The PANDA project at FAIR

Strong interactions studies with Antiprotons

The PANDA project at FAIR

Thierry HENNINO IPN Orsay, France

The structure and dynamics of hadrons IPN, 28 october 2010

GSI today

FAIR future facility

PANDA in the FAIR layout

PANDA physics motivation

•With antiprotons, we can have access to a broad sprectrum of QCD objects

Understand the confinement of quarks (charmonium) Find other forms of hadrons (glueballs and hybrids) Origin of mass of strongly interacting systems

Many others opportunities ^Nucleon

Meson Baryon

‘normal’

‘exotic’

PANDA physics motivation

LEAR PANDA

Charmonium spectroscopy

Many states predicted

• below the open charm threshold

• narrow states

• only a few states (8)

• can be formed directly in pp

• above the threshold

• existence of narrow states ( DD)

• new states found. What are they ?

Key parameters for spectroscopy

• statistics

• resolution

• AMAP decay channels with full event characterization

• different entrance channels

• angular distributions

Charmonium spectroscopy

X(3872):

’

,

, mol. states, tetraquark ??

Z(3931): ’_c2 2⁺⁺ (mass too low by 45 MeV)

X(3940):

’’

? But m too low,

too small, channel inconsistencies Y(3940):

’’

or

’

?? SU

(3) violating decay

Y(4260): 1

, but does not fit with any predicted state. Hybrid??

Y(4321) : ……

Beam energy ( M up to 5.4 GeV/c

)

L uminosity ( at least 10 × existing machines) Access to a large variety of J

states

Mass resolution ( < 1 MeV )

4 p coverage with B field and extended PID

Statistics ( ~10

to 10

events per running campaign )

P

A

N

D

A

Glueballs and hybrids

Morningstar,Peardon, PRD60(1999)34509 Morningstar,Peardon, PRD56(1997)4043

0^+- 2^+-

Glueballs and Hybrids

(J^PC = 0^-- , 0^+- , 1^-+ , 2^+- , 3^-+ …) qq, gg, ggg , qqg , qqqq

Numerous predictions:

•Bag model, Constituent gluon model

•Flux tube model, LQCD calculations High statistics (≥ 10⁴ events per running year) Energy (M up to 5.4 GeV/c²)

Resolution in formation (2 10^-5) Comparison e⁺e^-/ pp

• in e⁺e^- no glue

• in e⁺e^- formation gives only g like states

• in pp access to many J^PC states + glue

• Formation and production:

0^+- and 2^+- in production

0^+- and 2^+- NOT in formation

The 2 lowest oddballs predicted

LQCD

 |L-S|<J<L+S

 P=(-1)^L+1 (q and qbar have opposite parity)

 C=(-1)^L+S (only for non-flavored systems: u-ubar, s-sbar, etc.)

 G=(-1)^I+L+S

 L=0 (S-wave)  P=-

 S=0  0^{- +}

 S=1  1^{- -}

 L=1 (P-wave)  P=+

 S=0  1^{+ -}

 S=1  0^{+ +} , 1^{+ +} , 2^{+ +}

 L=2 (D-wave)  P=-

 S=0  2^{- +}

 S=1  1^{- -} , 2^{- -} , 3^{- -}

 L=3 (F-wave)  P=+

 S=0  3^{+ -}

 S=1  2^{+ +} , 3^{+ +} , 4^{+ +}

0 + + 1 + + 2 + + 3 + + 4 + +

0 - - 1 - - 2 - - 3 - - 4 - - 0 + - 1 + - 2 + - 3 + - 4 + - 0 - + 1 - + 2 - + 3 - + 4 - + Forbidden for u-ubar, d-dbar, s-sbar, etc…

Allowed for u-ubar, d-dbar, s-sbar, etc…

Quark-antiquark systems

PANDA specificity

Production of 

(1

, 2

)

• In e⁺e^- need of an intermediate step to reach these states

 Detector resolution dependant

In pp, can be seen in formation directly

 Rate measurement: ultimate

resolution given by the beam quality

s= 8  0.5 MeV

pp

pp

Further topics

• Open charm physics

• Spectroscopy

• Rare decays

• CP violation in charm sector

• EM physics

• …..

