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Probing resonance matter with HADES
„„EMMI Workshop and XXVI Max Born Symposium””
Wrocław 9Wrocław 9--1111.0.077.2009.2009
P. Salabura
Jagiellonian University/GSI
for the HADES collaboration
BBaryonic matter aryonic matter at 1-2 AGeVat 1-2 AGeV
Au+Au
moderate densities but long system life time
Baryonic matter: • /N = 1-3, T< 80 MeV, ~15 fm/c nucleons, baryonic resonances (~30%) 33, mesons(π0)~10%
“resonance matter”
What is still (after >20 years) exciting in this field ??
• e.m radiation from „resonance matter” – excessconnection to / in-medium properties ?
• Sub-threshold strangeness production: , K+ K- , - (1321)
~10fm/c
Composition of a barionic matter Rear probes: dielectrons & strangeness
HADES
Dielectrons from C+C @ 1.0 GeV DLS Data: Phys.Rev.Lett. 79 (1997) 1229
HADES : Phys. Lett. B 663 (2008) 43
HADES data projected into DLS acceptance
Very good agreement between 2 experiments full confirmation of DLS effect
DLS Data & Transport (1999) : W. Cassing, E.L. Bratkovskaya Physics Reports 308 (1999) 65
Excess ?? above what? do we have a good reference ? .. frankly speaking, no! elementary e+e- sources not fully known
0.0 0.2 0.4 0.6 0.810-8
10-7
10-6
10-5
10-4
10-3
10-2
0.0 0.2 0.4 0.6 0.810-8
10-7
10-6
10-5
10-4
10-3
10-2
HADES
HSD: Dalitz Dalitz Dalitz Dalitz Brems. NN Brems. N All
C+C, 1.0 A GeVno medium effects
1/N
dN/d
M
[1/G
eV /c
2 ]
HSD: Dalitz Dalitz Dalitz Dalitz Brems. NN Brems. N All
M [GeV/c2]
HADES
C+C, 1.0 A GeVin-medium effects: CB+DM
1/N
dN/d
M
[1/G
eV /c
2 ]E.L. Bratkovskaya and W. Cassing NPA 807, 214 (2008) & new. N-N bremss.OBE Kaptari & Kämpfer NPA 764 (2006) 338
2008
Reference: dielectrons from pp and Reference: dielectrons from pp and “quasi-free” pn @ 1.25 AGeV“quasi-free” pn @ 1.25 AGeV
pp/pn data are not described by recent OBE calculations !12
Model Calculations:a) NNNNe+e- OBE calculations Kaptari & Kämpfer (K&K) NPA 764 (2006) 338
b) , yield constraint by data. Dalitz decay Krivoruchenko et al. Phys. Rev. D 65 (2001) 017502 + VMD form-factor (Q. Wan and F. Iachello, Int. J. Mod. Phys. A 20 (2005) 1846)
Excess or no excess ?Excess or no excess ?
C+C data reproduced (within 20%) by superposition of NN interactions (reference) & scaling with pion production
Larger system size – Ar+KCl (4 larger Apart)-first evidence for the in-medium effect – baryonic radiation : i.e NN N N .. (fireball ~10x ) !
Different mechanism as at SPS ( pion annihilation)
preliminary
F ~ 3
Vector mesons Vector mesons // at SIS at SIS
p+p at 3.5 GeV
2005
40Ar+ 38KCl 1.75 AGeVp+ 92Nb 3.5 GeV
2008“on-line spectrum!”
• Systematic studies on / production at SIS has been started
• Verification of p+A from KEK (advantage lower beam energy ) & CBTAPS/CLAS
• Only consistent description of the pp/p+A/and A+A can give full picture
M() 15 MeV/c2
preliminary
preliminary
preliminary
KK++ K K-- / / -- p production at SIS roduction at SIS
NNNNKNNKNN
via ?
Strangeness Exchange : belived to be dominant
NK
NKNN
non-resonant resonant (->K+K- )
NNNKNKN
19
sub-threshold, OZI suppressed ?
