New experimental results on the strong interaction in kaonic atoms

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Nov 16, 2013 (3 years and 4 months ago)

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New experimental results on the strong
interaction in
kaonic

atoms

J. Marton

Stefan Meyer Institute

Austrian
Academy

of

Sciences
, Vienna

Seminar TUM, 27 June 2011

Outline


Low
-
energy

antikaon

interaction



motivation

of

new

studies



Solved

puzzles

Kaonic

atoms
:


Kaonic

hydrogen (strong
interaction

effect

on 1s)


Kaonic helium isotopes He
-
3,4 (strong interaction on 2p)



Open
questions

and

future

challenges

Kaonic

atoms


Precision data on
kaonic

deuterium


Precision data on kaonic
atoms

Z>2

Relation
kaonic

nuclei
:


Lamda
(1405)
and

ist
relation

to

the

quest
of

bound

strange

nuclear

systems

(K
-
pp, K
-
ppn

…)



Summary

and

Outlook

Seminar TUM, 27 June 2011

The
field


Studies of atomic bound systems with
strangeness (hadronic/kaonic atoms) provide
unique access to
strong interaction of antikaons
at
very

low

energies

(i.e. in
kaonic

atoms
)
.



Search for
exotic nuclei bound by
antikaon
(s)



Fascinating research field involving different
fields in physics (particle physics, nuclear physics,
atomic physics) and energies from GeV to
eV.



Unique research infrastructures in Europe
:
DAFNE/LNF, GSI, Jülich.

Seminar TUM, 27 June 2011

Sources

of

experimental
information

on
the

low

energy

(anti)
kaon
-
nucleon

interaction


Kaon
-
proton

scattering

data

(
old

data

with



large
errors
,
above

threshold



extrapolation
)


π
Σ
mass

spectrum



new

studies


Threshold

decay

ratios


X
-
ray

data

of

light

kaonic

atoms

(K
-
p, K
-
d, K
-
He)


Kaonic

hydrogen


increase

precision
,
threshold

data



important

input

for

theory



Kaonic

deuterium



first

experimental
studies


Kaonic

helium
-
4


2p
shift

small

(KEK 570),


„superstrong“
antikaon

nuclear

interaction

ruled

out?


Reliable

theory

has

to

cope

these

informations


Seminar TUM, 27 June 2011

Motivation
for

new

studies


The
low
-
energy

kaon
-
nucleon

interaction

is

neither

simple
nor

well
understood
:


Central importance for the physics of strong interaction has the dynamics driven
by
chiral

symmetry breaking in low
-
energy QCD.


Problems arise from the existence of
hyperon

resonances like the famous
Λ
(1405)
and

2/3
nucleon

K
-

absorption

(
c.f
. E.
Oset
, H.
Toki
, PRC74 (2006)
015207)
possibly

imitating

bound

states
.






The development of reliable theories is asking for precision data on the
threshold observables (e.g. shift/width of
kaonic

atom states).

Seminar TUM, 27 June 2011

Interesting

question
:

Two
-
pole
structure
??

Λ(1405) & Λ(1420)
and


their

impact


L
ow


E
nergy


A
ntikaon


N
ucleus


N
uclei


I
nteraction


S
tudies

Seminar TUM, 27 June 2011

EU
-
FP7

Solved

Puzzles


Seminar TUM, 27 June 2011

Seminar TUM, 27 June 2011

Kaonic

Hydrogen

Kaonic

hydrogen
and

deuterium


Principal

interaction

=
electromagnetic
.



Strong
interaction

manifests

in
hadronic

shift

and

width

of

the

1s
state



energy

displacement

from

the

electromagnetic

value

of

the

1s
state

and

broadening

due
to


K
-

absorption









calculated

solving

the

Klein
-
Gordon (KG)
equation

and

taking

into

account

vacuum

polarization

(VP)
and

final
size

(FS)
effect

(
accuracy

~
1eV
).


