K - interaction with nucleons at low-energy by AMADEUS Raffaele Del - - PowerPoint PPT Presentation

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K - interaction with nucleons at low-energy by AMADEUS Raffaele Del Grande 1,2 * 1 INFN Laboratori Nazionali di Frascati, Frascati, Italy 2 CENTRO FERMI - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma, Italy On the

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Raffaele Del Grande1,2*

1 INFN Laboratori Nazionali di Frascati, Frascati, Italy 2 CENTRO FERMI - Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Roma, Italy

On the behalf of the AMADEUS collaboration 25-29 November 2019 Technik Museum Speyer, Speyer, Germany

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K- interaction with nucleons at low-energy by AMADEUS

*raffaele.delgrande@lnf.infn.it

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Motivation

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Raffaele Del Grande 2

AMADEUS (Antikaonic Matter At DAΦNE: an Experiment with Unravelling Spectroscopy ) investigates low-energy K- absorption in nuclei with the aim to extract information on:

  • K-N interaction above and below threshold

○ Λ(1405) nature ○ kaonic bound states

  • K-NN, K-NNN, K-NNNN (multi-nucleon) interactions

○ essential for the determination of K--nuclei optical potential

  • In medium modification of the KbarN interaction

○ partial restoration of chiral symmetry → hadrons mass origin ○ Equation of State of Neutron Stars ○ modification of Λ(1405) and Σ(1385) properties in nuclear medium

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

K-p scattering amplitude

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Raffaele Del Grande 3

K-p scattering amplitude with Chiral models

  • Kyoto-Munich (KM)
  • Y. Ikeda, T. Hyodo, W. Weise, Nucl. Phys. A 881 (2012) 98
  • Murcia (MI , MII )
  • Z. H. Guo, J. A. Oller, Phys. Rev. C 87 (2013) 035202
  • Bonn (B2 , B4 )
  • M. Mai, U.-G. Meißner - Eur. Phys. J. A 51 (2015) 30
  • Prague (P)
  • A. C., J. Smejkal, Nucl. Phys. A 881 (2012) 115
  • Barcelona (BCN)
  • A. Feijoo, V. Magas, À. Ramos, Phys. Rev. C 99 (2019) 035211

Large discrepancies in the region below threshold!

[from A. Cieply talk at MENU2019 conference]

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Experimental constraints above threshold

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Raffaele Del Grande 4

K-p elastic and inelastic low-energy cross sections

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Experimental constraints above threshold

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Raffaele Del Grande 5

K-p elastic and inelastic low-energy cross sections no data for pK < 100 MeV/c

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Experimental constraints at threshold

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Precise SIDDHARTA measurement of kaonic hydrogen 1s level shift and width

  • M. Bazzi et al.. 2011. (SIDDHARTA Coll.), Phys. Lett. B704, 113
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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Below threshold

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No data below threshold NEW EXPERIMENTAL CONSTRAINTS ARE STRONGLY NEEDED!!

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

K-n scattering amplitude

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Raffaele Del Grande 8

Large spread in I=1 channel Experimental information is totally missing:

  • SIDDHARTA-2 → first experimental

constraint at threshold

  • AMADEUS → first experimental

constraint below threshold K-n scattering amplitude with Chiral models

[from A. Cieply talk at MENU2019 conference]

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The Λ(1405) state does not fit with the simple three quarks model (uds) and it is commonly accepted to be partially, a K ̄ N bound state. Chiral models: dynamical origin. Two poles of the scattering amplitude → pole positions is model dependent (relative contributions not measured experimentally)

Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Impact on Λ(1405) nature

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Λ (1405)

Narrow pole Broad pole Narrow pole Broad pole

[from M. Mai talk at NSTAR19 conference]

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The Λ(1405) state does not fit with the simple three quarks model (uds) and it is commonly accepted to be partially, a K ̄ N bound state.

Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Impact on Λ(1405) nature

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Raffaele Del Grande 10

Λ (1405)

Single pole ansatz (Esmaili-Akaishi-Yamazaki phenomenological potentials model): Very strongly attractive K

̄ N interaction → existence of deeply bound kaonic bound states

Kaonic Bound States

decay modes

[Phys. Lett. B 686 (2010) 23-28]

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

K-pp bound state

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Raffaele Del Grande 11 Experiments Theory

  • K

̄ N input model is critical for the theoretical interpretation

  • different bound state production mechanisms

are experimentally investigated

  • E15 → first clear evidence in K- induced

reactions (theoretical interpretation by Sekihara, Oset, Ramos)

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Impact on in-medium K ̄ N interaction

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  • Partial restoration of chiral

symmetry in medium kaon mass modification:

  • Impact on Equation of State (EoS) of Neutron Stars:

[Pal et al. (2000)]

K- condensate can change EoS-stiffness but: hyperons become more relevant at higher densities

[Gal et al. (2016)]

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Unprecedented studies of the low- energy charged kaons interactions in nuclear matter: solid and gaseous targets (H, 4He, 8Be, 12C ...) in order to obtain unique quality information about:

1. Controversial nature of the Λ (1405) and K

̄ N amplitude below threshold Yπ CORRELATION STUDIES

(i.e. Λπ and Σπ and final states) 2. Low

  • energy charged kaon cross sections

for momenta of 100 MeV/c 3. a) Interaction of K- with one and more nucleons (single and multi–nucleon K-

absorption) YN CORRELATION STUDIES

(i.e. Λ p, Σ0 p, and Λ t final states) b) possible existence of kaonic bound states 4.

YN scattering → extremely poor experimental information from scattering data

(helpful to understand the EoS of Neutron Stars)

Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Goals of AMADEUS

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

DAΦNE the Φ factory

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Best low momentum K- factory in the world Suitable for low-energy kaon physics: → Kaonic atoms (SIDDHARTA-2) → Kaon-nucleons/nuclei interaction studies (AMADEUS)

  • e+ e- at 510 MeV
  • φ resonance decays at 49.2 % in K+

K- back to back pair

  • Very low momentum (≈ 127 MeV)

K- beam

  • Flux of produced kaons: about

1000/second

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

AMADEUS step 0

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K- K+

e+ e-

Possibility to use KLOE materials as an active target

  • DC wall (750 μm C foil , 150 μm Al foil);
  • DC gas (90% He, 10% C4H10).

The KLOE detector

  • Cylindrical drift chamber with a 4π geometry and

electromagnetic calorimeter

  • 96% acceptance
  • ptimized in the energy range of all charged particles

involved

  • good performance in detecting photons and neutrons

checked by kloNe group

[M. Anelli et al., Nucl Inst. Meth. A 581, 368 (2007)]

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

K- absorptions at-rest and in-flight

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IN-FLIGHT (pΚ~ 100 MeV/c) AT-REST K- absorbed from atomic orbitals (pK ~ 0 MeV/c)

e-

pΚ~ 100 MeV/c

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Experimental constraints at threshold

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Large spread in I=1 channel Experimental information is totally missing:

  • SIDDHARTA-2 → first experimental

constraint at threshold

  • AMADEUS → First determination of the

non-resonant transition amplitude below threshold Investigated using: K- “n” → Λπ− to extract |f N-R Λπ (I=1)| below threshold K-n scattering amplitude with Chiral models

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Simultaneous fit : pΛπ− - mΛπ− - cos θΛπ−

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Raffaele Del Grande 18 [K. Piscicchia, S. Wycech, L. Fabbietti et al. Phys.Lett. B782 (2018) 339-345] [K. Piscicchia, S. Wycech, C. Curceanu, Nucl. Phys. A 954 (2016) 75-93]

Investigated using: K- “n” 3He → Λπ− 3He

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

Outcome of the measurement

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Investigated using: K- “n” 3He → Λπ− 3He

[K. Piscicchia, S. Wycech, L. Fabbietti et al. Phys.Lett. B782 (2018) 339-345] [K. Piscicchia, S. Wycech, C. Curceanu, Nucl. Phys. A 954 (2016) 75-93]

