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Alessandro Scordo HADRON 2015 18/09/2015

Shedding new Light on Kaon-Nucleon/Nuclei Interaction and its Astrophysical Implications with the AMADEUS experiment at DA F NE. Alessandro Scordo HADRON 2015 18/09/2015. Before starting….

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Alessandro Scordo HADRON 2015 18/09/2015

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  1. Shedding new Light on Kaon-Nucleon/Nuclei Interaction and its Astrophysical Implications with the AMADEUS experiment at DAFNE Alessandro Scordo HADRON 2015 18/09/2015

  2. Before starting…. The aim of this talk is to letyouinto the wonderfulpossibilities of the DAFNE acceleratortogether with the AMADEUS exp. No time for all the analysisdetails (and not so muchastrophysics…) All the presented MC simulationshavebeenperformedthanks to the veryimportantcollaboration of prof. Wycech(Warsaw)

  3. The DANEaccelerator e+ e-at 510 MeV -> at-rest • resonancedecaysat 49.2 % in K+ K- back to back pair Monochromaticbeam of lowmomentum K- (pk = 127 MeV/c) Currents of 2 A (e-) and 1 A (e+) KLOE detector

  4. What was done at DANEPast experiments Low-energy Kaon-nuclei processes Kaonic atoms Hypernuclei SIDDHARTA FINUDA FINUDA AMADEUS – step 0

  5. What Next @ DANE Low-energy Kaon-Nuclei Hyperon-Nuclei Kaonic atoms Hypernuclei SIDDHARTA-2 AMADEUS? AMADEUS Kaon mass

  6. AMADEUS AMADEUS collaboration 116 scientists from 14 Countries and 34 Institutes lnf.infn.it/esperimenti/siddharta and LNF-07/24(IR) Report on lnf.infn.it web-page (Library) AMADEUS started in 2005 and was presented and discussed in all the LNF Scientific Committees AntikaonMatterAtDANE: Experiments withUnravelingSpectroscopy EU Fundings FP7 – I3HP2 and HP3: Network WP9 – LEANNIS; WP24 (SiPM JRA); WP28 (GEM JRA)

  7. The scientific goal of AMADEUS 1) K-N potential → how deep can an antikaon be bound in a nucleus? - UKN strongly affects the position of the L(1405) state → we investigate it through (S-p)0 decay --- Y p CORRELATION - if UKN is strongly attractive then possible K- multi-N bound states → we investigate through (L/S-N) decay --- Y N CORRELATION Y-N potential → extremely poor experimental information from scattering data - UYN determines the strength of the final state YN (elastic & inelastic) → could be tested by Y N CORRELATION K-N → L/S p cross section below 100 MeV/c(analysis still to be started) Hypernuclei?

  8. Essential impact on the case of NEUTRON STARS

  9. Low-energy K- hadronic interactions studies with KLOE 2002-2005 data MC simulations show that : ~ 0.1 of K- stopped in the DC gas (90% He, 10% C4H10) ~ 2% of K- stopped in the DC wall (750 mm c. f. , 150 mm Al foil). Possibility to use KLOE materials as an active target Advantage: unprecedent resolution : p/p ~ 0.4 MeV/c 4-geometry with ~ 96% acceptance Calorimeter optimized for  : m ~ 7 MeV/c2 Vertex position resolution ~ 1 mm (in DC) Disadvantage: Non dedicated target → different nuclei contamination → complex interpretation .. but → new features .. K- in flight absorption. K- K+

  10. AMADEUS step-0: Pure Carbon target inside KLOE (2012) Dedicated run in november/december 2012 with a Carbon target 4/6 mm thickness Advantages: gain in statistics (~90 pb-1; analyzed 37 pb-1, x1.5 statistics) K- absorptions occur in Carbon at-rest.

  11. PART 1Y p CORRELATIONresonant VS non-resonant production study

  12. The 2 polespicture of (1405) two poles: (z1 = 1424+7-23– i 26+3-14 ; z2 = 1381+18-6– i 81+19-8 ) MeV mainly coupled to KN mainly coupled to  → line-shape depends on production mechanism Line-shape also depends on the decay channel : Pure I=0 (free from (1385) background)

  13. The goldenS0p0channel L(1405) signal searched by K- interaction with a bound proton in Carbon K- p → S0p0 detected via: (Lg)(gg) Mass limit on 12C at rest 2004-2005 data 2012 data Only at rest events (cut at mass limit)

  14. The S+p-channel Total H IF 4He AR 4He DC gas DC wall Total IF H IF 12C AR 12C Removing the H component is fundamental since it behaves like a high mass pole!!!

