Milano, 22 November 2012

Catalina Curceanu

(On behalf of DEAR and SIDDHARTA collaborations) LNF – INFN, Frascati

Milano, 22 November 2012

DEAR and SIDDHARTA

SIlicon Drift Detector for Hadronic Atom Research by Timing Applications

• LNF- INFN, Frascati, Italy

• SMI- ÖAW, Vienna, Austria

• IFIN – HH, Bucharest, Romania

• Politecnico, Milano, Italy

• MPE, Garching, Germany

• PNSensors, Munich, Germany

• RIKEN, Japan

• Univ. Tokyo, Japan

• Victoria Univ., Canada

EU Fundings: JRA10 – FP6 - I3H

FP7- I3HP2

Kaonic atoms:

the scientific aim

the determination of the isospin dependent KN scattering lengths through a

~ precision measurement of the shift and of the width

of the K

line of kaonic hydrogen and

the first measurement of kaonic deuterium

Measurements of kaonic Nitrogen (kaon mass) and kaonic

Helium 3 and 4 as well (2p level – deeply bound kaonic nuclei)

The strong int. width > Radiative trans. width

Kaonic atom formation

K

e

Auger Electron

Nucleus

2) Cascade

1) Initial capture

3) Strong interaction

stopped in a target medium

4) Absorption

K

^X-ray

Shift and Width

of last orbit ^{e.g. •} 1s for K-p, K-d

• 2p for K-He highly-excited state

deexcite

n ~ sqrt(M*/me) n’ ~ 25 (for K-p) (M* : K-p reduced mass)

K

Kaonic cascade and the strong interaction

e G

s p d f

K

~ 6.3 keV

= DE

E

}

E

n 4 3 2

1

K_b

SIDDHARTA Scientific program

Measuring the KN scattering lengths with the precision of a few percent will drastically change the present status of low-energy KN

phenomenology and also provide a clear assessment of the SU(3) chiral effective Lagrangian approach to low energy hadron interactions.

1. Breakthrough in the low-energy KN phenomenology;

2. Threshold amplitude in QCD 3. Information on L(1405)

4. Contribute to the determination of the KN sigma terms, which give the degree of chiral symmetry breaking;

5. 4 related alado with the determination of the strangeness content of the nucleon from the KN sigma terms

Antikaon-nucleon scattering lengths

Once the shift and width of the 1s level for kaonic hydrogen and deuterium are measured -) scattering lengths

(isospin breaking corrections):

e + i G /2 => a

-

eV fm

e + i G /2 => a

-

eV fm

one can obtain the isospin dependent antikaon-nucleon scattering lengths

a

-

= (a

+ a

)/2

a

-

= a

The DAFNE collider

beam of kaons



K+

K-

e^-

e^- e^- e^- e^- e^-

e^- e^-

e^- e^-

Flux of produced kaons: about 1000/second

e⁺

e⁺ e⁺

e⁺

e⁺ e⁺

e⁺ e⁺

The DAFNE principle

DAΦNE, since 1998

Suitable for low-energy kaon physics:

kaonic atoms

Kaon-nucleons/nuclei interaction studies

Φ → K

K

(49.1%)

Monochromatic low-energy K

(~127MeV/c)

• Less hadronic background due to the beam

( compare to hadron beam line : e.g. KEK /JPARC)

DAΦNE

• Number of bunches per beam 95 + 95

• Total current per beam e-/e+ (A) ˜ 1.3/1

• Peak luminosity(cm -2 s -1 )

0.7 x10

• Average luminosity (cm -2 s -1 ) ˜ 2 x10 ³¹

• Integrated luminosity per day (pb -1 ) 2.2 (best)

• Luminosity lifetime (h) ˜ 0.6

• Number of fillings per hour ˜ 1.7

• Injection frequency e-/e+ (Hz) 2/1

• Data acquisition during injection off

Total integrated luminosity in 2002 about 70 pb

Performances obtained in

2002 in the DEAR I.P.

