Vacuum straw tracker test beam run

Abstract

This memorandum of understanding requests beam time at Fermilab during the 2005 Meson Test Beam run to measure the detection inefficiency of vacuum straw tubes. One of the future kaon experiments at J-PARC has the goal to measure the branching ratio of the neutral kaon ''Golden Mode'' K{sub L} {yields} {pi}{sup 0} with a few hundred event sensitivity. This future J-PARC experiment is a follow up of a current KEK experiment, E391a which has been taking data since February 2004. E391a is a collaboration of five countries (Japan, United States, Russia, Korea, and Taiwan) with ten institutions (KEK, Saga U, Yamagata U, Osaka U, U of Chicago, Pusan U, JINR, NDA, Kyoto U, National Taiwan U, and RCNP). The branching ratio of K{sub L} {yields} {pi}{sup 0} {nu} {nu} is small, about 3 x 10{sup -11}. To first order, all kaon decays with final states with charged particles need to be vetoed, and those include K{sub e3}, K{sub {mu}3}, and K{sub {+-}0} (about 80% of all neutral kaon decay). The standard and typical veto power comes from sheet scintillator and may not be adequate. Vacuum straw tubes provides additional, independent and orthogonal veto power, but the detection inefficiency has not been known or measured in a detail way. The inefficiency of the straw has three sources, the electronics, the straw wall/wire, and the gas. We like to perform beam test to measure all three sources. There is much experience in straw detector technology, and some in vacuum straw technology (CKM R&D effort). The possible use of straws in the future K{sub L} {yields} {pi}{sup 0} {nu} {nu} experiment will allow absolute photon/electron energy calibration (via K{sub {+-}0} decays), possible measurement of photon inefficiencies (via K{sub 000} with {pi}{sup 0} Dalitz), and as mentioned, charged particle veto. The results of this proposed beam test will provide new knowledge on the absorption cross section and will direct us on design issues for future neutral kaon decay experiments. Regarding the straws, lots of R&D work has been done by the CKM collaboration, and we plan to use as much existing straws setup and related equipment as possible.