121710663
SPIN-2 GLUON - GRAVITON MODEL WITH BARYON NUMBER NONCONSERVATION
We have shown how a weak-strong gravity model with Higgs fields can contain a baryon-number-violating mechanism. If more than one set of Higgs particles are allowed, the Higgs-fermion coupling will generate the violation of baryon-number symmetry spontaneously. To illustrate our point, we present some numerical examples on quark and nucleon decay. We find that some of the quarks can decay into leptons, antileptons, and pions with very short lifetimes. The proton is found to be much more stable than the neutron and both have possible baryon-number-violating modes of decay with very long lifetimes.
122395245
Chiral symmetry breaking in QED for weak coupling
The authors examine the procedure for studying chiral symmetry breaking for weak coupling in QED. They note that while the lowest non-trivial order calculations using numerical solutions to the Schwinger-Dyson equation indicate a breaking of chiral symmetry, the neglected higher-order contributions to the effective potential have imaginary values which can indicate possible instabilities in the theory.
122132298
On the Green's Functions for the Bethe‐Salpeter Equation
Considering the Bethe‐Salpeter equation as a relativistic equation, we have studied the free particle Green's functions for unequal mass scalar bosons, interacting via a translationally invariant potential. The scattering Green's function found by Huang and DeFacio (HD) is presented for all possible Ω‐plane contours for the unequal masses case. Only two k‐plane contours are found to be physically interesting. The causal, advanced, and retarded Green's functions are listed in an appendix for unequal masses for the physical contour. The timelike Green's functions again require severe restrictions on the interaction potential as found by HD, and possible Bethe‐Salpeter bound states are briefly discussed.
122140676
SPIN-1 AND SPIN-2 GAUGE FIELDS IN UNIFIED SL(2N,C) MODELS
120766753
Stability of the electron in the SU(5) and GWS models
Within the framework of the SU(5) model and by using non-zero vacuum expectation values for both charged and neutral Higgs fields, the lifetime of the electron ( tau e) can be expressed in terms of the photon mass (mgamma ). Using the upper limit of 10-24 GeV for mgamma given by studies of Jupiter's magnetic field, a lower limit of 1027 years is obtained for tau e, while the upper limit of 10-36 GeV for mgamma given by studies of galactic magnetic fields yielded a lower limit of 1051 years for tau e. The values for tau e can be obtained without giving rise to light Higgs particles. In contrast, the standard GWS model with two Higgs doublets gave rise to comparable values for tau e, but yielded a light Higgs particle with masses similar to mgamma .
121902881
Unified SL(8,C) model of spin-2 gluons and gravitons
A unified version of $f\ensuremath{-}g$ gravity models with Higgs field has been constructed using the SL(8, $C$) group. Leptons and quarks are represented in a four-color scheme using the SU(4) group. When the Higgs fields exhibit a spontaneous breakdown of symmetry in the tree approximation, the spin-2 gluons ($f$) and fermions acquire mass while the graviton ($g$) remains massless. The Higgs-fermion interaction is renormalizable in contrast to the $\mathrm{SL}(2,C)\ensuremath{\bigotimes}\mathrm{SL}(6,C)$ gravity models. The spin-2 gluons include the three-color gluon, an exotic gluon which mixes leptons with hadrons, and a weak gluon which mediates only between leptons.
53540874
Dark matter induced nucleon decay: model and signatures
A bstractIf dark matter (DM) carries anti-baryon number, a DM particle may annihilate with a nucleon by flipping to anti-DM. Inspired by Hylogenesis models, we introduce a single component DM model where DM is asymmetric and carries B and L as -1/2. It can annihilate with a nucleon to an anti-lepton and an anti-DM at leading order or with an additional meson at sub-leading order. Such signals may be observed in proton decay experiments. If DM is captured in the Sun, the DM induced nucleon decay can generate a large flux of anti-neutrinos, which could be observed in neutrino experiments. Furthermore, the anti-DM particle in the final state obtains a relatively large momentum (few hundred MeV), and escapes the Sun. These fast-moving anti-DM particles could also induce interesting signals in various underground experiments.
119086309
Global extinction in spiral galaxies
Magnitude-limited samples of spiral galaxies drawn from the Ursa Major and Pisces Clusters are used to determine their extinction properties as a function of inclination. Imaging photometry is available for 87 spirals in the B, R, I, and K' bands. Extinction causes systematic scatter in color-magnitude plots. A strong luminosity dependence is found. Relative edge-on to face-on extinction of up to 1.7 mag is found at B for the most luminous galaxies but is unmeasurably small for faint galaxies. At R the differential absorption with inclination reaches 1.3 mag, at I it reaches 1.0 mag, and at K' the differential absorption can in the extreme be as great as 0.3 mag. The luminosity dependence of reddening can be translated into a dependence on rotation rate, which is a distance-independent observable. Hence, corrections can be made that are useful for distance measurements. The strong dependence of the corrections on luminosity act to steepen luminosity-line width correlations. The effect is greatest toward the blue, with the consequence that luminosity-line width slope dependencies are now only weakly a function of color.
121088924
Chemical Composition and Maximum Energy of Galactic Cosmic Rays
A model of the cosmic-ray energy spectrum is proposed that assumes various acceleration limits at multiple sources. The model describes the broken power-law energy spectrum of cosmic rays by superposition of multiple sources; a diffusive shock acceleration mechanism plays an essential role. The maximum energy of galactic cosmic rays is discussed based on a comparison of experimental data with calculations done using the proposed model. The model can describe the energy spectrum at very high energies of up to several times 1018 eV, but the observed highest-energy cosmic rays deviate from the model predictions, indicating a different origin, such as an extragalactic source. This model describes the steepening of the power index at the so-called knee. However, it was found that additional assumptions are needed to explain the sharpness of the knee. Two possible explanations for the structure of the knee are discussed in terms of nearby source(s) and the hard energy spectrum suggested by nonlinear effects of cosmic-ray acceleration mechanisms.
119212268
Broadband radio spectral observations of the solar eclipse on 2008-08-01 and its implications on the quiet Sun atmospheric model
Based on the joint-observations of the radio broadband spectral emissions of the solar eclipse on August 1, 2008 at Jiuquan (total eclipse) and Huairou (partial eclipse) at the frequencies of 2.00–5.60 GHz (Jiuquan), 2.60–3.80 GHZ (Chinese solar broadband radiospectrometer, SBRS/Huairou), and 5.20–7.60 GHz (SBRS/Huairou), the authors assemble a successive series of broadband spectra with a frequency of 2.60–7.60 GHz to observe the solar eclipse synchronously. This is the first attempt to analyze the solar eclipse radio emission under the two telescopes located at different places with broadband frequencies in the periods of total and partial eclipses. With these analyses, the authorsmade a semiempirical model of the coronal plasma density of the quiet Sun, which can be expressed as ne ≃ 1.42×109(r−2+1.93r−5) (cm−3), in the space range of r=1.039–1.212 R⊙, and made a comparison with the classic model.
122762455
TeV Gamma Ray Survey on the Direction of Fermi-LAT Pulsars with the Tibet Air Shower Array
We search for steady TeV γ-rays from 18 pulsars in the Fermi-LAT pulsar catalog using the Tibet air shower array. We observe 8 sources including the Crab against expected 0.41 sources at a significance of 2σ or more among the 18 pulsars. The chance probability from Poisson statistics is estimated to be 1.4×10-8.With the Crab excluded, it is estimated to be 1.8×10-7. These low chance probabilities clearly show that the Fermi pulsars have a statistically significant correlation with TeV γ-ray excesses observed by the Tibet air shower array.