Two pion production in pp evidence for a

Two pion production in pp + evidence for a D 21 dibaryon Orsay 2018 Tatiana Skorodko for WASA-at-COSY Collaboration

Family of non strange dibaryons Dyson & Xuong‘s Prediction State I J Asymptotic Configuration mtheor [Me. V] mexp [Me. V] Gexp [Me. V] ----------------------------------------------------------------D 01 0 1 Deuteron 1876 D 10 1 0 virtual 1 S 0 D 12 1 2 NN(1 D 2) N NN D 21 2 1 2160 D 03 0 3 2350 D 30 3 0 2350 1876 2160 1876 1878 DN threshold 2 -----------------------------------------------------------------

pn d* d 0 0 Argand diagram: M 2. 37 Ge. V G 70 Me. V Pole in 3 D 3 at 2380 10 - i 40 5 Me. V PRL 106 (2011) 242302 PRC 90 (2014) 035204

hadronic decays + I = 0+1 d PRL 106 (2011) 242302 I=1 ½ d + 0 I=0 2 d 0 0 PLB 721 (2013) 229 WASA data pn d*(2380) d* T. Skorodko PRC 88 (2013) 055208 PLB 743 (2015) 325 Phys. Scr. T 166 (2015) 014016 d* d* 4 s [Ge. V]

Established dibaryon states 0 S 1 – deuteron ground state 1 S – virtual state (NN FSI) 0 1 D – resonance structure at N threshold 2 0 D – d*(2380) resonance 3 Are there more states? 2 D 1 I(JP)=2(1+), 3 D 0 I(JP)=3(0+) ? I(JP)=0(1+) I(JP)=1(0+) I(JP)=1(2+) I(JP)=0(3+)

Where D 21 can be seen? I=2 only associated production pp + pp D 21

Model description – Valencia model Reasonable total cross sections from absolute calculations

Model description PLB 695 (2011) 115 + (1600) Roper + original Valencia model (Roper + ) modified Valencia model (reduced Roper + + 1600) + (1600)

Model description original Valencia model modified Valencia model

Isoscalar Single-Pion Production PLB 774 (2017) 599 0( N )=3[2 (pn pp ) - (pp pp 0)]

2320 Me. V Roper d*

Model description PLB 695 (2011) 115 + (1600) Roper + original Valencia model (Roper + ) modified Valencia model (reduced Roper + + 1600) + (1600)

pn NN PRC 88 (2013) 055208 PLB 743 (2015) 325 Phys. Scr. T 166 (2015) 014016 modified Valencia model + d* d*

Model description PLB 695 (2011) 115 + (1600) Roper + original Valencia model (Roper + ) modified Valencia model (reduced Roper + + 1600) + (1600)

Isospin decomposition T. Skorodko et al. , Phys. Lett. B 679(2009), 30

pp Roper pp +

Isospin decomposition T. Skorodko et al. , Phys. Lett. B 679(2009), 30

Results original Valencia model modified Valencia model + D 12 M = 2140 Me. V = 110 Me. V

Results modified Valencia model + D 12 If is dominate at Tp 1. 2 Ge. V (Valencia model) Mp + = Mp

Results modified Valencia model + D 12 If is dominate at Tp 1. 2 Ge. V (Valencia model) + =

Conclusions isospin relations for total cross sections demand the opening a new contribution in pp pp + differential Mp and + distributions show a clear deviation from the modified Valencia model calculations total and differential cross sections agree well with assumption that in case of pp pp + channel there is an additional production mechanism – the associated production of the isotensor N state D 21 the strength of D 21 excitation in measured energy range is compatible with the strength of excitation