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Investigation of the Λp correlated production in low-energy K- 12C interactions Raffaele Del Grande

K-p → Σ0π0 cross section

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[15] W. E. Humphrey and R. R. Ross, Phys. Rev. 127 (1962) 1305 [16] J. K. Kim, Columbia University Report No. NEVIS-149 (1966) [12] Y. Ikeda, T. Hyodo, W. Weise, Nucl. Phys. A 881 (2012) 98

P r e l i m i n a r y P r e l i m i n a r y

← MISSING

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In K--nuclei optical potential a K- multi-nucleon absorption term is necessary to fit the kaonic atoms data: VK-(ρ) = VK-

(1)(ρ) + VK- (2)(ρ)

[E. Friedman, A. Gal, Nucl. Phys. A 959, 66 (2017)]

[Hrtánková, J. & Mareš, J. Phys. Rev. C96, 015205 (2017)]

single nucleon term from chiral models

Kaon Meeting - 12 February 2018 Raffaele Del Grande

K- multi-nucleon absorptions

Kaon Meeting - 18 June 2018 Raffaele Del Grande 21

multi-nucleon term

Raffaele Del Grande

  • Single nucleon absorption (1NA):

K- “N” → Y π pionic processes

  • Two nucleon absorption (2NA):

K- “NN” → Y N

  • Three nucleon absorption (3NA):

K- “NNN” → Y (NN) non-pionic processes

  • Four nucleon absorption (4NA):

K- “NNNN” → Y (NNN)

bound nucleons = “N”, “NN”, “NNN”, “NNNN” bound or unbound nucleons = (NN), (NNN) Y = Λ, Σ 21

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Kaon Meeting - 12 February 2018 Raffaele Del Grande

Experimental search in K- induced reactions

FINUDA at DAΦNE: K-

stop + X → Λ + p + X’

detected particles

extracted parameters: BE = (115+6

  • 5 (stat.)+3
  • 4 (syst.)) MeV

Γ = (67 +14

  • 11(stat.)+2
  • 3(syst.)) MeV/c2
  • nly back-to-back Λp pairs (cosθΛp < -0.8)

[M. Agnello et al., Phys. Rev. Lett. 94, 212303 (2005)]

Interpreted as the signal of: K-pp → Λ + p

E549 at KEK: K-

stop + 4He → Λ + p + X’

detected particles

Using the missing mass information, three components to the invariant mass spectrum are found:

  • 1NA: K- single nucleon absorption
  • 2NA: K- two nucleon absorption
  • 2NA + conversion, multi-nucleon, or Bound State?

acceptance

[T. Suzuki et al., Mod. Phys. Lett. A23 (2008) 2520-2523.]

Kaon Meeting - 18 June 2018 Raffaele Del Grande 22 Raffaele Del Grande

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Simultaneous fit of:

  • Λp invariant mass;
  • angular correlation;
  • proton momentum;
  • Λ momentum.

Total reduced χ2 : χ2/dof = 0.94

Kaon Meeting - 12 February 2018 Raffaele Del Grande

Λp analysis: K- + 12C → Λ + p + R

Raffaele Del Grande

[R. Del Grande, K. Piscicchia, O. Vazquez Doce et al., Eur.Phys.J. C79 (2019) no.3, 190] [R. Del Grande, K. Piscicchia, S. Wycech, Acta Phys. Pol. B 48 (2017) 1881] 23

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Kaon Meeting - 12 February 2018 Raffaele Del Grande

Λp analysis: K- multi-nucleon absorption BRs and σ

Raffaele Del Grande

The ratio between the branching ratios of the 2NA-QF in the Λp channel and in the Σ0p is measured to be: and the ratio between the corresponding phase spaces is .

