Physics with Strange Physics with Strange Hadrons Hadrons

at the at the

SStorage Ring for torage Ring for AAnti-nti-PProtonsrotons

• Physics Highlights • Double Hypernuclei• H-Dibaryon• Properties of Baryons

• Experimental Details

Darmstadt, 5.4.2002

  

1. Physics Highlights1. Physics HighlightsG

LU

ON

NU

MB

ER

BM

QUARK NUMBER1 3 4 520 6 7

10

2345

HYBRIDSGLUE

BALLS

DI-BARYONS

General IdeaGeneral Idea

s

ud

s

dd

s

ds

s

ss

_

(Kaidalov & Volkovitsky)

quark-gluon string model

_

0

Use pp Interaction to produce a hyperon “beam” (t~10-10 s) which is tagged by the anithyperon or its decay products

_

- capture:

- p + 28 MeV

Production of Double HypernucleiProduction of Double Hypernuclei

-

3 GeV/c

Kaons_

trigger

p_

2. Capture of in

secondary target nucleus

2. Capture of in

secondary target nucleus

1.Hyperon-

antihyperonproductionat threshold

1.Hyperon-

antihyperonproductionat threshold

+23MeV

up to 500

-events per day !

3. -spectroskopy

with Ge-detectors

3. -spectroskopy

with Ge-detectors

- - capturecapture

-atoms: x-rays

conversion

• -(dss) p(uud) (uds) (uds)

• Q = 28 MeV

Conversion probability approximatly 5-10%

Hypernuclei and DeconfinementHypernuclei and Deconfinement

Quark Configuration

Quark Configuration

u d s

Baryon Configuration

Baryon Configuration

p n

s 21

p 23

s 21

p 23

5He5He

4He4He

W

su dusd dd

Tamura et al.

Single HypernucleiSingle Hypernuclei

YN interaction in nuclear mediumNuclear structurenon-mesonic weak decays

p pnn nn

weak baryon-baryon Interaction

Neutronenzahl

                 

                 

             

             

           

         

         

         

       

             

16Λ O 18

Λ O14Λ N 15

Λ N12Λ C 13

Λ C 14Λ C

9ΛB 10

Λ B 11Λ B 12

Λ B7ΛBe 8

ΛBe 9ΛBe10

Λ Be6ΛLi 7

ΛLi 8ΛLi 9

ΛLi4ΛHe 5

ΛHe6ΛHe 7

ΛHe 8ΛHe

4ΛH3

ΛH

1 2 3 4 5 6 7 8 9

4

8

7

6

3

5

2

1

10

9

Pro

ton

enza

hl

high resolution -spectroskopy

with germanium detectors

Double HypernucleiDouble Hypernuclei

Multi-Hypernuclei are terra incognita, but they exist !

1963: Danysz et al. 10Be

1966: Prowse 6He

1991: KEK-E176 13B

1991: KEK-E176 3 non-mesonic decays

2001: AGS-E906 4H (~15)

2001: KEK-E373 6He

1

6

10

13

Hyperkern ( ) ( ) ( ) ( )

4.1 3.1

11.0 6.7

16.2 11.4

A AB Z MeV B Z MeV

He

Be

B

NAGARA

6- 12 4

6 5

ΛΛ

-ΛΛ Λ

Ξ + C + He+t

He He+ π

He

p+

Kerne as FemtolaboratoryKerne as Femtolaboratory

H-Particle R.L. Jaffe (1977)

free coalescencet ~ 10-23s

nuclear breeder

t ~ 10-10s

neutron stars

S=-2 Nuclei and H-dibaryon statesS=-2 Nuclei and H-dibaryon states

H-particle in nucleus free H

(see e.g. T. Yamada, NP A691 (2001) 250c; (3q)+(3q) quark cluster model )

free H-dibaryonH-dibaryon in 10

YYBe

B=12.2 MeV B=24.0 MeV

Contributions to intrinsic quadrupole moment of baryons• One-gluon exchange• Meson exchange

J=1/2 baryons have no spectroskopic quadrupole moment

- Baryon:• J=3/2• long mean lifetime 0.82·10-10 s• only one-gluon contributions to quadrupole moment

(A.J. Buchmann Z. Naturforsch. 52 (1997) 877-940)

