Non-Linear/Non-Commutative Non-Abelian Monopoles

Using recently proposed non-linearly realized supersymmetry in non-Abelian gauge theory corrected to the order (alpha')^2, we derive the non-linear BPS equations in the background B-field for the U(2) monopoles and instantons. We show that these non-Abelian non-linear BPS equations coincide with the non-commutative anti-self-dual equations via the Seiberg-Witten map.Comment: 9 pages, LaTe

Nucleosynthesis in Type II Supernovae

Presupernova evolution and explosive nucleosynthesis in massive stars for main-sequence masses from 13 $M_\odot$ to 70 $M_\odot$ are calculated. We examine the dependence of the supernova yields on the stellar mass, ^{12}C(\alpha, \gamma) ^{16}O} rate, and explosion energy. The supernova yields integrated over the initial mass function are compared with the solar abundances.Comment: 1 Page Latex source, 10 PostScript figures, to appear in Nuclear Physics A, Vol. A616 (1997

Strings between branes

D-brane configurations containing fundamental strings are constructed as classical solutions of Yang-Mills theory. The fundamental strings in these systems stretch between D-branes. In the case of D1-branes, this construction gives smooth (classical) resolutions of string junctions and string networks. Using a non-abelian Yang-Mills analysis of the string current, the string charge density is computed and is shown to have support in the region between the D-brane world-volumes. The 't Hooft-Polyakov monopole is analyzed using similar methods, and is shown to contain D-strings whose flux has support off the D-brane world-volume defined by the Higgs scalar field, when this field is interpreted in terms of a transverse dimension. The constructions presented here are used to give a qualitative picture of tachyon condensation in the Yang-Mills limit, where fundamental strings and lower-dimensional D-branes arise in a volume of space-time where brane-antibrane annihilation has occurred.Comment: 35 pages, 16 eps figures, JHEP style; v2: a comment adde

Single Crystal Growth and Characterization of the Iron-Based Superconductor KFe2As2 Synthesized by KAs Flux Method

Centimeter sized platelet single crystals of KFe2As2 were grown using a self-flux method. An encapsulation technique using commercial stainless steel container allowed the stable crystal growth lasting for more than 2 weeks. Ternary K-Fe-As systems with various starting compositions were examined to determine the optimal growth conditions. Employment of KAs flux led to the growth of large single crystals with the typical size of as large as 15 mm x 10 mm x 0.4 mm. The grown crystals exhibit sharp superconducting transition at 3.4 K with the transition width 0.2 K, as well as the very large residual resistivity ratio exceeding 450, evidencing the good sample quality.Comment: 4 pages, 6 Postscript figure

Reconnection of Colliding Cosmic Strings

For vortex strings in the Abelian Higgs model and D-strings in superstring theory, both of which can be regarded as cosmic strings, we give analytical study of reconnection (recombination, inter-commutation) when they collide, by using effective field theories on the strings. First, for the vortex strings, via a string sigma model, we verify analytically that the reconnection is classically inevitable for small collision velocity and small relative angle. Evolution of the shape of the reconnected strings provides an upper bound on the collision velocity in order for the reconnection to occur. These analytical results are in agreement with previous numerical results. On the other hand, reconnection of the D-strings is not classical but probabilistic. We show that a quantum calculation of the reconnection probability using a D-string action reproduces the nonperturbative nature of the worldsheet results by Jackson, Jones and Polchinski. The difference on the reconnection -- classically inevitable for the vortex strings while quantum mechanical for the D-strings -- is suggested to originate from the difference between the effective field theories on the strings.Comment: 29 pages, 14 eps figures, JHEP style; references added, typos correcte

A Matrix Model for Baryons and Nuclear Forces

We propose a new matrix model describing multi-baryon systems. We derive the action from open string theory on the wrapped baryon vertex D-branes embedded in the D4-D8 model of large N holographic QCD. The positions of k baryons are unified into k x k matrices, with spin/isospin of the baryons encoded in a set of k-vectors. Holographic baryons are known to be very small in the large 't Hooft coupling limit, and our model offers a better systematic approach to dynamics of such baryons at short distances. We compute energetics and spectra (k=1), and also short-distance nuclear force (k=2). In particular, we obtain a new size of the holographic baryon and find a precise form of the repulsive core of nucleons. This matrix model complements the instanton soliton picture of holographic baryons, whose small size turned out to be well below the natural length scale of the approximation involved there. Our results show that, nevertheless, the basic properties of holographic baryons obtained there are robust under stringy corrections within a few percents.Comment: 30 pages. v3: more comments added, published versio

Real-time simulation of jet engines with digital computer. 1: Fabrication and characteristics of the simulator

The fabrication and performance of a real time jet engine simulator using a digital computer are discussed. The use of the simulator in developing the components and control system of a jet engine is described. Comparison of data from jet engine simulation tests with actual engine tests was conducted with good agreement

Lateral distribution of high energy hadrons and gamma ray in air shower cores observed with emulsion chambers

A high energy event of a bundle of electrons, gamma rays and hadronic gamma rays in an air shower core were observed. The bundles were detected with an emulsion chamber with thickness of 15 cm lead. This air shower is estimated to be initiated with a proton with energy around 10 to the 17th power to 10 to the 18th power eV at an altitude of around 100 gmc/2. Lateral distributions of the electromagnetic component with energy above 2 TeV and also the hadronic component of energy above 6 TeV of this air shower core were determined. Particles in the bundle are produced with process of the development of the nuclear cascade, the primary energy of each interaction in the cascade which produces these particles is unknown. To know the primary energy dependence of transverse momentum, the average products of energy and distance for various average energies of secondary particles are studied