Research Objectives
We want to set up a comprehensive framework for using lattice gauge methods with "domain wall quarks" (DWQ) for the calculation of weak matrix elements.
Computational Approach
The basic ingredient in the method is a calculation of the quark propagator. The novel element in our method is that it requires introduction of a ficitious fifth dimension. The T3E-600 and T3E-900 machines at NERSC have been used for these computations.
Accomplishments
We have demonstrated that DWQ start to exhibit the crucial symmetries of the continuum theory (chiral symmetries) with a modest extent in the 5th dimension, i.e. even when the number of lattice sites in the extra dimension is as few as about 10. In the work finished so far, we have obtained a number of key results including a calculation of the important matrix element, BK. Furthermore, our results show that DWQ have significantly improved scaling behavior: the discretization errors are O(a2) and not O(a). Our data indicate that the good scaling and chiral behavior of DWQ more than compensates for the added cost of the extra dimension.
Significance
The significance of this work is that it opens up an entirely new method for attacking some of the basic challenges in particle physics computations. For the past many decades we have not been able to understand the strength of some simple reactions such as K decays to pi x pi. Consequently we have been unable to test the Standard Model of Elementary Particles through existing data and with improved experiments that are now underway. Further progress with DWQ could enable us to test for clues for the new physics that lies beyond the Standard Model.
Publications
T. Blum and A. Soni. 1997. QCD with Domain Wall Quarks. Phys. Rev. D 56:174.
T. Blum and A. Soni. 1997. Domain Wall Quarks and Kaon Weak Matrix Elements. Phys. Rev. Lett. 79:3595. http://ojps.aip.org/prlo/top.html
The kaon B parameter.