APD Cryo Cooler

Varian Turbo Molecular Pump

CryoTiger, CCD Cooling CCD Electronics

Vacuum Chamber

Hydrogen Target Cell

CCD Pre-Amplifier Boards Cooling Lines

CCD55-Chip (total of 16 chips)

DEAR ^(DANE

Exotic Atom

Research) 2002 Cryogenic setup

Kaons from DANE

1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000

20 21 22 23 24 25

temperature [K]

pressure [mbar]

3.1% LHD

gas liquid

Cryogenic Hydrogen Target

working point: T = 23 K, P = 1.82 bar

hydrogen density: 3.1% of LHD, 2.2 g/l

DEAR Cryogenic Target Cell

CCD mounting, cryogenics and on-cell electronics

- fiber-glass frames

- cooling system mounted on the top

- minimized Al cold finger (behind CCDs)

- reduced diameter of the socket group and, consequently, of the vacuum chamber

DEAR on DA  NE (2002)

October – December 2002 DAQ

Collected data:

-Kaonic Nitrogen:

6 – 28 October (about 17 pb

– 10 pb

in stable conditions);

-Kaonic Hydrogen:

30 October – 16 December: about 60 pb

-Background data (no collisions) for KH:

16 – 23 December

Kaonic Nitrogen, 2001, ~ 3 pb^-1

Background subtracted spectrum

Kaonic Nitrogen, 10 pb^-1 (October 2002) Background subtracted spectrum

Kaonic Nitrogen

Kaonic Nitrogen Physics

• First determination of the yield of 3 Kaonic Nitrogen X-ray transitions:

7  6 (41.5 +/- 7.4 +/- 4.1)% stimulated activity in the 6  5 (55.0 +/- 3.9 +/- 5.5)% the field of atomic

5  4 ( 57.4 +/- 15.2 +/- 5.7)% cascade for exotic atoms

• Mass of the kaon – as a test measurement:

• m

- = 493.884 +/- 0.314 MeV

(Ph. D. thesis, Tomo Ishiwatari, Phys. Lett. B593 (1-4), (2004), pag. 48. )

October – December 2002 DAQ

Collected data:

-Kaonic Nitrogen:

6 – 28 October (about 17 pb

– 10 pb

in stable conditions);

-Kaonic Hydrogen:

30 October – 16 December: about 60 pb

-Background data (no collisions) for KH:

16 – 23 December

?

Kaonic Hydrogen (2002 data)- global fit

integrated luminosity: 60 pb^-1

4 6 8 10 12 14 16

0 20000 40000 60000 80000 100000 120000

K_a K_complex

X-ray energy (KeV)

Ev ents/ 60 eV

Kaonic Hydrogen spectrum with the fitting function (S/B=1/70)

K

+Fe

K

Zn

Au

W. Weise, Vienna, July 26, 2007

DEAR Results on the Shift and Width

Shift: e

= - 193 ± 37 (stat.) ± 6 (syst.) eV Width: G

= 249 ± 111 (stat.) ± 30 (syst.) eV

( Phys.Rev.Lett. 94, 212302 (2005))

2 independent analyses starting from the raw data giving consistent results

DEAR Results on kaonic hydrogen

widthG 1s[eV]

KpX

-500 0 0 500

200 400 600 800 1000

shift e_1s [eV]

Davies et al, 1979 Izycki et al, 1980

Bird et al, 1983

Repulsive-type attractive

KpX (KEK)

M. Iwasaki et al, 1997

e = - 323 ± 63 ± 11 eV G = 407 ± 208 ± 100 eV

DEAR

SIDDHARTA principal goal:

 Improve the precision of the measurement of kaonic hydrogen 1s level shift and width;

 Perform the first measurement of kaonic deuterium

This will allow to determine the isospin dependent antikaon nucleon scattering lengths at percent level precision

=> Achieved by improving drastically the S/B ratio, while keeping the excellent DEAR

energy resolution

Use instead of the CCD detectors of DEAR new X-ray triggerable device

Choice of the detector based on criteria:

-preserve good features of CCDs (efficiency, resolution);

-offer a timing ~ 1 ms – trigger

Large Area Silicon Drift Detector

(JRA10 – HadronPhysics, FP6)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 100

200 300 400 500 600 700 800

A (cm^-2)

FWHM (eV)

