Nucleus-nucleus collisions at the future facility in Darmstadt -

Compressed Baryonic Matter at GSI

Outline:

A future accelerator for intense beams of (rare) ions and antiprotons The CBM experiment: Exploring dense baryonic matter Observables Technical challenges and solutions

Peter Senger

SIS 100 Tm

SIS 300 Tm

U: 35 AGeV

p: 90 GeV

Structure of Nuclei far from Stability

Cooled antiproton beam:Hadron Spectroscopy

Compressed Baryonic Matter

The future international accelerator facility

Key features:Generation of intense, high-quality secondary beams of rare isotopes and antiprotons.Two rings: simultaneous beams.

Ion and Laser Induced Plasmas:

High Energy Density in Matter

The phase diagram of strongly interacting matter

CERN-SPS, RHIC, LHC: high temperature, low baryon density

AGS, GSI (SIS200): moderate temperature, high baryon density

Probing the Chiral phase transition

B 3-80 , T 130 MeV

Restoration of (spontaneously broken) chiral symmetry

Origin of hadron masses ?

The production of dense and/or hot hadronic matter

Compression + heating = quark-gluon (pion production) matter

neutron stars early universe

High energy Au+Au collisions in transport calculations

B. Friman, W. Nörenberg, V.D. Toneev Eur. Phys. J. A3 (1998) 165

Pion multiplicities per participating nucleons

Mapping the QCD phase diagram with heavy-ion collisions

B 6 0

B 0.3 0

baryon density: B 4 ( mT/2)3/2 x

[exp((B-m)/T) - exp((-B-m)/T)] baryons - antibaryons

Analysis of particle ratios with statistical model: chemical freeze-out

P. Braun-Munzinger

CBM physics topics and observables

1. In-medium modifications of hadrons onset of chiral symmetry restoration at high B

measure: , , e+e- open charm (D mesons) 2. Strangeness in matter (strange matter?) enhanced strangeness production ?

measure: K, , , , 3. Indications for deconfinement at high B anomalous charmonium suppression ?

measure: J/, D

softening of EOS

measure flow excitation function 4. Critical point event-by-event fluctuations 5. Color superconductivity precursor effects at T>Tc ?

Note: In heavy ion collisions

(, , ) e+e- not measured from 2 – 40 AGeV

J/ not measured below 158 AGeV

D mesons not measured at all

pn

++

K

e+

e-

p

Looking into the fireball …

… using penetrating probes:

short-lived vector mesons decaying into electron-positron pairs

Invariant mass of electron-positron pairs from Pb+Au at 40 AGeVCERES Collaboration S. Damjanovic and K. Filimonov, nucl-ex/0109017

≈185 pairs!

Signatures of the quark-pluon plasma ?

Enhanced production of strangenessAnomalous suppression of charmonium (J/)

Statistical hadron gas modelP. Braun-Munzinger et al.

Nucl. Phys. A 697 (2002) 902

Experimental situation : Strangeness enhancement ?Experimental situation : Strangeness production

in central Au+Au and Pb+Pb collisions

New results from NA49

Comparison of experimental data to results of transport codes E.L. Bratkovskaya, W. Cassing, M. van Leeuwen, S. Soff, H. Stöcker, nucl-th/0307098

“Flow generated by extra pressure generated by partonic interactions in the early phase of a central Au+Au/Pb+Pb collision”

Probing the high density fireball with charm production

W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745

25 AGeV Au+Au 158 AGeV Pb+Pb J/ multiplicityin central collisions 1.5·10-5 1·10-3 beam intensity 2·108/s 2·107/sinteractions 8·106/s (4%) 2·106/s (10%)central collisions 8·105/s 2·105/sJ/ rate 12/s 200/s 6% J/e+e- (+-) 0.7/s 12/sspill fraction 0.8 0.25 acceptance 0.25 0.1J/ measured 0.14/s 0.3/s 8·104/week 1.8·105/week

J/ experiments: a count rate estimate10 50 120 210 Elab [GeV]

Hadrons in the nuclear medium

SIS18 SIS300

SIS18: strangeness production at threshold probing in-medium properties at = 1 -3 0

SIS300: charm production near threshold probing in-medium properties at = 5 -10 0

Meson production in central Au+Au collisionsW. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745

Charmed mesons

Some hadronic decay modes

D (c = 317 m):D+ K0+ (2.90.26%)

D+ K-++ (9 0.6%)

D0 (c = 124.4 m):D0 K-+ (3.9 0.09%)

D0 K-+ + - (7.6 0.4%)

experimental challenges:low production cross sectionlarge combinatorial backgroundmeasure displaced vertex with resolution of 30m

D meson production in pN collisions

The critical point

gasliquid

coexistence

Below Tc: 1. order phase transitionabove Tc: no phase boundary

At the critical point:Large density fluctuations,critical opalescence

Event-by-event analysis by NA49: 5% most central Pb+Pb collisions at 158 AGeV

Purely statistical fluctuations !

