ICPAGQP 2005, Kolkata Probing dense baryonic matter with time-like photons Dilepton spectroscopy from 1 to 40 AGeV at GSI and FAIR Joachim Stroth Univ

ICPAGQP 2005, Kolkata

Probing dense baryonic matter with time-like photons

Dilepton spectroscopy from 1 to 40 AGeV at GSI and FAIR

Joachim Stroth

Univ. of Frankfurt


Toneev et al., 2004

The physics case

What are the properties of dense nuclear matter?

Dense matter Freeze-outFirst chance collisions

Its macroscopic properties depend on the microscopic structure!


The physics case

Probe the electromagnetic structure of (hot) and dense nuclear matter in the time-like region!

– What is the relevant excitation spectrum as the matter density increases?

– Where are the limits of hadronic existence?

Additional self-energy terms due to meson-

baryon coupling

J. Wambach et al.

0,0

,

T

T

qq

qq

Densebaryonicmatter

Partial restoration of chiral symmetry


Probing the interior of compressed matter

pn

++

K

p

e+

e-

Low-mass vector mesonsIn-medium spectral functions


The HADES spectrometer

• Geometry Full azimuth , polar angles 18o - 85o

Pair acceptance 0.35 About 80.000 detector channels

• Fast particle identification RICH

CsI solid photo cathode, No 80, C4F10 radiator

TOF (Scintillator rods)

TOFino (Scintillator paddles) temporary solution, RPC in future

Pre-Shower 18 pad chambers & lead converters

• Momentum measurement ILSE, super conducting toroid

B = 0.35 Tm

MDC Multi-wire drift chamber, single cell resolution 100 m

1 m



Experimental runs

• November 2001: commissioning run target = 5% – C+C 2 AGeV LVL1 triggered events (Mch.>3) : 45 Mevents45 Mevents

– C+C 1 AGeV LVL1 trigger : 7.3 Mevents7.3 Mevents– full coverage with inner MDC chambers (p/p 10% at 0.7 GeV/c)

• November 2002: C+C 2 AGeV, commissioning and physics runs – target= 2 x 2.5%, 56% LVL1 trigger + 44% LVL2 trigger 220 Mevents220 Mevents– 6 outer drift chambers (MDC) in 4 sectors

• October 2003: p+p commissioning run (1 GeV, 2 GeV) – full coverage with outer MDC III (4 MDC IV) (p/p 1.5 % at 0.7 GeV/c)

• February 2004: p+p 2GeV production run– target 5 cm l-H2 400 Mevents400 Mevents

• August 2004: C+C 1AGeV production run– 3x1.5 % target, 56% LVL1 trigger + 44% LVL2 trigger 650 Mevents650 Mevents


Fast 2nd level trigger

up to 20 kHz LVL1Fast multiplicity trigger

full event information digitised.

on-line selection of electron candidates

LVL2 triggered events are transported to mass storage

Suppression 10 - 100


On-line off-line comparison

• Trigger condition used in November 2002 run:

– At least one good electron candidate

– Ring matched with META hit

• Data rate reduced by 92 %

• Pair enhancement by factor of 9

• Single lepton efficiency of IPUs + matching 62%(pairs 82%)

Me+e- [MeV/c2]

Yie

ld /

even

t [a

.u]

e+e- > 40

Scaled down by 9.2 ! LVL2

LVL1

No bias on data


C+C @ 2 A GeV "Nov’02"

preliminary

No Efficiency / Acceptance Correction

• Minimal tracking analysis

• No in-medium contributions in the simulation.


C+C @ 1 A GeV “Aug'04”

All N+-

B+- = 2*sqrt(N++*N--)

S+- = N+- - B+-

M [MeV/c2]

Yie

ld /

1 M

e V/c

2

very preliminary

No Efficiency / Acceptance Correction


Meson-baryon coupling and in-medium spectral functions

Starting in 2006!

• Precision spectroscopy at nuclear ground state density

• Invariant mass resolution with outer tracking is 1 % in the vector meson mass region

M. Effenberger, Giessen

One possible scenario

e+

e-

208Pb

-

n

W.Schoen et al.

