Supernarrow dibarions L.V. Fil’kov P.N. Lebedev Physical Institute , Moscow EMIN - 2018
Supernarrow six-quark states nucleon (dibaryon) D N N G~ 10 100 MeV 6-quark states, decay of which into two nucleons is forbidden by the Pauli exclusion principle. M < 2mN + mp D → g + NN * Wide dibaryons : G~ 10 100 MeV Narrow dibaryons : G~ 1 10 MeV * Supernarrow dibaryons : G<< 1 keV G eV (-1)T+S P = +1
A formation of quark stars. The experimental discovery of SNDs would have important consequences for particle and nuclear physics and astrophysics. 1. A construction of an adequate QCD model. 2. Astrophysics: an evolution of compact stars. 3. Quark-gluon plasma: specific signals of a production of QGP with a big baryon density. 4. Nuclear physics: a formation of SND-nuclei; a region stability of neutron-rich nuclei. A formation of quark stars.
1. P.J.G. Mulders et al. (1980) MIT bag model: D(T=0; JP = 0─, 1─, 2─; M=2110 MeV), M > 2mN + mp D p NN D(1; 1─; M=2200 MeV) 2. L.V. Fil’kov (1986) M< 2mN + mπ D N N 3. V.B. Kopeliovich (1993) Chiral soliton model: D(T=1; JP = 1+; M ≃1940 MeV), D(0; 2+; M ≃1990 MeV) 4. T. Krupnovniskas et al. (2001) Canonically quantized biskyrmion model: M < 2mN + mp one dibaryon with J=T=0, two dibaryons with J=T=1 5. L.V. Fil’kov (2003) Mass formula for SND: T=1, J=1± M=1904 (J=1-), 1925 (1+), 1944 (1-), 1965 (1+), 1985 (1-), 2005 (1+)
D(T=1, JP =1 ±), l≈ 10-2 g N D 31S0 ωm=(M2-4m2)/2M N
Θ12=θn1- θn2
p + d p + X ∙ D → gNN q12 a few degrees L.V. Fil’kov, V.L. Kashevarov, E.S. Konobeevski et al., Phys.Rev. C61, 044004 (20000); Eur.Phys.J. A12, 369 (2001) Proton Linear Accelerator of INR (Moscow). TP = 305 MeV 1. D → g NN D → d 2. Correlations p1 + d → p2 + pX1 ∙ D → gNN q12 a few degrees ∙ D → gd sinqd ≤ M pdcms /(md pDls) → a few degrees ∙ D → NN Dqp ≃ 50o p1 p2 N d D Xi X1= N or N
The angular and energy distributions for the nucleon from the decay of the SND with M=1904 MeV
(2000); Eur.Phys.J. A12, 369 (2001); INR (Moscow) p1+d→p2+pX1 L.V. Fil’kov, V.L. Kashevarov, E.S. Konobeevski et al. Phys. Rev. C61, 044004 (2000); Eur.Phys.J. A12, 369 (2001); INR (Moscow) MpX1: 1904±2, 1926±2, 1942±2 SD: 6.0 7.0 6.3 G < 5 MeV (experimental resolutions) if X1 = n → MX1 = mn if X1 = g + n → MX1 mn Simulation of mass MX1 spectra gave: MX1 = 965, 987, 1003 MeV Experiment: MX1= 966±2, 986±2, 1003±2 X1= g + n
pp → p p+ X B. Tatischeff et al. (SPES3 (Saturn)) 2002 MX=1004, 1044, 1094 MeV SD≥ 10 MX≈966, 986 MeV from a small number of data
pp d1 pp M=1956 ± 2stat ± 6syst MeV A.S. Khrykin et al. Phys. Rev. C 64, 034002 (2001) Tp= 216 MeV, E 10 MeV, q = 900 M=1956 ± 2stat ± 6syst MeV Uppsala pp-bramsstralung data (H. Calen, et al., Phys. Lett. B427, 248 (1998)): upper limit 10 nb.
Research Center for Nuclear Physics (Japan) p1 d p2 pX p1 d p2 dX1 Research Center for Nuclear Physics (Japan) H. Kuboki et al. Phys. Rev. C 74, 025203 (2006) 1. No resonance structure in the missing mass spectra of pX and dX1 was observed. 2. No resonance structure in missing mass spectra of X was observed. It is at variance with the results of the work of B. Tatischeff et al. (Phys. Rev. Lett. 79, 601 (1997)) However, these states were observed in this work with a sufficiently high accuracy, which leads to doubt about correctness of results obtained at RCNP.
d0 + pn MAMI (Preliminary) V. Kashevarov, 8th Crystal Ball@MAMI Collaboration Meeting, Glasgo, March 27-29, 2006 MM(,0) – md (MeV) Red lines are SND peak positions from INR experiment
s = 25 – 14 nb Eg= 210 – 340 MeV Pg = 99% A. Cichocki, PhD (2003) LEGS B. Norum et al. (2018) Eg= 210 – 340 MeV Pg = 99% s = 25 – 14 nb
Mass Formulae for SND
N* (p1+k)2≈(p2+k)2=(M(N*))2 The decay of SND at θ12≤ 5o can lead to the formation of resonance-like states N*. The experimental observation of N* is an additional confirmation of the existence of SND.
Conclusion A series of experiments on the search for SNDs indicates the possibility of their existence. Negative results obtained in RCNP are at variance both with the observation of SNDs in INR and with the result of Tatischeff et al. (SPS3) on search for exotic baryons. However, the latter have been observed with a sufficiently high accuracy, which leads to doubt about correctness of the RCNP result. The sum rules for the masses of SND have been constructed. The values of the masses of SNDs obtained by means of the sum rules agree very well with the experimental data. The decay of SND at small θ12 leads to the formation of resonance-like states N*. The predicted values of the masses of N* are in good agreement with experimental data. The experimental observation of N* is an additional confirmation of the SND existence.