Precision Spectroscopy of Kaonic Helium-3 atoms X-rays at J-PARC

RIKEN Nishina Center, Japan

Masami IIOOn behalf of the J-PARC E17 collaboration

SNU1, SMI2, LNF3, RCNP4, Kyoto Univ.5, Univ. of Tokyo6,RIKEN7, KEK/J-PARC8, Tokyo Tech9, Tech. Munich Univ.10

The J-PARC E17 CollaborationH. Bhang1, M. Cargnelli2, S. Choi1, C. Curceanu3,

O. V. Doce3, S. Enomoto4, H. Fujioka5, Y. Fujiwara6,C. Guaraldo3, T. Hashimoto6, R. S. Hayano6, T.

Hiraiwa5,M. Iio7, S. Ishimoto8, T. Ishiwatari2, K. Itahashi7,

M. Iwasaki7, 9, H.Kou9, P. Kienle10, J. Marton2,Y. Matsuda6, H. Noumi4, H. Ohnishi7, S. Okada3,H. Outa7, F. Sakuma7, M. Sato6, M. Sekimoto8,

H. Shi6, D. Sirghi3, F. Sirghi3, T. Suzuki6,K. Tanida1, H. Tatsuno6, M. Tokuda9, D. Tomono7,

A. Toyoda8, K. Tsukada7, A. R. Vidal3, E. Widmann2,B. Wunschek2, T. Yamazaki6, 7, J. Zmeskal2..

IntroductionExperimental

MethodPreparation

StatusSummary

Contents

Introduction

Strong-interaction Shift and Width of Kaonic Helium

Last orbit of Kaonic atoms is sensitive to K--nucleus strong-interaction.

Nucleus

absorption

(Strong-interaction) 2p

3d

(Coulomb-only) 2p

DE2p: Shift G2p: Width

Atomic orbitals of Kaonic Helium

3d 2p X-rays

EMppp EEE 2

exp22 D

01/14

Long-standing Puzzle

S. Hirenzaki, Y. Okumura, H. Toki, E. Oset and A. Ramos Phys. Rev. C 61 (2000)

Last orbit energy level shift and width of kaonic atoms

02/14

Z=2

- Shift - - Width -197119791983

Avg.

There has been a long debate!

Past Measurements of K-4He

Majority of Theoretical Suggestion:Very small shift (~0 eV)

Experimental values:Very large shift (~40 eV)

Possibility of the Large Shift by Coupled-channel model

Deeply-bound kaonic nuclei predicted by Akaishi-Yamazaki

U0: Real part of the K--He strong interaction potential

Y.Akaishi:EXA05

Calculation results of the 2p level shift by Prof. Akaishi ( Coupled-channel + Optical potential )

repulsive

attractive

K--4He

K--3He

Direct search for the kaonic nucleus (K-pp) J-PARC E15 Exp. (Dr. Tukada)

03/14

Strong interaction 2p level Shift of Kaonic Helium-4 (E570)

04/14

WG71: C. E. Wiegand, R. Pehl, PRL27, 1410 (1971)BT79: C. J. Batty, et al., NPA326, 455 (1979)BR83: S. Baird, et al., NPA392, 297 (1983)

DE2p = 2 2 (stat) 2 (sys) eV

WG71: C. E. Wiegand, R. Pehl, PRL27, 1410 (1971)BT79: C. J. Batty, et al., NPA326, 455 (1979)BR83: S. Baird, et al., NPA392, 297 (1983)

Physics Letters B 653 (2007) 387-391KEK-E570 Publication

BT90: Global fittingC. J. Batty, NPA508, 89c (1990)

HZ00: SU(3) Chiral unitary modelS. Hirenzaki et al,. PRC61. 055205 (2000)

FR06: Consideration for nonlinearly density dependence (~0.4 eV as the lowest)E. Friedman, private communication (2006)

AK05: Coupled-Channel modelY. Akaishi, EXA05 proceedings (2005)

BT90, HZ00, FR06 AK05

Theoretical suggestion

repulsive

Difference between K--4He and K--3He

05/14

Y.Akaishi:EXA05

attractive

K--4He2 2(stat) 2(sys) eV

(KEK E570)repulsive

Y.Akaishi:EXA05

attractive

K--4He2 2(stat) 2(sys) eV

(KEK E570)repulsive

attractive

Y. Akaishi and T. Yamazaki Phys. Rev. C 65 044005 (2002)

K--3He

K--3HeK--4He

By specific shrinkage effect,There is difference between K--4He and K--3He

If it will be observed…

Large difference No difference

It supports the Deeply-bound theoryThe potential is shallow

No data exist yet on K--3He x-rays ! J-PARC E17

Experimental Method

J-PARC E17 (Precision Spectroscopy of K--3He 3d 2p X-rays)