Acta Phys.PolB27(1996)2959


nuclear matter at high densitiesCBM experiment

Facility for Antiproton and Ion Research

FAIRFAIR

Staged realization


The future of dielectron spectroscopy at FAIR

Heavy ion collisions Heavy ion collisions at interaction rates of up to 10at interaction rates of up to 1077 Hz Hz

andand

beam energies from 2 to 40 GeV/ubeam energies from 2 to 40 GeV/uCBM Detector

HADES

E < 10 AGeV

E > 10 AGeV

Talk by Peter Sengeron Wednesday


e+ e-e+e-

HADES acceptance at higher energies

ThermalSource

Accepted

YcmYcmYcmYcm

Y

pt

C+C 2 AGeV C+C 8 AGeV

1 GeV/c

1 GeV/c

0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3

J. Novotny, HADES collaboration meeting 2003

Electrons from:o-Dalitz, -Dalitz, , (-Dalitz), 40 % of geometrical cross section

Simulation


HADES with beam from SIS100

Compared to 2 A GeV– acceptance 40% lower– yields 2 orders of magnitude higher

Simulation


Experimental concept

Perform momentum measurement in a 1m3 volume with 1 T magnetic field.

Possibly a flexible configuration to optimize performance for different physics cases..

Both options, electronselectrons and muonsmuons are investigated.

Detector configuration CBM experimentHigh quality tracking to identify

"background" tracks (conversion, 0)


Dilepton spectroscopy at GSI and FAIR

Final C+C spectra 1 and 2 AGeV

, p, d, A on lH2, A

A+A heavy collision systems

2005

2010

2015tim

e [y

ear

AC

]

Dilepton spectroscopy in A+A at 10-40 AGeV

A+A medium up to 8-10 AGeV

Systematic study of the microscopic properties of dense baryonic matter


The Collaboration

Cyprus

University of Cyprus

France

Institut de Physique Nucléaire d'Orsay

Czech Republic

Nuclear Physics Institute, Rez

Czech Academy of Sciences, Rez

Germany

GSI, Darmstadt

FZR, Dresden

Johann Wolfgang Goethe-Universität Frankfurt

Justus Liebig Universität Giessen

Technische Universität München

Italy

INFN Catania

Università di Catania

INFN Milano

Università di Milano

Poland

Jagiellonian University of Cracow

Russia

LHE at JINR, Dubna

Institute for Nuclear Research, Moscow

MEPHI, Moscow

ITEP, Moscow

Spain

University of Santiago de Compostela

Universidad de Valencia-CSIC


The CBM Collaboration

Croatia: RBI, Zagreb

Cyprus: Nikosia Univ. Czech Republic:Czech Acad. Science, RezTechn. Univ. Prague France: IReS Strasbourg

Germany: Univ. Heidelberg, Phys. Inst.Univ. HD, Kirchhoff Inst. Univ. FrankfurtUniv. Mannheim Univ. MarburgUniv. MünsterFZ RossendorfGSI Darmstadt

Russia:CKBM, St. PetersburgIHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaLIT, JINR DubnaObninsk State Univ.PNPI GatchinaSINP, Moscow State Univ. St. Petersburg Polytec. U.

Spain: Santiago de Compostela Univ. Ukraine: Shevshenko Univ. , KievUniv. of Kharkov

Hungaria:KFKI BudapestEötvös Univ. Budapest

Korea:Korea Univ. SeoulPusan National Univ.

Norway:Univ. Bergen

Poland:Krakow Univ.Warsaw Univ.Silesia Univ. Katowice Portugal: LIP Coimbra

Romania: NIPNE Bucharest


Lepton candidate selection

Events with lepton multiplicity 1 in LVL1 triggered events: 1.2 %

Require META and RICH signal (LVL2)

+ matching with fully reconstructed tracks

linear z axis !

log. z axis !

yie

ld [

arb

. u

nit

s]

cut on


Signal to Background Nov02

preliminary

Ne+e- - CB

CBS/B =

<S/B> ~ 4:1 (M < 100 MeV/c2)

<S/B> ~ 1:2 (M > 100 MeV/c2)

inv. mass [MeV/c2]

S/B

Mass range Mass range [MeV/c2]:[MeV/c2]:

0 -> 1500 -> 150 150 -> 610150 -> 610 610 -> 1000610 -> 1000

Signal e+e- Signal e+e- pairspairs

14943 +- 7214943 +- 72 1357 +- 131357 +- 13 65 +- 965 +- 9

data

simulation

C+C Nov ‘02


Dielectrons in CBM

R. Karabowicz, Kraków, CBM Collaboration Meeting


Experiments with pion beams

• in-beam tracking of pions

• p and A reactions

Eth

resh

[GeV

]

Mx [GeV/c2]

/

pp->ppX

-p->Xn

Documents

ICPAGQP 2005, Kolkata Probing dense baryonic matter with time-like photons Dilepton spectroscopy from 1 to 40 AGeV at GSI and FAIR Joachim Stroth Univ