Strong
interaction

effect

on 2p
state

is

weak

(
meV
)
and

experimentally

undetermined
,
nevertheless

has

severe

consequences

for

the

x
-
ray

yield
.



Seminar TUM, 27 June 2011

FS
VP
KG
calc
m
e
s
calc
m
e
s
meas
s
s
E
E
E
E
E
E





.)
(
.
1
.)
.(
.
1
.
1
1

Energy

scales

involved


Phi
-
meson

formation

1.020.000.000
eV


K
-

energy

(
Phi

decay
)


16.000.000
eV


K
α

transition

energy

in K
-
p
6.500 eV


Strong

interaction

shift



280
eV


Accuracy

of
shift

determination

few

10 eV

Seminar TUM, 27 June 2011

Example
:
Kaonic

hydrogen
at

DAFNE/LNF

Challenge: Precision x
-
ray

spectroscopy


in a
particle

accelerator

environment

Particle

physics

meets

atomic

physics

Kaonic

hydrogen "puzzle"

Seminar TUM, 27 June 2011

KpX

@ KEK

DEAR@LNF

X
-
ray

experiments

gave

a
positive
energy

shift

of

the

1s
state

by

strong
interaction

in
kaonic

hydrogen.


in
the

contrary

scattering

experiments


indicated

a
negative
energy

shift
.


This

puzzling

situation

was
clarified

in
the

KpX

experiment

and

later

by

our

group

with

DEAR.

Threshold

data

on
kaonic

hydrogen

Seminar TUM, 27 June 2011

DEAR (2005)


1s

=
-

193
±

37 (stat.)
±

6 (syst.)

eV


1s

= 249
±

111 (stat.)
±

30 (syst.)

eV


a
K
-
p

= (
-
0.468
±

0.090
±

0.015) +


i(0.302

±
0.135
±

0.036)
fm



KpX

(1998)


1s

=
-

323
±

63 (stat.)
±

11 (syst.)

eV


1s

= 407
±

208 (stat.)
±

100 (syst.)

eV


a
K
-
p

= (
-
0.78
±

0.15
±

0.03) +


i(0.49

±
0.25
±

0.12)
fm

using

Deser
-
Trueman

(i.e.
lowest

order)




Most
precise

values

for

shift

and

width

from

DEAR

experiment

(CCDs)


But still
precision

limited (e.g.
error

bar
of

width

> 50%)


shift

vs.
width

(1
σ

errors
)
see

below

Result

on K
4
He 2p
shift


(E570 @ KEK)


Clarification of a


long
-
standing puzzle



puzzle

Seminar TUM, 27 June 2011

Solved

puzzles



Status
before

SIDDHARTA


Kaonic

hydrogen puzzle was
qualitatively

solved

(
sign
) but
precision

was limited
,
furthermore

the

case

of

kaonic

deuterium

was
unexplored



Kaonic

helium
-
4 puzzle was
quantitatively

solved

but
verification

was
asked

for

and

the

strong
interaction

in
helium
-
3 was
unexplored



this

was
solved

by

SIDDHARTA.



On
the

other

hand

precision

data

are

requested

for

reliable

theoretical

description

of

the

low
-
energy

anti
-
kaon

nucleon

interaction

and

in
the

context

of

the

existence

of

kaonic

nuclear

bound

states

Seminar TUM, 27 June 2011

New
experiments

--

new

(x
-
ray
)
detectors


Silicon Drift
Detectors

with

large
active

area


active

area



100 mm
2



Excellent

energy

resolution
,
timing

capability




Compact design,
arrangement

in
array



2 different SDD
types

for

exotic

atom

research



SDD
with

external

FET


(
commercial

product
, KETEK)


system

studied
:


K
-
4
He (E570/KEK)



SDD
with

on
chip

integrated

FET




SIDDHARTA (JRA10/EU
-
FP6)


systems

studied
: K
-
p, K
-
d ….

