Download Strangeness Production at Low Energies

Heidi
Schuldes
Heidi
Schuldes
for HADES
the HADES
Collaboration
for the
Collaboration
Heidelberg
DPGDPG
Heidelberg
20152015
Outline
Outline
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Introduction
Introduction
StrangenessProduction
atLowEnergies
Differential
analysis
& preliminary
results
of single
particles
Differential
analysis
& preliminary
results
of single
particles
in m in
-y m
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Strangeness
production
at SIS18
energies
Strangeness
production
at SIS18
energies
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HADES
HADES
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+
K K
K- ● K
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Φ-reconstruction
Φ-reconstruction
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Summary
Summary
HeidiSchuldes
t
Outline
§
Introduction
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Microscopicdescriptionofsub-threshold
strangenessproduction(K0 andL)
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Deepsub-thresholdstrangenessproduction
(K- andφ)
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Theglobalpicture
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Summary
ExperimentsatSIS18
DetailedStudyofMatterPropertiesatHighestμB
KaoS
FOPI
Nucl.Phys.A931(2014)
HADES
©Hossan
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§
§
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Heavy-ionbeamsfromSIS18:Ekin =1-2A GeV
Largestoppingandlongpenetrationtimes Baryondominatedsystem
Highdensitiesandmoderatetemperaturesatfreeze-out
Producedmattercharacterizedbyglobalproperties?
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StrangenessProductionatSISEnergies
Sub-thresholdStrangenessProduction
K0S
CentralAu+Au /Pb+Pb
CentralAu+Au /Pb+Pb
SIS18
SIS18
Datacompilation:Prog.Part.Nucl.Phys.66(2011)834-879
§ Allstrangehadronsproducedbelow/closetoNN-thresholds
§ Steepexcitationfunctionatlowenergies
§ LowerproductionyieldofK- (twoordersofmagnitudew.r.t.K+)
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Heidi Schuldes
for the HADES Collaboration
MicroscopicDescription
DPG Heidelberg 2015
K0S ProductionComparedtoTransportModelCalculations
[email protected] GeV
Outline
Introduction
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
K+
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PRELIMINARY
K●
Φ-reconstruction
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K0S
Summary
§ State-of-the-arttransportmodelcalculationsoverestimateyieldand
<Apart>dependenceisnotreproduced
HSD v711n: Phys rep, 308:65–233, January 1999
IQMD c8: Eur.Phys.J.,A1:151–169, 1998
UrQMD 3.4: Prog.Part.Nucl.Phys., 41:255–369, 1998
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Heidi Schuldes
for the HADES Collaboration
MicroscopicDescription
DPG Heidelberg 2015
K0S ProductionComparedtoTransportModelCalculations
[email protected] GeV
Outline
Introduction
●
●
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
K+
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PRELIMINARY
K●
Φ-reconstruction
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K0S
Summary
§ InclusionofrepulsiveKNpotentialreducesyieldand<Apart>
dependence
HSD v711n: Phys rep, 308:65–233, January 1999
IQMD c8: Eur.Phys.J.,A1:151–169, 1998
UrQMD 3.4: Prog.Part.Nucl.Phys., 41:255–369, 1998
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Heidi Schuldes
for the HADES Collaboration
MicroscopicDescription
DPG Heidelberg 2015
Pt DistributionofK0S andL ComparedtoTransportModelCalculations
[email protected] GeV
Outline
Introduction
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(normalization:600<pt <900MeV/c)
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K0S
Strangeness production at SIS18 energies
HADES (normalization:700<pt <1000MeV/c)
Differential analysis & preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
PRELIMINARY
PRELIMINARY
§ Modelsw/opotentialdonotmatchlowpt
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Heidi Schuldes
for the HADES Collaboration
MicroscopicDescription
DPG Heidelberg 2015
Pt DistributionofK0S andL ComparedtoTransportModelCalculations
[email protected] GeV
Outline
Introduction
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(normalization:600<pt <900MeV/c)
