Mikhail Bashkanov Encounters with Di-Baryons from the ABC-effect to a Resonance in the Proton-Neutron System Wasa-at-COSY

Content 2

Double-pionic fusion 3 np np  

The ABC-effect 4 np np  

History of the ABC effect Low mass enhancement in M  Alexander Abashian, Norman E. Booth Kenneth M. Crowe, Phys. Rev. Lett. 5, 258 (1960) M.Bashkanov et. al, Phys. Lett. B637 (2006) P. Adlarson et. al, Phys. Rev. C86 (2012) P. Adlarson et. al, Phys. Rev. Lett. 106 (2011)

Two-pion production 6 N*    “”“”   T p < 1.5 GeV

Isospin Decomposition T. Skorodko et al., PLB 679 (2009) 30 N * (1440)   (1600) 7

Expectations in total cross section 8

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

10 Angular distribution in the peak J=1 J=3

Quantum numbers of the structure Antisymmetrization: J p =1 + or 3 + : if L ΔΔ =0 pn  d*  ∆∆  d  0  0 pn  d  0  0 pn  d  0  0 I=0,1I=0I=0,2 I= excluded by  (  ). 3 + assigned 11

12 t-channel  “ABC effect” M  for different energies

13 Status of Theoretical Description pn  R    d     Δ Δ d π π p n I(J p ) = 0(3 + )

Isospin relations 14 I=0 I=1

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

16 M  in pN  d 

17 M  in pN  d 

18 M  in pN  d 

Isospin violation 19 +-+- 0000

20

21 pn  pp  -  0 ABC “expected”  Conventional process Conventional process +ABC P. Adlarson et al., arXiv: v1

22

Resonance in np np L=2 n L=4

24 Total pn cross-section SAID Devlin et al, PRD8, 136 (73) LisowskI et al, PRL49, 255(82)

25 Expectations p n n p SAID SAID with resonance

26 Expectation p n n p SAID

27 Reality p n n p SAID

28 pn Vector Analysing Power SAID

Conclusion 29

Multiplet 10  10=35  28  27  10   *  *  Y(  )=2 I(  )=0 Kim Maltman, Nucl. Phys. A501 (1989) 843

Mirror dibaryon 32   I(J p ) = 0(3 + ) d* u u u d d d I(J p ) = 3(0 + )   u u u u u u

Mirror Multiplet 10  10=35  28  27  10   *  *  *+  *  *  *+   *  *+  *  **   ++ ----

Beam polarization 0 Polarization 2 Polarization 1

35 Total cross section pp  d  +  0 Shimizu et al. F. Kren et al.

36 Total cross section pn  d  0  0

37 Total cross section pn  d  +  -

38 Total cross section pn  d  +  -

Kinematics 39 Proton spectator proton neutron dp  np + p sp

40 Status of the ABC Resonance decay channel branching status d      15 % observed d     25 % observed pp     7 % observed np     (12 %, predicted * ) data analysis WASA np     (31 %, predicted * ) data analysis HADES np (10 %, predicted) data analysis WASA * Fäldt & Wilkin, PLB 701 (2011) 619 * Fäldt & Wilkin, PLB 701 (2011) 619 Albaladejo & Oset, arXiv: [nucl-theor] Albaladejo & Oset, arXiv: [nucl-theor]