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New experimental results on the strong interaction in kaonic atoms. J. Marton Stefan Meyer Institute Austrian Academy of Sciences , Vienna. LEANNIS. Outline. New data from SIDDHARTA at LNF. Low- energy antikaon interaction – motivation of new studies Solved puzzles
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New experimental results on the strong interaction in kaonicatoms J. Marton Stefan Meyer Institute Austrian AcademyofSciences, Vienna LEANNIS Seminar TUM, 27 June 2011
Outline New datafrom SIDDHARTA at LNF • Low-energyantikaoninteraction – motivationofnewstudies • Solvedpuzzles Kaonicatoms: • Kaonic hydrogen (strong interactioneffect on 1s) • Kaonic helium isotopes He-3,4 (strong interaction on 2p) • Open questionsandfuturechallenges Kaonicatoms • Precision data on kaonicdeuterium • Precision data on kaonic atoms Z>2 Relation kaonicnuclei: • Lamda(1405) and ist relationtothe quest ofboundstrangenuclearsystems (K-pp, K-ppn …) • Summaryand 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 verylowenergies (i.e. in kaonicatoms). 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
Sourcesof experimental information on thelowenergy (anti)kaon-nucleoninteraction • Kaon-protonscatteringdata (olddatawith large errors, abovethreshold extrapolation) • πΣ massspectrum newstudies • Thresholddecayratios • X-raydataoflightkaonicatoms (K-p, K-d, K-He) • Kaonic hydrogen increaseprecision, thresholddata importantinputfortheory • Kaonicdeuterium first experimental studies • Kaonic helium-4 2p shiftsmall (KEK 570), „superstrong“ antikaonnuclearinteractionruled out? • Reliabletheoryhastocopetheseinformations Seminar TUM, 27 June 2011
Motivation fornewstudies Interestingquestion: Two-pole structure?? Λ(1405) & Λ(1420) and theirimpact • The low-energykaon-nucleoninteractionisneither 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) possiblyimitatingboundstates. • 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
LEANNIS EU-FP7 L ow E nergy A ntikaon N ucleus N uclei I nteraction S tudies Seminar TUM, 27 June 2011
Solved Puzzles Seminar TUM, 27 June 2011
Kaonic Hydrogen Seminar TUM, 27 June 2011
Kaonic hydrogen anddeuterium Principalinteraction = electromagnetic. Strong interactionmanifests in hadronicshiftandwidthofthe 1s state energydisplacementfromtheelectromagneticvalueofthe 1s stateandbroadening due toK-absorption calculatedsolvingthe Klein-Gordon (KG) equationandtakingintoaccountvacuumpolarization (VP) and final size (FS) effect (accuracy ~1eV). Strong interactioneffect on 2p stateisweak (meV) andexperimentallyundetermined, neverthelesshassevereconsequencesforthe x-rayyield. Seminar TUM, 27 June 2011
Energyscalesinvolved Particlephysicsmeetsatomicphysics Example: Kaonic hydrogen at DAFNE/LNF Challenge: Precision x-rayspectroscopy in a particleacceleratorenvironment Phi-mesonformation 1.020.000.000 eV K- energy (Phidecay) 16.000.000 eV Kαtransitionenergy in K-p 6.500 eV Stronginteractionshift 280 eV Accuracy of shiftdeterminationfew 10 eV Seminar TUM, 27 June 2011
Kaonic hydrogen "puzzle" KpX @ KEK X-rayexperimentsgave a positive energyshiftofthe 1s stateby strong interaction in kaonic hydrogen. in thecontraryscatteringexperiments indicated a negative energyshift. Thispuzzlingsituation was clarified in theKpXexperimentandlaterbyourgroupwith DEAR. DEAR@LNF Seminar TUM, 27 June 2011
