Spin-orbit interaction of lambda particles in nuclei

Brückner, W.; Faessler, M.; Ketel, T.; Kilian, K.; Niewisch, J.; Pietrzyk, B.; Povh, Bogdan; Ritter, H.G.; Uhrmacher, M.; Birien, P.; Catz, H.; Chaumeaux, A.; Durand, J.M.; Mayer, B.; Thirion, J.; Bertini, R.; Bing, O.

doi:10.1016/0370-2693(78)90458-6

Cited by 200 publications

(24 citation statements)

References 6 publications

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“…The first two peaks correspond to 1 − states and the B Λ value for the lowest 1 − state is not particularly well determined. In the CERN (K − , π − ) experiment [8], the third and fourth peaks correspond to substitutional 0 + states. At the larger momentum transfer of the stopped K − work at KEK [9], the same peaks contain contributions from both 0 + and 2 + hypernuclear states.…”

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confidence: 99%

“…It remains to be seen whether a full 1hω calculation, which incudes s Λ states coupled to positive-parity 1p2h states of the 15 N core, leads to significant energy shifts and some fractionation of the p −1 N p Λ strength. Historically, the first clear indication that the spinorbit splitting of the p Λ orbits is very small came from the observation that the separation between the 0 + states is very close to the underlying core-state separation [8]. Table I shows that the predicted major contributors to the third and fourth peaks involve both the p 1/2Λ and p 3/2Λ orbits and are indeed closely spaced for a Λ-spinorbit strength corresponding to the very small value of S Λ in Eq.…”

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confidence: 99%

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High-Resolution Spectroscopy ofNΛ16by Electroproduction

Cusanno¹,

Urciuoli²,

Acha³

et al. 2009

Phys. Rev. Lett.

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An experimental study of the 16 O(e, e ′ K + ) 16 Λ N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e, e ′ K + )Λ,Σ 0 exclusive reactions and a precise calibration of the energy scale. A groundstate binding energy of 13.76 ± 0.16 MeV was obtained for 16 Λ N with better precision than previous measurements on the mirror hypernucleus 16 Λ O. Precise energies have been determined for peaks arising from a Λ in s and p orbits coupled to the p 1/2 and p 3/2 hole states of the 15 N core nucleus.

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confidence: 99%

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confidence: 99%

High-Resolution Spectroscopy ofNΛ16by Electroproduction

Cusanno¹,

Urciuoli²,

Acha³

et al. 2009

Phys. Rev. Lett.

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“…Moreover, a very little know about the spindependent interaction such as spin-orbit force and hence the spin-orbit splitting in ΛN interaction has become a subject of study in strangeness physics. Lambda spin-orbit coupling has been found to be smaller than that of nucleons and no definite value is produced by the experiment [72,73,74,75]. The smallness of Λ spin-orbit splitting in ΛN interaction was first suggested in the (K − , π − ) reaction on 16 O [72].…”

Section: Lambda and Nucleon Spin-orbit Interaction Potentialsmentioning

confidence: 99%

“…Lambda spin-orbit coupling has been found to be smaller than that of nucleons and no definite value is produced by the experiment [72,73,74,75]. The smallness of Λ spin-orbit splitting in ΛN interaction was first suggested in the (K − , π − ) reaction on 16 O [72]. The smaller magnitude of Λ spin-orbit potential is encountered due to the presence of antisymmetric part of spin-orbit force in ΛN interaction and also by the energy difference of single-particle states of j = l -1/2 and j = l + 1/2.…”

