feasibility of hyperons study with ecal
DESCRIPTION
Feasibility of hyperons study with ECAL. Sergey Kiselev, ITEP Moscow, for the ECAL group Introduction Motivation Input info and assumptions Spectra Acceptance Multiplicity Signal Signal + Background Conclusions and next steps. Introduction. Hyperons with “neutral” decay modes: - PowerPoint PPT PresentationTRANSCRIPT
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Feasibility of hyperons study with ECAL
Sergey Kiselev, ITEP Moscow, for the ECAL group
Introduction Motivation Input info and assumptions Spectra Acceptance Multiplicity Signal Signal + Background Conclusions and next steps
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Introduction Hyperons with “neutral” decay modes:
Σ-(dds) n - Br=99.8% c=4.4 cm Σ+(uus) p o Br=51.6% c=2.4 cm Σ+(uus) n + Br=48.3% Σo (uds) Λ Br=100% c=2.2 10-9 cm o(uss) Λ o Br=99.5% c=8.71 cm
p, -, +, Λ p - can be identified by TOF. , n, o can be identified by ECAL. Measurements with the CBM (Compressed
Baryonic Matter) detector will be analyzed.
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Introduction - the CBM detector
Tracking: STS, TRD
Vertexing: STS
Hadron ID : TOF
Electron ID: RICH, TRD, ECAL
, neutral m, n: ECAL
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Motivation - 1 The pronounced kink
structure in the K+/+ ratio has caused speculations on a possible deconfinement phase transition around 30 AGeV
Which part of Λ is from the channel Σo Λ ?
How do Σ+ Σo Σ- excitation functions look like?
Excitation function of strangeness production in central Au+Au and Pb+Pb collisions.
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Motivation - 2 Hyperon-hyperon
interactions: to verify various ideas
on baryon-baryon interactions such as the flavor SU(3) symmetry
to clarify the properties of dense nuclear matter like neutron stars, in which abundant hyperons are expected to exist
Experimental method – momentum correlations between strange baryons.
baryon octet matrix
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Input info and assumptions CbmRoot package (04.10.2004), Geant3 105 UrQMD Au+Au central events at 25 AGeV TOF:
p, - : ideal tracking and PID, momentum resolution 1%, impact parameter cut b>0.1 cm, cross last 4 STS tracking stations (Zvtx < 40 cm)
ideal Λ p - reconstruction; ECAL:
: ideal PID, energy resolution 3%/√E, 6%/√E, 9%/√E n: ideal PID, momentum from ECAL time v=L/t, dp/p =
(1+(p/m)2) dL/L, time resolution 0.2, 0.4, 0.6, 0.8 ns dp/p = (1+(p/m)2) dt/t
ideal o reconstruction
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ- n -: spectra
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ- n -: acceptance
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ- n -: multiplicity
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ- n -: signal
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ- n -: signal + background
σt = 0.2 ns σt = 0.4 ns σt = 0.6 ns σt = 0.8 ns
S/B(%) 0.17 0.14 0.12 0.11
Signif. 22 20 18 18
Σ- n -: signal+background
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ+ p o: spectra
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ+ p o: acceptance
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ+ p o: multiplicity
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ+ p o: signal
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σ+ p o: signal + background
3%/√E 6%/√E 9%/√E
S/B(%) 0.37 0.19 0.13
Signif. 16 12 10
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σo Λ : spectra
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σo Λ : acceptance
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σo Λ : multiplicity and cuts
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σo Λ : signal
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Σo Λ : signal + background
3%/√E 6%/√E 9%/√E
S/B(%) 0.29 0.16 0.12
Signif. 10.5 7.7 7.0
13.03.2006 Workshop of European Research Group on Ultrarelativistic Heavy Ion Physics. Dubna-ITEP S.Kiselev
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Conclusions and next steps Conclusions:
S/B=0.1 – 0.3 %, needed statistics >107
Σ-, Σ+, Σo can be reconstructed with ECAL by the event-mixing technique
S/B(Σ+ p o) > S/B(Σ+ n +) Next steps:
o Λ o
More realistic simulations: tracking, PID, reconstruction