Seminar TUM, 27 June 2011

SIDDHARTA Collaboration



Garching Munich Vienna

Bucarest

Seminar TUM, 27 June 2011

Excellent for low
-
energy
kaon

physics:

kaonic

atoms


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)

Electron
-
positron

collider

DAFNE
at

LNF

Seminar TUM, 27 June 2011

DAFNE
Luminosity

DAFNE
operated

with

crab

waste

system



Higher
luminosity


SIDDHARTA
is

taking

data

only

between

injections

(
blue

dots
,
yellow

line
)


U
nder

good

conditions

during

SIDDHARTA
DAQ

L ~ 2.8 10
32



1.0 10
32

cm
-
2

s
-
1



Comparison

to

2002 DEAR
experiment
:

~ 3.0e31 cm
-
2

s
-
1


now

up

to

10
times

higher

!


SIDDHARTA
integrated

luminosity


on 23
Oct

2009: ~ 8 pb
-
1

!

18


calibration

Seminar TUM, 27 June 2011

SIDDHARTA SDD Array

144 SDDs =144 cm2
active

area


Seminar TUM, 27 June 2011

SIDDHARTA SDD

1Chip : 1 cm
2

Seminar TUM, 27 June 2011

21

x

y

z

SIDDHARTA Setup

Seminar TUM, 27 June 2011

New X
-
ray

detectors

(SDD
silicon

drift

detectors
)


timing

capability



background

suppression



by

using

the

kaon

-

X
ray

time
correlation


excellent

energy

resolution


high

efficiency
, large solid angle


performance

in
accelerator

environment

Scint

SDDs

Triple coincidence:

SDD
X

*
Scint
K

*
Scint
K

Scheme

of

SIDDHARTA

F

e
-

Goal:
measure

the

shift

and

broadening

of

the

X
ray

transition

of

kaonic

atoms

With

high

precision
.


Scint

e
+

K
-

K
+

SDDs

X

22


Seminar TUM, 27 June 2011

Seminar TUM, 27 June 2011

Background
suppression

X
-
ray

energy

[
keV
]

time [83
ns
/
ch
]

Efficient

background

suppression

by

using

the

kaon
-
xray

correlation

Seminar TUM, 27 June 2011

Beam
pipe

in
e
+
e
-

intersection

of

SIDDHARTA

SIDDHARTA
used

the

KLOE
intersection

of

DAFNE


Luminosity

increased

with

new

system

providing

a large
crossing

angle (
crab

waist

system
)

Kaon

window

Kaon

detectors

sitting

below


and

above

the

intersection

Seminar TUM, 27 June 2011

SIDDHARTA data overview

Seminar TUM, 27 June 2011



-

Kaonic

Hydrogen:
400pb
-
1
, most precise
measurement, submitted for publication, PLB,
arXiv:11053090v1


-

Kaonic

deuterium:
100 pb
-
1
, as an exploratory first
measurement ever, advanced analysis


-

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)


-

Kaonic

helium 3:

10 pb
-
1
, first measurement in the
world, published in Phys.
Lett
. B 697 (2011) 199



SIDDHARTA Measurements:

Seminar TUM, 27 June 2011

K
-
He4

PLB681(2009)310

Kaonic

Helium
-
4 @ SIDDHARTA

eV
)
syst
(
2
)
stat
(
6
0
.
.
exp






m
e
E
E
E
Seminar TUM, 27 June 2011

K
-
3
He (3d
-
2p)

Ti Ka

K
-
C

K
-
O

K
-
N

eV
)
(
4
)
(
2
2
2
sys
sta
E
p





1
st

Me3asurement:
Kaonic

Helium
-
3

.
.
exp
2
m
e
p
E
E
E



eV
)
(
5
.
3
)
(
4
.
2
0
.
6223
exp
sys
sta
E



eV
6
.
6224
.
.

m
e
E
QED value:

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

First
measurement

ever

Integr
.
Lum
. = 10 pb
-
1

only
!!!