[R. Del Grande, K. Piscicchia, O. Vazquez Doce et al., Eur.Phys.J. C79 (2019) no.3, 190 ]

24 Information on the in-medium dynamics

[J. Hrtánková, A. Ramos, arXiv:1910.01336, submitted to Phys. Rev. C]

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Kaon Meeting - 12 February 2018 Raffaele Del Grande

Λp analysis: K- pp bound state

Raffaele Del Grande

K-pp bound state contribution completely overlaps with the K-2NA

25 [R. Del Grande, K. Piscicchia, O. Vazquez Doce et al., Eur.Phys.J. C79 (2019) no.3, 190] [R. Del Grande, K. Piscicchia, S. Wycech, Acta Phys. Pol. B 48 (2017) 1881]

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Kaon Meeting - 12 February 2018 Raffaele Del Grande

Λp analysis: K- pp bound state

Raffaele Del Grande

K-pp bound state contribution completely overlaps with the K-2NA

26 [R. Del Grande, K. Piscicchia, O. Vazquez Doce et al., Eur.Phys.J. C79 (2019) no.3, 190] [R. Del Grande, K. Piscicchia, S. Wycech, Acta Phys. Pol. B 48 (2017) 1881]

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Kaon Meeting - 12 February 2018 Raffaele Del Grande fit with

all Λp events fit with back-to-back Λp events [M. Agnello et al., Phys. Rev. Lett. 94, 212303 (2005)]

COMPATIBLE!!!

Raffaele Del Grande

Λp analysis: K- pp bound state search

FINUDA at DAΦNE AMADEUS at DAΦNE BRs evaluation

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  • nly back-to-back Λp

pairs (cosθΛp < -0.8)

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Kaon Meeting - 12 February 2018 Raffaele Del Grande Raffaele Del Grande

Λt analysis: Cross section and BR for 4NA

AMADEUS analysis

PRELIMINARY

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Previous data:

  • in 4He: bubble chamber experiment

/M. Roosen, J. H. Wickens, II Nuovo Cimento 66, 101 (1981)/

  • nly 3 events compatibile with Λt kinematics found

→ global, no 4NA

  • in solid targets: 6,7Li, 9Be (FINUDA)

/Phys. Lett. B, 229 (2008)/ 40 events, only back-to-back data → global, no 4NA

GOLDEN CHANNEL to extrapolate the K- 4NA K- + “ppnn” → Λ + t

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Kaon Meeting - 12 February 2018 Raffaele Del Grande Raffaele Del Grande

Λt analysis: Cross section and BR for 4NA in K- 4He→Λt process

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BR(K-4He(4NA) → Λt) < 2.0 × 10-4 /Kstop (95% c. l.) σ(100 ± 19 MeV/c) (K-4He(4NA) →Λt) = = (0.81 ± 0.21 (stat) +0.03

  • 0.04 (syst)) mb

preliminary

BR(K-12C(4NA) → Λt 8Be) = 1.5 ± 0.5 × 10-4 (stat) /Kstop σ( K-12C (4NA) →Λt 8Be) = 0.58 ± 0.11 (stat) mb σ( K-12C (4NA) →Σ0t 8Be) = 1.88 ± 0.35 (stat) mb

preliminary

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Summary

Raffaele Del Grande 30 BR(K-4He(4NA) → Λt) < 2.0 × 10-4 /Kstop (95% c. l.) σ(100 ± 19 MeV/c) (K-4He(4NA) →Λt) = = (0.81 ± 0.21 (stat) +0.03

  • 0.04 (syst)) mb

BR(K-12C(4NA) → Λt 8Be) = 1.5 ± 0.5 × 10-4 (stat) /Kstop σ( K-12C (4NA) →Λt 8Be) = 0.58 ± 0.11 (stat) mb σ( K-12C (4NA) →Σ0t 8Be) = 1.88 ± 0.35 (stat) mb

K-p → Σ0π0 cross section K-n amplitude below threshold Λ t channel: 4NA BRs and σ Λ p channel: 2NA, 3NA and 4NA BRs and σ

Preliminary

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Kaon Meeting - 12 February 2018 Raffaele Del Grande

Thank You

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