The CBM heavy-quark program

NEW TRENDS IN HIGH-ENERGY PHYSICS(experiment, phenomenology, theory)

Alushta, Crimea, Ukraine, September 3 - 10, 2011

Iouri VassilievCBM Collaboration

Physics case: Exploring the QCD phase diagram

Projects to explore the QCD phase diagram at large μB:

RHIC energy-scan, NA61@SPS, MPD@NICA bulk observables

CBM@FAIR/SIS-300 bulk and rare observables, high statistic!

SPS-CERN

CBM

LHC RHIC

The equation-of-state at high B

• collective flow of hadrons• particle production at threshold energies (open charm) Deconfinement phase transition at high B • excitation function and flow of strangeness (K, , , , )• excitation function and flow of charm (J/ψ, ψ', D0, D, c)• charmonium suppression, for J/ψ and ψ' ?

QCD critical endpoint• excitation function of event-by-event fluctuations (K/π,...)

Onset of chiral symmetry restoration at high B

• in-medium modifications of hadrons (,, e+e-(μ+μ-), D)

21/04/23 I.Vassiliev, CBM 3

SPS Pb+Pb 30 A GeV

The mission:

SIS-300 SIS-100

D0, D+, Ds+ , c , D*

D0, D+, J/

P.SengerJ/,

21/04/23 I.Vassiliev, CBM 4

HSD simulations

Charm production at threshold

• J/ and open charm suppression measured

• charmonium in hot and very dense matter?

• open charm in hot and very dense matter?

D

Nuclear effects at low energy

21/04/23 I.Vassiliev, CBM 5

central Au+Au 25AGeV791 mc track 697 recoRef primary eff = 94.6%

80 mslxir039

up to 107 Au+Au reactions/sec (J/ψ) determination of (displaced) vertices with high resolution ( 50 m) identification of leptons and hadrons fast and radiation hard detectors self-triggered readout electronics high speed data acquisition and online event selection

Finder: 80 msFitter: 1.6 msPV : 51.2 msK0

S : 32.8 msTotal 165.6 ms/16 cpu

697 reconstructed tracksRef. prim. eff = 96%All set eff = 88%dp/p = 1.2%

700 160 p 53 K32 KS

~1 -

0.022 -

front view

SIMDized tracking

Online: track finder, track fitter, PV finder, V0 finder, -, - finder

e+/-

π+/-

RICH + TRD:e identification efficiency 85 % π-suppression 104

Rings: up to 100 per event~ 6cm diameter~ 20 photo electrons

finding eff. 95.3%multi-anode PMT

glass mirror with Al+MgF2 high-rate TRD

Charmonia (di-electron channel)

Signal and background yields from physics event generators (HSD, UrQMD) Full event reconstruction based on realistic detector layout and response

Electron id:RICH and TRD

π suppression: factor 104

dominant background: e from π0 Dalitz

4 1010 events

J/ψ

Charmonia (di-electron channel)

Muon detection

low-mass vector mesonlow-mass vector mesonmeasurementsmeasurements

≡ 7.5 λII

≡ 13.5 λI

Fe

20 20 2

0 30

35 1

00 cm

JJ//measurementsmeasurements

256 pads 3.5×8 mm2

Straw tubes

GEM detectors

trigger

J/ψ, ψ'

Signal and background yields from physics event generators (HSD, UrQMD) Full event reconstruction based on realistic detector layout and response

3.8 1010 events

6 J/ψ recorded in 1010 events (b=0) (20 J/ψ per hour)

J/ψ → μ+μ-

p+C 30 GeV

Au+Au 25 AGeV

Charmonia (di-muon channel)

Open charm. Sensors for the MVD

Monolithic Active Pixel Sensors(MAPS, also CMOS-Sensors)

• Invented by industry (digital camera)• Modified for charged particle

detection since 1999 by IPHC Strasbourg

• Also foreseen for ILC, STAR…

CBM

wish list

MAPS*

(2003)

MAPS*

(2009)

Single point res. ~ 5 µm 1.5 µm 5 µm

Material budget < 0.3% X0 ~ 0.1% X0 ~ 0.05% X0

Rad. hard. non-io. >1013 neq 1012 neq/cm² >3x1013 neq

Rad. hard. io > 3 Mrad 200 krad > 1 Mrad

Time resolution < 30 µs ~ 1 ms ~ 30 µs

Best values reached

Monolithic Acitive Pixel Sensors in commercial CMOS processCBM: 5 µm single point resolution

Micro Vertex Detecor (MVD) Development

first demonstrator tested in beam!