Seminar TUM, 27 June 2011

Kaonic

Helium
-
3 relative transition yields


preliminary (Ph D thesis A.
Scordo
)

Seminar TUM, 27 June 2011

Kaonic

Helium
-
4
relative transition yields


preliminary (Ph D thesis A.
Scordo
)

Seminar TUM, 27 June 2011

Comparison of results

Shift [eV]

Reference

KEK E570

+2
±
2
±
2

PLB653(07)387

SIDDHARTA (He4 with 55Fe)

+0
±
6
±
2

PLB681(2009)310

SIDDHARTA (He4)

+5
±
3
±
4

arXiv:1010.4631,

PLB697(2011)199

SIDDHARTA (He3)

-
2
±
2
±
4

*error bar

2
2
)
(
)
(
syst
stat



Seminar TUM, 27 June 2011

K
4
He vs. K
3
He

Seminar TUM, 27 June 2011

SIDDHARTA

K
4
He
ε
2p
= +5
±

3(
stat
)
±

4(
syst
)

K
3
He
ε
2p
=
-
2
±

2(
stat
)
±

4(
syst
)

Y.
Akaishi
,
Proc
. EXA05, Austrian
Academy

of

Science Press,

eds
. A.
Hirtl
, J.M., E. Widmann, J.
Zmeskal

Isotope
shift

seems

to

be

rather

small

but
isotopic

effect

might

be

detectable

Seminar TUM, 27 June 2011

Outlook: Experiment on K
3
He at J
-
PARC


The
experiment

E17 at J
-
PARC has European partners

(LNF/Italy, SMI/Austria). SMI is responsible for the x
-
ray
detector systems.

The
experiment

E17
is

in
preparation
,
schedule

strongly
depends

on beam
availability

at

J
-
PARC after
earthquake
.

Independent
precision

measurement

KHe
-
3
at

J
-
PARC

-

Enhancing

the

precision

in
ε
2p


e

e
SDDs

Ti/Cu foil

X
-
ray tube

Data taking
at DAFNE
-
Calibration

calibration data


Estimated

systematic error ~ 3
-
4 eV

Seminar TUM, 27 June 2011


e

e


K

K
SDDs

degrader

Scintillators

Production data

Data taking
at DAFNE
-

Production

Seminar TUM, 27 June 2011

Kaon

BG

Kaon gate

Background gate

SDD Timing vs. Energy

(asynchronous background)

for
K
-
p

data

Seminar TUM, 27 June 2011

Kaonic hydrogen

Hydrogen

spectrum

K
α

K
β

higher

Background estimation

KO76

KN65

Cu

Ti K
α

Ti K
β

KC65

KC75

KO65

KC54

KAl87


value

K
-
p

K
α

simultaneous

fit

Deuterium

spectrum

Seminar TUM, 27 June 2011

EM value

K
-
p K
α

Kaonic hydrogen

K
α

K
β

higher

Residuals of K
-
p x
-
ray spectrum

after subtraction of fitted background

Seminar TUM, 27 June 2011


1S
= −283
±

36(stat)
±

6(
syst
)
eV



1S
= 541
±

89(stat)
±

22(
syst
)
eV




With
relative
yields
of K lines known



error on position < 20
-
25
eV

KAONIC HYDROGEN results

Seminar TUM, 27 June 2011

Submitted

to

Phys.
Lett
. (May 2011)

SIDDHARTA

Kaonic

hydrogen
result (2011)

Seminar TUM, 27 June 2011




-

most reliable and precise


measurement ever


-

need to study K
-
d!





SIDDHARTA
-
2

Kaonic

Hydrogen
with

SIDDHARTA

arXiv:1105.3090

16 May 2011

Seminar TUM, 27 June 2011

KN
interaction

at

threshold

Seminar TUM, 27 June 2011

B.
Borasoy
, R.
Nißler

and

W. Weise,

Phys.
Rev
.
Lett
. 94, 213401 (2005)

K
-
p: repulsive
character

at

threshold
,
attractive

below

threshold

threshold

DEAR data

real part

Imag. part

SIDDHARTA

Re

Im

Λ
(1405)

