Observation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow><mml:mi mathvariant="normal">Λ</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>Hyperhydrogen by Decay-Pion Spectroscopy in Electron Scattering

Esser, A.; Nagao, Shijo; Schulz, Florian; Achenbach, P.; Gayoso, C. Ayerbe; Böhm, R.; Borodina, O.; Bosnar, D.; Bozkurt, V.; Debenjak, L.; Distler, M. O.; Friščić, I.; Fujii, Y.; Gogami, T.; Hashimoto, Osamu; Hirose, Satoshi; Kanda, H.; Kaneta, M.; Kim, E.; Kohl, Y.; Kusaka, J.; Margaryan, A.; Merkel, H.; Mihovilovič, M.; Müller, U.; Nakamura, S. N.; Pochodzalla, J.; Rappold, C.; Reinhold, J.; Saito, Takehiko; Lorente, A. Sánchez; Majos, S. Sánchez; Schlimme, B. S.; Schoth, M.; Sfienti, C.; Širca, S.; Tang, L.; Thiel, M.; Tsukada, K.; Weber, A.; Yoshida, K.

doi:10.1103/physrevlett.114.232501

Cited by 100 publications

(59 citation statements)

References 28 publications

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“…A new measurement of the hypertriton bound state has been presented which points to a noticeably larger binding energy [73]. Measurements of 4 Λ H and 4 Λ He with improved accuracy in order to determine the amount of charge-symmetry breaking more precisely have been performed [63,71] or are on the way [94]. There are also attempts to shed more light on the elementary Y N interaction directly via studies of the Λp correlation function measured in heavy-ion collisions or high-energy pp collisions [95][96][97].…”

Section: Discussionmentioning

confidence: 99%

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Hyperon–nucleon interaction within chiral effective field theory revisited

2020

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The ΛN and ΣN interactions are considered at next-to-leading order in SU(3) chiral effective field theory. Different options for the low-energy constants that determine the strength of the contact interactions are explored. Two variants are analysed in detail which yield equivalent results for ΛN and ΣN scattering observables but differ in the strength of the ΛN → ΣN transition potential. The influence of this difference on predictions for light hypernuclei and on the properties of the Λ and Σ hyperons in nuclear matter is investigated and discussed. The effect of the variation in the potential strength of the ΛN -ΣN coupling (also called Λ − Σ conversion) is found to be moderate for the considered 3 Λ H and 4 Λ He hypernuclei but sizable in case of the matter properties. Further, the size of three-body forces and their relation to different approaches to hypernuclear interactions is discussed.PACS. 12.39.Fe Chiral Lagrangians -13.75.Ev Hyperon-nucleon interactions -21.30.Fe Forces in hadronic systems and effective interactions

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Section: Discussionmentioning

confidence: 99%

“…We refrain from addressing the long-standing and still unsettled issue of the large charge symmetry breaking (CSB) [54,[68][69][70] observed in the binding energies of the 4 Λ He and 4 Λ H systems [63,71] here in detail. Indeed, there is no explicit CSB in the ΛN EFT potentials employed in the present study.…”

Section: Three-and Four-body Systemsmentioning

confidence: 99%

Hyperon–nucleon interaction within chiral effective field theory revisited

2020

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“…For example, binding energies of A = 3 and 4 hypernuclei can be obtained by solving "exact" Faddeev or Yakubovsky equations [1][2][3] based on such Y N interactions. So-called ab initio methods like the no-core shell model allow one to perform rigorous calculations even for hypernuclei beyond the s shell [4][5][6][7][8][9][10] and, so far, studies for hypernuclei up to 13 Λ C have been reported [8].…”

Section: Introductionmentioning

confidence: 99%

“…This concerns also the binding energies of the A = 4 system where new measurements have been performed in an attempt to settle the long-standing issue of the large charge symmetry break-ing (CSB) observed in the binding energies of the 4 Λ He and 4 Λ H hypernuclei [12]. The new measurements, performed for the 4 Λ H (0 + ) state [13,14] and the splitting between the 4 Λ He 0 + and 1 + levels [15] differ noticeably from the earlier values in the literature [16]. Another binding energy that has been challenged lately is that of the hypertriton 3 Λ H. Here the value for the separation energy, accepted as benchmark for decades, is E Λ = 0.13±0.05 MeV [17], while a new measurement by the STAR collaboration suggests a value of 0.41 ± 0.12 MeV [18].…”