• first station 5cm downstream of target

• high position resolution!

Chip-on-polyamide

Sensor development:double-sided micro-strips, stereo angle 15o, pitch 60 μm300 μm thick, bonded toultra-thin micro-cables,radiation hardness

STS in thermalenclosure

Detector planes: ultra-light weight ladder structure

Prototypes: full CBM sensor, ultrathin cables

Development of the Silicon Tracking System (STS)

21.04.23 14

MC RECO

XY Rear View

e+

e-

p

p

K-

-

+

Reconsruction time << 1ms

e+

e-

p

p

K-

-

+

MC

p+C 30GeV SIS-100

-electrons

50 pile up + -electrons by 100k protons

21.04.23 15

Primary vertex reconstruction

pC 30 GeV

4.5 tracks central, 1 track mbias

K-

+

+

2geo

D+

21/04/23 I.Vassiliev, CBM 1621.04.23 16

Open charm at SIS-100Invariant mass spectra

3 cut 4 cut

MD+ HSD=2.710-8

BR = 0.095

with PV BG suppressed 10-30 times!

eff = 13.2 % eff = 11.6 %

p+C 30GeV D+ K- ++

21/04/23 I.Vassiliev, CBM 1721.04.23 17

Invariant mass spectra

with PV BG suppressed

p+C 30GeV

D0 K- ++-

MD0 HSD = 2.9(8.8)10-8

BR = 7.7%Eff = 1.7%

K-

+

-

2geo

D0

+

3 cut

1012 central events

Primary vertex reconstructionAu+Au @ 25AGeV

450 tracks central100 tracks mbias

50 ms

450 primary tracks

IR: 0.1MHz = 300 Au ions-electrons!

479

12389

t = 30 s

Open charm (Au+Au @ 25 AGeV)z-vertex reconstruction

D0K-+

KK--

+

Out

er a

cc.

Inne

r 2

prim > 3

2geo < 3 Eff =10.4%

K0S

eff~12.0%

2prim > 3

2geo < 3

q>0 proton mass

Open charm Reconstruction Quality Control

22

Open charm Reconstruction Quality Control

21/04/23 I.Vassiliev, CBM 2323

Strategy: background suppression keeping maximum of efficiency

single track parameters based cuts: χ2

prim impact parameter value 6.0-7.5 IP impact parameter cut (upper value) 0.5 mm protons ID by TOF track transverse momentum pt > 0.3 GeV/c (D0 only)multiple track (particle) parameters based cuts: χ2

GEO geometrical constrained fit 3.0 χ2

TOPO topological constrained fit 2.0-3.0 charm particle to primary vertex DCA < 20(30) m Zvertex < 2(3.5) mm c

21/04/23 I.Vassiliev, CBM 2424

χ2prim impact parameter value 6.5-7.5

2 = r2/2

r

pv

21/04/23 I.Vassiliev, CBM 2525

χ2geo geometrical constrained fit 3.0

K

2geo

21/04/23 I.Vassiliev, CBM 2626

Zvertex geo > 350 m

27

χ2topo topological constrained fit 2.0-3.0

PVK-

+

+2geo

2topo

D+2

prim

21/04/23 I.Vassiliev, CBM 2828

charm particle impact parameter < 20 m

21/04/23 I.Vassiliev, CBM 2929

Zvertex < 2 mm (new cut)