Thresholddata on kaonic hydrogen • Most precisevaluesforshiftandwidthfromDEARexperiment (CCDs) • But still precisionlimited (e.g. error bar ofwidth > 50%) • shift vs. width (1 σerrors) seebelow DEAR (2005) 1s = - 193 ± 37 (stat.) ± 6 (syst.) eV 1s = 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.) eV 1s = 407 ± 208 (stat.) ± 100 (syst.) eV aK-p = (-0.78 ± 0.15 ± 0.03) + i(0.49 ±0.25± 0.12) fm usingDeser-Trueman (i.e. lowest order) Seminar TUM, 27 June 2011
Result on K4He 2p shift(E570 @ KEK) Clarification of a long-standing puzzle puzzle Seminar TUM, 27 June 2011
Solvedpuzzles – Status before SIDDHARTA Kaonic hydrogen puzzle was qualitativelysolved (sign) but precision was limited, furthermorethecaseofkaonicdeuterium was unexplored Kaonic helium-4 puzzle was quantitativelysolved but verificationwas askedforandthestrong interaction in helium-3 was unexplored this was solvedby SIDDHARTA. On theotherhandprecisiondataarerequestedforreliabletheoreticaldescriptionofthelow-energy anti-kaonnucleoninteractionand in thecontextoftheexistenceofkaonicnuclearboundstates Seminar TUM, 27 June 2011
New experiments -- new (x-ray) detectors • Silicon Drift Detectorswith large activearea activearea 100 mm2 • Excellentenergyresolution, timingcapability • Compact design, arrangement in array • 2 different SDD typesforexoticatomresearch • SDD withexternal FET (commercialproduct, KETEK) systemstudied: K-4He (E570/KEK) • SDD with on chipintegrated FET SIDDHARTA (JRA10/EU-FP6) systemsstudied: K-p, K-d …. Seminar TUM, 27 June 2011
SIDDHARTA Collaboration Garching Munich Vienna Bucarest Seminar TUM, 27 June 2011
Electron-positroncollider DAFNE at LNF • 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) Excellent for low-energy kaon physics: kaonicatoms Seminar TUM, 27 June 2011
DAFNE Luminosity DAFNE operatedwithcrabwastesystem Higher luminosity SIDDHARTA istakingdataonlybetween injections (bluedots, yellowline) Undergoodconditionsduring SIDDHARTADAQ L ~ 2.8 1032– 1.0 1032cm-2 s-1 Comparisonto 2002 DEAR experiment: ~ 3.0e31 cm-2 s-1 nowupto 10 timeshigher ! SIDDHARTAintegratedluminosity on 23 Oct 2009: ~ 8 pb-1 ! calibration Seminar TUM, 27 June 2011 18
SIDDHARTA SDD Array 144 SDDs =144 cm2 activearea Seminar TUM, 27 June 2011
SIDDHARTA SDD 1Chip : 1 cm2 Seminar TUM, 27 June 2011
y x z SIDDHARTA Setup Seminar TUM, 27 June 2011 21
New X-raydetectors (SDD silicondriftdetectors) timingcapability backgroundsuppression byusingthekaon - X ray time correlation excellentenergyresolution highefficiency, large solid angle performance in acceleratorenvironment Schemeof SIDDHARTA Goal: measuretheshiftandbroadening ofthe X raytransitionofkaonicatoms Withhighprecision. SDDs SDDs X K- Scint F e+ e- Scint Triple coincidence: SDDX * ScintK * ScintK K+ Seminar TUM, 27 June 2011 22
Background suppression Efficientbackgroundsuppressionbyusingthekaon-xraycorrelation X-rayenergy [keV] time [83 ns/ch] Seminar TUM, 27 June 2011
Beam pipe in e+e-intersectionof SIDDHARTA SIDDHARTA usedthe KLOE intersectionof DAFNE Luminosityincreasedwithnewsystemproviding a large crossing angle (crabwaistsystem) Kaonwindow Kaondetectorssittingbelow andabovetheintersection Seminar TUM, 27 June 2011
SIDDHARTA data overview Seminar TUM, 27 June 2011
SIDDHARTA Measurements: - 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 Seminar TUM, 27 June 2011
Kaonic Helium-4 @ SIDDHARTA PLB681(2009)310 K-He4 Seminar TUM, 27 June 2011
1st Me3asurement: Kaonic Helium-3 Integr. Lum. = 10 pb-1only!!! arXiv:1010.4631v1 [nucl-ex], PLB697(2011)199 K-3He (3d-2p) QED value: First measurementever Ti Ka K-O K-C K-N Seminar TUM, 27 June 2011
Kaonic Helium-3 relative transition yields preliminary (Ph D thesis A. Scordo) Seminar TUM, 27 June 2011