Produce high baryon densitiesin heavy ion collisions at 4 – 40 AGeV.

Build an universal experiment which measures simultaneously both hadrons and electrons: , K, , , , p, , , , , D, J/(multiplicities, phase-space distributions, centrality, reaction plane).

Perform systematic measurements using a dedicated accelerator:High beam intensity and duty cycle,Excellent beam quality,High availability

Our approach towards the study of superdense baryonic matter

Experimental challenges

beam intensities up to 109 ions/sec, 1 % interaction target: 107 Au+Au reactions/sec (1000 charged particles in central Au+Au collisions at 25 AGeV) determination of (displaced) vertices with high resolution ( 30 m)

identification of electrons and hadrons

Silicon: 7 planes, 3 Mio pixel, 1.5 Mio strips

Experimental concept

Radiation hard Silicon pixel/strip detectors

in a magnetic dipole field

2 electron detectors: pion suppression by 104- 105

Particle identification: TOF, RICH

Electromagnetic calorimeter

High speed data acquisition and trigger system

Silicon tracker in B field: tracking, momentum

RICH1 ( 30): electrons RICH2: high-momentum pions ( 3-4

GeV/c)

TRDs: tracking, electrons ( 2000):

RPC: particle identification via TOF, kaon-pion separation up to 3-4

GeV/c

ECAL: electrons, gammas, 0,0

The CBM Experiment

Central Au+Au collision at 25 AGeV:URQMD + GEANT4

160 p 400 -

400 + 44 K+ 13 K-

CBM R&D Collaboration : 35 institutions 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. MünsterFZ RossendorfGSI Darmstadt

   

Russia:CKBM, St. PetersburgIHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaSINP, Moscow State Univ.

Spain: Santiago de Compostela Univ.  Ukraine: Shevshenko Univ. , Kiev

USA: LBNL Berkeley

Hungaria:KFKI BudapestEötvös Univ. Budapest

Italy: INFN CataniaINFN Frascati

Korea:Korea Univ. SeoulPusan Univ.

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

Romania: NIPNE Bucharest

R&D working packages Feasibility, Simulations

D Kπ(π)GSI Darmstadt, Czech Acad. Sci., RezTechn. Univ. Prague

,ω, e+e-

Univ. KrakowJINR-LHE Dubna

J/ψ e+e-

INR Moscow

Hadron ID Heidelberg Univ,Warsaw Univ.Kiev Univ. NIPNE BucharestINR Moscow

GEANT4: GSI

TrackingKIP Univ. HeidelbergUniv. MannheimJINR-LHE Dubna

Design & constructionof detectors

Silicon PixelIReS StrasbourgFrankfurt Univ.,GSI Darmstadt,RBI Zagreb,Krakow Univ. LBNL Berkeley

Silicon StripSINP Moscow State U.CKBM St. PetersburgKRI St. Petersburg

RPC-TOFLIP Coimbra, Univ. S. de Compostela,Univ. Heidelberg,GSI Darmstadt,NIPNE BucharestINR MoscowFZ RossendorfIHEP ProtvinoITEP Moscow

Fast TRDJINR-LHE, DubnaGSI Darmstadt,Univ. MünsterINFN Frascati

Straw tubesJINR-LPP, DubnaFZ RossendorfFZ Jülich

ECAL ITEP Moscow

RICH IHEP Protvino

Trigger, DAQKIP Univ. HeidelbergUniv. MannheimGSI DarmstadtKFKI BudapestSilesia Univ.

MagnetJINR-LHE, DubnaGSI Darmstadt

AnalysisGSI Darmstadt,Heidelberg Univ,

Data Acquis.,Analysis

Project cost (M€)

Total: 675

Buildings: 225.5 SIS100: 70.1 SIS200: 39.6 Coll. Ring: 45.0 NESR: 40.0 HESR: 45.0e-ring: 15.0 Beamlines: 21.0 Cryo, etc: 44.1

SFRS: 40.7CBM: 27.0AP: 8.7Plasma phys.: 8.0p-linac: 10.0PANDA: 28.4pbar targ.: 6.9

Project evolutionOct. 2000: 1. International Workshop on a future accelerator facility

Oct. 2001 : Submission of the Conceptual Design Report

Nov. 2002: Positive evaluation report of the German science council

Feb. 2003: Project approved by the German federal government (170 M€ foreign contributions requested)

Oct. 2003: 2. International Workshop on the future accelerator facility

Spring 2004: Letters of intent

In 2004: New GSI structure

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

SIS18 Upgrade 70 MW Connection

Proton-Linac

TDM#

SIS100 Transfer Line SIS18-SIS100

High Energy Beam Lines

RIB Prod.-Target, Super-FRSRIB High+Low Energy Branch

Antiproton Prod.-TargetCR-Complex

HESR & 4 MV e- –CoolingNESR

SIS200*8 MV e- –Cooling

e-A Collider

SIS100/200 Tunnel, SIS Injection+Extraction+Transfer

Transfer Buildings/Line Super-FRS,Auxiliary Bldgs., Transfer Tunnel to SIS18,Building APT, Super-FRS, CR-ComplexRIB High+Low Energy Branch,