Image of a baryon at the quark level

EM processes

• Inverse Compton scattering pp  gg

• handbag diagram

• GDA parametrize the soft part

• low s: 0.2 pb at q²=30 (GeV/c)²

 200 events per running campain

• rejection of background: p⁰p⁰ and p⁰g ??

 ECAL resolution to separate g from p⁰

• Time-Like Form factors

• pp  e

e

(from s=5 to 30 (GeV/c)

)

• Exclusive channels:

• Transition Density Amplitude (B. Pire et al)

• TL FF in unphysical region by e⁺e^-X (X=g, p⁰, r)

• Axial FF of the nucleon (E. Tomasi et al)

Facteurs de forme Space-like et Time-like











  

  _{CM CM}

CM

t  t 

t

 p



2 2

2 2 2

2

sin )

cos 1

) ( 1 (

) 8 (cos

TL TL E

M p

G G d M

dσ

_ _ q²<0

e^- e^-

p p

q²>0

e^-

e⁺ p

p

q² FFs complexes FFs réels

Unphysical region

Space-like

Time-like

G_E(0)=1 G_M(0)=_p

p+p ↔ e⁺+e^- e+p  e+p

p+p ↔ e+ +e- +p0

Accès direct à |G_E| et |G_M| par ds/dW

G_E et G_M paramétrisent le courant hadronique SL

TL

s(ppe⁺e^-) dans l’approximation à 1 photon

Analyticité

Propriétés asymptotiques ( q²  ∞ )

Relations de dispersion

3.52 (GeV/c)²

N_tot=1.1 106 N_tot=64000 N_tot=2000

Taux de comptage et séparation |G E |/|G M |

 Simulation de la réaction p p  e⁺e^-

 Section efficace normalisée sur les données

 3 hypothèses: G_E=0, |G_E|=|G_M| and |G_E|=3|G_M|

~120 jours, L = 2. 10

cm

s

= 2 fb

G_E=0 G_E=G_M G_E=3G_M

Non corrigé de l’acceptance et de l’efficacité Erreurs statistiques seules

Séparer pp  e ⁺ e ^- du bruit



 Herméticité du détecteur

 Identification de particules PID

 Trajectographie, corrélations en θ and φ

 Coupures sur M_inv ou M_manq





 π⁺π^- dominant

 μ⁺μ^- ~ e⁺e^-  facile à séparer

 K⁺K^-~ π⁺π^- , mais m_K > m_p

 Cinématique très proche de e⁺e^-

 PID crucial



 s(p⁰p⁰)/s(ee)=10⁴ -10⁵ à q²=8.2 (GeV/c)²

 p⁰p⁰  g g e⁺ e^- e⁺ e^- (Dalitz et conversion)

 facile à éliminer

 Herméticité

 M_inv(e⁺e^-) / 6 corps

2.4 10⁶

cos_CM

1.5 10⁵

q² = 8.21 (GeV/c)²

s(p p )/s(e+ e- )

3 corps ou plus

2 corps (π

π

,μ

μ

,K

K

,π

π

)

Canaux chargés

Canaux neutres (p⁰p⁰)

Réjection de p ⁺ p ^



PID

 Probabilité calculée pour chaque détecteur

 MVD, STT , DIRC , ECAL , MUO

 Probabilité combinée normalisée

 Complémentarité des détecteurs à des impulsions différentes



Fit cinématique

 Conservation p et E

 CL >0.001

 CL(e⁺,e^-)>10×CL(p⁺,p^-)

36 / 9 / 2.3 / 0.6

s_exp= 2 mrad ECAL

DIRC STT

p e

Estimation de la précision atteinte

TL M TL E

G q G

R( ²)

Erreur prédite sur

|G_E|/|G_M| à PANDA

|G_E|=|G_M|

Présent 5 % 20% 50% -- -- PANDA < 1 % 2% 10% 23% 50%

D|G_M|/|G_M|

VMD Iachello VMD étendu

« QCD inspired »

Medium effects

Hayashigaki, PLB 487 (2000) 96 Morath, Lee, Weise, priv. Comm.

D^

50 MeV

D

D⁺ vacuum nuclear medium

p K

25 MeV

100 MeV

K⁺

K^ p^ p^ QCD ground state contains qq and also glue

condensate

Effects of non-vanishing < qq > + r and T dependance have lead to considerable theoretical work

The r and T dependance of the qq

condensate has triggered many experiments.