Kaonic

deuterium

Seminar TUM, 27 June 2011

Once the shift and width of the
1s

level for
kaonic

hydrogen and
kaonic

deuterium are measured
-
)
scattering lengths a
0
, a
1

(
isospin

breaking corrections):







1
1
1
1
1
1










fm
eV
a
i
fm
eV
a
i
d
K
s
s
p
K
s
s


1
1
0
)
(
2
1
a
a
a
a
a
d
K
p
K





“To summarize, one may expect that the
combined analysis of the forthcoming
high
-
precision data from
DEAR/SIDDHARTA collaboration on
kaonic

hydrogen and deuterium will
enable one to perform a stringent

test of the framework used to describe
low

energy
kaon

deuteron scattering, as
well as to extract the values of a0 and a1
with a reasonable accuracy.
However, in
order to do so, much theoretical work
related to the systematic calculation of
higher
-
order corrections within the non
-
relativistic EFT is still to be carried out.”
(from:
Kaon
-
nucleon scattering lengths
from
kaonic

deuterium,
Meißner
,
Raha
,
Rusetsky
, 2006,
arXiv:nucl
-
th
/0603029)

KN

(6
-
5)

KC

(6
-
5)

KO

(6
-
5)

KC

(6
-
4)

KAl

(8
-
7)

KC

(7
-
5)

X ray energy (keV)

Kaonic deuterium spectrum (preliminary:

fit for shift about 500 eV, width about 1000eV, K
a

/ Kcomplex = 0.4

KO

(7
-
6)

KO

(9
-
7)

KTi

(11
-
10)

Cu

K
a

KC (5
-
4)

KAl

(7
-
6)

KN

(5
-
4)

KAl

(10
-
8)

Pb

L
b

Kd

Kcom

Kd

K
a

Seminar TUM, 27 June 2011

46






K
-
p
most

precise

measurement
;
paper

submitted

for

publication



K
-
d
first

measurement

ever
,
exploratory

measurement
,
small



signal
,
significance

~ 2
s,
paper

in
preparation
; SIDDHARTA
-
2



K
4
He
measured

for

the

first

time in
gaseous

target
,


two

papers

published




K
3
He
first

time
measurement

,
paper

published


Summary

of

SIDDHARTA

analyses

status

Seminar TUM, 27 June 2011

Some

open
questions


Precision
data

on
antikaon
-
nucleon

interaction

requires

study

of

KD
to

extract

scattering

lengths

a
0

and

a
1
,
important

input

for

theory
.


Λ
(1405)


pole
structure

?
Consequences
?


Strength

of

antikaon
-
nucleon

interaction

below

threshold
.



Seminar TUM, 27 June 2011

New
ideas

SIDDHARTA
-
2

Seminar TUM, 27 June 2011

SIDDHARTA2

-

Kaonic

deuterium measurement


-

Kaonic

helium transitions to the 1s level



-

X
-
ray studies of other light
kaonic

atoms (KO, KC,…)


-

Heavier
kaonic

atoms measurement (Si,
Pb
…)


-

Kaon

radiative

capture


L
(1405) study


SIDDHARTA
-
2
Strategy

Seminar TUM, 27 June 2011

New precision studies of the strong interaction in
kaonic

atoms at DAFNE


Seminar TUM, 27 June 2011

Enriched

physics

case

(
keV
-
MeV

γ

detection):



Seminar TUM, 27 June 2011




new target design



new SDD arrangement



vacuum chamber



more cooling power



improved trigger scheme



shielding and anti
-
coincidence


SIDDHARTA
-
2 setup

improvements

SIDDHARTA
-
2 Setup

Seminar TUM, 27 June 2011

Trigger
scheme
,
shielding

Seminar TUM, 27 June 2011

Seminar TUM, 27 June 2011



SIDDHARTA

autumn 2009

SIDDHARTA
-
2

new

-

geometry

-

gas density

-

timing

resolution

improve
-
ment

factor

gas

cell: diameter x height (cm)

13.9 x 15.5

17 x 14

entrance

distance from IP (cm)

20

15

gas density

rel.

