Abstract
We propose to search for the charge symmetry breaking reaction dd -> alpha pi0 just above threshold using a magnetic channel and an array of Pb-glass detectors located in the T-region of the IUCF Cooler ring. Within the framework of a chiral effective interaction, the largest contribution to the isospin-breaking term comes directly from the difference between the up and down quark masses. Observations of the dd -> alpha pi0 reaction at the expected level would represent a significant confirmation of this theoretical approach and lead to an independent measure of the quark mass difference.
Recommendation
The committee appreciates the significant progress made by the collaboration during the last year; it especially approves of the increase in manpower and the new management plan with clear responsibilities. Although the dd -> 4He pi0 cross section cannot be predicted reliably within a factor of 10, the experiment appears to be feasible. Nevertheless, concern was raised by the committee about the dd -> 4He pi0 experiment considering the finite lifetime of the Cooler ring operations. Possibilities should be explored whether the time schedule for dd -> 4He pi0 could be advanced by three months without impacting the ongoing tagged neutron program that uses some of the same floor space. Furthermore, the committee recommends putting firm milestones in place. Considering all aspects of Cooler ring operation and laboratory resources, the director should determine the milestones and should decide whether they are met. We recommend that the "magnetic channel" completion target date should be considered as the first of such milestones. We approve them for 30 shifts in calendar year 2000 and encourage them to make to commissioning and production running more efficient.