low- energy anti- kaon nucleon and nuclei interactions

19th IUPAP Conference on Few Body Problems 1

Low-energy anti-kaon nucleon and nuclei interactions

J. MartonStefan Meyer Institute

Austrian Academy of Sciences, Vienna

LEANNIS


Scope

• A kind of overview on open problems and current and future attempts to solve them (here I want to focus on dedicated experiments)

• Topics which are in the scope of the LEANNIS network of the EU project HadronPhysics2

• Few Body problems involving strangeness: Specific talks on theoretical approaches and experiments (experiments: M. Iio, O. Vazques Doce, S. Okada, Y. Fujiwara) at this Conference

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LEANNIS


Content

• Motivation for new (experimental) studies

• Exotic (hadronic) atoms – threshold data

– Kaonic hydrogen isotopes (strong interaction effect on 1s)– Kaonic helium isotopes (strong interaction on 2p)

• Search for bound strange nuclear systems (K-pp, K-ppn …)

– K- stopped– K- in-flight– pp collisions

• New ideas

• Status and Outlook

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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 Λ(1405)

• Problems arise also due to 2 nucleon K- absorption possibly imitating bound states

• The development of reliable theories suffers from the lack of precision data on the

observables at threshold (e.g. shift/width of kaonic atoms)

19th IUPAP Conference on Few Body Problems

Interesting question:Two-pole structure??Λ(1405) & Λ(1420) and their impact

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Sources of experimental information on the low energy (anti)kaon-nucleon interaction

• Kaon-proton scattering data (old data with large errors, above threshold extrapolation)

• πΣ mass spectrum• Threshold decay ratios• X-ray data of light kaonic atoms (K-p, K-d, K-He): see talks by S. Okada and Iio

at this conference– Kaonic hydrogen increase precision, threshold data important input for theory – Kaonic deuterium first experimental studies, threshold data important input

for theory – Kaonic helium-4 2p shift small (KEK 570), rules out „superstrong“ antikaon

nuclear interaction– Kaonic helium-3 first experimental studies

• Reliable theory has to cope these informations



Kaonic hydrogen and deuterium

• Strong interaction effects manifest in hadronic shift and width of the 1s state, i.e. deviation from the electromagnetic value of the 1s state and broadening due to absorption

• which can be calculated with an accuracy of about 1eV by solving the Klein-Gordon (KG) equation and taking into account vacuum polarization (VP) and final size (FS) effect.

• Strong interaction effect on 2p state is weak (meV) and experimentally undetermined, but has severe consequences for the x-ray yield

FSVPKGcalcme

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calcmes

measss

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X-ray yields

Strong interaction on 2p level 2p width Γ2p

Γ2p limits yield - but is poorly known

M. G. Raisi and S.Z. Kalantari, PRA 79 (2009) 012510

2p width

R.C. Barrett, A.Deloff 0.014 - 46 meV

PRC 60(1999)025201

T. Koike et al. 25 meV PRC 53 (1996) 79

M.P. Faifmann 4±2 meV Proc. DAFNE99

K-d

K-p

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Threshold data on kaonic hydrogen


DEAR (2005)1s = - 193 ± 37 (stat.) ± 6 (syst.) eV1s = 249 ± 111 (stat.) ± 30 (syst.) eV

aK-p = (-0.468 ± 0.090 ± 0.015) + i(0.302 ±0.135± 0.036) fm

KpX (1998)1s = - 323 ± 63 (stat.) ± 11 (syst.) eV1s = 407 ± 208 (stat.) ± 100 (syst.) eV

aK-p = (-0.78 ± 0.15 ± 0.03) + i(0.49 ±0.25± 0.12) fmusing Deser-Trueman (i.e. lowest order)

KpX@KEK solved the so-called "kaonic hydrogen puzzle" interaction is repulsivePrecision limited (e.g. error bar of width > 50%)Most precise values for shift and width from DEAR experiment (CCDs)But still precision limitedshift vs. width (1 σ errors) see below


Close interconnection between experiment and theory

• ExampleK-p: extraction of scattering lengths from experimenta dataEven more challenging is the case of kaonic deuterium

• Lowest order: Deser-Trueman

• NLO: Isospin breaking corrections

))1(ln21(22

22

311

311

pKpKpKpKs

s

pKpKs

s

aai

ai

U.-G- Meißner, U. Raha and A. Rusetsky, Eur. Phys.J. C35 (2004) 349

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KN interaction at threshold


B. Borasoy, R. Nißler and W. Weise, Phys. Rev. Lett. 94, 213401 (2005)

K-p: repulsive at threshold, attractive below threshold

threshold

DEAR data

real part

Imag. part

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New experiments -- new (x-ray) detectors

• Silicon Drift Detectors with large active areaactive area 100 mm2

• Excellent energy resolution, timing

• 2 different types for exotic atom research SDD with external FET

(commercial product, KETEK)system studied: K-4He (E570/KEK), K-3He (E17/J-PARC)

SDD with on chip integrated FET SIDDHARTA (JRA10/EU-FP6)systems to be studied:K-p, K-d ….



Kaonic nuclear clusters ?