Duplets cut

21/04/23 I.Vassiliev, CBM 30

Invariant mass spectra Au+Au @ 25 AGeV

1.6k

600

21/04/23 I.Vassiliev, CBM 31

Invariant mass spectra Au+Au @ 25 AGeV

21/04/23 I.Vassiliev, CBM 32

Invariant mass spectra Au+Au @ 25 AGeV. C+C @ 25AGeV

21/04/23 I.Vassiliev, CBM 33

D0+D0 D++D- Ds+ c

+

decay channel K-+ K-+ + K-K+ + p K-+

MHSD1.5·10-4 4.2·10-5 5.4·10-6

MSM8.2·10-4 8.4·10-5 1.4·10-4 4.9·10-4

BR(%) 3.8 9.5 5.3 5.0

geo. acc.(%) 29.2 40.1 32.8 71

z-resolution (m) 52 56 60 69

total eff. (%) 3.95 4.75 1.0 0.05

m (MeV/c2) ~11 ~11 ~11 ~11

S/B2 0.16/0.5 1.24/2.5 5.0 0.6

Yield/1012mb HSD 14k+41k 47k+89k 0.7k

Yield/1012mb SHM 78k+225k 95k+179k 19k 3.2 k

Open charm properties table (25AGeV)

21.04.23 33

Open Charm Triggers

D0 K-+ (K-++-) D+ K-+ +

Ds K- K+ +

c p K- +

DVT

PVK-

+

+

D+

2geo

2topo

Background Background

D+2

prim

DKT

Open Charm Trigger-algorithm

L1CATrackFinder SIMD

L1KFTrackFitter SIMD

Charm Track Candidates Selection χ2prim > N

Charm Pairs χ22geo

< 3.0, zv <1 cm χ2

topo < 3.0, minv > 1.3 GeV

Charm Triplets χ23geo+topo < 3.0 ☺

D+c Ds

☺D0☻

☻

RFmb = 125RFcen = 14

accepted

acceptedrejected

N = 3

21/04/23 I.Vassiliev, CBM 36

Detached Vertex Trigger:

RFmb = 125RFcen = 14

CBM timeline 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

R&D detectors & read-out systems

construction detectors & read-out systems

installation, commissioning

first data taking

21/04/23 I.Vassiliev, CBM 38

Croatia:Croatia: RBI, ZagrebSplit Univ.

China:China:CCNU WuhanTsinghua Univ. USTC Hefei

Czech Republic:Czech Republic:CAS, RezTechn. Univ.Prague

France: France: IPHC Strasbourg

Hungaria:Hungaria:KFKI BudapestBudapest Univ.

Norway:Norway:Univ. Bergen

Russia:Russia:IHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHEP, JINR DubnaLIT, JINR DubnaMEPHI MoscowObninsk State Univ.PNPI GatchinaSINP MSU, Moscow St. Petersburg P. Univ.

Ukraine:Ukraine: T. Shevchenko Univ. KievKiev Inst. Nucl. Research

Germany: Germany: Frankfurt Univ. IKFFrankfurt Univ. FIAS GSI Darmstadt Giessen Univ.Heidelberg Univ. P.I.Heidelberg Univ. KIP Heidelberg Univ. ZITIHZ Dresden-RossendorfMünster Univ. Tübingen Univ. Wuppertal Univ.

Korea:Korea:Korea Univ. SeoulPusan Nat. Univ.

RomaniaRomania: : NIPNE BucharestUniv. Bucharest

India:India:Aligarh Muslim Univ.Panjab Univ. Rajasthan Univ.Univ. of Jammu Univ. of KashmirUniv. of CalcuttaB.H. Univ. VaranasiVECC KolkataSAHA KolkataIOP BhubaneswarIIT KharagpurGauhati Univ.

Poland:Poland:AGH Krakow Jag. Univ. KrakowSilesia Univ. KatowiceWarsaw Univ.

The CBM Collaboration: 55 institutions, 450 members

15st CBM Collaboration Meeting, April 12-16, 2010, GSI Darmstadt

Highest net-baryon densities at FAIR

• high (net-)baryon and energy densities created in central Au+Au collisions

beam energy

max. /0

max [GeV/fm3]

time span

~FWHM

5 AGeV 6 1.5 ~ 8 fm/c

40 AGeV 12 > 10 ~ 3.5 fm/c

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Ra

ndru

p, J

. C

leym

ans

PR

C7

4, 0

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