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RISS 인기검색어
- 검색키워드
- 저자 : Dujmic, Denis (검색결과 1 건)
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Open charm production at HERA-B
Dujmic, Denis The University of Texas at Austin 2001 해외박사(DDOD)
소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.
A proton beam with a momentum of 920 GeV/c is collided with a carbon wire target (<math> <f> <rad><rcd>s</rcd></rad></f> </math> = 42 GeV) at a rate of 2–5 MHz during the commissioning of the HERA-B experiment. Events that had a lepton candidate with a transverse momentum greater than 1 GeV/c (1.5 GeV/c) are reconstructed and written to tape. The analysis uses 2.6 million events triggered in the muon channel. Performance of the Ring Imaging Čerenkov detector is described in detail, as well as the algorithm for positive particle identification, its efficiency, and pion-kaon separation. Detection of charm decays is carried out in two decay channels: <italic> D</italic><super>0</super> → π<italic>K</italic> and <italic>D</italic><super> +</super> → ππ<italic>K</italic>. Signals obtained in the measurement are statistically significant with cross sections for all <italic>x<sub>F </sub></italic> of <math> <f> <g>s</g><inf>D<sup>0</sup>+<a><ac>D</ac><ac>&d1;</ac></a><sup> 0</sup></inf></f> </math> = 80 ± 27(stat) ± 61(syst) μb/nucleon for <italic> D</italic><super>0</super> + <italic>D¯</italic><super>0</super>, and <math> <f> <g>s</g><inf>D<sup>+</sup>+D<sup>-</sup></inf></f> </math> = 52 ± 20(stat) ± 39(syst) μb/nucleon for <italic> D</italic><super>+</super> + <italic>D</italic><super>−</super>. For comparison with other experiments, these measurements are converted into the total forward cross section for <italic>cc¯</italic> production <math> <f> <g>s</g><inf>c<a><ac>c</ac><ac>&d1;</ac></a></inf></f> </math> = 39 ± 10(stat) ± 21(syst) μb/nucleon for <italic> x<sub>F</sub></italic> > 0. This value is consistent with an estimate based on <italic>QCD</italic> calculations and other measurements. The production cross sections for two control channels <italic>J/ψ </italic> → μμ and <italic>K<sub>S</sub></italic> → ππ are also measured. The reconstructed <italic>J/ψ</italic> signal leads to a cross section of (420 ± 80) nb/nucleon, with nuclear dependence taken as <italic>A</italic><super>0.92</super>. <italic>K<sub>S</sub></italic> signal has cross section of 19.1 ± 1.8 mb/nucleon, with <italic>A</italic><super> 0.718</super>. Both measurements are in a good agreement with expectations. A set of detected <italic>D</italic> mesons was used to search for additional vertices that belong to <italic>B</italic> meson decays. It allows setting a limit for <italic>bb¯</italic> production at <150 nb. This work presents a contribution to the commissioning of the HERA-B experiment, and an extension of its research program to the physics of open charm decays.
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