KaonicHelium-4 relative transition yields preliminary (Ph D thesis A. Scordo) Seminar TUM, 27 June 2011
Comparison of results *error bar Seminar TUM, 27 June 2011
K4He vs. K3He Y. Akaishi, Proc. EXA05, Austrian Academyof Science Press, eds. A. Hirtl, J.M., E. Widmann, J. Zmeskal SIDDHARTA K4He ε2p= +5 ± 3(stat) ± 4(syst) K3He ε2p= -2 ± 2(stat) ± 4(syst) Isotope shiftseemstoberathersmall but isotopiceffectmightbedetectable Seminar TUM, 27 June 2011
Outlook: Experiment on K3He at J-PARC Independent precisionmeasurement KHe-3 at J-PARC - Enhancingtheprecision in ε2p 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 availabilityat J-PARC after earthquake. Seminar TUM, 27 June 2011
Data taking at DAFNE -Calibration Estimated systematic error ~ 3-4 eV calibration data SDDs Ti/Cu foil X-ray tube Seminar TUM, 27 June 2011
Production data SDDs degrader Scintillators Data taking at DAFNE - Production Seminar TUM, 27 June 2011
SDD Timing vs. Energy for K-p data Kaon BG Kaon gate Background gate (asynchronous background) Seminar TUM, 27 June 2011
Hydrogen spectrum EM value K-p Kα Kaonic hydrogen Kα Kβ higher KC54 KC65 simultaneous fit Ti Kα KO65 Ti Kβ KC75 KN65 KO76 KAl87 Cu Deuterium spectrum Background estimation Seminar TUM, 27 June 2011
Residuals of K-p x-ray spectrum after subtraction of fitted background Kaonic hydrogen higher Kα Kβ EM value K-p Kα Seminar TUM, 27 June 2011
KAONIC HYDROGEN results e1S= −283 ± 36(stat) ± 6(syst) eV G1S= 541 ± 89(stat) ± 22(syst) eV With relative yields of K lines known error on position < 20-25 eV Submittedto Phys. Lett. (May 2011) Seminar TUM, 27 June 2011
Kaonic hydrogen result (2011) SIDDHARTA 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 interactionatthreshold K-p: repulsive characteratthreshold, attractivebelowthreshold threshold real part Re Λ(1405) Im SIDDHARTA Imag. part DEAR data B. Borasoy, R. Nißlerand W. Weise, Phys. Rev. Lett. 94, 213401 (2005) Seminar TUM, 27 June 2011
Kaonicdeuterium “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) Seminar TUM, 27 June 2011 Once the shift and width of the 1s level for kaonic hydrogen and kaonic deuterium are measured -) scattering lengths a0, a1 (isospin breaking corrections):
Kaonic deuterium spectrum (preliminary: fit for shift about 500 eV, width about 1000eV, Ka / Kcomplex = 0.4 KC (5-4) KC (6-5) KO (6-5) KO (7-6) KN (6-5) KC (7-5) Cu Ka KAl (8-7) KO (9-7) KAl (10-8) Pb Lb KAl (7-6) KC (6-4) KN (5-4) KTi (11-10) Kd Kcom Kd Ka Seminar TUM, 27 June 2011 X ray energy (keV)
Summaryof SIDDHARTA analysesstatus • K-p mostprecisemeasurement; papersubmittedforpublication • K-d firstmeasurementever, exploratorymeasurement, small • signal, significance~ 2s, paper in preparation; SIDDHARTA-2 • K4He measuredforthefirst time in gaseoustarget, • twopaperspublished • K3He first time measurement , paperpublished Seminar TUM, 27 June 2011 46
Some open questions Precision dataon antikaon-nucleoninteractionrequiresstudyof KD toextractscatteringlengths a0and a1, importantinputfortheory. Λ(1405) – pole structure ? Consequences? Strengthofantikaon-nucleoninteractionbelowthreshold. Seminar TUM, 27 June 2011
New ideasSIDDHARTA-2 SIDDHARTA2 Seminar TUM, 27 June 2011
- 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…)- Kaonradiative capture – L(1405) study SIDDHARTA-2 Strategy Seminar TUM, 27 June 2011
New precision studies of the strong interaction in kaonic atoms at DAFNE Proposal submitted in 2010Addendum 2011 Enrichedphysicscase (keV-MeVγ detection): Seminar TUM, 27 June 2011