HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for...

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HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration

Transcript of HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for...

Page 1: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

HADES experiments investigating in-

medium hadron properties

P. Salabura

Jagiellonian University

for the HADES collaboration

Page 2: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Study of hadron properties in dense and hot nuclear matter

Rear Probes:

dielectrons penetrating probes

emissivity and in medium hadron masses :

vector mesons (/e+e-) chiral sym.

strangeness production : , K , (1321)

EOS, K in-medium potentials, …

Strategy:

Reference measurements in N +N

and A+A at 1-2 AGeV (<2015) and

in future at SIS100 8-10 AGeV (FAIR)

Goal: to cover interesting and not fully covered region of baryonic matter at low T • „emissivity” of compressed matter • hadron properties in matter

e+ e- e+ e-

K+

e+ e-

K-

experiment: chemical freeze-out

RHIC BES Na61

CBMFair

HADES

HADES @ FAIR

L. McLerran, R.D. Pisarski 2007

Page 3: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Side View

START

FWFW

High Acceptance DiHigh Acceptance Di-E-Electron Spectrometerlectron Spectrometer

Beams from SIS18: protons, nuclei , pions

Spectrometer with high invariant mass resolution - 2% at /

Versatile detector for rear probes :

• dielectrons (e+,e-)

• strangeness: , K,0 , -

• Upgrade(2010): new DAQ (20 KHz, Tof-RPC (tof ~80 ps)

GeometryFull azimuth, polar angles 18 - 85 e+e- pair acceptance 0.35~ 80.000 channels, segmented solid or LH2 targets

1 m

RPC (from 2010)

Page 4: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

HADES programme (so far) HADES programme (so far)

• pp reactions

(1.25, 2.2, 3.5 GeV)dp reactions (1.25 GeV)

• nucleus + nucleus

C+C, Ar+KClAu+Au (2012)

• p + nucleus (Nb @ 3.5 GeV)

• e+e- production in N+N – reference reactions for A+A

• single and double production (barion resonances in N+N)

• , , production- hadr.channels and rear e+e- decays

(new UL in PDG)

• (1405) , (1385) (new PDG entry)

• K0 production

• low mas e+e- „excess” : (DLS puzzle, emissivity,..) • kaon production : K0

s • Hyperon production; , , (1321)• production• -p, p-p, , correlations

• / mesons in cold nuclear matter• strangeness production K,

Page 5: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Low mass e+e- excess : „DLS puzzle”Low mass e+e- excess : „DLS puzzle”

DLS data: R.J. Porter et al.: PRL. 79 (1997) 1229

Calculation: E.L.Bratkovskaya et al. PLB445 (1999) 265

before HADES (< 2008) HADES data projected in DLS acceptance

HADES data: Agakishiev et al., PLB 663 (2008) 43

HADES fully confirms DLS results

• What about „excess” ? Is it true in-medium effect ? or not understood elementary process?

Page 6: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

N+N reference (I): e+e- in p+pN+N reference (I): e+e- in p+p

Important source: pe+e- Dalitz decay

Time Like (q2 >0) (J=3/2) ->N (J=1/2) * transition:

22

2

2

2222

232, qqq

Δf G

mq

GGqm C

Δ

EM2

-

dq

)eNe(Δd

Calculations: Vector Meson Dominance Krivoruchenko et al. PRD 65 (2001) 017502G. Ramalho and T. Pena arxiv: 1205.2575v1 (2012)F. Dohrmann et al., Eur. Phys. J. A 45, 401 (2010)

G(q2 ) ? el. Transition Form Factors : extented baryon structure !

complemenary to (space like) N ( data: JLAB/Mainz/Bates)

HADES: PLB690 (2010)118

qqq

e-

e+

pion cloud

e+

e-

GM (q2) VMD

+

p

e+*

p

p

p

e+e-

pe+e-

Page 7: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

N+N reference (II): e+e- in n+p N+N reference (II): e+e- in n+p

calculations: R. Shyam and U. Mosel Phys. Rev. C 82:062201, 2010 data: HADES

• production – fixed by COSY, WASA data

• bremsstrahlung pnpne+e- (non resonant), why it is so

much different from pp?

R. Shyam and U. Mosel Phys. Rev. C 82:062201, 2010

charge pion exchange & pion eFormFactor

~2

DLS

Large isospin effect at 1-2 AGeV!

p

n

n

p

+

for example:

e+e-

yie

ld r

atio

dp/

pp

Page 8: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

CC compared to NN reference. CC compared to NN reference.

NN and C+C normalized to the individual N(0 )

C+C data (1 and 2 AGeV !) reproduced (within 20%) by superposition of NN interactions

(reference) – no room (within error bars) for in-medium effects

data: H

AD

ES

PLB

690 (2010)118

contribution subtracted

PR

L98

(20

07

) 05

23

02ra

tio

CC

/NN

cocktail: „long lived sources”-freeze out

baryons

Page 9: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Vector mesons in medium- motivationVector mesons in medium- motivation

p - beams

SIS 18

SIS 200T [MeV] 300

LHC

RHIC

SPS

G.E. Brown / M. Rho: Scaling of masses with -condensate (PRL 1989, 1991)

T. Hatsuda / S. Lee: QCD sum rules PRC46(1992)R34

uqqqqmm **

how it begun..

second graph is related to elementary process:

hadronic many body interactions- spectral functions..

