3,026 research outputs found
The Galactic cosmic-ray Sun shadow observed by HAWC
The magnetic field of the Solar corona is difficult to measure directly.
However, indirect observations of the solar corona are possible using the
deficit in flux of cosmic rays coming from the direction of the Sun. Low-energy
cosmic rays (~GeV) are deflected by the inner magnetic field of the Sun and the
interplanetary magnetic field frozen into the solar wind. In contrast,
high-energy cosmic rays (~TeV and above) are absorbed in the Sun's photosphere
producing a shadow in the Sun's nominal position viewed from Earth. Several
ground-based instruments have observed the effects of the heliospheric magnetic
field on the size of the sun shadow and its position. The High-Altitude Water
Cherenkov Observatory (HAWC) is an air shower array located in the central
region of Mexico that observes TeV cosmic rays at a rate of about 15 kHz. in
this work, we present preliminary images of the sun shadow from data collected
by HAWC during 2013 and 2014 for different energy ranges.Comment: Presented at the 34th International Cosmic Ray Conference (ICRC2015),
The Hague, The Netherlands. See arXiv:1508.03327 for all HAWC contribution
Quantization of canonical cones of algebraic curves
We introduce a quantization of the graded algebra of functions on the
canonical cone of an algebraic curve C, based on the theory of formal
pseudodifferential operators. When C is a complex curve with Poincar\'e
uniformization, we propose another, equivalent construction, based on the work
of Cohen-Manin-Zagier on Rankin-Cohen brackets. We give a presentation of the
quantum algebra when C is a rational curve, and discuss the problem of
constructing algebraically "differential liftings"
Weight function for the quantum affine algebra
In this article, we give an explicit formula for the universal weight
function of the quantum twisted affine algebra . The
calculations use the technique of projecting products of Drinfeld currents onto
the intersection of Borel subalgebras of different types.Comment: 25 page
SOS model partition function and the elliptic weight functions
We generalize a recent observation [arXiv:math/0610433] that the partition
function of the 6-vertex model with domain-wall boundary conditions can be
obtained by computing the projections of the product of the total currents in
the quantum affine algebra in its current
realization. A generalization is proved for the the elliptic current algebra
[arXiv:q-alg/9703018,arXiv:q-alg/9601022]. The projections of the product of
total currents are calculated explicitly and are represented as integral
transforms of the product of the total currents. We prove that the kernel of
this transform is proportional to the partition function of the SOS model with
domain-wall boundary conditions.Comment: 21 pages, 5 figures, requires iopart packag
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