At GSI, CERN, KEK, Bonn, JLAB… in the r, w and f region (the so-called vector meson) Effects also in the scalar meson sector (p, K ) With PANDA, on may have access to the glue part of the QCD vacuum in the charm sector

Medium effects on cc

Meson

h

[0^-+]

J/y

[1^]



[0,1,2⁺⁺]

Y(3686) [1^]

Y(3770) [1^]

Width(fm/c) 11 40000 20/200/100 100000 700000

Expected mass shift

-5 MeV to

-8 MeV

-7 MeV to -10 MeV

-40 MeV to -60 MeV

-100 MeV to

-130 MeV

-120 MeV to

-140 MeV Observation

(BR)

gg

( 4 10^4 )

e

e

( 6 10^2 )

J/y g

( .01 / .3 / 0.2 )

e

e

( 8 10^3 )

e

e

( 8 10^5 )



Stark effect:

Peskin, Luke, Lee Potential models:

Brodsky et al QCD sum rules:

Weise, Klingl, Lee

1-10 events per day

Medium effects

Other interesting possibilities

• J/ y in the medium (relation to QGP) under controlled kinematics: a few 100 counts/day

• Effect on open charm mesons D

and D

• no rescattering free decay channel and ct too large  no direct observation possible

• production threshold lowered due to modified in-medium mass (10 MeV effect might be detectable from a rate measurement)

• partially masked by fermi motion  seems however handable

• 10⁵ D⁺D^-/year (‘good’ events ?? )

•Anti K in matter ….

Hypernuclear physics

u/d quarks replaced by 2 s-quarks

Only 6 double-strange nuclei seen today Unique possibility for LL interaction studies

X^- capture:

X^-p  LL + 28 MeV

X

3 GeV/c

Kaon

s

_

X

L L

trigger

p_

Slowing down 2.

and capture of X^ in secondary

target nucleus

1.

Hyperon- antihyperon

production at threshold

+28MeV

g

3.

g-spectroscopy with Ge-detectors

g

What is PANDA made of ?

• ‘No empty space’  Almost full hermiticity

• High rate capability : up to 10

p interactions per sec

• Tracking of + & - from 100 MeV/c up to 10 GeV/c

• High resolution EM calorimetry (0.01  10 GeV/c)

• Vertex measurements

• Extended PID capabilities ( g, e,  , p , K, p)

• As low as possible material budget

• High level, fast and flexible triggering system

• High Energy p Storage Ring with cooling

GSI today

FAIR future facility

PANDA in the FAIR layout

High Energy Storage Ring

• Circumference 442 m

• Injection at 3.7 GeV/c

• Acceleration / cooling p

: 1.5 – 15 GeV/c

• High intensity mode

2 10¹¹ p/s L= 2. 10³² cm^-2s^-1

p/p= 10^-4 (stoch. cooling)

• High resolution mode

2 10¹¹ p/s L= 2. 10³¹ cm^-2s^-1

p/p= 10^-5 (e^- cooling)

• Keep open possibility for

polarised p

Le détecteur PANDA (antiProton ANnilation at DArmstadt

Forward Spectrometer Target Spectrometer

ECAL

RICH

MUON MUON

TRACKING

E/HCAL

DIRC

Contribution IPN Orsay

Target spectrometer

• Solenoidal field 2 T

•Uniformity 2%

•Gas jet, droplet target, solid

• density up to 2. 10¹⁵ at.cm^-2

•MVD for vertex tracking

• s_rj=100 m (D⁺ have ct=310 m)

•Tracking detector (TPC/STT)

• s= 1%

•DIRC for PID

•ECAL for e and g

•Muons detection

TS

Tracking detector

Micro Vertex Detector

• requirements

• vertex detection ( ct(D⁺) ~310 m )

• s_xy and s_z < 100 m

• low material budget X/X₀ < 4%

• high rates

• design

• 5 concentric barrels + 6 disks

• Hybrid pixel (50×200/100×100

m²)

• Strip detectors

• 540 modules totalling 70000 ch.

• dE/dx measurements for PID

x/X₀=f()

Tracking with TPC

• Parameters

• L=1.2 m, r=0.15-0.42 m

• Drift field E || B v=28 mm/s

• Gas: Ne/CO2 (+CH4/CF4)

• Multi-GEM stack for amplification and ion backflow suppression

• Pad size ~2 x 2 mm2  100000 ch.

