Role of a triangle singularity in the πN(1535) contribution to γp→pπ0η

Abstract

Role of a triangle singularity in the πN(1535) contribution to γp → pπ 0 η

Considerations on the Schmid theorem for triangle singularities

“…1 of Ref. [31]). Yet, even then, the N * (1535) contribution to the γp → π 0 η p gives a distinctive signature, both theoretically and experimentally.…”

“…In the study of Ref. [31] one compares the loop contribution with the tree level from γ p → ∆(1700) → η ∆(1232) → ηπ 0 p and they are of the same order of magnitude. A remarkable feature is that the coherent sum of tree level and loop does not change much the contribution of the tree level, even if the loop contribution is sizable, and is smaller than the incoherent sum of both processes (see Fig.…”

“…The former recent works on triangle singularities have stimulated many works on the issue [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Further information can be found in the report [47].…”

Triangle singularities in $$B^-\rightarrow D^{*0}\pi ^-\pi ^0\eta $$ B - → D ∗ 0 π - π 0 η and $$B^-\rightarrow D^{*0}\pi ^-\pi ^+\pi ^-$$ B - → D ∗ 0 π - π + π -

“…In Ref. [45], a triangle singularity develops in the γ p → pπ 0 η → π 0 N (1535) process and there Im(t T ) has a peak at the expected energy of the triangle singularity while the Re(t T ) has no peak. Similarly, in the study of N (1700) → π in Ref.…”

Role of a triangle singularity in the $\pi N(1535)$ contribution to $\gamma p \rightarrow p \pi^0 \eta$

“…2. The full result of the π 0 η production shown with the black-solid line in the figure is obtained Figure 2: The π 0 η production cross section [10]. The points with error bar are the data shown in Ref.…”