D. P. Coupal

Determination of ±s from a differential-jet-multiplicity distribution in e+e- collisions at ss =29 and 91 GeV

We measured the differential jet-multiplicity distribution in {ital e}{sup +}{ital e}{sup {minus}} annihilation with the Mark II detector. This distribution is compared with the second-order QCD prediction and {alpha}{sub {ital s}} is determined to be 0.123{plus minus}0.009{plus minus}0.005 at {radical}{ital s}{approx}{ital M}{sub {ital Z}} (at the SLAC Linear Collider) and 0.149{plus minus}0.002{plus minus}0.007 at {radical}{ital s}=29 GeV (at the SLAC storage ring PEP). The running of {alpha}{sub {ital s}} between these two center-of-mass energies is consistent with the QCD prediction.

Measurement of the K0(896) radiative width.

Primakoff production of the K/sup 0asterisk/(896) by incident K/sub L/s was observed in the energy range 100--200 GeV. Production from Cu and Pb targets was measured simultaneously leading to a new value for the K/sup 0asterisk/(896) radiative width GAMMA(K/sup 0asterisk/(896)..-->..K/sup 0/+..gamma..) of 116.5 +- 9.9 keV. The result agrees with a previous determination while being considerably more precise and allows for more stringent tests of quark-model relations among the radiative widths of the low-lying vector mesons.

Particle identification using dEdx in the mark II detector at the SLC

Abstract The central drift chamber in the Mark II detector at the SLAC linear collider has been instrumented with 100 MHz flash-ADCs. Pulse digitization provides particle identification through the measurement of average ionization loss in the chamber. We present the results of a study of system performance and outline the systematic corrections that optimize resolution. The data used are from a short test run at PEP with one third of the FADCs installed, and an extensive cosmic ray sample with the fully instrumented chamber.

The BaBaR drift chamber project

The BaBar Drift Chamber is now under construction. We review its design, the progress in the construction of the components, the plan for assembly and stringing and we present test results obtained with a prototype exposed at SLAC to cosmic rays. We also report on projected dE/dx performance from beam tests done with a chamber with a different cell design.

A Bipolar front end integrated circuit for the BaBar helium drift chamber

Abstract A Bipolar chip consisting of 4 channels, each with a digital, and an analog output has been developed for use with the BaBar drift chamber. The full design is described and results from the prototype are presented.

Determination of. alpha. sub s from a differential-jet-multiplicity distribution in e sup + e sup minus collisions at radical s =29 and 91 GeV

We measured the differential jet-multiplicity distribution in {ital e}{sup +}{ital e}{sup {minus}} annihilation with the Mark II detector. This distribution is compared with the second-order QCD prediction and {alpha}{sub {ital s}} is determined to be 0.123{plus minus}0.009{plus minus}0.005 at {radical}{ital s}{approx}{ital M}{sub {ital Z}} (at the SLAC Linear Collider) and 0.149{plus minus}0.002{plus minus}0.007 at {radical}{ital s}=29 GeV (at the SLAC storage ring PEP). The running of {alpha}{sub {ital s}} between these two center-of-mass energies is consistent with the QCD prediction.

Measurement of theK0/emph>(896)radiative width

Primakoff production of the K/sup 0asterisk/(896) by incident K/sub L/s was observed in the energy range 100--200 GeV. Production from Cu and Pb targets was measured simultaneously leading to a new value for the K/sup 0asterisk/(896) radiative width GAMMA(K/sup 0asterisk/(896)..-->..K/sup 0/+..gamma..) of 116.5 +- 9.9 keV. The result agrees with a previous determination while being considerably more precise and allows for more stringent tests of quark-model relations among the radiative widths of the low-lying vector mesons.

Measurement of the K/sup 0/(896) radiative width

Primakoff production of the K/sup 0asterisk/(896) by incident K/sub L/s was observed in the energy range 100--200 GeV. Production from Cu and Pb targets was measured simultaneously leading to a new value for the K/sup 0asterisk/(896) radiative width GAMMA(K/sup 0asterisk/(896)..-->..K/sup 0/+..gamma..) of 116.5 +- 9.9 keV. The result agrees with a previous determination while being considerably more precise and allows for more stringent tests of quark-model relations among the radiative widths of the low-lying vector mesons.