f decay channels

1
f and ? resonance decay modes Georgy Sharkov ITEP
2
?,? resonances
If resonance decays before kinetic freeze-out
? Possible rescattering of hadronic daughters
? Reconstruction probability decrease for
hadronic mode
A.V. Stavinsky, Acta Phys. Polon B40 1179-1184,
2009
?(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 ?c0
(c? 37 fm)
3
t
hadrons
with without QGP
quarksgluons
4
Model
l0ctß/v(1-ß2) (ß1/3 for this
estimate) 15fm(for f) 8fm(for ?)
li
l0
?
?
f
?
li2fm for any hadron 1fm for any pair of
hadrons
l
hadronization
Kinetic freeze-out
5
Model

• Upper line lepton mode

Splitting two hadron and hadron-photon modes
l -decay products trajectory length within
matter
f
ß 1/3
?
l,fm
6
Is it really possible measurement?

• Existing data from PHENIX STAR
• B
• B
• B
• B

f/w ? ee-
f ? KK-
w ? pp-p0, p0g
f ? ?g ?
7
F(1020) ? K K- B.R. 0.49 c? 44
fm F(1020) ? ee- B.R. 0.000296 c? 44 fm
dAu
PHENIX
F? K K-
STAR Preliminary
vsNN 200 GeV
AuAu
PHENIX
vsNN 200 GeV
F? ee-
8
?(782) ? p p- p0 B.R. 0.89 c? 23
fm ?(782) ? p0? B.R. 0.089 c? 23
fm ?(547) ? p p- p0 B.R. 0.23 c? 167225
fm
PHENIX
?,?? p p- p0
pp
AuAu
pp
?? p0?
PHENIX
vsNN 200 GeV
?? p0?
PHENIX
9
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-

10
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

11
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 CBM conditions with
  realistic simulations

12
Model requirements

• realistic representation of particles (?!)
• evolution in time
• distinguish particles produced in dense and rare
  phases

EPOS

• Energy conserving quantum mechanical multiple
  scattering approach,based on
• Partons (parton ladders)
• Off-shell remnants, and
• Splitting of parton ladders.

13

Statistical Hadronization Models P.
Braun-Munzinger, I. Heppe, J. Stachel, Phys. Lett
B465 (1999) 15 F. Becattini, J. Manninen , M.
Gazdzicki, Phys.Rev. C73 (2006) 044905,
hep-ph/0511092 J. Cleymans, H. Oeschler, K.
Redlich, S. Wheaton, Phys.Rev. C73 (2006) 034905,
hep-ph/0511094 J. Rafelski, M. Danos, Phys.
Lett. 97B (1980) 279 J. Rafelski, J. Letessier,
J. Phys. G Nucl. Part. Phys. 28 (2002) 1819 and
blast-wave fits E. Schnedermann, J. Sollfrank, U.
Heinz, Phys. Rev. C48 (1993) 2462 8 F. Retiere,
J.Phys. G30 (2004) S827-S834, nucl-ex/0405024 J.
Adams, STAR Collaboration, Phys. Rev. Lett. 92
(2004) 112301 I. Kraus, NA49 Collaboration,
J.Phys. G31 (2005) S147-S154
14
EPOS
vs200GeV dAu
K. Werner Nucl. Phys. B175 (2008) 81
PbPb _at_ 17.3 GeV (SPS)
AuAu _at_ 200GeV (RHIC)
Klaus WERNER, Phys. Rev. Lett. 98, 152301 (2007),
arXiv0704.1270.
15
EPOS UrQMD p
16

• Generate EPOS statistics
• Check all decay modes
• Tune EPOS output for CBMROOT
• Produce CBMROOT events with full ECAL

17
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18
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19
UrQMD EPOS
20
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21
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22
Extra slides
23
Direct photons analysis
Re URQMD ftn15 (fwd)
a1(1260)
?'
?
K
"hm, yes photons are mesons in urqmd. however,
photons should not be calculated within the
urqmd, but explicitely outside with a different
code. everybody should ignore all processes with
photons involved. we will move them out of the
model in the next version. cheers, Marcus
Bleicher"
f1(1285)
UrQMD code

• Only from decay
• 2 ?? elastic scatterings(?!)

24
Formulas

Stavinskiy,ITEP,10.06.08
25
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-
26
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!
27
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-.
28
Yield comparison between f?ee- and f? KK-
Question 1 Have we observed changes of yield
between ee- and KK- ?
Comparison of integrated yield is not enough,
because mass modification effects depend on the
pT region. Low pT mesons tend to decay inside the
hot/dense matter
f
f
Low pT
High pT
In addition, To determine the integrated yield,
an extrapolation to lower pT is needed. There is
a large uncertainty in the calculation.
Thus, pT-dependent information is essential for
comparison.
Now, we should ask
Have we observed changes of spectra between ee-
and KK- ?
29
What is the difference?

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

Stavinskiy,ITEP,10.06.08
30
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
31
Measurements of w in wide pT range
pT spectra of w are measured for several decay
modes in dAu and pp.
w
dAu
pp
Spectra show good agreement among several decay
channels.
32

• Branching ratios as an instrument for density
  integral measurements
• ? mesons (? mesons)
• new source of information
• Interplay between different ALICE
  subdetectors(?)

Stavinskiy,ITEP,9.04.08
33
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34
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