SDD PIN Si(Li) 150 K 5.9 keV line

PIN Tsh=20us

Si(Li) Tsh=20us

SDD Tsh=1us

Spectroscopic resolution and timing : detector comparison

The Silicon Drift Detector with on-chip JFET

JFET integrated on the detector

• capacitive ‘matching’: C_gate = C_detector

• minimization of the parasitic capacitances

• reduction of the microphonic noise

• simple solution for the connection detector-electronics in monolithic arrays of several units

SDD layout – readout side

sensitive area 3 x 100 mm²

chip size: 34 x 14 mm²

integrated temperature sensors

SDD-subunit

2 array of 3 cm

SDD

18 cm

SDD unit

DAFNE UPGRADE

Crabbed waist is realized with a sextupole in phase with the IP in X and at /2 in Y

2_z

2_x



z x

2_x/

2_z*

e+ b_Y e-

1. Large Piwinski’s angle  = tg( )

/ 

2. Vertical beta comparable with overlap area b



/ 

3. Crabbed waist transformation y = xy’/(2  )

Crabbed Waist in 3 Steps

P. Raimondi, November 2005



1. Large Piwinski’s angle

 = tg( )

/ 

2. Vertical beta comparable with overlap area

b



/ 

3. Crabbed waist transformation

y = xy’/(2  )

Crabbed Waist Advantages

a) Geometric luminosity gain b) Very low horizontal tune shift

a) Geometric luminosity gain b) Lower vertical tune shift

c) Vertical tune shift decreases with oscillation amplitude d) Suppression of vertical

synchro-betatron resonances

a) Geometric luminosity gain

b) Suppression of X-Y betatron and synchro-betatron resonances



Parameters for DAFNE-upgrade

Horizontal beta @ IP 0.2 m (1.7 m - old)

Vertical beta @ IP 0.65 cm (1.7 cm)

Horizontal tune 5.057

Vertical tune 5.097

Horizontal emittance 0.2 mm.mrad (0.3)

Coupling 0.5%

Bunch length 20 mm

Total beam current 2 A

Number of bunches 110

Total crossing angle 50 mrad (25 mrad)

Horizontal beam-beam tune shift 0.011

Vertical beam-beam tune shift 0.080

L => 2.2 x 10

cm

s

SIDDHARTA

SIlicon Drift Detector for Hadronic Atom Research by Timing Applications

• LNF- INFN, Frascati, Italy

• SMI- ÖAW, Vienna, Austria

• IFIN – HH, Bucharest, Romania

• Politecnico, Milano, Italy

• MPE, Garching, Germany

• PNSensors, Munich, Germany

• RIKEN, Japan

• Univ. Tokyo, Japan

• Victoria Univ., Canada

EU Fundings: JRA10 – FP6 - I3H

FP7- I3HP2

Silicon Drift Detector - SDD

1Chip : 1 cm²

1 cm ² x 144 SDDs

44

y x

z

SIDDHARTA overview

510 MeV/c

510 MeV/c 127 MeV/c

Δp/p=0.1%

Target

)

SIDDHARTA data

SIDDHARTA results:

- Kaonic Hydrogen: 400pb

, most precise measurement ever,Phys. Lett.

B 704 (2011) 113, Nucl. Phys. A881 (2012) 88; Ph D

- Kaonic deuterium: 100 pb

, as an exploratory first measurement ever, draft of paper Phys. Lett. B; Ph D

- Kaonic helium 4 – first measurement ever in gaseous target; published in Phys. Lett. B 681 (2009) 310; NIM A628 (2011) 264 and Phys. Lett.

B 697 (2011);; PhD

- Kaonic helium 3 – 10 pb

, first measurement in the world, published in Phys. Lett. B 697 (2011) 199; Ph D

- New: widths and yields of KHe3 and KHe4 - Phys. Lett. B714 (2012) 40; ongoing: KH yields; kaonic kapton yields; -> publications

SIDDHARTA – important TRAINING for young researchers

2p level shifts for

Kaonic Helium atoms

DE_2p(eV) G_2p (eV)

-41±33 -

-35±12 30±30

-50±12 100±40

-43±8 55±34

Kaonic helium atom data (Z=2)

1971

1979

1983

Average of above

Kaonic helium atoms theoretical values

Shift (eV) Ref.