• Prototype system K-pp


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Recent developments in theory

Faddeev calculationsSee talk by N. Shevchenko at this Conference

Binding energy: 55 – 70 MeVDecay width: 95 – 110 MeV

N. Shevchenko, et al. PRL 98 (2007) 082301N. Shevchenko et al. PRC (2007) 044004Y. Ikeda, T. Sato PRC 76 (2007) 035203

Variational calculations

Binding energy: 20 - 50 MeVDecay width: 40 - 100 MeV

T. Yamazaki, Y. Akaishi PRC 76 (2007) 045201A. Dote, T. Hyodo, W. Weise NPA 804 (2008) 197A. Dote, T.Hyodo, W. Weise PRC 79 (2009) 014003

VC

OBELIX, NPA789 (2007)222

FINUDA PRL94 (2005) 212303

DISTO, preliminaryProc. EXA/LEAP09, Hyp. Int. in print

FC

FINUDA PRL94 (2005) 212303

OBELIX, NPA789 (2007)222

DISTO, preliminaryProc. EXA/LEAP09, Hyp. Int. in print

FCVC

K-pp: Comparison experiment-theoryVC … Variational calculationsAY02 … VC Akaishi and Yamazaki PL B535 (2002) 70FC … Faddeev calculations

AY02

AY02

Not a clear picture


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Production of antikaon-mediated bound nuclear cluster (KNC)?

• stopped K- reactions on light nuclei

• in-flight K- reactions

• protons on proton (or light nuclei)

• heavy ion collisions

• antiproton induced reactions

• dedicated experiments• exclusive measurement

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Search for kaonic nuclear clusters with AMADEUS at LNF


AMADEUS collaboration:114 scientists from 13 Countries and 33 Institutes

lnf.infn.it/esperimenti/siddhartaand

LNF-07/24(IR) Report on lnf.infn.it web-page (Library)

Search for kaonic nuclear systemswith S-1 using K- stopped in helium gas and employing the modified KLOEapparatus at DAΦNE/LNFfor exclusive experiments

See talk by O. Doce Vazquez

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K-pp production in pp reaction with FOPI


KppK

Kppp )1405(*

p p

p p Experimental search for the most simple KNC – the prototype system ppK- with• missing mass spectroscopy• invariant mass reconstruction

Presently taking data at GSI

p on hydrogen target at 3 GeV

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Search for K-pp in flight (E15@J-PARC)

• 3He(K-,n) reaction, experiment in connection with E17

K-

3He (liquid)reaction

Search for K-pp bound state withMissing mass spectroscopy andInvariant mass reconstruction

K-ppcluster

neutron

L p

p

p-

Charged particles decay

Missing mass spectroscopyby n detectiondecay

Invariant mass reconstruction



New ideas

• Search for kaonic nuclear clusters S-2 (double strangeness)• Production via antiproton annihilation proposed, EB> 100 MeV

QKpnnKKKHep

GeVKKKKpp

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098.0

Proposed by P.Kienle (*), T.Yamazaki and W.Weise (**) (*) Int. Jour. Mod. Phys. A 22 (2007)365(**) arXiv:nucl-th/0507058 v1 (2005)

Idea supported by Obelix data


New experiments?

• Requirements for pbar annihilation studies at rest:(J. Zmeskal et al. Proc. EXA08, Hyp. Int. In print)

– Low-energy pbar beam: AD/CERN, FLAIR/FAIR– Detector for exclusive annihilation studies

in nuclei

• Start counter – scintillating fibers with Geiger Mode - APD readout

• PID – with a TPC - GEM (similar as proposed for PANDA)

• For neutral particle detection - a Calorimeter with alternating scintillating fibres – lead layers (KLOE-type)

– High statistics


Status and Outlook• New experiments on threshold data (shift, width) of light kaonic atoms are

running (SIDDHARTA@LNF) or in preparation (E17@J-PARC)

• Threshold data are crucial prerequisites for the theoretical description (enhancement of the predictive power for sub-threshold)

• Challenge: Nature of Λ(1405) – 2-pole structure? Can one investigate this question experimentally?

• Theoretical studies on the question of kaonic nuclear clusters are ongoing (Faddeev, variational calculations)

• Evidence for existence of kaonic nuclear clusters (FINUDA, OBELIX, DISTO, …)

• New fully exclusive experiments with various reactions are indispensible and are in preparation

• New idea: Kaonic nuclear cluster with double strangeness produced in antiproton annihilation


Thank you

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

No phenomenon is a real phenomenon until it is an observed phenomenon. John Archibald Wheeler

http://www.brainyquote.com/quotes/quotes/j/johnarchib201713.html


Spare


Interconnection experiment-theory cont‘d• Extrapolation of subthreshold behavior from experimental dataπΣ mass spectrum extrapolation from analysis of data above threshold(B. Borasoy, R. Nissler and W. Weise, Eur.J. A25 (2005) 79)

Precision threshold data (SIDDHARTA) will increase the predictive power

K-p threshold


Experiments

• KN threshold studies by x-ray spectroscopy (SIDDHARTA@LNF, E17@J-PARC)– see talks by S. Okada and Iio at this conference

• Search for quasi-bound nuclear systems with S=-1 (E549@KEK, DISTO, FOPI@GSI, E15@J-PARC, AMADEUS@LNF)– see talk by O. Doce Vazquez on AMADEUS at this Conference

• Search for quasi-bound nuclear systems with S-2 (OBELIX, CERN AD, FLAIR)


Comparison of chiral and phenomenological KN interaction

T. Hyodo and W. Weise, PR C77 (2008) 035204

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1420

low- energy anti- kaon nucleon and nuclei interactions

Documents

data old data

outlook19th iupap conference

p state

body problems33motivation

body problems6

physics of strong interaction

body problems leannis1

threshold data important