Fundamental Properties of BaryonsFundamental Properties of Baryons

3 2 2( )(3 )iQ d r r z r

s

ss

1/ 221/ 2

(3 ( 1)) 0z

Js z J

Q J J J

A very strange AtomA very strange Atom

atoms by produktion

hyperfine splitting in -atom

electric quadrupole moment of

• prediction Q= (0 - 3.1) 10-2 fm2

• E(ℓ=10 ℓ=9) ~ 515 keV

• EQ ~ few keV for Pb

-

spin-orbit Eℓs ~ (Z)4 ℓm

quadrupole EQ ~ (Z)4Qm3

spin-orbit Eℓs ~ (Z)4 ℓm

quadrupole EQ ~ (Z)4Qm3

Q= +0.02 fm2

Q= - 0.02 fm2

high resolution -spectroscopy

Experimental DetailsExperimental Details

-- properties properties

minimal distance production capture

initial momentum 100-500 MeV/c range ~ few g/cm2

- mean lifetime 0.164 ns

DetektorkonzeptDetektorkonzept

hermetic (4)

high rate

PID (, e, , , K, p)

trigger (e, , K, D, )

compact (€)

modular

Elektronenkühler

InjektionKicker Septum

Solid state-micro-tracker• thickness ~ 3 cm

High rate Germanium detector

The Solid State Micro TrackerThe Solid State Micro Tracker

electronic „emulsion“ detector

real time tracking of• incoming -

• decay products (p,)

different absorbers as secondary target

two posibilities• capillar detector (2D)• pixel detector (3D)

NAGARA

6

5

-

Λ

12 4

6 -ΛΛ

ΛΛΞ + C + He+

He

t

He + π

He

p+

Capillary-DetektorCapillary-Detektor

glas capillary filled with liquid scintillator

20m - interaction (CHORUS)

fast readout: hybrid-photomultiplier+ALICE pixel chip ?!

only 2D projection

CMOS Monolythic Active Pixel CMOS Monolythic Active Pixel SensorSensor

Technology borrowed from digital still and video cameras

p wellpixel circuit

industrial fabrication process (low cost)

system-on-a-chip (amplifier, ADC...)

good spatial resolution (~1m)

thin (20-50 m seems possible)

example: MIMOSA Chip (IReS/LEPSI)

charge collection by diffusion time

100-150 ns

Prospects for MAPSProspects for MAPS

The good performance of CMOS MAPS in charge particle detection has been successfully demonstrated with small scale prototypes:

~99%, ~1.5-2.5 m, S/N~20-40

Further optimization of the sensitive element design is under way

Large scale prototype sensors (2x2 cm2 - 12x2 cm2) are expected soon (0.6 mm AMS process)

Development of an advanced design of processing electronics with more functionalities at a pixel and chip levels, more data processing ‘on-chip’, data sparsification – a major task

Sensor radiation hardness is expected to be improved via design studies R&D program on CMOS MAPS TESLA VD in a collaboration with several other centers just started – aim for the detector design by 2004.

Yu. GornushkinYu. Gornushkin 7th International Conference on Advanced Technology and Particle Physics, 17 /10/2001 7th International Conference on Advanced Technology and Particle Physics, 17 /10/2001

SetupSetup

beam: 3 GeV/c, 1mm; no halo (roman pots?)

Tracking detector for -

• 2-3 cm thick

• sandwich structure (50m+150m)

• secondary target support, cooling

p--

readout

primary target

secondary target

pixel detector

ConclusioConclusionn

Strange baryons offer a unique and important complement to the presented program at the Storage ring for Anti Protons.

Many interesting technical challenges:• Solid state micro tracker• high rate germanium arrayG

LU

ON

NU

MB

ER

BM

QUARK NUMBER1 3 4 520 6 7

10

2345

HYBRIDSGLUE

BALLS

DI-BARYONS

Das HESR TeamDas HESR Team

T. Barnes, D. Bettoni, R. Calabrese,

W. Cassing, M. Düren, S. Ganzhur,

A. Gillitzer, O. Hartmann, V. Hejny,

P. Kienle, H. Koch, W. Kühn, U. Lynen,

R. Meier, V. Metag, P. Moskal, H. Orth,

S. Paul, K. Peters, J. Pochodzalla,

J. Ritman, M. Sapojnikov, L. Schmitt,

C. Schwarz, K. Seth, N. Vlassov,

W. Weise, U. Wiedner

HHEESSRR

„Quarks, quarks, quarks.“