13,821 research outputs found
A Comment on Fundamental Strings in M(atrix) Theory
We present a solution of M(atrix) theory describing type IIA fundamental
string. Our construction is based on the central charge of the longitudinal
membrane (= fundamental string), the BPS saturation condition and the relation
between M(atrix) theory and supersymmetric Yang-Mills theory. The fundamental
string corresponds to a photon in supersymmetric Yang-Mills theory.Comment: 11 pages + 2 uuencoded eps figures, LaTeX, errors corrected and
arguments generalize
String junctions on backgrounds with a positively charged orientifold plane
By means of the heterotic/type IIB duality, we study properties of junctions
on backgrounds with a positively charged orientifold seven-plane and D-branes,
which are expected to give seven dimensional Sp(r) gauge theories. We give a
modified BPS condition for the junctions and show that it reproduces the
adjoint representation of the Sp(r) group.Comment: 16 pages + 3 eps figures, LaTeX, a reference adde
Elliptic Ding-Iohara Algebra and the Free Field Realization of the Elliptic Macdonald Operator
The Ding-Iohara algebra is a quantum algebra arising from the free field
realization of the Macdonald operator. Starting from the elliptic kernel
function introduced by Komori, Noumi and Shiraishi, we can define an elliptic
analog of the Ding-Iohara algebra. The free field realization of the elliptic
Macdonald operator is also constructed.Comment: 42 page
Right-handed Neutrinos as Superheavy Dark Matter
We propose that right-handed neutrinos are very long-lived dark matter. The
long lifetime is realized by the separation of the wavefunction of right-handed
neutrinos and that of other fermions in an extra dimension. Such long-lived and
superheavy dark matter can naturally explain observed ultra high energy cosmic
rays above the GZK cutoff (5 * 10^{19} eV) and huge amounts of cold dark matter
simultaneously. Furthermore, the exponentially suppressed Yukawa couplings of
right-handed neutrinos leads to the high predictablilty on the mass parameter
of the neutrinoless double beta decay, as all the models which predict very
small neutrino mass of one generation.Comment: 11 pages, 5 figures, to appear in JHE
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