RQMD vs data for p±, π± and K± at θlab=970 in p+A at E=10.14 GeV

Sergey Kiselev, ITEP

• Kinematical limits

• Input info

• RQMD: multiplicities

• RQMD: angle distributions

• Spectra: RQMD vs data

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Kinematical limits

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Input info• Data from Yad.Fiz. 57 (1994) 1452

p+A A=Be,Al,Cu,Ta θlab=970 p±, π±, K± tables for f=A-1 E d3σ/d3p vs p absolute normalization error ~ 25%

• RQMD (Relativistic Quantum Molecular Dynamics) Phys. Rev. C52 (1995) 3291. RQMD produces hadrons through the excitation of baryonic and mesonic resonances. Heavy resonances (more than 2 GeV for baryons and more than 1 GeV for mesons) are treated in the string picture following the Lund model and all particles are allowed to reinteract (baryon-baryon, baryon-meson, and meson-meson). The model provides a complete time-dependent description of the evolution of each event. The probabilities for excitation of specific channels are governed by experimental cross-sections to the extent possible. The formation points of hadrons are taken from the properties of resonance decay and string fragmentation.

Input info• RQMD min. bias events (b<R=1.1 A1/3)

•Analysis θlab=970 ± 70

f=A-1 E σin ΔN/ (p2 Δ p ΔΩ Nevents with partic.) σin = 2πR2

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Be Al Cu TaNumber of RQMD events 1.3 106 4 105 105 105

Part with participants(%) 78 89 94 98

RQMD: multiplicities

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p+ π+ π- 102 K+ 103 K- 104 p-

Be 1.8 1.1 0.9 5.1 6.1 1.5

Al 2.9 1.4 1.1 7.0 9.2 1.4

Cu 4.5 1.5 1.4 8.4 10.0 0.7

Ta 8.1 1.6 1.8 11.0 14.0 0.6

average multiplicities

RQMD: angle distributions

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Spectra for Be: RQMD vs data

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Spectra for Al: RQMD vs data

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Spectra for Cu: RQMD vs data

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Spectra for Ta: RQMD vs data

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Spectra: slopes

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fit by ~ exp(-p/p0) in the overlap region

π+ π- p+

Be 70 ± 3 / 65 ± 3 70 ± 3 / 69 ± 2 92 ± 2 / 98 ± 2

Al 80 ± 3 / 71 ± 4 78 ± 3 / 74 ± 4 103 ± 2 / 99 ± 2

Cu 83 ± 4 / 91 ± 8 83 ± 4 / 75 ± 7 103 ± 3 / 107 ± 2

Ta 86 ± 3 / 81 ± 6 83 ± 3 / 83 ± 5 109 ± 2 / 103 ± 2

p0 for data / RQMD

slopes are the same

ConclusionRQMD reasonably reproduces the p+A data at 10 GeV

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One can hope the RQMD code can be used for 6 GeV

One can think on optimalset up position to study π0 out of the1+3N kinematicallimit