1,241 research outputs found
Observations of celestial X-ray sources above 20 keV with the high-energy scintillation spectrometer on board OSO 8
High-energy X-ray spectra of the Crab Nebula, Cyg- XR-1, and Cen A were determined from observations with the scintillation spectrometer on board the OSO-8 satellite, launched in June, 1975. Each of these sources was observed over two periods of 8 days or more, enabling a search for day-to-day and year to year variations in the spectral and temporal characteristics of the X-ray emission. No variation in the light curve of the Crab pulsar was found from observations which span a 15-day period in March 1976, with demonstrable phase stability. Transitions associated with the binary phase of Cyg XR-1 and a large change in the emission from Con A are reported
Detection of high energy X-rays from the galactic center region
Observations of the galactic center region made with the high energy X-ray detector on OSO-8 are discussed. A strong hard X-ray which was detected during these observations from the vicinity of the galactic center are examined. The counting rate spectrum and the photon number spectrum of the flux are determined. Comparisons with the high energy X-ray fluxes observed from sources in the region by others are discussed
Unified Universal Seesaw Models
A set of Grand Unified Theories based upon the gauge groups SU(5)_\L \times
SU(5)_\R, SO(10)_\L \times SO(10)_\R and SU(4)_\C \times SU(4)_\L \times
SU(4)_\R is explored. Several novel features distinguish these theories from
the well-known , and SU(4)_\C \times SU(2)_\L \times SU(2)_\R
models which they generalize. Firstly, Standard Model quarks and leptons are
accompanied by and mix with heavy SU(2)_\L \times SU(2)_\R singlet partners.
The resulting fermion mass matrices are seesaw in form. Discrete parity
symmetries render the determinants of these mass matrices real and eliminate CP
violating gauge terms. The unified seesaw models consequently provide a
possible resolution to the strong CP problem. Secondly, \sinsq at the
unification scale is numerically smaller than the experimentally measured
scale value. The weak angle must therefore increase as it evolves down in
energy. Finally, proton decay is suppressed by small seesaw mixing factors in
all these theories.Comment: 22 pages with 2 figures not included but available upon request,
CALT-68-185
Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?
Several works analyzing the new physics contributions from the Left-Right
Symmetric Model to the CP violation phenomena in the neutral B mesons can be
found in the literature. These works exhibit interesting and experimentally
sensible deviations from the Standard Model predictions but at the expense of
considering a low right scale \upsilon_R around 1 TeV. However, when we stick
to the more conservative estimates for \upsilon_R which say that it must be at
least 10^7 GeV, no experimentally sensible deviations from the Standard Model
appear for indirect CP violation. This estimate for \upsilon_R arises when the
generation of neutrino masses is considered. In spite of the fact that this
scenario is much less interesting and says nothing new about both the CP
violation phenomenon and the structure of the Left-Right Symmetric Model, this
possibility must be taken into account for the sake of completeness and when
considering the see-saw mechanism that provides masses to the neutrino sector.Comment: LaTex file. 19 pages, 4 figures. Change in the way the paper address
the problem. As a result, change in title, abstract, and some sections.
Conclusions unchanged. Version to appear in Foundations of Physics Letter
Conjunction and Disjunction in Infectious Logics
In this paper we discuss the extent to which conjunction and disjunction can be rightfully regarded as such, in the context of infectious logics. Infectious logics are peculiar many-valued logics whose underlying algebra has an absorbing or infectious element, which is assigned to a compound formula whenever it is assigned to one of its components. To discuss these matters, we review the philosophical motivations for infectious logics due to Bochvar, Halldén, Fitting, Ferguson and Beall, noticing that none of them discusses our main question. This is why we finally turn to the analysis of the truth-conditions for conjunction and disjunction in infectious logics, employing the framework of plurivalent logics, as discussed by Priest. In doing so, we arrive at the interesting conclusion that —in the context of infectious logics— conjunction is conjunction, whereas disjunction is not disjunction
On the Hadronic Beam Model for Gamma-ray Production in Blazars
We consider, herein, a model for gamma-ray production in blazars in which a
relativistic, highly-collimated electron-proton beam interacts with a dense,
compact cloud as the jet propagates through the broad and perhaps narrow line
regions (BLR and NLR) of active galactic nuclei (AGN). During the propagation
of the beam through the cloud, the process of excitation of plasma waves
becomes an important energy loss mechanism, especially for mildly relativistic
proton beams. We compute the expected spectra of gamma-rays from the decay of
neutral pions produced in hadronic collisions of the beam with the cloud,
taking into account collisionless losses of the electron-proton beam. This
model may explain the X-ray and TeV gamma-ray (both low and high emission
states) of Mrk 421 as a result of synchrotron emission of secondary pairs from
the decay of charged pions and gamma-ray emission from the decay of neutral
pions for the plausible cloud parameters. However clouds can not be too hot and
too dense. Otherwise the TeV gamma-rays can be attenuated by the bremsstrahlung
radiation in the cloud and the secondary pairs are not able to efficiently
produce synchrotron flares because of the dominant role of inverse Compton
scattering.
The non-variable -ray emission observed from Mrk 421 in the EGRET
energy range cannot be described by the -rays from decay of neutral
pions provided that the spectrum of protons in the beam is well described by a
simple power law. These -rays might only be produced by secondary pairs
scattering the soft non-variable X-rays which might originate in the inner part
of the accretion disk.Comment: 14 pages,3 figures, latex, submitted to Ap
Testing quark mass matrices with right-handed mixings
In the standard model, several forms of quark mass matrices which correspond
to the choice of weak bases lead to the same left-handed mixings ,
while the right-handed mixings are not observable quantities. Instead, in
a left-right extension of the standard model, such forms are ansatze and give
different right-handed mixings which are now observable quantities. We
partially select the reliable forms of quark mass matrices by means of
constraints on right-handed mixings in some left-right models, in particular on
. Hermitian matrices are easily excluded.Comment: 12 pages RevTex, no figures. Minor corrections. Comment on SO(10)
changed and one reference adde
Sub-dekahertz ultraviolet spectroscopy of 199Hg+
Using a laser that is frequency-locked to a Fabry-Perot etalon of high
finesse and stability, we probe the 5d10 6s 2S_1/2 (F=0) - 5d9 6s 2D_5/2 (F=2)
Delta-m_F = 0 electric-quadrupole transition of a single laser-cooled 199Hg+
ion stored in a cryogenic radio-frequency ion trap. We observe
Fourier-transform limited linewidths as narrow as 6.7 Hz at 282 nm (1.06 X
10^15 Hz), yielding a line Q = 1.6 X 10^14. We perform a preliminary
measurement of the 5d9 6s2 2D_5/2 electric-quadrupole shift due to interaction
with the static fields of the trap, and discuss the implications for future
trapped-ion optical frequency standards.Comment: 4 pages, 4 figures, submitted for publicatio
CP asymmetries in penguin-induced B decays in general left-right models
We study CP asymmetries in penguin-induced b -> s\bar{s}s decays in general
left-right models without imposing manifest or pseudomanifest left-right
symmetry. Using the effective Hamiltonian approach, we evaluate CP asymmetries
in B^\pm -> \phi K^{(\ast)\pm} decays as well as mixing induced B meson decays
B -> J/\psi K_s and B -> \phi K_s decays. Based on recent measurements
revealing large CP violation, we show that nonmanifest type model is more
favored than manifest or pseudomanifest type.Comment: 16 pages, 12 eps figure
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