXiv:1106.3482] that the two-Higgs-doublet-model potential may exhibit a maximum of 13 distinct accidental symmetries. Such a classification is based on a six-dimensional bilinear scalar field formalism realizing the SO(1,5) symmetry group. This note presents the transformation relations for each of the 13 symmetries in the original scalar field space and their one-to-one correspondence to the space of scalar bilinears, thereby providing firm support for the completeness of the classification.
Soft masses in supersymmetric SO(10) GUTs with low intermediate scales
2011
The specific shape of the squark, slepton and gaugino mass spectra, if measured with sufficient accuracy, can provide invaluable information not only about the dynamics underpinning their origin at some very high scale such as the unification scale ${M}_{G}$, but also about the intermediate scale physics encountered throughout their renormalization group equations evolution down to the energy scale accessible for the LHC. In this work, we study general features of the TeV scale soft supersymmetry breaking parameters stemming from a generic mSugra configuration within certain classes of supersymmetry $SO(10)$ GUTs with different intermediate symmetries below ${M}_{G}$. We show that particula…
T Violation and CPT Tests in Neutral-Meson Systems
2014
The review covers transitions between M0 and M0bar in all four systems M0 = K0, D0, B0 and Bs. These systems are ideal laboratories for studying the discrete symmetries T and CPT. The properties of time reversal T are discussed in classical and quantum mechanics. T violation in K0 K0bar transitions has been observed in 1970 independent of assuming CPT symmetry by using the Bell-steinberger unitarity relation. Improvements of this observation are reviewed including the latest results in 2013. They show with high significance that CP violation in K0 K0bar transitions is only T violation without any CPT violation. Transitions in the other three systems do not show CP violation so far and there…