- (1321) S=-2 deep subthreshold (~600 MeV) not measured
Strangeness Exchange + network of reactions sensitvity to EOS
KYA. Andronic, P. Braun-Munzinger,B. K. Redlich, NPA 765 (2006) SIS?
// Production in ArKCl @ 1.75AGeV Production in ArKCl @ 1.75AGeV
/ ~1 fixed to pp data , yield in line with mT scal.
R(/) = 4.2*10-3 *f OZI rules for N-N
enhanced R(/) in HI as compared to N-N()close to stat. model (THERMUS) !(no suppression)
different absorption?
M =1017,8 ± 0.9 MeV/c2
= 6.2 MeV/c2
e+e-e+e-
=236 MeV
OZI
preliminary
S. Wheaton and J. Cleymans, hep-ph/0407174
// K K-- ratio ratioStatistical model K. Redlich, H. Oeschler-priv.comm
Teff=693
Teff=894
/K- =0.340.13 & is enhanced is important source of K- in HI collisions at SIS
HADES: accepted PRC: arXiv:0902.3487
Teff=848
-- p productionroduction in Ar+KCl @ 1.75 AGeV in Ar+KCl @ 1.75 AGeV
23.01.2009P.Salabura
identification: p
p
HADES data
THERMUS fit S. Wheaton and J. Cleymans, hep-ph/0407174
?
T= 703 b=74615 (MeV)RC =2.6 0.4 fmRfireball =6 0.7 fm 2=2.1 (no - )
preliminary
23.01.2009
Outlook: future expOutlook: future exp..Upgrade RPC, DAQ, MDC1Upgrade RPC, DAQ, MDC1, EM Calorimeter (for SIS100), EM Calorimeter (for SIS100)2008/92008/9/10/10
Hades Hades goes togoes to FAIR ( 8 AGeV) FAIR ( 8 AGeV)> 2013> 2013 (SIS100)(SIS100)
20112011
+ N, + N, + A + A resonance ( resonance (, N, N**) radiative decays, strangeness ) radiative decays, strangeness
20102010
AgAg + +AgAg @ @ Au+Au Au+Au dielectrons ( dielectrons (//) , strangeness (K) , strangeness (K--KK+ + . . , ,))2009-20112009-2011
SIS18SIS18
increase of Mul(/) by 2 orders of magnitue !!
CBM
HADES
23.01.2009 P.Salaura 12
The CollaborationThe Collaboration
GSIGSI
SISSIS
Catania (INFN - LNS), Italy
Cracow (Univ.), Poland
Darmstadt (GSI), Germany
Dresden (FZD), Germany
Dubna (JINR), Russia
Frankfurt (Univ.), Germany
Giessen (Univ.), Germany
Milano (INFN, Univ.), Italy
München (TUM), Germany
Moscow (ITEP,MEPhI,RAS),
Russia
Nicosia (Univ.), Cyprus
Orsay (IPN), France
Rez (CAS, NPI), Czech Rep.
Sant. de Compostela (Univ.), Spain
Valencia (Univ.), Spain
Coimbra (Univ.), LIP, Portugal
23.01.2009 P.Salabura
BACK-UP SLIDESBACK-UP SLIDES
Conference
Side View
START
FWFW
3
High Acceptance DiHigh Acceptance Di-E-Electron Spectrometerlectron Spectrometer
Beams from SIS18: pions, protons, nuclei
high invariant mass resolution (2% at / mass) and powerful PID capabilities : p/π/K/e
Large acceptance for sys. studies :
• dielectrons (e+,e-)
• strangeness: K,0 , , ,
GeometryFull azimuth, polar angles 18 - 85 e+e- pair acceptance 0.35~ 80.000 channels, segmented solid or LH2 targets
1 m
P.Salabura
23.01.2009 P.Salabura
N-N Bremsstrahlung
E.L. Bratkovskaya and W. Cassing arXiv:0712.0635v1
NN ("quasielastic")-non resonant
• Strong + electromagnetic process (OBE models)
1
2
e+
e- + =
resonant -baryon resonances ()
1
2
+
collection of results from E.L Bratkovskaya & W. Cassing: Nucl.Phys A 807, 214 (2008).