• Simulations

• s_rj= 0.15 mm s_z= 1 mm

• p/p=1%

• s(dE/dx)=6% (40 to 80 meas.)

•Challenges

• continuous flow

• space charge

Tracking with STT

• 5000 individual straws

• X/X

= 1 % minimum

• s

= 0.15 mm, s

=2.9 mm

• mom. resol. s

/p

=1.2%

• high counting rates

• Ar/CO

at 2 bar

• Skew angle +-3°

•Lower dE/dx resol. 10%

•Tracklet length uncertainty

• fewer independant ‘cells’ (27)

4-10axial layers 5skewed double-layers

7axial layers

= 12.2 m s= 176 m Single tube

resolution measured

Cerenkov

• separate  , p , K and p up to ~1.5 GeV/c

• DIRC’s in TS:

• fused silica bars

• mirror imaging

• photon detection (PMTs)

• RICH in FS

• Aerogel or C

F

• ring detection

Focusing barrel DIRC geometry

t_prop=f(j)

1 )

cos(  

 n

Cerenkov effect: emission of light on a cone if v>c

Detector Surface Solid

Radiator

Particle Track

Cherenkov Photon Trajectories

Target Spec. ECAL

• ^coverage

• Hermiticity (98%)

• ~20000 crystals

• compact (X₀=0.9 cm)

• E ^resolution

• 1.9% at 1 GeV

• timing properties

• t ≤ 10 ns

• excellent res. s=0.5 ns

• broad dyn. range

• 10 MeV to 10 GeV

• APD in B field

• operated at -25°C

• radiation tolerant

backward end cap

145°-175° 16-sector barrel 22°-145°

forward end cap

10°-22°

Muon detection

•Muon identification

•Range system

•Muon: only EM

interaction  long range

• p, K,p: strongly

interacting  ‘stopped ’

Iron/Mini Drift Tubes sandwich

MDT detector

^

Forward spectrometer

• 

×

= 10° × 5°

• 8 stations with x.y meas.

• Mini Drift Cell

• s = 100 m

• tracking in B field

• ∫Bdz=2Tm

• p/p = 1% at 5 GeV/c

• Shashlyk ECAL

• Pb / Scint / WLS  4% E^-1/2

• Hadron calorimeter HCAL

• Fe / Scint / WLS  .34 E^-1/2

• RICH

• C₄F₁₀ or aerogel

• TOF

• muons detectors

FS

STT Tracker

ECAL RICH

HCAL

EMC

DIRC

Méthode de la moyenne tronquée avec une coupure ajustée en fonction de l’impulsion (s_rf (STT)=150 m) s(Gauss) = 10% (16 mesures)

1 GeV/c

N_g= 15 - 30

s(mrad) = 10/(N_g)^1/2

 1.8 à 2.5 mrad

E/p vs p Extension gerbe Efficacité (e) Réseau de neurone

hadronic shower

36 / 9 / 2.3 / 0.6

Particle Identification

DE in STT

Conclusion

• PANDA offers new, challenging and brillant future for precise studies of QCD objects in excellent experimental conditions

• FAIR and PANDA ready by 2018/9 for experiments

• PANDA is an international collaboration of ~450 physicists, representing 50 laboratories over 17 countries

• FAIR cost: 1200 M€ (75% paid by Germany, 25% by other countries)

• PANDA cost: 60 M€ (out of which ~1/4 for the calorimeter)

Basel, Beijing, Bochum, Bonn, IFIN Bucharest, Brescia, Catania, Cracow, Dresden, Edinburg, Erlangen, Ferrara, Frankfurt, Genova, Giessen, Glasgow, GSI, KVI Groningen, Inst. of Physics Helsinki, FZ Jülich, JINR Dubna, Katowice, Lanzhou, LNF, Mainz, Milano, Minsk, TU München, Münster, Northwestern, BINP

Novosibirsk, Pavia, Piemonte Orientale, IPN Orsay, IHEP Protvino, PNPI St. Petersburg, KTH Stockholm, Stockholm, Dep. A. Avogadro Torino, Dep. Fis. Sperimentale Torino, Torino Politecnico, Trieste, TSL Uppsala, Tübingen, Uppsala, Valencia, SINS Warsaw, TU Warsaw, AAS Wien