Mark Fischler

Effects of large mass fermions on MX and sin2θW

Abstract Some effects of heavy quarks and leptons are analyzed in the standard SU(5) model. We evaluate the two-loop corrections to the SU(3), SU(2), and U(1) β-functions incorporating the effects of large Yukawa couplings of the fermions to the Higgs bosons. The corrections to M X and sin 2 θ W are found to be small for fermion masses less than ∼240 GeV.

The ACP multiprocessor system at Fermilab

Abstract The Advanced Computer Program at Fermilab has developed a multiprocessor system which is easy to use and uniquely cost effective for many high energy physics problems. The system is based on single board computers which cost under

Young–tableau methods for Kronecker products of representations of the classical groups

1500 each to build including 2 Mbytes of on board memory. Expansion to 6 Mbytes is now available. These standard VME modules each run experiment reconstruction code in Fortran at speeds approaching that of a VAX 11/780. The first system, now with 100 processors, has been operated for six months, with essentially no down time, by computer operators in the Fermilab Computer Center. An interface from Fastbus to the Branch Bus has been developed for online use which has been tested error free at 20 Mbytes/s for 48 hours. ACP hardware modules are available commercially.

Absence of phase transition in QCD with massless quarks

Diagrammatic methods for decomposing Kronecker products of arbitrary representations of any of the classical groups are presented. For convenience, efficient ways of computing the dimensions and quadratic Casimir’s C2(R) are also given. These methods seem more useful for hand calculations than the method of Schur functions (or characteristic polynomials). An appendix presents the Kronecker products for any two representations of dimension ⩽100.

Software for the ACP multiprocessor system

Abstract SU(3) lattice gauge theory with four flavors of massless Susskind fermions is studied on a small (4 4 ) lattice. The fermion determinant is treated in an exact manner. It is observed that the phase transtion which is seen in the pure gauge theory on that lattice disappears when the fermionic determinant is included in the action.

Use of the Fermilab Advanced Computer Program Multi-Microprocessor as an on-Line Trigger Processor

Abstract Software has been developed for use with the Fermilab ACP multiprocessor system (described in an accompanying paper). The software was designed to make a system of a hundred independent node processors as easy to use a single, powerful CPU. Subroutines have been developed by which a users host program can send data to and get results from the program running in each of his ACP node processors. Utility programs make it easy to compile and link host and node programs, to debug a node program on an ACP development system, and to submit a debugged program to an ACP production system.

Crossbar switch backplane and its application

The Fermilab Advanced Computer Program is constructing a powerful multi-microprocessor system for data analysis in high-energy physics. The system will use commercial 32-bit microprocessors and be programmed in Fortran-77. A large array of support software allows easy migration of user applications from a uniprocessor environment to the multiprocessor, as well as providing sophisticated program development, debugging, and error handling and recavery tools. This system will provide computing power with a cost effectiveness of

The ACP Branch Bus and Real Time Applications of the ACP Multiprocessor System

3000-4000 per VAX 11/780 equivalent. We describe here the applications of this system as an on-line trigger processor. The low cost, commercial availability, compatibility with off-line analysis programs, and high data bandwidths (up to 160 MByte/sec) make this system an ideal choice for such real-time applications.

ACP/R3000 processors in data acquisition systems

A crossbar switch backplane design (bus switch backplane) is described. This backplane holds a maximum of 16 modules and allows simultaneous communications between up to eight pairs of modules. The aggregate data transfer rate on the backplane is 160 Mb/s. The bus switch backplane is an essential part of the Advanced Computer Program (ACP) Multiple Array Processor, a superconductor for site-oriented problems. The first application of this machine is in lattice gauge theory calculations. The bus switch backplane also finds ready application in data acquisition schemes based on the ACP multimicroprocessor system. >

The Fermilab lattice supercomputer project

The ACP Branchbus, a high speed differential bus for data movement in multiprocessing and data acquisition environments, is described. This bus was designed as the central bus in the ACP multiprocessing system. In its full implementation with 16 branches and a bus switch, it will handle data rates of 160 MByte/sec and allow reliable data transmission over inter rack distances. We also summarize applications of the ACP system in experimental data acquisition, triggering and monitoring, with special attention paid to FASTBUS environments.