Photoproduction of Photoproduction of K K + + near near threshold threshold ► Main features of the reaction Main features of the reaction ► Kinematics Kinematics ► K K + meson identification meson identification ► TAPS calibration for charged TAPS calibration for charged particles particles ► MC simulation conditions MC simulation conditions ► Results Results ► Summary Summary Kashevarov, CB@MAMI Collaboration Meeting, Basel
Photoproduction of K + L(1405) near threshold. Main features of the reaction Kinematics K + meson identification TAPS calibration for charged particles MC simulation conditions Results Summary. V.L. Kashevarov, CB@MAMI Collaboration Meeting, Basel 2006. g p → K + L (1405). - PowerPoint PPT Presentation
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Photoproduction ofPhotoproduction of KK++ near near thresholdthreshold
►Main features of the reactionMain features of the reaction►KinematicsKinematics►KK++ meson identification meson identification►TAPS calibration for charged particlesTAPS calibration for charged particles►MC simulation conditionsMC simulation conditions►ResultsResults►SummarySummary
► Tagger bin = 2 MeVTagger bin = 2 MeV► Ladder = 800 kHz (Main tagger from 900 MeV)Ladder = 800 kHz (Main tagger from 900 MeV)► Tagging efficiency = 0.4Tagging efficiency = 0.4► Live time = 60%Live time = 60%► LH2 target length = 5 cmLH2 target length = 5 cm► Front of TAPS – Center of target = 120 cmFront of TAPS – Center of target = 120 cm► Old PID and MWPC, but without any materials in Old PID and MWPC, but without any materials in
forward directionforward direction► No Cherenkov detectorNo Cherenkov detector► Total cross section for 1480 MeV = 100 nbTotal cross section for 1480 MeV = 100 nb
ResultsResults
E K+ = F (E cluster) E K+ = F (ToF) E = 1475 MeV
( K +) M (MeV)
ResultsResults
( K +) M (MeV)
(1)(1)oo o o n nooPartial Partial contributioncontribution0.8% (0.06%)0.8% (0.06%)(2)(2)o o pp
oo1.8% (0.13%)1.8% (0.13%)
(3)(3) KK++ {{oo p p ) ) 44.8% (0.25%).8% (0.25%)
(4)(4) KK++ { { ((++n n ) ) nn 2.8% (0.45%) 10.2% (0.9%)10.2% (0.9%)
Results : InvMassResults : InvMass
(on ) o ( o n ) * ( o n o )
(1)(1)oo o o nnooPartial Partial contributioncontribution0.6% 0.6% (2)(2)o o pp
oo0.8%0.8% 1.4% 1.4%
(p ) o ( p ) * ( p o )
Results : InvMassResults : InvMass(3)(3) KK++ {{oo p p ) ) 22.4% .4%
(4)(4) KK++ { { ((++nn ) ) nn 4.2% 6.6% 6.6%
+ ( n) + n n * (
n)
+ ( o p) * ( o
p)
SummarySummary
► The best way for investigation of the reaction is to The best way for investigation of the reaction is to measure MM( measure MM( ,K ,K++););
► Coincidences between KCoincidences between K++ and two or three final and two or three final state particles are needed to suppress background;state particles are needed to suppress background;
► Endpoint tagger would be very useful;Endpoint tagger would be very useful;► TAPS detector allows to do a good identification of TAPS detector allows to do a good identification of
KK++ mesons for cluster size < 3 and cluster energy < mesons for cluster size < 3 and cluster energy < 200 MeV;200 MeV;