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K0S
Strangeness production at SIS18 energies
HADES (normalization:700<pt <1000MeV/c)
Differential analysis & preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
PRELIMINARY
PRELIMINARY
§ Modelsw/opotentialdonotmatchlowpt
§ BetterdescriptionofkaonspectrawithKNpotential(noeffectforL)
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Heidi Schuldes
for the HADES Collaboration
MicroscopicDescription
DPG Heidelberg 2015
Pt DistributionofK0S andL ComparedtoTransportModelCalculations
[email protected] GeV
Outline
Introduction
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(normalization:600<pt <900MeV/c)
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K0S
Strangeness production at SIS18 energies
HADES (normalization:700<pt <1000MeV/c)
Differential analysis & preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
PRELIMINARY
PRELIMINARY
§
§
§
Ø
Modelsw/opotentialdonotmatchlowpt
BetterdescriptionofkaonspectrawithKNpotential(noeffectforL)
L pt spectrumbestdescribedbyUrQMD
NomodeldescribessimultaneouslykaonandL results
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DeepSub-thresholdStrangenessProduction
K- /K+ Production- ComparisontoKaoS
PRELIMINARY
PRELIMINARY
§ NostrongcentralitydependenceofK- /K+ ratio
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DeepSub-thresholdStrangenessProduction
K- /K+ Production- ComparisontoKaoS
*40%mostcentral
PRELIMINARY
PRELIMINARY
PRELIMINARY
KaoS:Phys.Rev.C75:024906,2007
§ NostrongcentralitydependenceofK- /K+ ratio
§ EffectivetemperatureofK- systematicallybelowK+
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DeepSub-thresholdStrangenessProduction
K- /K+ Production- ComparisontoKaoS
*40%mostcentral
PRELIMINARY
PRELIMINARY
PRELIMINARY
KaoS:Phys.Rev.C75:024906,2007
§ NostrongcentralitydependenceofK- /K+ ratio
§ EffectivetemperatureofK- systematicallybelowK+
Ø Interpretation:Productioncoupledviastrangeness
exchangereaction+laterfreeze-outofKPhys.Rept.510(2012)119-200
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DeepSub-thresholdStrangenessProduction
φ MesonastheGameChanger
Compilationofdata::
Prog.Part.Nucl.Phys.66(2011)834-879
§ Constantφ /K- ratioathighenergies
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DeepSub-thresholdStrangenessProduction
φ MesonastheGameChanger
PRELIMINARY
HADESAr+KCl Phys.Rev C80(2009)025209
FOPINi+Ni Nucl.Phys.A714(2003)89-123
FOPIAl+Al arXiv:1512.06988
§ Enhancedφ /K- ratioatenergiesbelowNN-thresholdinsmallsystems
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DeepSub-thresholdStrangenessProduction
φ MesonastheGameChanger
BR(φ ->K+K- )=48.9%
PRELIMINARY
*
*40%mostcentral
Compilationofdata::
Prog.Part.Nucl.Phys.66(2011)834-879
§ Au+Au @√𝑠 =2.41GeV:φ/K- =0.52± 0.16
Ø ~25%ofallmeasuredK- fromφ feed-down(andnotfroms-exchange)
Ø φ importantsourceforK- productionbelowNN-threshold
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Heidi Schuldes
for the HADES Collaboration
DeepSub-thresholdStrangenessProduction
φ MesonsasSourceofK-
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
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Strangeness production at SIS18 energies
HADES
PRELIMINARY
Differential analysis
& preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
§ Feed-downcontributionfromφ decayscanexplainlowerinverseslope
parameterofK- T(K-)=84± 6MeVincomparisontoK+ T(K+)=104± 2MeV
§ Measuredrapiditydistributionreproducedbycocktail
Ø Noindicationforsequentialkaonfreeze-out
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DeepSub-thresholdStrangenessProduction
φ MesonsasSourceofKFOPI:Eur.Phys.J.A52(2016)no.6,177
no feed-down
correction
K- feed-down
corrected
§ Feed-downcontributionfromφ decayschangesconclusiononkaon
potential
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Heidi Schuldes
for the HADES Collaboration
StrangenessProduction:TheGlobalPicture
<Apart>DependenceofMultiplicities
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
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PRELIMINARY
PRELIMINARY
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
§ Samedependenceonnumberof
participatingnucleons:
Summary
M𝑢𝑙𝑡~<Apart>α:α=1.35± 0.07
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K+
KΦ-reconstruction
§ NotexpectedfromdifferentNNthresholds
