Search for double-Λ hypernuclei and the H-dibaryon in the (K−,K+) reaction on 12C

Yamamoto, K.; Alburger, D.E.; Barnes, P. D.; Bassalleck, B.; Berdoz, A.; Biglan, A.; Burger, Tobias; Carman, D. S.; Chrien, R. E.; Davis, C. A.; Fischer, H.; Franklin, G.; Franz, J.; Gan, L.; Ichikawa, A. K.; Iijima, T.; Khaustov, P.; Kondō, Y.; Koran, P.; Landry, M.; Lee, L.; Lowe, J.; Magahiz, R.; May, M.; McCrady, R.; Merrill, F. E.; Meyer, C. A.; Page, S. A.; Paschke, K.; Pile, P.; Quinn, B.; Ramsay, W. D.; Rusek, A.; Sawafta, R.; Schmitt, H.; Schumacher, R. A.; Stotzer, R.; Sutter, Reto; Takéutchi, F.; Oers, W. T. H. van; Yosoi, M.; Zeps, V.

doi:10.1016/s0370-2693(00)00299-9

Cited by 30 publications

(18 citation statements)

References 24 publications

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“…[8] as a deeply bound state below the ΛΛ threshold. Despite extensive searches such as in the BNL-E885 experiments [98], deeply bound H dibaryons have not been observed. The discovery of the double-Λ hypernucleus ( 6 ΛΛ He) in the Nagara event [99] finally excluded the possibility of deeply bound H dibaryon, as the two Λ particles can decay strongly into the core nucleus and the H dibaryon if the H mass is below the ΛΛ threshold by more than the ΛΛ separation energy (B ΛΛ = 7.25 ± 0.19…”

Section: Exotic Dibaryonsmentioning

confidence: 99%

Exotic hadrons in heavy ion collisions

et al. 2011

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We investigate the possibilities of using measurements in present and future experiments on heavy ion collisions to answer some longstanding problems in hadronic physics, namely identifying hadronic molecular states and exotic hadrons with multiquark components. The yields of a selected set of exotic hadron candidates in relativistic heavy ion collisions are discussed in the coalescence model in comparison with the statistical model. We find that the yield of a hadron is typically an order of magnitude smaller when it is a compact multiquark state, compared to that of an excited hadronic state with normal quark numbers. We also find that some loosely bound hadronic molecules are formed more abundantly than the statistical model prediction by a factor of two or more. Moreover, due to the significant numbers of charm and bottom quarks produced at RHIC and even larger numbers expected at LHC, some of the proposed heavy exotic hadrons could be produced with sufficient abundance for detection, making it possible to study these new exotic hadrons in heavy ion collisions.

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Section: Exotic Dibaryonsmentioning

confidence: 99%

Exotic hadrons in heavy ion collisions

et al. 2011

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“…Experimental constraints on, and phenomenological models of, the H-dibaryon can be found in Refs. [2,3,4]. While experimental studies of doublystrange hypernuclei restrict the H-dibaryon to be unbound or to have a small binding energy, the most recent constraints on the existence of the H-dibaryon come from heavy-ion collisions at RHIC, from which it is concluded that the H-dibaryon does not exist in the mass region 2.136 < M H < 2.231 GeV [5], effectively eliminating the possibility of a loosely-bound H-dibaryon at the physical light-quark masses.…”

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confidence: 99%

Evidence for a BoundHDibaryon from Lattice QCD

et al. 2011

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We present evidence for the existence of a bound H-dibaryon, an I = 0, J = 0, s = −2 state with valence quark structure uuddss, at a pion mass of mπ ∼ 389 MeV. Using the results of Lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of L ∼ 2.0, 2.5, 3.0 and 3.9 fm at a spatial lattice spacing of bs ∼ 0.123 fm, we find an H-dibaryon bound by B H ∞ = 16.6 ± 2.1 ± 4.6 MeV at a pion mass of mπ ∼ 389 MeV.It is now well established that quantum chromodynamics (QCD), the theory describing the dynamics of quarks and gluons, and the electroweak interactions, underlie all of nuclear physics, from the hadronic mass spectrum to the synthesis of heavy elements in stars. To date, there have been few quantitative connections between nuclear physics and QCD, but fortunately, Lattice QCD is entering an era in which precise predictions for hadronic quantities with quantifiable errors are being made. This development is particularly important for processes which are difficult to explore in the laboratory, such as hyperon-hyperon and hyperon-nucleon interactions for which knowledge is scarce, primarily due to the short lifetimes of the hyperons, but which may impact the late-stages of supernovae evolution. In this letter we report strong evidence for a bound H-dibaryon, a six-quark hadron with valence structure uuddss, from n f = 2 + 1 Lattice QCD calculations at light-quark masses that give the pion a mass of m π ∼ 389 MeV.The prediction of a relatively deeply bound system with the quantum numbers of ΛΛ (called the H-dibaryon) by Jaffe [1] in the late 1970s, based upon a bag-model calculation, started a vigorous search for such a system, both experimentally and also with alternate theoretical tools. Experimental constraints on, and phenomenological models of, the H-dibaryon can be found in Refs. [2,3,4]. While experimental studies of doublystrange hypernuclei restrict the H-dibaryon to be unbound or to have a small binding energy, the most recent constraints on the existence of the H-dibaryon come from heavy-ion collisions at RHIC, from which it is concluded that the H-dibaryon does not exist in the mass region 2.136 < M H < 2.231 GeV [5], effectively eliminating the possibility of a loosely-bound H-dibaryon at the physical light-quark masses. Recent experiments at KEK suggest there is a resonance near threshold in the H-dibaryon channel [6].The first study of baryon-baryon interactions with Lattice QCD was performed more than a decade ago [7,8]. This calculation was quenched and with m π > ∼ 550 MeV. The NPLQCD collaboration performed the first n f = 2+ 1 QCD calculations of baryon-baryon interactions [9,10] at low-energies but at unphysical pion masses. Quenched and dynamical calculations were subsequently performed by the HALQCD collaboration [11,12]. A number of quenched Lattice QCD calculations [13,14,15,16,17,18] have searched for the H-dibaryon, but to date no definitive results have been reported. Earlier work concluded that the H-dibaryon does not exi...

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“…Since then, experiments [3][4][5][6] and other theoretical calculations [7,8], including a few pioneering lattice QCD calculations [9][10][11][12][13][14], have been seeking evidence of its existence. In 1997, Bashinsky and Jaffe [15] reviewed 28 model predictions on the mass of the H-dibaryon, which vary from 1.1 to 2.9 GeV.…”

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confidence: 99%

Present Constraints on the H-Dibaryon at the Physical Point From Lattice QCD

et al. 2011

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The current constraints from lattice QCD on the existence of the H-dibaryon are discussed. With only two significant lattice QCD calculations of the H-dibaryon binding energy at approximately the same lattice spacing, the forms of the chiral and continuum extrapolations to the physical point are not determined. In this brief report, we consider the constraints on the H-dibaryon imposed by two simple chiral extrapolations. In both instances, the extrapolation to the physical pion mass allows for a bound H-dibaryon or a near-threshold scattering state. Further lattice QCD calculations are required to clarify this situation.

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Search for double-Λ hypernuclei and the H-dibaryon in the (K−,K+) reaction on 12C

Cited by 30 publications

References 24 publications

Exotic hadrons in heavy ion collisions

Exotic hadrons in heavy ion collisions

Evidence for a BoundHDibaryon from Lattice QCD

Present Constraints on the H-Dibaryon at the Physical Point From Lattice QCD

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