06/14

For determination the 2p level shift with precision of a few eV( E570 equivalent )

Beam-line Drift Chamber (BLC)

Cherenkov counter

Scintillation counter

L3He

CDCCDH

CarbonDegrader SDDx8K- x-rays

KETEK products(http://www.ketek.net./)

High-resolution x-ray energy measurement

Silicon Drift Detector (SDD)

180eV @6.4keVSiLi(Past exp.) x2

Secondarycharged particle

Kaons stopping point measurement with drift chambers for

- Incident Kaons (BLC) - Secondary charged particles (CDC)

Fiducial volume cut

Fluorescence x-rays from Titanium and Nickel foils

Channel to Energy Conversion

In-beam energy calibration

(p-)Ti&Ni foils

Preparation status

Experimental Setup

07/14

K1.8BR Experimental Area

5 m

BeamlineSpectrometer

Cylindrical Detector System (CDS)

Liquid 3He Target System

Silicon Drift Detectors

Q7

Q8D4

S3

D5

Hodoscope

Scintillation counter stack

Beam line chamber 1-2

Beam line chamber 3-4

Cherenkov counter

Timing counters

Beamline Spectrometer

08/14

First beam! (February, 2009)

For E17 (Stop) 1) 0.7 GeV/c K(+/-) beam tuning 2) Momentum measurement by TOF 3) Range measurement

For E15 (in-flight) 4) 1.0 GeV/c K(+/-) beam tuning 5) Momentum measurement by TOF

Beam Tuning Plan

Installation of the beamline detectors is completed.

Start from 1.1 GeV/c unseparated (+)

Results of February tuning

D5

D4

Q8

Solenoid (CDS)

Cherenkov counters(GC, AC, WC)

BHD

T0 Distance BHD-T0:

7.7m p-K TOF(cal.) : 2.3 nsec @1.1GeV/c

p+:K+ (cal.) : ~540:1 @1.1GeV/c

- Slewing correction- Offset tune (offline)

BHD->T0 TOF (nsec)

pe+/m+/p+

K+

Results p-K TOF: ~2.4 nsec p+:K+: ~9000:40

Success of the K+ identification

0.7 GeV/c stopped K- (Autumn of 2009) 09/14

Cylindrical Detector System (CDS)

10/14

Hodoscope Counter (CDH)

Cylindrical Drift Chamber (CDC)Solenoid Magnet

Max magnetic field: 0.7 TAperture: f=1.2m, L=1.2m

Size: ID=300 mm, OD=1060 mm, L=950 mm

Read-out : 1816 chDrift length: ~9 mm (hexagonal)

Layer: 15 (7 super layers)A(3)U(2)V(2)A(2)U(2)V(2)A(2)

Plastic Scintillator Size: 99x30x700 mm3 (WxTxL)

Configuration: 36 modules

Strange and exotic systems, 17:30 Friday, Sep. 4 K. Tsukada “A search for deeply-bound kaonic nuclear states at J-PARC ”

1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.00

50

100

150

200

250

Temperature [K]V

apor

Pre

ssur

e [h

Pa]

He-3He-4

Liquid 3He Target for E15

11/14

Temperature in the Target Cell 1.3 K

Pressure in the Target Cell 33 hPa

Liq. 4He Consumption 45 L/day

Heat Load to the 1K Parts 0.19 W

Cooling test with 200L 3He gas

Development of the 3He cooling system was completed !

1 2 3 4 5 6

1.1

1.2

1.3

1.4

1.5

Time [hour]

Tem

pera

ture

[K]

Evaporator Heat Exchanger Target Cell

1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.00

50

100

150

200

250 He-3 He-4

Measurement

R&D for installation of the x-ray detection device to inside the target system

Calculation

Silicon Drift x-ray Detector (SDD)New SDD & Preamp

Effective area: 100 mm2

KETEK products(http://www.ketek.net./)

KETEK products

12/14

In the vacuum chamber Testbench

SDD

Cover

Preamp

SDD Housing

SDD Housing Temp. : 140 KPreamp Temp. chip : 246 K cover : 160 K

Resolution: ~150 eV (FWHM)

Fitted with Gauss+tail for Ka / Kb(common s & tail slope)

R&D forSDD installation to the LHe-3 target

13/14

Target cell (1.3 K)

SDD (~120K) Radiation Shield (~80K)Pre-AMP (150~200K)

Pre-AMP box (~80K)

K-

x-rays

Parallel Session - Few-hadron systems16:20 Friday, Sep. 4 Y. Fujiwara “J-PARC E17 experiment”

Summary

14/14

Kaonic-3He Balmer-series x-rays will be measured with precision of a few eV (E17).

