13 research outputs found
Observation of exotic meson production in the reaction at 18 GeV/c
An amplitude analysis of an exclusive sample of 5765 events from the reaction
at 18 GeV/c is described. The
production is dominated by natural parity exchange and by
three partial waves: those with and . A
mass-dependent analysis of the partial-wave amplitudes indicates the production
of the meson as well as the meson, observed for the
first time decaying to . The dominant, exotic
(non- partial wave is shown to be resonant with a mass of
GeV/c^2 and a width of GeV/c^2 . This exotic state, the , is produced with a
dependence which is different from that of the meson, indicating
differences between the production mechanisms for the two states.Comment: 5 pages with 4 figure
Partial-wave analysis of the eta pi+ pi- system produced in the reaction pi-p --> eta pi+ pi- n at 18 GeV/c
A partial-wave analysis of 9082 eta pi+ pi- n events produced in the reaction
pi- p --> eta pi+ pi- n at 18.3 GeV/c has been carried out using data from
experiment 852 at Brookhaven National Laboratory. The data are dominated by
J^{PC} = 0^{-+} partial waves consistent with observation of the eta(1295) and
the eta(1440). The mass and width of the eta(1295) were determined to be 1282
+- 5 MeV and 66 +- 13 Mev respectively while the eta(1440) was observed with a
mass of 1404 +- 6 MeV and width of 80 +- 21 MeV. Other partial waves of
importance include the 1++ and the 1+- waves. Results of the partial wave
analysis are combined with results of other experiments to estimate f1(1285)
branching fractions. These values are considerably different from current
values determined without the aid of amplitude analyses.Comment: 22 pages, 8 figure
Evidence for Exotic J^{PC}=1^{-+} Meson Production in the Reaction pi- p --> eta pi- p at 18 GeV/c
Details of the analysis of the eta pi- system studied in the reaction pi^{-}
p --> eta pi^{-} p at 18 GeV/c are given. Separate analyses for the 2 gamma and
pi+ pi- pi0 decay modes of the eta are presented. An amplitude analysis of the
data indicates the presence of interference between the a(2)(1320)- and a
J^{PC}=1^{-+} wave between 1.2 and 1.6 GeV/c^2. The phase difference between
these waves shows phase motion not attributable solely to the a(2)(1320)-. The
data can be fitted by interference between the a(2)(1320)- and an exotic 1^{-+}
resonance with M = 1370 +-16 +50 -30} MeV/c^2 and Gamma = 385 +- 40 +65 -105
MeV/c^2. Our results are compared with those of other experiments.Comment: 50 pages of text and 34 figure
Evidence for Exotic Meson Production in the Reaction at 18 GeV/c
The system has been studied in the reaction at 18 GeV/c. A large asymmetry in the angular distribution is
observed indicating interference between L-even and L-odd partial waves. The
is observed in the = wave, as is a broad
enhancement between 1.2 and 1.6 GeV/c^{2} in the wave. The
observed phase difference between these waves shows that there is phase motion
in addition to that due to decay. The data can be fitted by
interference between the and an exotic resonance with ) MeV/c^2 and ) MeV/c^2
Design and Performance of a Cesium Iodide Detector
The design, construction, and performance of a 198-element CsI detector built for Brookhaven experiment E852 is described. Design considerations for the array included such factors as rate, magnetic field, sensitivity and acceptance. Signals were obtained with a photodiode/preamplifier combination using PIN photodiodes. Data were taken over the course of two runs during the summers of 1993 and 1994. A calibration procedure using halo-muons is described. The gain, energy resolution, and position resolution of the detector are discussed. Finally, the ability of the detector to be used as a low energy photon veto is illustrated using the data. PACS numbers: xx.xx Typeset using REVT E X I. INTRODUCTION Brookhaven experiment E852 has been under design and construction for several years and had its first large-scale data run in the summer of 1994. The purpose of the experiment is to search for exotic mesons such as glueballs, hybrids, and multiquark states. The experiment will concentrat..