STAR Strangeness Summary 2003

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STAR Strangeness Summary 2003
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STAR Strange Spectra _at_ 200 GeV
X
STAR Preliminary
K0s
STAR Preliminary
f
STAR Preliminary
K
L
STAR Preliminary
W
K
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Spectra in d-Au
K d-Au 200 GeV
_
X
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Spectra p-p
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130 GeV Data
All strange particles seem to increase linearly
with h- No step functions, no big surprises
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Strangeness Enhancement/Suppression
Same plots just normalized to top Au-Au or
p-p. Emphasizes more common wisdom that yields
are suppressed in p-p not enhanced in Au-Au
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?B/B ratios
No obvious onset of pQCD Ratios flat to pt 4GeV
All 3 collision types show similar ratios at mid-y
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Chemical Fit to Au-Au 200 GeV data
More points are coming including the resonances
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Ratio centrality dependence and dep. on s

• X Nonlinear function of Nch,
• 2 degrees polynomial ?
• L/Nch flat with centrality

Strangeness enhancement and saturation from
peripheral to central collisions. (similar when
compared to SPS results)
The drop of dNdy/Nbin is smaller for X than L and
pbar due to the enhancement effects.
X-
L
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Resonance Ratios
STAR Preliminary
Au-Au and p-p vs200GeV
r -gt pp (1.3 fm/c) K -gt Kp ( 4
fm/c) L(1520) -gtpK (13 fm/c)
UrQMD signal loss
K(892) ?(1520) SPS (17
GeV) 1 66 50 RHIC
(200GeV) 2 55 30
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mt scaling in Au-Au and p-p
Left plots mt spectra
Works for p-p not for Au-Au Again evidence for
flow. However p-p spectra NOT identical for all
mass
Right plots mt spectra divided by common power
law fit
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ltptgt for Au-Au and p-p collisions
Warning the Au-Au is still being sent to me so
more to come and it may move a small bit
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ltptgt vs Centrality
p, K, p - ltptgt increase with centrality -
Heavy mass increase faster All consistent with
radial flow
Sorry these should be merged but we havent done
that yet
f and X seems to flow differently Early
freeze-out too?
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Mult. Dependence of p-p
Harder collisions give higher mult. and higher
ltptgt
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Fitting Au-Au data to Blastwave
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Rcp for h-,K, L, X, W, and f
f follows K not L. Baryon meson effect. Not mass
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Strange V2
Good agreement with Hydro at low pt
Scaling by quark number works at intermediate pt
except for pions- resonance problem? partonic
coalesnce? Break down at pt/n lt 0.6 GeV
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The pT Scale of RAA and v2 for KS and ?
The saturation of v2 and fall of RCP are
correlated. In a scenario with partonic energy
loss followed by unmodified fragmentation, a
larger v2 would be associated with a smaller
RCP. At intermediate pT species dependence
contradicts a simple partonic energy loss and
unmodified fragmentation picture.
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L/K0s for different centralities

• UA1 data from?pp collisions at ?s 630 GeV.
• Very good agreement between UA1 and peripheral
  AuAu.
• Large baryon enhancement, relative to mesons, in
  central AuAu.

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Rcp for Ks, ? and f in dAu

• Statistical error only
• Both reconstruction efficiency and vertex finding
  correction included
• ? Rcp is flat at 1.4 when pt gt 2GeV/c
• Ks Rcp is flat at 1.2 when pt gt 2GeV/c
• f Rcp is closer to Ks than L.

STAR Preliminary
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HBT vs mt
Wiedemann and Heinz expect to drop with
1/mat due to collective flow.
(a 0.5)
Rinv for K0s does not seem to obey same mt
scaling
Need more detailed studies before conclusive
statement made