- meson at 2 x N

S. L

eupo

ld e

t al.

NP

A 7

41 (

2004

) 81

, NP

A 7

80 (

2006

) 18

7

Dalitz decay

prefered by data

Data : Na60 EPJC 59 (2009) 607calculations: Hess/Rapp: NPA806(2008)339.

Page 10: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Vector mesons in cold matter- experimentsVector mesons in cold matter- experiments

217 MeV

CLAS PRL 99 (2007) 262302 direct : meson line shape

• no mass shift• broadenning

• mass shift m*/m0 =1 – 0.09N/ 0

KEK-E325 PRL 96 (2006) 092301

CLAS: PRL 105 (2010) 0112301CBTAPS: PRL 100 (2008) 192302

absorption

VXN

VXAA AT

indirect: transparency

tot

eemesoneeeeN

large absorption

* tot, 210 MeV !

meson (SPRING8, ANKE)

* ~ 33 - 50 MeV

* N v VN

+A1.1-3.3 GeV

p+Cu 12 GeV

Page 11: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

p+p vs p+Nb @ 3.5 GeVp+p vs p+Nb @ 3.5 GeV

• large acceptance at small Me+e- and p (<1 GeV/c) ( first measurement at low p !)

• p+p cockail : based on known sources fixed to data 0 // / , with constant eTFF

underestimeted e+e- yield below VM pole missing component? -> higher resonances (, N*)

pp data scaled by„Apart” scaling

„fast” pe+e->0.8 GeV/c „fast” pe+e-< 0.8 GeV/c

Nuclear modification factor

data: arXiv:1205.1918 submitted to PRL

Page 12: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Fixing resonance contribution : exclusive Fixing resonance contribution : exclusive channels in p+p @ 3.5 GeVchannels in p+p @ 3.5 GeV

pn+ pp0

ppe+ e-

Preliminary

…many differential distribution studied for pp0 , pn+, pp, pp

RNe+e- constant eTFFM. Zetenyi et. al. Heavy Ion Phys. 17 (2003) 27

no off shell coupling to VM assumed lower limit for e+e- emission

/ from data (hadronic dec.)

missing yield related to low mass resonances and off shell VM !

Page 13: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

e+e- excess in p+Nb e+e- excess in p+Nb

„excess over pp reference”„slow” (p<0.8 GeV/c) pairs

clear excess in p+A below VM pole

- secondary reactions : +N (1720,..)(N* (1520),..) NNe+e- ?

el. TFF important ! constraint from ppe+e- …… work in progress

- in medium modification ? answer only after understanding of the p+p reference

RpA (vs p) – increase at small momenta : largest for the „-region” BUT NOT for peak

strong absorption consistent with CBTAPS (+A) results!

Rpa vs momentum

Me+e

Page 14: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

e+e- pairs from Ar+KCl @ 1.756e+e- pairs from Ar+KCl @ 1.756

Cocktail with „freeze-out” comp.

first ->e+e- observation at SIS18 energies

first evidence for „true” excess

Excess yield scales with system size ~ Apart1.4 multistep processes?

component subtracted

data PRC84(2001)014902

Page 15: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

15

Transport model Transport model results results for Ar+KCl for Ar+KCl

Transport models: not consistent picture

don’t describe (yet) pn data „excess” region dominated by but

different predictions ! Me+e->0.60 dominates complicated

vacumm structure !

Are in-medium effects needed? Not clear yet… systematic studies needed new Au +Au data are essential!

E.L. Bratkovskaya, W. Cassing, NPA 807 (2008) 214

GiBUU: J. Weil at al., arXiv:1106.1344v1

Page 16: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

and and // ratio in Ar + KCl ratio in Ar + KCl

meson plays important role (~18%) in K-

production at SIS18 energies

• Statistical model describe rates with no

suppression (i.e OZI rules) !

R/ A+A : enhanced production and absorption?

K+K- e+e-

R/ A+A >> R/ in NN and πN reactions

w.r.t N-N threshold

Page 17: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Double strange Double strange -- (1321) in Ar+KCl (1321) in Ar+KCl

P.Salabura

640 MeV below NN threshold !

data: PRL 103 (2009) 132310

data: EPJA 47 (2011) 21 SHM: S. Wheaton, J. Cleymans, Comp. Phys. Comm. 180 (2009) 84

production significantly larger then transport model (UrQMD) and statistical model predictions

Note that also is enhanced and is not suppressed at all all have ss(bar) content !