HESR ( ground level),NESR, AP-cave,e-A Collider, PP-cave

CBM-Cave, Pbar-Cave, Reinjection SIS100

Civil Construction

Civil Construction 1

Civil Construction 3

Civil Construction 2

Civil Construction 4

I

IV

III

V

II

Concept for staged Construction of the International Facility for Beams of Ions and Antiprotons

2,7x1011 /s 238U28+ (200 MeV/u) 5x1012 protons per puls

1x1011/s 238U28+ (0.4-2.7GeV/u) ->RIB (50% duty cycle)

2.5x1013 p (1-30 GeV)3-30 GeV pbar->fixed target10.7 GeV/u 238U -> HADES*

1x1012/s 238U28+

100% duty cyclepbar cooledp (1-90 GeV)

35 GeV/u 238U92+

NESR physicsplasma physics

Experiment Potential

#Construction Tunnel Drilling Machine

General Planning

Civil Construction Production and Installation *SIS200 installation during SIS100 shut down

Kopenhagen 2003

1. Titel 1 min2. Anlage 23. phasediagram 1 4. Hot dense matter 25. qq condensate 16. Filme 27. Pionen Excitation 18. Transport 19. Phasendiagramm 2 10. Observable 211. Dilepton Sonde 0.512. CERES Daten 113. QGP 0.514. NA49 1 15. Transport 116. cc production 1 20 min17. J/psi Vergleich 118. Inmedium K, D 119. Excitation HSD 120. Excit. D-mesons 121. Requirements 122. CBM 1 123. CBM2 2 24. URQMD 125. Collaboration 126. Working packages 127. Costs 128. Schedule 129. Workshop 0 Summe 13

International Accelerator Facility for beams of Ions and Antiprotons

HADES

CBM

The nuclear reaction experiment at the future facility at GSI

A+A at 2-8 AGeV

A+A at 8-40 AGeV

Au+Au @ 25 AGeV central collision

URQMD event,GEANT simulation: B = 1 T

160 p 400 - 400 + 44 K+ 13 K-

-

p

+

midrapidity

80%

60%incl. decay

67%incl. decay

20%

30%

Acceptance

Au+Au 25 AGeV

URQMD event, GEANT simulation

J/ (x105)

e+e-

0e+e-

counts

(x10-4)

cut: pT 1 GeV/c

e+, e- opening angle

J/ (x105)

counts

e+, e- transverse momentum

cut: 10o

without cuts (incl. misident. pions)

with cuts: pt(e+,e-) > 1 GeV/c, lab 25o, > 10o

e+e-

e+e-

J/e+e-

NJ/ = 1.6

DDe+e-+X

e+e-

counts

counts sum

Au+Au 25 AGeV: e+e- invariant mass spectra

PLUTO simulations: 10 Mio. events

signal/background 10

Simulations on open charm detection: D0+K-

performed by V. Friese (GSI)

Assumptions:

• Au+Au at 25 AGeV (<m>: 328 +, 13 K-)• Perfect track finding• Perfect particle identification• No magnetic field• Silicon detector thickness 100 m

Tools:

URQMD event generatorGEANT4 transport code ROOT data analysis

D0

+ +

K-

K-

p + pK

b

bK

Lab CMpair

vz

*

Suppression of combinatorial background by the following cuts:

invariant mass window mD = 1864 25 MeV displaced decay vertex vz > 0 back to back emission in c.m. system (* = 180o) impactparameter bpair = b bK

colinearity of D and decay products (momentum vectors)

Identification of D-mesons (open charm) Example: D0 K-+

Displaced decay vertex D0 K-+

signal

background

S/B

Vertex resolution: vz = 19 m

Cut : vz > 0,3 mm

Cut-efficiency:Signal: 58.0 %background : 2.7 x 10-4

Impact parameters of K- and + at z=0

bpair = bK x b

Cut : bpair < -0,004 mm2

Cut-efficiency:Signal: 90.3 %background: 23.7 %

signal

background

Colinearity (pointing angle)

Cut : p < 5º

Cut-efficiency:Signal: 99.9 %Background : 12.5 %

signal

background

Total efficiency:Signal: 48.4 %background : 5 x 10-6

ev

m

ND

BSSNR

MeV

5,7/0

Sensitivity :

For <D0> = 10-3 (HSD-Model) und m = 10 MeV: 3-limit reached at 1,6 x 106 eventsSignal/Background 1.8

At a reaction rate of 1 MHz (Au+Au central collisions):D0 detection rate (incl. branching ratio): 13.000 / h

Efficiencies, sensitivity and rates