11 research outputs found
Pulsar PSR B0656+14, the Monogem Ring, and the Origin of the `Knee' in the Primary Cosmic Ray Spectrum
The Monogem ring is a bright, diffuse, 25-degree-diameter supernova remnant
easily visible in soft X-ray images of the sky. Projected within the ring is a
young radio pulsar, PSR B0656+14. An association between the remnant and pulsar
has been considered, but was seemingly ruled out by the direction and magnitude
of the pulsar proper motion and by a distance estimate that placed the pulsar
twice as far from Earth as the remnant. Here we show that in fact the pulsar
was born very close to the center of the expanding remnant, both in distance
and projection. The inferred pulsar and remnant ages are in good agreement. The
conclusion that the pulsar and remnant were born in the same supernova
explosion is nearly inescapable. The remnant distance and age are in remarkable
concordance with the predictions of a model for the primary cosmic ray energy
spectrum in which the `knee' feature is produced by a single dominant source.Comment: 4 pages, to appear in the Astrophys. J. Lett. Full size color figure
can be found at http://www.thorsett.org/researc
QCD corrections to the production of at the ILC
A precise calculation of the top quark pair production associated with a hard
photon is essential for testing the electroweak property of the top quark in
the Standard Model (SM). We investigate the one-loop QCD corrections to the
process at the International Linear Collider
(ILC), and find that the -factor can be as large as 1.238 (1.105, 1.060) for
a center-of-mass energy GeV. The transverse momentum
distributions of the top quark and photon are respectively shown at leading
order (LO) and next-to-leading order(NLO). Due to the asymmetric rapidity
distribution of the top (anti-top) quark, we also study the top quark
forward-backward asymmetry () in production at
NLO, which is found to be 45.82 (55.25, 55.89)% for
GeV.Comment: 12 pages, 5 figures, version acceptd by Phys. Lett.
Measurement of air shower cores to study the cosmic ray composition in the knee energy region
Since 1996, a hybrid experiment consisting of an emulsion chamber and a burst
detector array and the Tibet-II air shower array has been operated at
Yangbajing (4300 m above sea level) in Tibet. This experiment can detect
air-shower cores, called burst events, accompanied by air showers in excess of
about 100 TeV. Using the burst event data observed by this experiment, we
discuss the primary cosmic ray composition around the knee in comparison with
the Monte Carlo simulations. In this paper, we show that all the features of
burst events are wholly compatible with the heavy enriched composition in the
knee energy region.Comment: 20 pages, 21 figures, to appear in Physical Review
Alien Registration- Legage, Newton (Rockland, Knox County)
https://digitalmaine.com/alien_docs/14398/thumbnail.jp
Alien Registration- Legage, Newton (Rockland, Knox County)
https://digitalmaine.com/alien_docs/14398/thumbnail.jp