<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">Σ</mml:mi></mml:math>Hyperons in the Nucleus

Bart, S.; Chrien, R. E.; Franklin, Wilbur A.; Fukuda, T.; Hayano, R. S.; Hicks, K.; Hungerford, E. V.; Michael, R.; Miyachi, T.; Nagae, T.

doi:10.1103/physrevlett.83.5238

Cited by 117 publications

(113 citation statements)

References 16 publications

(7 reference statements)

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“…Namely, the binding energies of Λ can be well-Σ-nucleus potential (Lane term) [12]. The existence of the Lane term was also suggested in light nuclear systems from the systematic difference between the inclusive (K − ,π ± ) spectra [10]. All of the other experiments could not find any bound Σ-hypernuclear state, and failed to give any significant constraint on the Σ-nucleus potential.…”

Section: Introductionmentioning

confidence: 99%

Σ-nucleus potential studied with the(π−,K+)reaction on medium-to-heavy nuclear targets

Saha¹,

Noumi²,

Abe³

et al. 2004

Phys. Rev. C

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109

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In order to study the Σ-nucleus optical potential, we measured inclusive (π − , K + ) spectra on medium-to-heavy nuclear targets: CH2, Si, Ni, In and Bi. The CH2 target was used to calibrate the excitation energy scale by using the elementary process p + π − → K + + Σ − , where the C spectrum was also extracted. The calibration was done with ±0.1 MeV precision. The angular distribution of the elementary cross section was measured, and agreed well with the previous bubble chamber data, but with better statistics, and the magnitudes of the cross sections of the measured inclusive (π − , K + ) spectra were also well calibrated. All of the inclusive spectra were found to be similar in shape at a region near to the Σ − binding energy threshold, showing a weak mass-number dependence on the magnitude of the cross section. The measured spectra were compared with a theoretical calculation performed within the framework of the Distorted Wave Impulse Approximation (DWIA). It has been demonstrated that a strongly repulsive Σ-nucleus potential with a non-zero size of the imaginary part is required to reproduce the shape of the measured spectra.

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Section: Introductionmentioning

confidence: 99%

Σ-nucleus potential studied with the(π−,K+)reaction on medium-to-heavy nuclear targets

Saha¹,

Noumi²,

Abe³

et al. 2004

Phys. Rev. C

Self Cite

109

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“…1 H) as 1.6M eV respectively. Search for heavier Σ hypernuclei has been carried out by several authors [6], [8], [9], [10], [11], [36] without success. P. K. Saha et al studied inclusive (π − , K + ) spectra on C, Si, Ni, In and Bi targets and concluded that a Σ-nucleus potential is strongly repulsive in such relatively heavy nuclei [6].…”

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confidence: 99%

Generalized mass formula for non-strange and hypernuclei withSU(6) symmetry breaking

Samanta

Chowdhury

Basu

2006

J. Phys. G: Nucl. Part. Phys.

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A simultaneous description of non-strange nuclei and hypernuclei is provided by a single mass formula inspired by the spin-flavour SU(6) symmetry breaking. This formula is used to estimate the hyperon binding energies of Lambda, double Lambda, Sigma, Cascade and Theta hypernuclei. The results are found to be in good agreement with the available experimental data on 'bound' nuclei and relativistic as well as quark mean field calculations. This mass formula is useful to estimate binding energies over a wide range of masses including the light mass nuclei. It is not applicable for repulsive potential.Keywords : Hypernuclei, Hyperon binding energy, Exotic nuclei, Mass formula, Separation Energy. PACS numbers: 21.80.+a, 21.10.Dr, 32.10.Bi, 12.90.+b The hypernuclear physics is of great importance in many branches of physics. Of particular interest is the understanding of strange particles in baryonic matter, since many questions in heavy-ion physics, particle physics and astrophysics are related to the effect of strangeness (S) in nuclear matter. Moreover, the contribution of the hyperons strongly influences the mass of neutron stars as well. In the past decade considerable amount of spectroscopic informations were accumulated experimentally on the Λ 0 (S=-1)hypernuclei. The Λ separation energies were determined for the ground states of about 40 Λ hypernuclei including several double-Λ hypernuclei [1], [2]. Doubly strange hypernuclei also arise in a form of Ξ − (S=-2) hypernuclei and were studied both theoretically In this scenario, an exotic hyperon Θ + (S=+1, mass ∼1530 MeV, width <15 MeV ) with exotic pentaquark structure was predicted in 1997 [12]. Announcement of its discovery at Spring-8, Japan [13] sparked an avalanche of activities in the field of hyperons and hypernuclei [14]. Now a question has arisen whether the Θ + hyperon really exists [15] and if so, whether it will be bound in a nucleus [16], [17]. Calculations in a relativistic mean-field formalism (RMF) suggest that as there is an attractive Θ + -nucleus interaction, the Θ + particle can be bound in nuclei and, the Θ + hypernuclei would be bound more strongly than Λ hypernuclei [18]. Recent calculations in quark mean-field (QMF) model also support existence of bound Θ + hypernuclei and predict that in comparison to Λ hypernuclei more bound states are there in Θ + hypernuclei [19]. While a search for bound Theta hypernuclei is on, for a large number of hypernuclei, including double Lambdas, Cascade and Sigmas, more experimental data are needed. One also needs to have an apriori estimation of their possible binding energies in a wide mass range for planning of the experiment and to locate the peaks in the experimental missing mass spectra.Although the Λ, Σ, Ξ and Θ hyperons are all baryons, no single mass formula exists which can predict the binding energies of all of them on the same footing as the non-strange nuclei. In this work we present a generalized mass formula for both the strange and non-strange nuclei which does not disregard the normal nu...

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“…Further, the crossover density ρ co , where V Ξ − (ρ B = ρ co )=0, is taken to be equal to that for the Λ [52]. As for the V Σ − , recent (K − , π ± ) experiment at BNL [79] suggests a strong isospin dependence in the Σ-nucleus potential. It has been shown that the experimental data is compatible with the analysis by the Nijmegen model F for the baryon-baryon interaction, which gives a repulsive isoscalar part and a large positive isospin dependent term (Lane potential) for the Σ-nucleus potential [78].…”

Section: Potential Contributionmentioning

confidence: 99%

Kaonic modes in hyperonic matter and p-wave kaon condensation

Muto

2002

Nuclear Physics A

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Kaon excitations (kaonic modes) are investigated in hyperonic matter, where hyperons (Λ, Σ − , Ξ − ) are mixed in the ground state of neutron-star matter. P -wave kaon-baryon interactions as well as the s-wave interactions are taken into account within chiral effective Lagrangian, and the nonrelativistic effective baryon-baryon interactions are incorporated. When the hyperon Λ is more abundant than the proton at high baryon density, a proton-particle-Λ-hole mode, which has the K + quantum number, appears in addition to other particle-hole modes with the K − quantum number. It is shown that the system becomes unstable with respect to a spontaneous creation of a pair of the particle-hole modes with K + and K − quantum numbers, stemming from the p-wave kaon-baryon interaction. The onset density of this p-wave kaon condensation may be lower than that of the s-wave K − condensation.

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ΣHyperons in the Nucleus

Cited by 117 publications

References 16 publications

Σ-nucleus potential studied with the(π−,K+)reaction on medium-to-heavy nuclear targets

Σ-nucleus potential studied with the(π−,K+)reaction on medium-to-heavy nuclear targets

Generalized mass formula for non-strange and hypernuclei withSU(6) symmetry breaking

Kaonic modes in hyperonic matter and p-wave kaon condensation

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