Results from PS185 Johansson, T.; Barnes, P.D.; Bassalleck, B. ...
Nuclear physics. A,
08/1999, Letnik:
655, Številka:
1
Journal Article
Recenzirano
The PS185 experiment at LEAR/CERN has studied strangeness production in antiproton-proton collisions. Exclusive final states of antihyperon-hyperon pairs have been measured in order to investigate ...strange-quark production dynamics. A comprehensive data set is available for the
ΛΛ
channel and observables include total and differential cross sections, polarisations and spin correlations. Data from other hyperon channels, such as
Σ
0Λ + c.c.
,
Σ
+Σ
+
and
Σ
−Σ
−
, are also available. The analysis of a spin transfer measurement for the
pp →
ΛΛ
reaction using a polarised proton target is in progress.
An experiment to study double-strangeness systems was performed at the BNL-AGS via the (K
−,K
+) reaction using a diamond target and scintillating fiber (SCIFI) blocks (E885). A search for the H ...dibaryon through the stopped Ξ
− process is one of the objectives. The number of stopped Ξ
−'s is about 9,000, and the expected sensitivity of the H dibaryon search is more than one order of magnitude higher than that of the previous experiment at KEK-PS (E224).
During the 1993 AGS heavy ion run, experiment E886 conducted a strangelet search in Au + Pt reactions, with beam momentum of 10.8 GeV/c per nucleon. Presented here are the upper limit for strangelet ...production, invariant cross sections for p, t, d
3He,
4He,
6He,
8He,
6Li,
7Li,
8Li and
7Be, along with a demonstration of their agreement with a coalescence model fit to data collected by E886 during the 1992 engineering run, and upper limits for production cross sections for other rare objects, such as (H dibaryon)-nucleus systems. All results reported here are preliminary.
This study examines the presidential addresses of the 21 women presidents of the National Conference of Social Work. Although content analysis is difficult because the speeches cross seven decades, ...three components stood out: The women presidents primarily used their expertise as power, used partisan leadership techniques with a conservative slant, and avoided discussing women or women’s issues. The authors argue that these three stylistic components reflect the common desire of the women presidents to advance the professional status of social work, under conditions of subdominant professional and gendered status, despite the span of years.
In an effort to evaluate the use of electrokinetic capillary technology for therapeutic and diagnostic drug monitoring, samples were analysed batchwise with an automated, high-throughput capillary ...electrophoretic instrument coupled to an inexpensive PC data acquisition and evaluation system. Examples studied included the capillary electrophoretic (HPCE) determination of bupivacaine in drain fluid collected after pulmonary surgery and the micellar electrokinetic capillary chromatographic (MECC) determination of antipyrine in human plasma. Analyses for antipyrine could be accomplished without any sample pretreatment whereas bupivacaine required extraction prior to analysis. Antipyrine determination was effected through external calibration using either peak areas, relative peak areas or peak heights. The intraday and interday reproducibilities (n = 15) of the evaluated concentrations were 1.5-3% and 5-6%, respectively. For bupivacaine, determination based on internal and external calibration employing peak areas and peak heights was investigated. The intraday and interday reproducibilities (n = 5) of bupivacaine concentrations were about 1% and 2%, respectively, for internal calibration and both about 5% for external calibration. The electrokinetic capillary data compared well with data obtained by gas chromatography (bupivacaine) and high-performance liquid chromatography (antipyrine).
Spin-transfer observables for p p-->Lambda Lambda have been measured using a transversely polarized frozen-spin target and a beam momentum of 1.637 GeV/c. Current models of the reaction near ...threshold are in good agreement with existing measurements performed with unpolarized particles in the initial state but produce conflicting predictions for the spin-transfer observables Dnn and Knn (the normal-to-normal depolarization and polarization transfer), which are measurable only with polarized target or beam. Measurements of Dnn and Knn presented here are found to be in disagreement with predictions from these models.
The reaction
p
p→
Λ
Λ
was examined by LEAR experiment PS185/3 at 1.525 and 1.640 GeV/c. The proton target was transversely polarized in order to measure the depolarization and spin transfer. ...Theoretical calculations of
D
nn, the component of the depolarization normal to the production plane, differ greatly according to whether quark-gluon or meson-exchange models are employed. The measured
D
nn and spin transfer
K
nn appear to be inconsistent with the specific models cited.
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