-0.13±0.02 Batty, NPA508 (1990) 89c

-0.14±0.02 Batty, NPA508 (1990) 89c

-1.5 Akaishi, Porc. EXA05

There are two types of theories compared to the experimental results:

Optical-potential model:

(theoretical calculations based on kaonic atom data)

Tiny shift (DE_2p  0 eV)

Recent theoretical calculations:

Akaishi-Yamazaki model of deeply-bound kaon-nucleus states

Predicts a possible maximum shift:

DE_2p of ± 10 eV

New K ⁴ He results by KEK PS E570

PLB 653 (2007) 387

DE

=2±2(stat.)±2(syst.) eV)

K⁴He 3d→2p: 1500 events 3x higher statistics

2x better Energy resolution 6x better S/N

Solving the kaonic helium puzzle

Old experiments:

Large shift (-43±8 eV)

E570 experiment:

Small shift (+2±2±2 eV) Theory:

DE2p  0 eV or

< ± 10 eV

Difference between the new and the old experiments Experimental confirmation need!

SIDDHARTA experiment

Kaonic ⁴ He data

SIDDHARTA experiment

The Kaonic

He X-ray data were taken for about two weeks in January 2009.

In this period, an integrated luminosity of about 20pb

was collected.

This corresponds to about 4.7 × 10

kaons

detected by the kaon detector.

SDD spectrum of X-ray uncorrelated with kaon production.

Ti and Mn X-ray peaks are produced by the ⁵⁵Fe source in normal condition of beam

Energy resolution: FWHM (@6.4 keV): 151 ± 2 eV

Energy calibration

Target Ti foil

Fe55

Degrader K-He data taking

Triple coincidences

Background suppression

more than 10⁴

Energy spectrum of K- ⁴ He X-rays

Energy of K⁴He L_a (3d2p) line:

E

= 6463.6±5.8 eV

New results of K- ⁴ He 2p level shift

E_exp = 6463.6±5.8 eV E_e.m. = 6463.5±0.2 eV

DE = E

– E

= 0±6(stat) ±2(syst) eV

Published in PLB 681(2009) 310-314

“kaonic helium puzzle”

solved

SIDDHARTA’s results is consistent with the

results obtained by E570 experiment

Summary of the K- ⁴ He shifts

Data taking periods of SIDDHARTA in 2009

DANE shutdown in Summer

New alignment of setup

Improve S/N ratio

K-He3 data (~4days)

55Fe source:

Good for reduce sys. error on K-⁴He

Bad for “background” events on K-H,K-D Removed ⁵⁵Fe source in other data

SDD X-ray energy spectra

Calibration data with X-ray tubeNot correlated to Kaon signalsSelected with K+K- & SDD timing

Production data

Kaon detector

Time difference between SDD & Kaon detector providing kaonic atom X-ray energy spectra with a

high background suppression.

DAFNE shutdown in Summer

Kaonic

Helium data SIDDHARTA experiment

The Kaonic-

He X-ray data were taken for about 4 days in November 2009.

In this period, an integrated luminosity of

about 16 pb

was collected.

K-³He (3d-2p)

Ti Ka

K-C K-O K-N

eV 6 .

. 6224

._m 

Ee

eV )

( 4 )

( 2

2

2 sta sys

E

 -  

D

Kaonic Helium-3 energy spectrum

. . exp

2p

E E

E  - D

eV ) (

5 . 3 ) (

4 . 2 0 .

exp 6223 sta sys

E   

QED value:

X-ray energy of K-3He 3d-2p

arXiv:1010.4631v1 [nucl-ex], PLB697(2011)199

World First！

Observation of K-³He X-rays Determination of

strong-interaction shift

DANE shutdown in Summer

K-4He (3d-2p)

eV ) ( 4 ) ( 3

2 5 sta sys

E _p  +   D

More date on K- ⁴ He 2p level shift

arXiv:1010.4631v1 [nucl-ex], PLB697(2011)199

Summary of the results

Experiment Target Shift [eV] Reference

KEK E570 Liquid +2±2±2 PLB653(07)387

SIDDHARTA (He4 with 55Fe) Gas +0±6±2 PLB681(2009)310 SIDDHARTA (He4) Gas +5±3±4 arXiv:1010.4631,

PLB697(2011)199 SIDDHARTA (He3) Gas -2±2±4

*error bar ^{  (stat)2 +(syst)2}

2p level widths for

Kaonic Helium atoms

Experimental results for the widths of kaonic helium atoms

Average:

Theory:

Γ_2p(K-⁴He and K-³He)= 1-2eV

S. Baird et al., Nucl Phys. A392 (1983) 297

“The shift measurements are seen to be in good agreement. The situation for the width values is much less satisfactory and the

error bars of the two measured values do not overlap.