LHD

< 1.5 %

3 %

upper trigger scint.

4.9 x 6 cm
2


diameter

9 cm

dist. from IP (cm)

6

13

triggers per kaonpair

9.4 %

5.3 %

K
-

gasstops per kaonpair (triggered)

0.78 %

1.94 %

Signal

827 /pb
-
1

2035 /pb
-
1

2.5

trigger per signal

188

39

4.8


synchr. continous backgr.

/Signal /
keV

at ROI

0.3

%

0.
08 %

3.8

KC / Signal (kaonic lines from wall stops)

4 %

0.2 %

20

SDD

timing resolution (ns)

750

500

1.5

Kaonic

deuterium

with

SIDDHARTA

Seminar TUM, 27 June 2011

Kaonic

helium

K
lines
?

Seminar TUM, 27 June 2011

Traditionally

2p
orbit

is

assumed

to

be

last
orbit
, but
there

might

be

a
chance

to

detect

also
the

2p
-
1s
transition

(E~30
keV
)
giving

significant

information

about

the

antikaon
-
nucleus

interaction
.

???

Shift

2p ~ 0 eV

D.N. Michael, PR158 (1967) 1343

G.R.
Burleson

et al., PRL 15 (1965) 70

???

New experiments


Spectroscopy of kaonic atoms with Z>2 improving
the

precision

of

the

data

set

Seminar TUM, 27 June 2011

C.J.
Batty

et al.,
Nucl
. Phys. A329 (1979) 407
-
426

e.g. K
-
O

ε=
-
25
±
18 eV

The
Lamba
(1405)
Resonance


Generated

by

the

attractive

Kbar
-
N
interaction


Quasi
-
bound

state

decaying

into

Σπ


Predicted

by

Dalitz

and

Tuan in 1959


After
more

than

50
years

still a
challenging

object

in
experiment

and

theory


Relation
to

nuclear

bound

states

mediated

by

the

attractice

Kbar
-
N
interaction

Seminar TUM, 27 June 2011

Λ
(1405)
structure
-

a
key

topic


****
star

object

in PDG


Structure

of

Λ
(1405)?






Akaishi
-
Yamazaki

proposed

Λ
(1405)
to

be

an K
-
p
bound

state

opening

the

direct

opportunity

(„
doorway
“)
to

produce

kaonic

nuclei

(e.g. K
-
pp)


V.K. Margas et al.
Phys.Rev
.
Lett
. 95 (2005) 052301:


2
-
pole
structure


Seminar TUM, 27 June 2011

R. J. Hemingway,

Nucl
. Phys. B253, 742 (1985).

M=1406.5

4.0
MeV

Γ=50

2
MeV

Studies on
Λ
(1405)


ANKE


HADES


J
-
Lab


J
-
PARC


SIDDHARTA2

Seminar TUM, 27 June 2011

R. J. Hemingway,

Nucl
. Phys. B253, 742 (1985).

Search

for

K
-
p


Λ(1405) +


With

SIDDHASRTA
-
2

(after an
idea

of

S.
Wycech
)

Outlook


SIDDHARTA2 in
preparation


Highest

priority
:
Kaonic

deuterium

x
-
ray

spectrum


Impact
for

theory
,
extraction

of

isospin
-
dependent

scattering

lengths

a
0

and

a
1


Search

for

K
-
transition

in K
-
He


K
-
p


Λ(1405) +



Independent
information

on
Λ(1405)


Close
collaboration

of

experimentalists

and

theoreticions

extremely

important

(LEANNIS)


LEANNIS in HadronPhysics2
till

end
of

2011


LEANNIS in HadronPhysics3
accepted

by

EC (2012
-
2014)

Seminar TUM, 27 June 2011

Preview

Seminar TUM, 27 June 2011

Thank

you

Seminar TUM, 27 June 2011

If you haven't found something strange during
the day, it hasn't been much of a day.

(John Wheeler)

Spare

Seminar TUM, 27 June 2011