Section: Lambda and Nucleon Spin-orbit Interaction Potentialsmentioning

confidence: 99%

A Study of Multi-Λ Hypernuclei Within Spherical Relativistic Mean-Field Approach

et al. 2017

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Abstract. This research article is a follow up of earlier work by M. Ikram et al., reported in International Journal of Modern Physics E 25, 1650103 (2016) wherein we searched for Λ magic numbers in experimentally confirmed doubly magic nucleonic cores in light to heavy mass region (ie.16 O − 208 P b) by injecting Λ's into them. In present manuscript, working within the state-of-art relativistic mean field theory with inclusion of ΛN and ΛΛ interaction in addition to nucleon-meson NL3* effective force, we extend the search of lambda magic numbers in multi-Λ hypernuclei using the predicted doubly magic nucleonic cores 292 120, 304 120, 360 132, 370 132, 336 138, 396 138 of elusive superheavy mass regime. In analogy to well established signatures of magicity in conventional nuclear theory, the prediction of hypernuclear magicity are made on the basis of one-, two-Λ separation energy (SΛ, S2Λ) and two lambda shell gaps (δ2Λ) in multi-Λ hypernuclei. The calculations suggest that the Λ numbers 92, 106, 126, 138, 184, 198, 240, and 258 might be the Λ shell closures after introducing the Λ's in elusive superheavy nucleonic cores. The appearance of new lambda shell closures other than the nucleonic ones predicted by various relativistic and non-relativistic theoretical investigations can be attributed to the relatively weak strength of spin-orbit coupling in hypernuclei compared to normal nuclei. Further, the predictions made in multi-Λ hypernuclei under study resembles quite closely with the magic numbers in conventional nuclear theory suggested by various relativistic and non-relativistic theoretical models. Moreover, in support of Λ shell closure the investigation of Λ pairing energy and effective Λ pairing gap has been made. We noticed a very close agreement of the predicted Λ shell closures with the survey made on the pretext of SΛ, S2Λ and δ2Λ except for the appearance of magic numbers corresponding to Λ = 156 which manifest in Λ effective pairing gap and pairing energy. Also, lambda single-particle spectrum is analyzed to mark the energy shell gap for further strengthening the predictions made on the basis of separation energies and shell gaps. Lambda and nucleon spin-orbit interactions are analyzed to confirm the reduction in magnitude of Λ spin-orbit interaction compared to the nucleonic case, however interaction profile is similar in both the cases. Lambda and nucleon density distributions have been investigated to reveal the impurity effect of Λ hyperons which make the depression of central density of the core of superheavy doubly magic nuclei. Lambda skin structure is also seen.

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“…In particular, p-shell hypernuclei were studied well and it was found that the spin-orbit splitting of Λ orbits are quite small [15].…”

Section: Counter Experiments Via the (Kmentioning

confidence: 99%

Investigation of high-precision Λ hypernuclear spectroscopy via the (e,e'K<sup>+</sup>) reaction

Kawama

2011

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The study of Λ hypernuclear structure is very interesting in point of the understanding of the interaction between Λ and nucleon (ΛN interaction) and its "strange" structure itself due to the containment of a Λ hyperon which has a strangeness as a new degree of freedom. In the several way to study the Λ hypernuclei, the (e� e � K + ) reaction spectroscopy is a powerful tool for the precise investigation of Λ hypernuclear structure.The purpose of the preset thesis is the establishment of the experimental design with the efficient data analysis method for the (e� e � K + ) hypernuclear spectroscopic experiment in the wide mass region (from A=7 to A=52). It is very challenging to perform the (e� e � K + ) spectroscopic experiment with such a heavy target, because of the huge electron background due to the bremsstrahlung process. In the experiment, it is required to obtain the necessary hypernuclear yield, suppressing the background event ratio. We achieved these requirements by newly constructing the high resolution electron spectrometer (HES) and splitter magnet (SPL) dedicated to the (e� e � K + ) spectroscopic experiment. The HES consists of two quadrupole magnets and a dipole magnets (Q-Q-D) with a momentum resolution of dp/p = 3 × 10 �4 at p = 0.84 GeV/c. It was used being vertically tilted by 6.5 degree so as to optimize signal to noise ratio and hypernuclear yield.The SPL is a dipole magnet. The experimental target was placed at the entrance of this magnet. The role of the SPL is to separate four kind of particles; scattered kaons, photons created by the bremsstrahlung, the post beam and scattered electrons. In addition, since the SPL is a part of the kaon and electron spectrometers. We designed the magnet shape carefully considering these points.The experiment was performed with 2.344 GeV/c electron beam from CEBAF at Jefferson Lab. The experimental setup consists of the HES, SPL and HKS (high momentum resolution kaon spectrometer). The HKS is also a Q-Q-D type spectrometer with the momentum resolution of dp/p = 2 × 10 �4 at p = 1.2 GeV/c. In the data analysis, the particle momentum calibration was the most important procedure. At the initial point, the particle momentum was obtained from the calculated magnetic field map of the spectrometer whose accuracy is an order of 10 �2 . The initial momentum was calibrated by two step, the the magnetic field map improvement and the calibration with known masses of Λ/Σ 0 which were observed by the CH 2 target data. As a result of the calibration, the momentum resolutions of HKS and HES were estimated as 4 × 10 �4 and 6 × 10 �4 , respectively. Though these values are the double of the designed value, it was achieved to obtain the Λ/Σ 0 peaks with the same order of the designed energy from the original calculated magnetic field.The cross section was calculated with the several estimated factors. The averaged p(γ * � K + )Λ cross section in the HKS acceptance, (0.90 < cos(θ CM K � ) < 1.0) was calculated as 227±12±26 [nb/sr], which is consistent within the error...

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Spin-orbit interaction of lambda particles in nuclei

Cited by 200 publications

References 6 publications

High-Resolution Spectroscopy ofNΛ16by Electroproduction

High-Resolution Spectroscopy ofNΛ16by Electroproduction

A Study of Multi-Λ Hypernuclei Within Spherical Relativistic Mean-Field Approach

Investigation of high-precision Λ hypernuclear spectroscopy via the (e,e'K<sup>+</sup>) reaction

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