photoproduction of l(1405)/s(1385)
DESCRIPTION
Photoproduction of L(1405)/S(1385). M. Niiyama. TPC data w/ CH2 and carbon target. g p K + S(1385) K + L p 0 K + p p - p 0. g p K + L(1405) K + S p ∓ K + p + p - n. Physics Motivation structure of Λ*(1405). - PowerPoint PPT PresentationTRANSCRIPT
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Photoproduction of M. Niiyama
p K++0p0p K++∓-n
TPC data w/ CH2 and carbon target.
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Physics Motivation structure of Λ*(1405)
• To measure in medium modification of the lineshape of • First, measure the production cross section from free proton in CH2
E. Oset et al.
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TPC
E // B
700mm
Target holder
High voltage plane
Wire & padplane
Drift field cage
Beam
Active volume (cylindrical shape) 700 mm in length 400 mm in diameter
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• The mass difference between and is too small to be separated by missing mass mm(K+).• Detect decay products and distinguish these two hyperon resonances.• Measure the production ratio / using TPC data• Extract the absolute value of and from liquid hydrogen target with the input of measured production ratio.p K++0p0p K++∓-n
Outline
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spectrum of in 2 Ebins
p K++0p0
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Spectrum of comparison with Ahn-san’s
measurement at LEPS
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Angular distribution of from decay. (angle K in CM)Ahn-san’s measurement This work
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spectrum of in 2 Ebins
p K++∓-n
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Ratio of in 2 Ebins GeV 0.54±0.17 GeV 0.084±0.076
GeV GeV
|t| GeV^2 |q|^2 (GeV/c^2
t nor q^2 doesn’t change.Edependence should be due to the other reason.
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Absolute value of the differential cross section
Fit to MM(K+) spectrum of liq. H2 data with the input of production ratio of /
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Summary
he production cross section of decreases in higher photon energy region. It seems not due to t-dependence or q^2-dependence. It should be due to the other production mechanism.
We have measured the ratio of The absolute value is obtained using LH2 data.
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MC
p K+
in 2 tbins
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spectrum of in 2 tbins
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mm(K) for tagged eventsin 2 tbins
|t|<0.22 |t|>0.22