2,072 research outputs found
On the source contribution to the Galactic diffuse gamma rays above 398 TeV detected by the Tibet AS{\gamma} experiment
Potential contribution from gamma-ray sources to the Galactic diffuse gamma
rays observed above 100 TeV (sub-PeV energy range) by the Tibet AS{\gamma}
experiment is an important key to interpreting recent multi-messenger
observations. This paper reveals a surprising fact: none of the 23 Tibet
AS{\gamma} diffuse gamma-ray events above 398TeV within the Galactic
latitudinal range of |b| < 10 deg. come from the 43 sub-PeV gamma-ray sources
reported in the 1LHAASO catalog, which proves that these sources are not the
origins of the Tibet AS{\gamma} diffuse gamma-ray events. No positional overlap
between the Tibet AS{\gamma} diffuse gamma-ray events and the sub-PeV LHAASO
sources currently supports the diffusive nature of the Tibet AS{\gamma} diffuse
gamma-ray events, although their potential origin in the gamma-ray sources yet
unresolved in the sub-PeV energy range cannot be ruled out.Comment: 5 pages, 2 figures Accepted for publication from The Astrophysical
Journal Letters. arXiv admin note: text overlap with arXiv:2309.1607
Air Shower Simulation and Hadronic Interactions
The aim of this report of the Working Group on Hadronic Interactions and Air
Shower Simulation is to give an overview of the status of the field,
emphasizing open questions and a comparison of relevant results of the
different experiments. It is shown that an approximate overall understanding of
extensive air showers and the corresponding hadronic interactions has been
reached. The simulations provide a qualitative description of the bulk of the
air shower observables. Discrepancies are however found when the correlation
between measurements of the longitudinal shower profile are compared to that of
the lateral particle distributions at ground. The report concludes with a list
of important problems that should be addressed to make progress in
understanding hadronic interactions and, hence, improve the reliability of air
shower simulations.Comment: Working Group report given at UHECR 2012 Symposium, CERN, Feb. 2012.
Published in EPJ Web of Conferences 53, 01007 (2013
Instanton Number of Noncommutative U(n) gauge theory
We show that the integral of the first Pontrjagin class is given by an
integer and it is identified with instanton number of the U(n) gauge theory on
noncommutative . Here the dimension of the vector space that
appear in the ADHM construction is called Instanton number. The calculation is
done in operator formalism and the first Pontrjagin class is defined by
converge series. The origin of the instanton number is investigated closely,
too.Comment: 6 color figures, 27 pages, some comments and references are
added,typos fixe
Resolved 24.5 micron emission from massive young stellar objects
Massive young stellar objects (MYSO) are surrounded by massive dusty
envelopes. Our aim is to establish their density structure on scales of ~1000
AU, i.e. a factor 10 increase in angular resolution compared to similar studies
performed in the (sub)mm. We have obtained diffraction-limited (0.6") 24.5
micron images of 14 well-known massive star formation regions with
Subaru/COMICS. The images reveal the presence of discrete MYSO sources which
are resolved on arcsecond scales. For many sources, radiative transfer models
are capable of satisfactorily reproducing the observations. They are described
by density powerlaw distributions (n(r) ~ r^(-p)) with p = 1.0 +/-0.25. Such
distributions are shallower than those found on larger scales probed with
single-dish (sub)mm studies. Other sources have density laws that are
shallower/steeper than p = 1.0 and there is evidence that these MYSOs are
viewed near edge-on or near face-on, respectively. The images also reveal a
diffuse component tracing somewhat larger scale structures, particularly
visible in the regions S140, AFGL 2136, IRAS 20126+4104, Mon R2, and Cep A. We
thus find a flattening of the MYSO envelope density law going from ~10 000 AU
down to scales of ~1000 AU. We propose that this may be evidence of rotational
support of the envelope (abridged).Comment: 21 pages, accepted for A&
Excitation of Giant Monopole Resonance in Pb and Sn Using Inelastic Deuteron Scattering
The excitation of the isoscalar giant monopole resonance (ISGMR) in
Sn and Pb has been investigated using small-angle (including
) inelastic scattering of 100 MeV/u deuteron and
multipole-decomposition analysis (MDA). The extracted strength distributions
agree well with those from inelastic scattering of 100 MeV/u
particles. These measurements establish deuteron inelastic scattering at E 100 MeV/u as a suitable probe for extraction of the ISGMR strength with
MDA, making feasible the investigation of this resonance in radioactive
isotopes in inverse kinematics.Comment: 5 pages, 4 figures. To be published in Phys. Lett.
Euler number of Instanton Moduli space and Seiberg-Witten invariants
We show that a partition function of topological twisted N=4 Yang-Mills
theory is given by Seiberg-Witten invariants on a Riemannian four manifolds
under the condition that the sum of Euler number and signature of the four
manifolds vanish. The partition function is the sum of Euler number of
instanton moduli space when it is possible to apply the vanishing theorem. And
we get a relation of Euler number labeled by the instanton number with
Seiberg-Witten invariants, too. All calculation in this paper is done without
assuming duality.Comment: LaTeX, 34 page
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