Statistical model analysis of hadron yields at SIS energies

StrangenessWorkshopWarszawa2016

ManuelLorenzfortheHADEScollabora@on

1

Outline:

•  Introduc@on•  Sta@s@calpar@cleproduc@on,Freeze-outandthePhasediagram

•  Sta@s@calmodelinsmallsystems:•  Ar+KCl@1.76AGeV•  p+Nb@3.5GeV•  Transport

•  FirstresultsforcentralAu+Au@1.23AGeV

•  Parameteriza@on•  Freefit•  Kine@cvs.chemicalfreeze-out

•  Summaryandconclusion

•  Outlook:WhatelsetoexpectfromAu+Au (andthefuture)

[MeV]bµ

0 200 400 600 800 1000 1200

T [M

eV]

0

50

100

150

200 RHIC/SPS/AGS (a)

RHIC/SPS/AGS/SIS (b)

HADES (Ar+KCl)

]2Mass [MeV/c0 200 400 600 800 1000 1200

[MeV

]ef

fT

020406080

100120140160180

-π 0s/K+K p φ Λ

2

[MeV]bµ

0 200 400 600 800 1000 1200

T [M

eV]

0

50

100

150

200 RHIC/SPS/AGS (a)

RHIC/SPS/AGS/SIS (b)

HADES (Ar+KCl)

Sta@s@calmodel

Ensembletheory

AnderesBildkeinePunkte

Eur. Phys. J., A 47(21)Par%cleproduc%onfromahomogeneoussource:

Freeze-outpoints:a)  Andronicet.al.(GrandcanonicalT,µB)Nucl.Phys.A789(2007)334-356a)  Cleymans,Becabni(Strangenesscanonical+γS)Phys.Rev.C73(2006)034905Measurementsatdifferent√slineupinacommonfreeze-outcurve(E/N≈1GeV)

CentralAu+AuandPb+Pb

Grandcanonicalensemble

Quantumnumbersconservedonaverageusingchemicalpoten@als

Parameters:T,µ=µBµsµQ,V(usuallyµsandµQarefixedfromini@alcondi@ons)

3

[MeV]bµ

0 200 400 600 800 1000 1200

T [M

eV]

0

50

100

150

200 RHIC/SPS/AGS (a)

RHIC/SPS/AGS/SIS (b)

HADES (Ar+KCl)

Sta@s@calmodel

Howtointerpretthisapparentequilibrium,especiallyatlowenergies?Testmodelalsoinreferencesystemse.g.p+A

Ensembletheory

AnderesBildkeinePunkte

Eur. Phys. J., A 47(21)Par%cleproduc%onfromahomogeneoussource:

Freeze-outpoints:a)  Andronicet.al.(GrandcanonicalT,µB)Nucl.Phys.A789(2007)334-356a)  Cleymans,Becabni(Strangenesscanonical+γS)Phys.Rev.C73(2006)034905Measurementsatdifferent√slineupinacommonfreeze-outcurve(E/N≈1GeV)

CentralAu+AuandPb+Pb

Grandcanonicalensemble

Quantumnumbersconservedonaverageusingchemicalpoten@als

Parameters:T,µ=µBµsµQ,V(usuallyµsandµQarefixedfromini@alcondi@ons)

4

Sta@s@calmodelatSISenergies

Ensembletheory

AnderesBildkeinePunkte

Strangenesscanonical(exactlyconserved)

Yieldsreduced(canonicalsuppression)

•Notenoughtoexplaindata:

•Strangenesshastobeconservedexactlyinavolumesmallerthanthevolumeofthesystem(radius:RC<Rv)

•Empiricalunder-satura@onparameter(γS)

•φmeson(hiddenstrangeness,notsuppressedbyRCbutstronglybyγS)

InthestrangenesscanonicalensembleµBconstrainedby:π/p,K+/K-(duetostrangenesscontentintheΛ)Tconstrainedby:K/π,φ/K(p/Λ)(usuallyRcorγSisalsoinvolved,strongcorrela@onbetweendifferentparametersAddi%onalinput:HadronspectrumandBRtofinalstatesYieldsvs.ra%os:Cancella@onofsystema@cerrorsRandRcdeterminedLimitednumberofhadronyieldsmeasuredatlowenergies!