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StrangenessProduction:TheGlobalPicture
<Apart>DependenceofMultiplicities
Charged Kaon- & φ-Reconstruction
in Au+Au @ 1.23 AGeV
KaoS [email protected] GeV
Heidi Schuldes
for the HADES Collaboration
DPG Heidelberg 2015
PRELIMINARY
Outline
Introduction
●
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
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+
K
KΦ-reconstruction
Summary
§ Samedependenceonnumber
ofparticipatingnucleons:
M𝑢𝑙𝑡~<Apart>α:α=1.35± 0.07
§ Notexpectedfromdifferent
NN-thresholds
Ni+Ni/Al+Al ≈1.9A GeV
§ Sameobservationathigher
energiesandsmallercollision
systems(αK+=1.34± 0.16,
αK-=1.22± 0.27,constantφ/K-)
KaoS:Phys.Rev.C75:024906,2007
FOPI:Phys.Rev.C94(2016)no.1,014901
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Heidi Schuldes
for the HADES Collaboration
StrangenessProduction:TheGlobalPicture
<Apart>DependenceofMultiplicities
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
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PRELIMINARY
PRELIMINARY
●
Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
§ Samedependenceonnumberof
participatingnucleons:
Summary
M𝑢𝑙𝑡~<Apart>α:α=1.35± 0.07
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K+
KΦ-reconstruction
§ NotexpectedfromdifferentNNthresholds
Ø Universalcentralitydependence
ofstrangenessproduction
§ Cansystembetreated
macroscopically?
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Heidi Schuldes
for the HADES Collaboration
ChemicalFreeze-Out
StatisticalHadronization Model
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
PRELIMINARY
*20%mostcentral
§ HadronyieldswelldescribedbySHMwithglobalparameters:T,μB,RV,RC
THERMUSv2.3
Comput.Phys.Commun.180:84-106,2009 21
Heidi Schuldes
for the HADES Collaboration
ChemicalFreeze-Out
StatisticalHadronization Model
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
PRELIMINARY
*20%mostcentral
*40%mostcentral
§ HadronyieldswelldescribedbySHMwithglobalparameters:T,μB,RV,RC
§ Strangenesscanonicallysuppressed
φ /K- ratio
THERMUSv2.3
Comput.Phys.Commun.180:84-106,2009 22
Heidi Schuldes
for the HADES Collaboration
ChemicalFreeze-Out
StatisticalHadronization Model
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
●
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Strangeness production at SIS18 energies
HADES
Differential analysis & preliminary results of single particles in mt-y
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K+
KΦ-reconstruction
Summary
PRELIMINARY
*20%mostcentral
§
§
§
§
HadronyieldswelldescribedbySHMwithglobalparameters:T,μB,R,RC
Strangenesscanonicallysuppressed
φ /K- ratio
T,μB higherthanexpected
Moreparticlespeciesincluded
Radiuslowerthanexpected
Eigenvolumes
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Heidi Schuldes
for the HADES Collaboration
CascadeProductionPuzzle
DPG Heidelberg 2015
Xi- Enhancement
Outline
Introduction
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Eur.Phys.J. A47 (2011) 21
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Strangeness production at SIS18 energies
PRL 114 (2015) 212301
HADES
Differential analysis & preliminary results of single particles in mt-y
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p+Nb
K+
KΦ-reconstruction
Summary
Ar+KCl
SHM
@1.76AGeV
PRELIMINARY
§ StrongexcessofX§ Alreadypresentincoldnuclearmatter
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Heidi Schuldes
for the HADES Collaboration
KineticFreeze-Out
SimultaneousBlastWaveFit
DPG Heidelberg 2015
[email protected] GeV
Outline
Introduction
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PRELIMINARY
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Strangeness production at SIS18 energies
HADES
Phys.Rev.C48,2462
Differential analysis & preliminary results of single particles in mt-y
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§ Blastwavemodel:
K+
KΦ-reconstruction
Summary
Linearflowvelocityprofile:
§ Proton,KaonandPionspectra
welldescribedbysimultaneous
blastwavefitwithglobal
parameters:
*Fatpointsincludedinfit
*0-10%mostcentral,syserrondiffcountrate5%
j:0-20%mostcentral,syserrondiff.countrate10%
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Freeze-OutParameter
ComparisontoWorldData
#0-20%mostcentral
STARarXiv:1701.07065,2016
*0-10%mostcentral
#
*
*
§ Globalfreeze-outparametersfitwellintotrendofworlddata
