16,156 research outputs found

### Reduced, tame and exotic fusion systems

We define here two new classes of saturated fusion systems, reduced fusion
systems and tame fusion systems. These are motivated by our attempts to better
understand and search for exotic fusion systems: fusion systems which are not
the fusion systems of any finite group. Our main theorems say that every
saturated fusion system reduces to a reduced fusion system which is tame only
if the original one is realizable, and that every reduced fusion system which
is not tame is the reduction of some exotic (nonrealizable) fusion system

### Dust formation around AGB and SAGB stars: a trend with metallicity?

We calculate the dust formed around AGB and SAGB stars of metallicity Z=0.008
by following the evolution of models with masses in the range 1M<M<8M
throughthe thermal pulses phase, and assuming that dust forms via condensation
of molecules within a wind expanding isotropically from the stellar surface. We
find that, because of the strong Hot Bottom Burning (HBB) experienced, high
mass models produce silicates, whereas lower mass objects are predicted to be
surrounded by carbonaceous grains; the transition between the two regimes
occurs at a threshold mass of 3.5M. These fndings are consistent with the
results presented in a previous investigation, for Z=0.001. However, in the
present higher metallicity case, the production of silicates in the more
massive stars continues for the whole AGB phase, because the HBB experienced is
softer at Z=0.008 than at Z=0.001, thus the oxygen in the envelope, essential
for the formation of water molecules, is never consumed completely. The total
amount of dust formed for a given mass experiencing HBB increases with
metallicity, because of the higher abundance of silicon, and the softer HBB,
both factors favouring a higher rate of silicates production. This behaviour is
not found in low mass stars,because the carbon enrichment of the stellar
surface layers, due to repeated Third Drege Up episodes, is almost independent
of the metallicity. Regarding cosmic dust enrichment by intermediate mass
stars, we find that the cosmic yield at Z=0.008 is a factor 5 larger than at
Z=0.001. In the lower metallicity case carbon dust dominates after about 300
Myr, but at Z=0.008 the dust mass is dominated by silicates at all times,with a
prompt enrichment occurring after about 40 Myr, associated with the evolution
of stars with masses M =7.5 -8M.Comment: 14 pages, 10 figures, 2 Tables, accepted for publication in MNRA

### Algebraic Characterization of Vector Supersymmetry in Topological Field Theories

An algebraic cohomological characterization of a class of linearly broken
Ward identities is provided. The examples of the topological vector
supersymmetry and of the Landau ghost equation are discussed in detail. The
existence of such a linearly broken Ward identities turns out to be related to
BRST exact antifield dependent cocycles with negative ghost number.Comment: 30 pages, latex2e file, subm. to Journ. of Math. Phy

### Nonrenormalization theorems for N=2 Super Yang-Mills

The BRST algebraic proofs of the the nonrenormalization theorems for the beta
functions of N=2 and N=4 Super Yang-Mills theories are reviewed.Comment: 3 pages, contribution to SUSY 2000 Encyclopedi

### Hard Cosmic Ray Sea in the Galactic Center: a consistent interpretation of H.E.S.S. and Fermi-LAT $\gamma$-ray data

We present a novel interpretation of the gamma-ray diffuse emission measured
by H.E.S.S. in the Galactic Center (GC) region and the Galactic ridge. Our
starting base is an updated analysis of PASS8 Fermi-LAT data, which allows to
extend down to few GeV the spectra measured by H.E.S.S. and to infer the
primary CR radial distribution above 100 GeV. We compare those results with a
CR transport model assuming a harder scaling of the diffusion coefficient with
rigidity in the inner Galaxy. Such a behavior reproduces the radial dependence
of the CR spectral index recently inferred from Fermi-LAT measurements in the
inner GP. We find that, in this scenario, the bulk of the Galactic ridge
emission can be naturally explained by the interaction of the diffuse,
steady-state Galactic CR sea interacting with the gas present in the Central
molecular zone. The evidence of a GC PeVatron is significantly weaker than that
inferred adopting a conventional (softer) CR sea.Comment: Oral contribution to the International Cosmic Ray Conference (ICRC
2017), 12-20 July 2017, Bexco, Busan, Kore

### KLOE results at the Frascati $\phi$-factory DA$\Phi$NE

The KLOE experiment at the Frascati $\phi$-factory DA$\Phi$NE has collected
about 0.5 fb$^{-1}$ of data till the end of the year 2002. These data allow to
perform a wide physics program, ranging from the physics of charged and neutral
kaons to radiative $\phi$-decays. Results are presented for the $K_L$ lifetime
and the semileptonic processes $K_{S,L} \to \pi e \nu$. From the light meson
spectroscopy program, results on the decays $\phi \to f_0(980)\gamma,
a_0(980)\gamma$ as well as $\phi \to \eta \gamma, \eta' \gamma$ are presented.Comment: 5 pages, 3 figures, Proceedings contribution to the 10th Int.
Symposium on "Meson-Nucleon Physics and the Structure of the Nucleon"
(MENU04), Beijing, China, Aug. 30 - Sept. 4, 200

- …