We employed the similar technique as KEK-PS E570 (SDD, In-beam energy calibration, Fiducial volume cut )

Detector construction is in progress. (Beam line detectors, CDS, LHe-3 target, SDD)

K1.8BR beamline tuning was started. We succeeded in identification of K+ by TOF measurement.

Soon, we will start data taking at J-PARC

Thank you!

Spare Slides

Isospin-dependence of Kaonic Helium atoms

K--4He Shift K--4He Shift

K--4He Width

2 2(stat) 2(sys) eV

Not so large(~40 eV)

U0 MeV

Y. Akaishi:EXA05

05/14

No data exist yet on K--3He x-rays ! J-PARC E17

K--4He Shift K--3He Shift

K--4He Width

2 2(stat) 2(sys) eV

U0 MeV

Y. Akaishi:EXA05

Large shift (~10eV)will be observed?

09/00

Beam Line Detectors for Stopped K- Experiment

K-

CDC

End cap of Solenoid

Cerenkov Counter (LC1, LC2)

Scintillation

counter (T1)

Degrader for

adjustment

Main CarbonDegrader

Scintillation

counter (T0)

Small Drift Camber (BLC)

Liq. 3He Target

88 mm

250 mm

Small Beam Line Drift Chamber (BLC)

Effective area: 80 x 80 mm2

2.5 mm pitch16 sense wires/layer8 Layers

(X X' Y Y' X X' Y Y')

J-PARC K1.8BR Beam Line

Main Ring (50 GeV) Switch Yard

Hadron Hall

J-PARC Hadron Facilities

K1.8BR

06/14

T1

0.6 0.7 0.8 0.9 1 1.1101

102

103

104

105

106

107

Momentum [GeV/c]

Yie

ld a

t FF

[Cou

nts/

spill

] Negative Kaon Negative Pion

BG Pion

Primary proton: 30GeV, 9mA (DAY-1)

Horizontal (cm) Ve

rtic

al (c

m)

1.1 GeV/c

27.573 m

2.6 msr·%

6.0 mm

2.9 mm

Max Momentum

Beam line length

Acceptance

Horizontal extent @FF (rms)

Vertical extent @FF (rms)

Beam profile@FF

Horizontal

Vertical

0 5 10 15 20 25

40

40

30

30

20

10

0

10

20

D1

Q1

Q2

D2

Q3

O1

Q4

IF

S1

CM

ES

CM

S2

Q5

Q6

D3

S3

Q7

D3

Q8

VI

FF

MS

Distance from Production Target [m]

Exte

nt o

f Kao

n be

am [c

m]

06/14

ES1

0.1 M kaons/spill

Beam time estimation

Monte Carlo simulation + Sanford-Wang

To obtain statistics comparable to KEK-E570

E570 statistics : 3d->2p 1500events (s ~2eV)

for ~20 days (w/ 8 SDDs)K- yield : x 2SDD acceptance : x 3

Beam time for physics run: 3.5 days

Primary Proton beam: 30GeV-9mA

08/14

At 1/10 of full intensity, E17 can be performed with ~1 monthWe don’t require the good K/Pi separation (for in-beam calibration)

We proposed E17 as DAY-1 experiment at J-PARC.

E17 has been approved in DAY-1, Stage-2.

Stopped-K- selection

In-flight decay or Reactions

SDDs&FoilsDrift Chamber

T0 counters

K-

Secondary charged particle

L4HeⅡ

X-rays

Degrader

z-vertex

Beam Direction

Light output

The background events in the target cell were removed by the T0 counters.

Target region

Energy calibration

SDD self-triggered events High statistical characteristic X-ray peaks of Ti & Ni

Stopped-K- triggered events Fiducial volume cut

Stopped-K- selection

SDD timing cut

Channel to Energy Conversion

Spectrum analysisMain peak Voigt function

Convolution of the Gaussian and LorentzianResponse of SDD Shelf + Tail function

Shelf function : Convolution of the Gaussian and Step functionTail function : Convolution of the Gaussian and Exponential

High statistical spectral fitting (Self-triggered events)

The parameters were estimated

Compton scattering Tail function

K-

Scattering

Monte Carlo Simulation

(Geant4)

K--4He X-rays(3d>2p)

Compton scattering effect

The parameters were estimated by fitting the simulated spectrum

Pileup effect Gaussian Typical pileup waveforms

(FADC) The parameters were estimated by FADC data

Systematic errorResponse function

Fitting by the high-statistic spectra for self-triggered events

Consideration of the energy dependence of the detector resolution

Intensity ratios of the shelf and tail components to main-peak :

