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S.Kiselev, ITEP Introduction Input info selection of events background and signal

Estimation of background with RQMD for baryon system from  3N+3N  π 0 +6N in C+Be at T/A=3.2 GeV. S.Kiselev, ITEP Introduction Input info selection of events background and signal. Introduction.

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S.Kiselev, ITEP Introduction Input info selection of events background and signal

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  1. Estimation of background with RQMD for baryon systemfrom  3N+3N π0+6N in C+Be at T/A=3.2 GeV S.Kiselev, ITEP Introduction Input info selection of events background and signal ITEP meeting, S.Kiselev

  2. Introduction Our goal: using the high momentum π0 as a trigger, study the baryon system produced in 3N+3N π0+6N An instrument: collisions of light nuclei C+Be T/A=3.2 GeV on ITEP-TWAC An idea to estimate the background: select events with the number of nucleon-participants, Nprod ≥ 6 among Nprod find 6N with minimal momentum, pmin select events with p6Nmin < pcut (=100 MeV/c) remove this 6N from each event, rest nucleons - background add the π0+6N system, these 6N - signal ITEP meeting, S.Kiselev

  3. Input info • RQMD4.12 generator • 105 min. bias C+Be events at T/A=3.2 GeV (b<RC + RBe) • 3N+3N π0+6N at T/A=3.2 GeV • π0 will be detected at θc.m.=900  pcumul = 2.86 GeV/c, • (px =0, py = - pcumul , pz =0) • the momentum of every N of the 6N system, • (px =0, py = pcumul /6, pz =0) • is smearing with σx = σy = σz = σsmear (= 170 MeV/c) • our “detector” covers the cone with 450 around the y axis ITEP meeting, S.Kiselev

  4. C+Be T/A=3.2 GeV, event selection ~ 8N in min. bias events 58% of events with Nprod ≥ 6 • GEANT codes: • 1 γ 7π0 8 π+ 9 π- 10 K0L • 11 K+ 12 K- 13 n 14 p • K0S17 η 18 Λ19 Σ+ • 20Σ0 21 Σ- 22 Ξ0 23 Ξ- 16% of events with p6Nmin < 100 MeV/c ITEP meeting, S.Kiselev

  5. Background and signal our “detector” covers the cone with 450 around the y axis Background signal Background+ signal < NNbkg > = 0.66 < NNsig > = 5.40 a strong peak from the signal, S/B ~ 0.7/0.03 ~ 20 ITEP meeting, S.Kiselev

  6. Δp distribution for nucleons in the ‘signal area’ ‘signal area’: y = 0 ± 0.3, pt = 0.5 ± 0.2 GeV/c < NNbkg > = 0.32, < NNsig > = 4.16 ITEP meeting, S.Kiselev

  7. sensitivity to pcut: p6Nmin < 200 MeV/c 29% of events with p6Nmin < 200 MeV/c Background signal Background+ signal < NNbkg > = 0.59 < NNsig > = 5.40 S/B ~ 0.6/0.03 = 20  weak sensitivity to pcut ITEP meeting, S.Kiselev

  8. sensitivity to pcut: Δp distribution < NNbkg > = 0.28, < NNsig > = 4.15  weak sensitivity to pcut ITEP meeting, S.Kiselev

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