The error on the quoted average has been taken from the external variance of the measured values.”

New experiment for the widths of the 2p state for kaonic helium: SIDDHARTA experiment

C.J. Batty, Nucl. Phys. A 508 (1990) 89

E. Friedman, Proc. Inter. Conf. on Exotic Atoms (EXA11), arXiv:1111.7194v1[nucl-th]

Results for the widths of K-3He and K-4He

The energyshift and broadening of the 3d→2p transition can be obtained from the peak fit using a Voigt Function V=V(, G), where G represents the strong-intercation 2p width and  was fixed using the values obtained from the energy resolution of the detector.

The systematic error was evaluated from the uncertainity of the resolution .

In addition, since the K-3He peak partially overlaps the K-O transition, the systematic error of the width of K-3He includes the uncertainity of its intensity.

Correlation of the shifts and widths of K-3He and K-4He

SIDDHARTA’s results gave significantly smaller values both for shift and width

*error bar _{ (stat)}² _+(syst)²

Comparison of the experimental results The average value of the K-⁴He

experiments performed in the 70’s and 80’s is plotted with the open triangle.

Kaonic Hydrogen

Kaon

BG

Kaon gate

Background gate

SDD Timing vs. Energy

(asynchronous background)

for K-p data

Kaonic hydrogen

Hydrogen spectrum

K

K

Background estimation

KO76 KN65

Cu Ti Kα

Ti Kβ

KC65

KC75

KO65 KC54

KAl87

EM value K-p Kα

simultaneous fit

Deuterium

spectrum

EM value K-p Kα

Kaonic hydrogen

K

K

higher

Residuals of K-p x-ray spectrum

after subtraction of fitted background

e

= −283 ± 36(stat) ± 6(syst) eV G

= 541 ± 89(stat) ± 22(syst) eV

If relative yields would have been known error on position < 20-25 eV

KAONIC HYDROGEN results

Kaonic Hydrogen results:

- most reliable and precise measurement ever

- need to go for Kd! -> SIDDHARTA-2

Kaonic hydrogen yield

Ph D thesis ongoing HeXi Shi, Univ. Tokyo

\

SIDDHARTA–2

93

94

• new target design

• new SDD arrangement

• vacuum chamber

• more cooling power

• improved trigger scheme

• shielding and anti-coincidence (veto) The SIDDHARTA-2 setup,

essential improvements

95

Target cell SDDs SDD- electronic K^-

Veto counter Kaon monitor upper scintillator

K⁺ Kaon monitor

lower scintillator

Kaonstopper:

K⁺-K^- discrimination

Interaction region

96

97

Kao ni c deu teriu m, 6 0 0 pb

model input

shift = - 660 eV width= 1200 eV

DA F NE represents (as always did) an (THE) EXCELLENT FACILITY in the sector of

low-energy interaction studies of kaons with nuclear matter.

It is actually the IDEAL facility for kaonic atoms studies as SIDDHARTA has demonstrated

SIDDHARTA-2 team is ready to restart the

measurements, having a multi-step strategy,

strating with the Kaonic deuterium

SIDDHARTA2 strategy – phases

1) Kaonic deuterium measurement - 1st measurement:

and R&D for other measurements

2) Kaonic helium transitions to the 1s level – 2nd measurement, R&D

3) Other light kaonic atoms (KO, KC,…)

4) Heavier kaonic atoms measurement (Si, Pb…) 5) Kaon radiative capture – L(1405) study

6) Investigate the possibility of the measurement of other types of hadronic exotic atoms (sigmonic hydrogen ?)

7) Kaon mass precision measurement at the level of <10 keV

SPARE

ECT* Workshop a Ottobre

New trends in the low-energy QCD in the strangeness sector:

experimental and theoretical aspects

Exotic atoms (kaonis) – a new precision era started, where Italy and Japan are the

protagonist:

(KEK) DA  NE

JPARC (E15, E17, P31...other ideas ongoing)