  15. The Non-ResonantLp-channel Preliminary non-resonant / resonant absorption ratio: - at rest ~ 2.3 - in flight ~ 4.1 c2/ (ndf – np) = 1.5 non-resonant / resonant absorption ratio: - at rest ~ 2.3 - in flight ~ 4.1 c2/ (ndf – np) = 1.5 counts/(10MeV/c) Counts/(0.04) +++ Data ----- Global fit cosqp (MeV/c) pp (MeV/c) counts/(3MeV/c2) Σ/Λ nuclear conversion K-N→Σ π Absorptions in 12C (from Carbon wall data) ΣN→ΛN Non-Resonant (in-flight) (at-rest) Resonant S* (in-flight) (at-rest) mp (MeV/c)

  16. PART 2 Single & multi – nucleon K- absorptionkaonic nuclear clusters investigation through Lp,t / S0pcorrelation

  17. Λp correlation study Fit 3D (PΛ, Pp, θΛp) ----- K-N → Σπ + Σp/Λp conversion in 4He ----- K-H → Σπ + Σp/Λp conversion in 12C - No fragmentation (higher mass) - Residual fragmented (lower mass) ----- K-NN → Λπp (higher mass) ----- K-NN → Σπp (lower mass) ----- K-NN → Σp + Σp/Λp conversion in 4He ----- K-NN → Λp (higher mass) ----- K-NN → Σ0p (lower mass) ----- Uncorrelated background +++ Data ---- Global fit Preliminary without 3NA MΛp (MeV/c2)

  18. Λp correlation study Fit 3D (PΛ, Pp, θΛp) with 3NA We need to fix the yield of 2NA/3NA absorption!!! never measured before

  19. Λt correlation studies in 4He 150 events in gas of the DC (He + C4H10 ) red line - back to back events (cosΘΛt ) < -0.95 4NA process : - highest part of invariant mass - back-to-back topology Clear back-to-back enhancement of Λt events

  20. Λt correlation studies in 4He:preliminary mass and angle simulataneous fit Preliminary data • Highest statistics ever in the Λt channel --- carbon data from DC wall --- 4NA K- 4He → Λt in flight MC --- 4NA K- 4He → Λt at rest MC --- 4NA K- 4He → Σ0t , Σ0 → Λγ MC --- 4NA K- 4He → Σ0t , Σ0 → Λγ MC BR(K-4He(4NA) → Λt) < 1.1 x 10-4 /Kstop σ(100 MeV/c) (K-4He(4NA)→Λt) = (0.41 ± 0.13 (stat ) +0.01 -0.02 (sys)) mb paper in preparation

  21. S0p correlation study Final fit 2NA-QF clearly separated From other processes From the contributions to the fit, the yields are extracted for K- stop

  22. Absorption results ...is there room for the signal of a ppK- bound state? Repeat the fit with the inclusion of a simulated bound state in a grid with different values for the Binding Energy and Width: B.E. : 15-75 MeV/c2 (15 MeV/c2 steps) Width: 30-70 MeV/c2 (20 MeV/c2 steps)

  23. S0p correlation study Fit with ppK- Best solution: (best c2 and higher yield) - B.E. = 45 MeV/c2 - Width = 30 MeV/c2 Significance: 1 s

  24. PART 3Exploring the possibility to study Hypernuclei

  25. L hypernuclei with K- at rest on Carbon Pion momentum (MeV/c): 272.72 NMWD: Proton momentum (MeV/c): (273550) MeV/c Looking for a monochromaticpion and a proton in coincidence

  26. π- momentum 273 MeV/c (corresponding to the ground state, with B =10.8 MeV)

  27. Conclusions The DAFNE accelerator, together with the AMADEUS experiment, represents a uniquepossibility to perform complete studies in the low-energystrangenesssector SIDDHARTA & AMADEUS experimentsalreadyobtainedexcellentresults SIDDHARTA could take new data in 2017 AMADEUS isstillnot an approvedexperiment, itisusingoldexisting KLOE data, yet….. 1) Alreadyshown impressive capabilities to investigate severalprocesses 2) Manychannelshavebeenstudied and papers are in preparation 3) Even more channelsstillhave to be opened….there’s room for everyone! The final goal is to have the possibility to have a DEDICATED experiment in order to really investigate the KN, YN, L(1405), hypernucleiphysics with no contaminations Ifyou are interested in such a possibility….join the cause! We are looking for otherinstitutes/universities/groups to becomemembers of the AMADEUS collaboration

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