( /35.2 2 FEWFWHME N D: average energy for electron-hole creation (3.81 eV)WN: Contribution noise to resolutionF: Fano factor (~0.12 for Si), E: X-ray energy ~ 1 eV

Compton scatteringLECS(Low Energy Compton Scattering) package

The error of the total compton scattering cross section was few percent

5 % (Intensity fluctuation) = ~ 0.4 eVPileup effect

The error of intensity ratio was plus or minus 10 percent from the error of pileup evens identification by the FADC analysis

10 % (Intensity fluctuation) = ~ 0.4 eV

Derivation of the 2p level strong interaction shift

Transition E570 measurements EM calculation

3d 2p 6467.0 2.5 (stat) 6463.54d 2p 8723.5 4.5 (stat) 8721.75d 2p 9761.4 7.6 (stat) 9766.8

EM calculation (T. Koike) - Vacuum polarization - Nuclear finite size effect - Relativistic recoil effect - Electron screening effect - Totally corrected energy levels

The strong interaction shift of 3d, 4d and 5d levels were negligibly small

( ( ( ( ( ( EMd

EMdnddnp EEEEE ,2,,2,2 D

3d 2p transition energy : 6467 3 (stat) 2 (sys) eV

2p level strong interaction shift : 2 2 (stat) 2 (sys) eV

Spare Slides (E15)

Deeply-bound Kaonic Nuclei

01/12

Y.Akaishi & T.Yamazaki, PLB535, 70(2002).

method B. E. WidthAkaishi, YamazakiPLB535(2002) 70 ATMS 48 MeV 61 MeV

K. Swe Mynt, AkaihiAPFB05

Gaussian baseRearrangement-channel

Ivanov, Kienle, Marton, Widmannnucl-th/0512037 Field theoretic approach 115 MeV 28 MeV

Dote, WeiseYKIS06 AMD

Ikeda, SatoHYP06 Faddeev 55 MeV 40 MeV

Arai, Yasui, OkaJPS06-2 L*N model 87 MeV

Shevechenko, Gal, Maresnucl-yh/0610022 Faddeev 55-70 MeV 95-110 MeV

Koike, Harada PLB652, 262 (2007).DWIA

Recent theoretical progress (K--pp)

Experimental Search for Kaonic Nuclei

02/12

Deeply-bound Kaonic Nuclei really exist?FOPI/GSI

ＦＩＮＵＤＡ

K-pp?

AGS E930

E548/KEK

E549/KEKOBELIX

O(K-,n)

There is no evidence that it exists or not !

We will perform the new experiment at J-PARC (E15)

J-PARC E15 (Search for K--pp deeply-bound kaonic nuclear state)

04/11

+K- 3He

NC

15 m

+K-pp n

Reaction

Missing mass spectroscopy

K-pp search withTOF measurement of neutron

L

p pp-

Decay

Invariant mass reconstruction

K-pp search with decay particles measurement

The conclusive evidence will be obtained with measurement of formation and decay by J-PARC E15

Expected Spectrometer Performance I

Missing mass resolution – Neutron flight path = 12 m– ToF time resolution = 150 ps

Expected Spectrometer Performance II

mass resolution K-ppLp Lppw/o chamber-resolution 5.8 MeV/c2 1.6MeV/c2

w/ chamber-resolution 18.7MeV/c2 2.5MeV/c2

momentum resolution for p, K, p

Calculated using Geant4

Invariant mass of Lp (MeV)

S0 channel L channel

GK-pp= 60 MeV

we can distinguish the two non-mesonic decay modes for K--pp

– K-pp Lp pp-p – K-pp S0p gLp gpp-p

Invariant mass resolution for K--pp and L

Signals from K-pp and “Two nucleon absorption”

K- 3He reaction

3He(K-,n) K-pp formation

@ 1GeV/c K- andB.E. = 100 MeV

~ 1.3 GeV/c

@ 1GeV/c K-~ 1.5GeV/c

neutron

Two nucleon absorption 　K- 3He reaction

Lp

p p

neutron

Lp

p p (spectator)

Almost stop

~ 500 MeV/c

“Two nucleon absorption process” can be identified!

Expected Kinematics for K--pp Decay

L vtxK--pp vtx

p

pp-

n~1300MeV/c

~400MeV/c~150MeV/c

~500MeV/cp

p p-

Binding energy = 100MeV/c2

Isotropic decay of K--pp with forward neutron

Calculated using Geant4

Neutron Counter

09/11

20x5x150 cm3 Plastic Scintillator 　Configuration : 16 (wide) x 7 (depth)Surface area : 3.2m X 1.5m 　

3.2 m

1.5 m

E549 neutron counter set x2

E15 NC Support Frame