Two-pion program at WASA
Mikhail BashkanovEncounters with Di-Baryons from the ABC-effect to a Resonance in the Proton-Neutron System
Wasa-at-COSY1Content2Double-pionic fusion3npnpppThe ABC-effect4npnpppHistory of the ABC effectLow 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) 223-228
P. Adlarson et. al, Phys. Rev. C86 (2012) 032201P. Adlarson et. al, Phys. Rev. Lett. 106 (2011) 242302Two-pion production6N*DDDN*sDD(1600)Tp < 1.5 GeV
Isospin Decomposition
T. Skorodko et al.,PLB 679 (2009) 30N*(1440)DDD(1600)7Expectations in total cross section
89
ABC resonance70 MeVTotal cross section pn d00 P. Adlarson et. al Phys. Rev. Lett. 106:242302, 2011NN*(1440)10
Angular distribution in the peak
J=1J=3Quantum numbers of the structureAntisymmetrization: Jp=1+or 3+ : if L=0
pn d* d 00 pn d 00I=0,1I=0I=0,2I=01+3+
1+ excluded by ().3+ assigned 1112
t-channel ABC effectM for different energies13Status of Theoretical Descriptionpn R DD dp0p0
dpnI(Jp) = 0(3+)Isospin relations14I=0I=115Total cross section pN d P. Adlarson et. al Phys. Lett. B721 (2013) 229
16M in pN d
17M in pN d
18M in pN d
Isospin violation
19+-00Non-fusion channel2021
pn pp-0ABC expectedPreliminaryConventional processConventional process +ABCP. Adlarson et al., arXiv: 1306.5130v1Elastic channel22233+ Resonance in npnpL=2npL=424Total pn cross-section
SAIDDevlin et al, PRD8, 136 (73) LisowskI et al, PRL49, 255(82)25
Expectationspnnp
SAIDSAID with resonance
26Expectationpnnp
SAID
27Realitypnnp
SAID
28pn Vector Analysing Power
SAIDVery PreliminaryConclusion29Thank youMultiplet1010=35282710**Y()=2I()=0Kim Maltman, Nucl. Phys. A501 (1989) 843Mirror dibaryon32DDI(Jp) = 0(3+)d*uuudddI(Jp) = 3(0+)DDuuuuuuMirror Multiplet1010=35282710***+***+**+**++++--Beam polarization0Polarization 2Polarization 1
35Total cross section pp d+0 Shimizu et al.F. Kren et al.
36Total cross section pn d00
37Total cross section pn d+-
38Total cross section pn d+- Kinematics
39Proton spectatorprotonneutrondpnp + psp40Status of the ABC Resonancedecay channel branching status------------------------------------------------------------------------d p0p0 15 % observedd p+p- 25 % observed ppp0p- 7 % observednpp0p0 (12 %, predicted*) data analysis WASAnpp+p- (31 %, predicted*) data analysis HADESnp (10 %, predicted) data analysis WASA
* Fldt & Wilkin, PLB 701 (2011) 619 Albaladejo & Oset, arXiv:1304.7698 [nucl-theor]