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Summary
Microscopicdescription:
§ KaonspectrabestdescribedbyIQMDwithpotential,
however,doesnotdescribeL spectra
Ø Nomodeldescribesallparticlespeciessimultaneously
Deepsub-thresholdstrangenessproduction:
§ φ sizeablesourceforK- production
§ Feed-downcanexplainlowereffectivetemperature
andrapidityspectrumofKØ Noindicationforsequentialfreeze-outofK+/KTheglobalpicture:
§ Universalcentralitydependenceofstrangeness
production
§ SHMdescribesparticleyields(exceptX-)
K0S
PRELIMINARY
PRELIMINARY
PRELIMINARY
BACKUP
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φ /K- ratio
Excitationfunction
PRELIMINARY
UrQMD tuned:J.Phys.G43(2016)1,015104
HADESAr+KCl Phys.Rev C80(2009)025209
FOPINi+Ni Nucl.Phys.A714(2003)89-123
FOPIAl+Al arXiv:1512.06988
Compilationdatahigherenergies:
Prog.Part.Nucl.Phys.66(2011)834-879
§
Ø
Ø
Ø
φ/K- =0.52± 0.16
~26%ofallmeasuredK- fromφ feed-down
TrendexpectedfromSHMwhenopenstrangenesssuppressedbyRC
Firsttransportmodeltodescribedata:UrQMD (tuned)whenincludingnew
decaychannelsfromhighmassbaryonicresonances
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K+ vs.Transport
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K+ vs.Transport
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StrangenessProductionatSISEnergies
Xiupperlimit
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BlastWaveFit
Systematicerrorinvestigation
*0-10%mostcentral
§ Variationofparticlespeciesincludedinsimultaneousfit
§ Strongesteffectifprotonsorboth,p+ andp-, areexcludedfromfit
Ø Conservativeerrorstillspectrapublished
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BlastWaveFit
Centralitydependence
*onlystatisticalerrors
§ Slightlylowerkineticfreeze-outparametersformoreperipheralcollisions
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BlastWaveFit
Centralitydependence
STARarXiv:1701.07065,2016
*onlystatisticalerrors
§ Slightlylowerkineticfreeze-outparametersformoreperipheralcollisions
§ Differentbehaviorathigherenergies
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Chemicalvs.KineticFreeze-out
§ Tchem consistentwithTkin obtainedfromblastwavefittotransverse
massspectraofhadronsandfromextrapolationofmassdependence
ofeffectivetemperatures
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StrangenessProductionatSISEnergies
Xiupperlimit
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StrangenessProductionatSISEnergies
Kaonflow
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K- /K+ ratio
CentralitydependenceandcomparisontoKaoS
* * 0-40%mostcentral
PRELIMINARY
PRELIMINARY
§ NostrongcentralitydependenceofK- /K+ ratioobserved
§ K- /K+ ratiofitsenergydependenceofKaoS data
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Multidifferentialanalysisofpions andprotons
Highstatistics(1outof30days)
ππPRELIMINARY
p
PRELIMINARY
PRELIMINARY
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φ /K- ratio
Centralitydependence
§ φ/K- ratioalmostconstantasfunctionofcentrality
§ SimilartrendobservedfromFOPIforNi+Ni @1.9AGeV
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Centrality
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K+Production
Centralitydependent
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Efficiency*acceptance
K-
K+
φ
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Efficiency*acceptance
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Invariantmassφ
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HADESPerformance
Au+Au at√𝑠 =2.41GeV
Highinteractionrates
§ Beam:1.5x106 Auions/s
§ Triggerratesupto8kHz
Centralitydependence
§ 40%mostcentralcollisions
§ 2.1x109 eventsanalyzed
CBMcollab arXiv:1607.01487[nucl-ex]
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HADESPerformance
Au+Au at1.23AGeV
ExcellentParticleIdentification
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HADESPerformance
ReconstructionofStrangeHadronsinAu+Au at√𝑠 =2.41GeV
LargeAcceptance
*40%mostcentral
K0S
K0S
Ø 4πMultiplicities
Extrapolationinmt:
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Reconstructionofφ Mesons
BR(φ ->K+K- )=48.9%
MEbackground
* Notused for
signal extraction!
*40%mostcentral
§ Firstmeasurement of f mesons sofar below NN-threshold
§ Intotalabout 1000f reconstructed
Ø Multi-differentialanalysis possible
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