Section: Introductionmentioning

confidence: 99%

Implications of an increased Λ-separation energy of the hypertriton

Haidenbauer

Meißner

et al. 2020

Physics Letters B

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Stimulated by recent indications that the binding energy of the hypertriton could be significantly larger than so far assumed, requirements of a more strongly bound 3 Λ H state for the hyperon-nucleon interaction and consequences for the binding energies of A = 4, 5 and 7 hypernuclei are investigated. As basis a Y N potential derived at next-to-leading order in chiral effective field theory is employed, Faddeev and Yakubovsky equations are solved to obtain the corresponding 3-and 4-body binding energies, respectively, and the Jacobi no-core shell model is used for 5 Λ He and 7 Λ Li. It is found that the spin-singlet Λp interaction would have to be much more attractive which can be, however, accommodated within the bounds set by the available Λp scattering data. The binding energies of the 4 Λ He hypernucleus are predicted to be closer to the empirical values than for Y N interactions that produce a more weakly bound 3 Λ H. The quality of the description of the separation energy and excitation spectrum for 7 Λ Li remains essentially unchanged.PACS. 13.75.Ev Hyperon-nucleon interactions -21.80.+a Hypernuclei -21.30.Fe Forces in hadronic systems and effective interactions arXiv:1909.02882v1 [nucl-th]

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“…The source of this inconsistency is attributed to the charge symmetry breaking (CSB) in ΛN interaction. Recent reports on precise measurements for 4 Λ H at MAMI [1] and 4 Λ He at J-PARC [2] support the large CSB effect in the ΛN interaction suggested by old emulsion experiments.…”

Section: Introductionmentioning

confidence: 91%

Study of Λ-n Interaction via FSI in γ+d Reaction

Kaneta¹

2017

Proceedings of the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015)

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In this paper we present our motivation for an experiment to measure the scattering length and the effective range of the Λ-n interaction via γ + d reaction using NKS2 spectrometer at Research Center of Electron Photon Science (ELPH), Tohoku University. The effective range approximation is adopted as an approach to estimate the contribution of the enhancement effect in the spectrometer acceptance. For this purpose, we outline and describe the already completed upgrades and further intended improvement in preparation for the new experiment. KEYWORDS:Baryon-Baryon interaction, strangeness, photo-reaction IntroductionThe NKS2 collaboration has been studying the strangeness photoproduction in γ + d reaction near the threshold at ELPH-TOHOKU. A new future focus now includes investigating the Λn interaction via a K + measurement in γ + d reaction. Most of the past efforts involving the ΛN interaction were made through hypernuclei. Results from these studies have highlighted a discrepancy between experimental data and theoretical calculations for the Λ binding energy of 4 Λ H and 4 Λ He. The source of this inconsistency is attributed to the charge symmetry breaking (CSB) in ΛN interaction. Recent reports on precise measurements for 4 Λ H at MAMI [1] and 4 Λ He at J-PARC [2] support the large CSB effect in the ΛN interaction suggested by old emulsion experiments.One of the keys to understand the ΛN CSB is a comparison of Λp with Λn interaction by direct measurement. Presently there are no reported data sets for Λn scattering primarily due to lack of a neutron target and difficulty in experimental setup. In contrast, there have been reported data for Λp interaction from scattering experiments. Consequently, the S-wave Λn scattering length is still not determined. To obtain information about the Λn interaction, we propose a different kind of experiment from hypernuclear studies, which require not only details on the interaction, but also discussions on nuclear structure. The K + measurement in γ+d reaction should yield important information on inelastic scattering and the low energy region of Λn interaction.Theoretical studies show that the cross section of K + production differs in γ + d from γ + p by the final state interaction (FSI) of Λn. The effect appears in the production threshold region and is roughly 10 times larger in forward and backward region in CM system [3][4][5][6]. NKS2 experimentThe NKS2 spectrometer is located downstream of a real photon beam line in the 2nd experimental hall at ELPH. The photon tagging system is located in a synchrotron ring and provides timing and energy information for the generated photons. The photon beam is produced by bremsstrahlung from electrons scattered by a carbon wire inserted into the path of the orbiting electrons and the recoil electrons are measured by the tagger. energy of orbiting electrons with a maximum electron energy of the stretcher booster ring of 1.2 GeV. More detailed information on the photon tagging system can be found elsewhere [7].The booster ring was re...

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Observation ofHΛ4Hyperhydrogen by Decay-Pion Spectroscopy in Electron Scattering

Cited by 100 publications

References 28 publications

Hyperon–nucleon interaction within chiral effective field theory revisited

Hyperon–nucleon interaction within chiral effective field theory revisited

Implications of an increased Λ-separation energy of the hypertriton

Study of Λ-n Interaction via FSI in γ+d Reaction

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