Mikhail Bashkanov Dibaryons at COSY Wasa-at-COSY

Types of particles/resonances color anticolor white Meson Baryon Mikhail Bashkanov "Dibaryons"2

Possible particles Pentaquark Meson-Baryon molecule Hexaquark Baryon-Baryon molecule Mikhail Bashkanov "Dibaryons"3 Tetraquark Meson-Meson molecule

Deuteron to Deltaron 4 Threshold pn 2.2 MeV deuteron ΔΔ 80 MeV d* I(J p ) = 0(1 + ) I(J p ) = 0(3 + ) u u u d d d u u u d d d

WASA 4  Detector π π p d   n  

6 “d* resonance”  70 MeV Total cross section pn  d  0  0 P. Adlarson et. al Phys. Rev. Lett. 106:242302, 2011  NN*(1440)

7 Angular distribution in the peak J=1 J=3 P. Adlarson et. al Phys. Rev. Lett. 106:242302, 2011

8 The extracted properties of the new particle pn  dibaryon    d     Δ Δ d π π p n I(J p ) = 0(3 + ) Mikhail Bashkanov "Dibaryons"

9 Total cross section pN  d  P. Adlarson et. al Phys. Lett. B721 (2013) 229

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11 From fusion to free case pn  d*    d  Δ Δ d π π p n pn  d*    NN  Δ Δ π π p n N N Fäldt & Wilkin, PLB 701 (2011) 619 Fäldt & Wilkin, PLB 701 (2011) 619 Albaladejo & Oset, Phys.Rev. C88 (2013) Albaladejo & Oset, Phys.Rev. C88 (2013)

12 pn  pn  0  0 d* Conventional process Conventional process +d* d* P. Adlarson et al., Phys.Lett. B743 (2015)

Dibaryon non-fusion decays 13 PLB 743 (2015) 325 d* PRC 88 (2013) HADES arXiv: arXiv:

Dibaryon hadronic decays 14 pn  d*(2380) PRL 112 (2014) PRC 90, (2014) PLB 721 (2013) 229 PRL 106 (2011) PRC 88 (2013) PLB 743 (2015) 325 WASA data d*

15 The decay modes of the dibaryon ChannelPublications d     M. Bashkanov et. al Phys.Rev.Lett. 102 (2009) P. Adlarson et. al Phys. Rev. Lett. 106:242302, 2011 P. Adlarson et. al Phys.Lett. B721 (2013) d     P. Adlarson et. al Phys.Lett. B721 (2013) pp     P. Adlarson et. al Phys. Rev. C 88, np     P. Adlarson et. al Phys.Lett. B743 (2015) 325 npA. Pricking, M. Bashkanov, H. Clement. arXiv: P. Adlarson et al. Phys. Rev. Lett. 112, , (2014) P. Adlarson et al. Phys. Rev. C 90, , (2014) pn e + e - M. Bashkanov, H. Clement, Eur.Phys.J. A50 (2014) He  M. Bashkanov et. al Phys.Lett. B637 (2006) P. Adlarson et. al Phys. Rev. C 91 (2015) 1, He  P. Adlarson et. al Phys.Rev. C86 (2012) activities from other groups Mikhail Bashkanov "Dibaryons" M. Bashkanov, Stanley J. Brodsky, H. Clement Phys.Lett. B727 (2013)

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17 pn  d*    d  Δ Δ d π π p n pn  d*    NN  Δ Δ π π p n N N pn  d*  pn p n n p

18 Expectations p n n p SAID SAID with resonance A. Pricking, M. Bashkanov, H. Clement: arXiv:

19 p n n p SAID A. Pricking, M. Bashkanov, H. Clement: arXiv:

20 p n n p SAIDNew SAID solutions P. Adlarson et al. Phys. Rev. Lett. 112, , (2014)

Dimensionless partial wave amplitudes 21 Re Im SP07 SP14 Dimensionless partial wave amplitudes Resonance in the pn system P. Adlarson et al. Phys. Rev. Lett. 112, , (2014)

22 Argand plot P. Adlarson et al. Phys. Rev. Lett. 112, , (2014) P. Adlarson et al. Phys. Rev. C 90, , (2014)

23 Argand plots P. Adlarson et al. Phys. Rev. Lett. 112, , (2014) P. Adlarson et al. Phys. Rev. C 90, , (2014)

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Deuteron 25 n p np L=2 0.9 fm 4 fm L=0

Deltaron vs Hexaquark 26 Δ Δ ΔΔ L=2 0.9 fm L=0 1.2 fm 0.7 fm F. Huang et al, arXiv:

d*(2380) internal structure and the ABC effect 27 Δ Δ ΔΔ L=2 0.9 fm L=0 1.2 fm M. Bashkanov et al, arXiv:

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Mirror dibaryon 29   I(J p ) = 0(3 + ) d* u u u d d d I(J p ) = 3(0 + )   u u u u u u Freeman J. Dyson, Nguyen-Hue Xuong Phys. Rev. Lett. 13(1964) 815 Avraham Gal, Humberto Garcilazo Nucl. Phys. A928, (2014), 73

 *  *+  *  *  *+    *  *  *+  *  **   ++ ---- d* How many ways can you combine 6q? Isospin Strangeness

Z=+4 dibaryon isospin coefficients p p p p I

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34 p p p p Δ Δ p p p p p p p p

35 Double-Roper

Charge Z=+4 dibaryon upper limit 36

NN vs ΔΔ 37 Threshold pn pn 2.2 MeV 66 keV deuteron ΔΔ ΔΔ ? 80 MeV d* Z=+4

 *  *+  *  *  *+    *  *  *+  *  **   ++ ---- d* How many ways can you combine 6q? Isospin Strangeness

d*(2380) SU(3) multiplet   *  *  39 J p = 3 +

Strange Dibaryon Isospin Strangeness  *  *+  *  *  *+    * d*

d*(2380) in photoproduction? 41 R. Gilman and F. Gross nucl-th/ (2001) T. Kamae, T. Fujita Phys. Rev. Lett. 38, Feb 1977, 471 H. Ikeda et al., Phys. Rev. Lett. 42, May 1979, 1321 d* I(J p ) = 0(3 + )

The benchmark measurement 42 Newly installed Edinburgh polarimeter M.H. Sikora, D.P. Watts et al, Phys.Rev.Lett. 112 (2014) Mikhail Bashkanov "Dibaryons" Measure polarization of both proton and neutron ! d*

Conclusion The very first dibaryon d*(2380) is established Mass Width Quantum numbers Main decay branches Structure: Hexaquark vs Molecule? No convincing signs for the mirror dibaryon (charge Z=+4) so far Size and shape of the conventional background? Mirror multiplet (28-plet) is likely to be unbound 43

45 Δ Δ d π π  d Mikhail Bashkanov "Dibaryons" A. Fix, H. Arenhoevel. Eur. Phys. J. A 25, 115, (2005).

Z=+4 dibaryon Δ Δ π π N N p p p p WASA, HADES

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48 M(GeV)12345exp unbound  1.Dyson-Xuong, PRL 13 (1964) Mulders-Aerts-de Swart, PRD 21 (1980) Oka-Yazaki, PLB 90 (1980) Mulders-Thomas, JPG 9 (1983) A. Gal, H. Garcilazo Nucl.Phys. A928 (2014) 73-88