5

Light systems: Ar+KCl vs. p+Nb

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Ar+KCl@1.76AGeV

•  Sta@s@calmodelworksreasonablywellatlowenergiesformedium-sizedsystem•  StrongexcessoftheΞ-•  Φmesondescribedwithoutsuppression(Rc)

THERMUSV3.0:S.Wheaton,J.Cleymans:Comput.Phys.Commun.180:84-106,2009EtamesoninterpolatedfromTAPSmeasurementat1.5and2AGevinCa+Ca

arxiv.org/abs/1512.07070

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p+Nb@3.5GeV

Verysimilarfitforp+NbasforAr+KCl!

StrongexcessoftheΞ-alreadypresentincoldnuclearmauer

Sta%s%calmodelgivessimilarresultsforp+AandlightA+Acollisions!

THERMUSV3.0:S.Wheaton,J.Cleymans:Comput.Phys.Commun.180:84-106,2009

arxiv.org/abs/1512.07070

8

ApparentequilibriuminUrQMD

J.Steinheimer,M.Lorenz,F.Becabni,R.Stock,M.Bleicherarxiv.org/abs/1603.02051 9

Very first results for yields from central Au+Au collisions

@1.23 A GeV

10

0 1 2 3 4 5 6 7 8 9

yiel

d

4−10

2−10

1

210

410510

=2.4 GeVNNs√Data, =788MeV fixed,

bµT=59MeV fixed,

0.2fm±=10.8V0.1fm, R±=3.5CR/ndof=9.32Χ

Exp/

THER

MU

S

0

1

2

3

partA p -π η Λ +K s0K -K φ

Au+AudatavsTandμBparameterized

0-20%mostcentral

Cleymans,Oeschleretal,Phys.Rev.C73:034905,2006

THERMUSV2.3:S.Wheaton,J.Cleymans:Comput.Phys.Commun.180:84-106,2009 11

0 1 2 3 4 5 6 7 8 9

yiel

d

4−10

2−10

1

210

410 =2.4 GeVNNs√Data, 25,±=883MeV

bµ2MeV, ±T=68

0.9fm±=5.8V0.3fm, R±=2.1CR/ndof=2.32Χ

Exp/

THER

MU

S

0

0.5

1

1.5

2

partA p -π η Λ +K s0K -K φ

Au+Audatavsfreefit

0-20%mostcentral

Goodminimum,butratherhighvaluesforμBandTTHERMUSV2.3:S.Wheaton,J.Cleymans:Comput.Phys.Commun.180:84-106,2009 12

Chemicalfreeze-out

13

Chemicalfreeze-out

14

arXiv:1512.08025[nucl-th]

Kine@cfreezeout

]2Mass [MeV/c0 200 400 600 800 1000 1200

[MeV

]ef

fT

020406080

100120140160180

-π 0s/K+K p φ Λ

Tchem

TkinextractedfromSiemens-Rassmusenfittopspectra

15

0-20%mostcentral

Summary

ExcessofXialreadypresentincoldnuclearmauerDescrip@onofp+Awithasta@s@calmodelverysimilartothoseforAr+KCl(andtoCa+CafromUrQMD)Implica@onsandInterpreta@on!FirstfittoAu+AuhadronyieldsshowshigherTandμBthanexpectedfromparameteriza@ons,toearlytocall!Systema@cstudiesofmodels/parameters/yields/minimum/..

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Whatelse?

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Lightnuclei:perfectlydescribedbySHMatLHC

18

(Low)Ptspectra,L,K0s,K+HBTLightnucleiConstrainingresonancesFlowanisotropiesFluctua@onsDileptonradia@on

Verysensi@vetomuBatSIS18energies

Dileptons

19SzymonHarabaz,PatrickSellheim

Constrainingtheresonancecontribu@ons

20GeorgyKornakov

Itera@veprocedure

Fluctua@onsofconservedchargesandmuchmore

21

Flowanisotropies HBT Conversionanalysis

MelanieSzala,RomainHolzmann

SashaSadovsky,BehruzKardan,FredericKornas RolandKoue ClaudiaBehnke,Chris@naDeveaux

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p+p@4GeV:Xicrosssec@onReferencemeasurementinNNAg+Ag@1.65AGeVXi-spectraPhi,K-differen@alPioninducedreac@oninaddi@on

Futurebeam@meproposals

T.Galatyuk

PhotoJanMichaelHosan

Thankyou! 23

Ar+KClalapNb

24

Kine@cfreeze-outAr+KCl

]2Mass [MeV/c0 200 400 600 800 1000 1200

[MeV

]ef

fT

020406080

100120140160180

0π0sK η Λ

25

Kine@cfreeze-outAr+KCl

26

Kine@cfreeze-out

27

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