KEK effort for high field magnets

KEK has emphasized efforts to develop the RHQNb3Al superconductor and a sub-scale magnet reaching 13 T towards the HL-LHC upgrade in last years. In addition, relevant R&D regarding radiation resistance has been carried out. For higher field magnets beyond 15 T, HTS in combination with A15 superconductors should be one of baseline materials. However, all these superconductors are very sensitive to stress and strain and thorough understanding of behaviour is truly desired for realization of high field magnets. KEK has launched a new research subject on stress/strain sensitivity of HTS and A15 superconductors in collaboration with the neutron diffraction facility at J-PARC and High Field Laboratory in Tohoku University. Present activity for high field magnets at KEK is reported.Comment: 4 pages, contribution to the EuCARD-AccNet-EuroLumi Workshop: The High-Energy Large Hadron Collider, Malta, 14 -- 16 Oct 2010; CERN Yellow Report CERN-2011-003, pp. 41-4

The moduli of representations of degree 2

There are 6 types of 2-dimensional representations in general. For any groups and any monoids, we can construct the moduli of 2-dimensional representations for each type: the moduli of absolutely irreducible representations, representations with Borel mold, representations with semi-simple mold, representations with unipotent mold, representations with unipotent mold over ${\Bbb F}_2$, and representations with scalar mold. We can also construct them for any associative algebras.Comment: 76 page

Data storage and retrieval system

The Data Storage and Retrieval System (DSRS) consists of off-the-shelf system components integrated as a file server supporting very large files. These files are on the order of one gigabyte of data per file, although smaller files on the order of one megabyte can be accommodated as well. For instance, one gigabyte of data occupies approximately six 9 track tape reels (recorded at 6250 bpi). Due to this large volume of media, it was desirable to shrink the size of the proposed media to a single portable cassette. In addition to large size, a key requirement was that the data needs to be transferred to a (VME based) workstation at very high data rates. One gigabyte (GB) of data needed to be transferred from an archiveable media on a file server to a workstation in less than 5 minutes. Equivalent size, on-line data needed to be transferred in less than 3 minutes. These requirements imply effective transfer rates on the order of four to eight megabytes per second (4-8 MB/s). The DSRS also needed to be able to send and receive data from a variety of other sources accessible from an Ethernet local area network

Interactions between Octet Baryons in the SU_6 Quark model

The baryon-baryon interactions for the complete baryon octet (B_8) are investigated in a unified framework of the resonating-group method, in which the spin-flavor SU_6 quark-model wave functions are employed. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon interaction. We then proceed to explore B_8 B_8 interactions in the strangeness S=-2, -3 and -4 sectors. The S-wave phase-shift behavior and total cross sections are systematically understood by 1) the spin-flavor SU_6 symmetry, 2) the special role of the pion exchange, and 3) the flavor symmetry breaking.Comment: 11 pages, 6 figures, submitted to Phys. Rev. C (Rapid Communication