..to be continued with Ag+Ag

Page 18: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Kaons in nuclear matterKaons in nuclear matter

G.E Brown et.al NPA 567 (1994) 937, T. Waas, e al. PLB 379 (1996) 34J. Schaffner-Bielich, et al.. NPA 625 (1997),..

indirect measurements :

K+/K0 considered as good quasiparticle

at SIS K+ 5 fm (weak absorption)

repulsion from spectator matter :flow out of plane (KAOS data PRL.95 (2005)

012301,FOPI-> Y. Leifels talks this afternoon ) reduced yield at low pt (p): ( FOPI, ANKE data

PRL102(2009)183591)

Acta Phys. Hung. A22 2005 21

(1405)

K- K-

N-1

K- in medium: more complicated spectral function

(1405) physics : entry to K- in mediumproperties , kaonic clusters ppK- .., kaonic atoms,..

Page 19: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

KK00s s in medium potential and in medium potential and (1405) (1405)

K0s in Ar+KCl @ 1.756 GeV

data: PRC 82 (2010) 044907

IQMD : repulsive UKN 38 MeV

(1405) –bound K- N system?

(1405) pole

• pole shift? intereference with non. res ? importnat bench mark for theory

Preliminary

• new data will come from p+A • ..and Au+Au (+ flow measurement)

Page 20: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Au+Au run (finished 3 weeks ago) at 1.23 AGeVAu+Au run (finished 3 weeks ago) at 1.23 AGeV

• Thank to essential HADES upgrade (DAQ,MDC,RPC_TOF)

Ready for campaigns at FAIR SIS100!

on line PID

vertex reconstruction

Page 21: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

SSummary:ummary: Low mass pair production in light systems (C+C) explained by known 0 cross sections

and baryonic sources fixed from the NN reference reactions:

pn- bremsstrahlung + Dalitz are the essential e+ e- sources explaining „DLS” puzzle

OBE models come closer to pp/pn data : further studies are on-going

for larger systems , Ar+KCl, evidence for onset of pair excess over NN reference :

radiation from „resonance (, N*) matter”: New Au+Au data are of key importance !

in-medium effects on (A+A and p+A) are not clear yet :

determination of -meson shape in N-N collisions (vacumm) is far from trivial and requires

better understanding of /N* - couplings el.Transition Form Factors , work is in progress

absorption of and enhanced production in nuclear matter can be explain large R /

new K0S data support repulsive KN in-medium potential ; (1405) is crucial for antykaon

properties in nuclear matter

Large production yields (above SHM predictions) of double strange (1321)

Page 22: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Outlook:Outlook:

2012-2013 - HI collisions (Au+Au/Ag+Ag) at SIS18 with upgraded HADES continuation of

dielectrons + strangeness programme (also K+,K- , e+e-, flow measurements)

> in discussion: pion beams : el.TFF of baryon resonances, pion, strangeness production

> 2016 - HADES at FAIR (SIS100) - zero day experiment- part of CBM physics programme

HADES

CBM

stay tuned: lot of new interesting results are expected !

Page 23: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

23.01.2009 P.Salabura 23

The CollaborationThe Collaboration

GSIGSI

SISSIS

Cracow (Univ.), Poland

Darmstadt (GSI), Germany

Dresden (FZD), Germany

Dubna (JINR), Russia

Frankfurt (Univ.), Germany

Giessen (Univ.), Germany

München (TUM), Germany

Moscow (ITEP,RAS), Russia

Nicosia (Univ.), Cyprus

Orsay (IPN), France

Rez (CAS, NPI), Czech Rep.

Sant. de Compostela (Univ.), Spain

LIP, Portugal

Page 24: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Gross properties of the baryonic Gross properties of the baryonic matter matter

Au+Au

1-2 AGeV : moderate densities but long system life time

Baryonic matter:

• /N = 1-3, T< 80 MeV, ~12-14 fm/c

nucleons, baryonic resonances (~30%) 33

mesons(π0) ~10% “resonance (, N*) matter”

• Sub-threshold production of (, , K- K+, ) :

• confined to high density zone

• Multi-step processes ~ Apart >1

S.Vogel et al. (URQMD) arXiv:0710.4463v2

Rapp & Wambach Adv. Nucl. Phys. 25 (2000)

N+N->N , +NN +N +

ex: production

SIS

AGSSPS

K+

K-

/

P/ e+e- 10-6 !

Page 25: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Upcoming experiments : Au+Au and Upcoming experiments : Au+Au and Ag+Ag (2010-2012) Ag+Ag (2010-2012)

simulation: 4 weeks of beam (no in-medium effects included)

½(pp+pn)

• maximum excess (intermdediate mass)

• High statistics differential studies of excess

centrality, dN/dmt , angular distributions

counts

• Ag+Ag : maximal density VM (/)

production rate at SIS18

• High stat. spectroscopy of VM region

• Strangeness programme

Page 26: HADES experiments investigating in- medium hadron properties P. Salabura Jagiellonian University for the HADES collaboration.

Resonance reconstruction Resonance reconstruction strangenessstrangeness

->+-

Ar + KCl @ 1.75 AGeV: excellent rec. capabilities

->p+-

K0s ->+ + -

->K+ + K-

GeV/c2

first observation at SIS