• bremsstrahlung OBE calculations:
Kaptari & Kämpfer, NPA 764 (2006) 338:
K&K OBE calculation:
pn bremsstrahlung 4 larger
(simplified picture!)
10
16
e+e- e+e- Invariant mass spectrum decompositionInvariant mass spectrum decomposition
e+e- decays
• Mesons (known)
• Baryon resonances (not measured !) – important at lower beam energies SIS18
•Two-body decays (known):
e+
e-
e+
e-
e+
e-
Example cocktailHADES data p+p @ 3.5 GeV compared to model calc.
pp @3.5 GeV
0
/
23.01.2009 P.Salabura
23.01.2009 P.Salabura
DLS
Vector mesons: pairs from DLS
Data: Calculations: C.Ernst et alPhys. Rev. C58 (1998)
• signal not visible due to resolution
• enhancement below / pole – resonance radiation ?
• Coupling of to N*(1520), N*(1700) ?
• Coupling of to N*(1535) ?
Relevant for in-medium :
extended VDM
Ch. Fuchs Phys. Rev. C68 (2003) 014904
Conference
Invariant Mass Spectra ofInvariant Mass Spectra of
0SK p KK
2
0
MeV/c1.9
0.1S/B
000.51
0
SK
SK
2MeV/c4.2
3.0S/B
000.145
2MeV/c2.6
1.1S/B
168
and, 0SK
23.01.2009 ConferenceP.Salabura
KK00-Nucleon Potential-Nucleon Potential
Kaon-Nucleon Potential: 30 MeV @ =0
(HADES and IQMD)
C. Hartnack, J. Aichelin, H. Oeschler
Results from FOPI (HSD)
KN-Potential is repulsive with a strength of U=20 MeV
23.01.2009 ConferenceP.Salabura
20
p+p @ 1.25 GeV - p+p @ 1.25 GeV - Dalitz decay Dalitz decay
Dalitz decaye++
e--
p
e--
Time-like - N transition branching ratio BR(M) ?
EM-formfactors (GM , GE, GC)?
q2 = M2inv(e+e-) = M*
2 > 0
*
grey band Iachello. VMD
QED
PLUTO calculations:
a) NN-bremsstrahlung Kaptari & Kämpfer (K&K) b) Dalitz decay Krivoruchenko et al. Phys. Rev. D 65 (2001) 017502 +VMD form-factor (Q. Wan and F. Iachello, Int. J. Mod. Phys. A 20 (2005) 1846)
PRELIMINARY
22
2
2
2222
232, qqq
Δf G
mq
GGqm C
Δ
EM2
-
dq
)eNe(Δd
VMD
23.01.2009 P.Salabura
21
d+pd+pppspecspec e+e-X @ 1.25 AGeV – e+e-X @ 1.25 AGeV –
„quasifree” p-n collisions„quasifree” p-n collisions
selection of np reactions via spectator proton in Forward Wall
spectator "tag" Mult. 1 FW (0.5–7)
cocktail:a) np-Bremsstrahlung a-la Kaptari & Kämpfer, and (constrained by data)b) Fermi momentum of nucleon in deuterium from N-N Bonn potential
neutron „target” proton
protonneutron
e+ e–
PRELIMINARYpspec
pc
No satisfactory description of pp and pn data!!
23.01.2009 P.Salabura
22
log. z axis !
e-
e+
hadron : lepton suppression ~10-4
Particle IDentificationParticle IDentification
ee--
ee++
pp 21)2/sin(2 Minv =
p
1 p
2TargetTarget
RICH
HADRONS
Momentum vs velocity (Momentum vs velocity (ββ))
dE/dx in MDC & TOFdE/dx in MDC & TOF
LEPTONS(RICH tagging)(RICH tagging)
Kaon identification
23.01.2009 P.Salabura