f and ? decay modes ratios

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f and ? decay modes ratios

Possible rescattering of hadronic daughters
? Reconstruction probability decrease for
hadronic mode
?(782) ? p p- p0 B.R. 0.89 (c? 23
fm) ?(782) ? p p- B.R. 0.017
?(782) ? p0? B.R. 0.089 ?(782)
? ee- B.R. 0.000072 f(1020) ? K
K- B.R. 0.49 (c? 44 fm) f(1020) ?
?? B.R. 0.013 f(1020) ? ee-
B.R. 0.000297
Stavinskiy,13.09.08
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Decay modes ratios- new source of information
t
hadrons
with without QGP
quarksgluons
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Model
l0ctß/v(1-ß2) (ß1/3 for this
estimate) 15fm(for f)8fm(for ?)

li2fm for any hadron 1fm for any pair
of hadrons
li
l0
?
?
f
?
l
hadronization
Kinetic freeze-out
4

Results

• Upper line lepton mode

Splitting two hadron and hadron-photon modes
l -decay products trajectory length within
matter
f
ß 1/3
?
Stavinskiy,13.09.08
l,fm
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PHENIX
STAR
AuAu
vsNN 200 GeV
?? p0?
f? ee-
Is it really possible measurements?
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Extended f ? KK- analysis
Consistency between f ? KK- and f ?ee-
f
dAu
0-20
M.B.
pp

• f?KK- measurements have been extended to both
  higher and lower pT using new methods, i.e. no
  kaon ID and single kaon ID methods.
• The three independent kaon analyses are
  consistent with each other.

In pp, spectra of ee- and KK- show reasonable
agreement!
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Low pT mesons tend to decay inside the hot/dense
matter
f
f
Low pT
High pT
Thus, pT-dependent information is essential for
comparison.
8
Spectra comparison between f?ee- and f? KK-
AuAu
M.B.
40-92
20-40
Errors are too large to make any clear statement
about the comparison of spectra for f ? ee- and
f ? KK-.
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• F ? information early stages of the collision
• F ? different production for hadronic and
  leptonic channels
• K ? time between chemical and kinetic freeze-out

S. Pal et al., Nucl.Phys. A707 (2002) 525-539

• If resonance decays before kinetic freeze-out ?
  not reconstructed due to rescattering of
  daughters
• K0 (c? 4 fm) survival probability ? time
  between chemical and kinetic freeze-out, source
  size and pT of K0
• Chemical freeze-out ? elastic interactions pK ?
  K0? pK regenerate K0(892) until kinetic
  freeze-out
• K0/K may reveal time between chemical and
  kinetic freeze-out

Chemical freeze-out
Kinetic freeze-out
P. Fachini BNL,SQM2007
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K ? Ratios
Chemical freeze-out
Kinetic freeze-out
Chemical Kinetic freeze-out

• K/K- ? pp ratio reproduced by thermal model at
  chemical freeze-out ? AuAu reproduced by thermal
  model at kinetic freeze-out

11
Y. Nakamiya Hiroshima University, Japan for the
PHENIX collaboration QM 2008, India

• Branching ratio between ee- and KK- may be
  sensitive to mass modification, since Mphi is
  approximately 2 ? MK.
• -gt Compare yields of f?ee- and f? KK-

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F Production ? KK- and ee-
ee-
KK-

• The leptonic channel yield is a little higher
  than hadronic channel
• More accurate measurement is required to confirm
  whether there is branch ratio modification

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What is the difference?

• Modes absorbtion vs Mass modification
• Standard mesons vs modified mesons
• f?KK f???
• Modes absorbtion vs K/K ratio
• Reference- Lepton modes vs thermal model
• Hadronization stage vs equilibrium stage
• Modes absorbtion vs both other approaches
• Internal cross-check - 3 modes

Stavinskiy,ITEP,13.09.08
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Real sMN in matter can differ from that in
free space

• ? photoproducton on nuclear targets (ELSA)
• M.Kotulla et al.,
  ArXiv nucl-ex/08020980
• s?N 70 mb (in nuclear medium, 0.5 lt P lt1.6
  GeV/c)
• s?N 25 mb (in free space - the model
  calculations)
  
• ? photoproducton on nuclear targets
• T.Ishikawa et al.,
  Phys.Lett.B608,215,(2005)
• sfN 35 14 mb (in nuclear medium)
• sfN 10 mb (in free space)
• f-puzzle

photoproducton on nuclear targets
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To Do

• To make calculations for the effect of interest
  within realistic model
• To create algorithm for photonic modes
  identification in AA interactions
• To check this algorithm for ALICECBM conditions
  with realistic simulations

Stavinskiy,ITEP,13.09.08
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Extra slides
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Formulas

Stavinskiy,ITEP,10.06.08
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Electron, hadron and photon in PHENIX
f/w ? ee-

• PHENIX acceptance
• -0.35 lt ? lt 0.35
• 2 x 90in azimuthal angle for two arms
• Event selection
• BBC
• Electron ID
• RICH
• EMCal

• photon ID
• EMCal

• Hadron ID
• TOF
• EMCal-TOF

w ? pp-p0, p0g
f ? KK-
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Why ? ?(common part)

• The????meson was proposed in the middle of
  80(Koch,Muller,Rafelski PR142,ShorPRL54) as one
  of the most promising QGP messengers because of
  the following reasons
• an enhancement of ??meson, as well as other
  strange hadrons in QGP phase
• ??interaction cross section is small and ??will
  keep information about the early hot and dense
  phase
• ???meson spectrum is not distorted by feeddown
  from resonance decays
• strangeness local conservation for ??? ???

Stavinskiy,ITEP,9.04.08