Calculation of η′ Decay Modes Using Chiral Perturbation Theory

Precision Measurement of the Branching Fractions of η′ Decays

“…Decays of the η 0 meson have inspired the study of a wide variety of physics issues, e.g., η − η 0 mixing, the light quark masses, as well as physics beyond the standard model. Hence considerable theoretical effort has been devoted to investigate its decay dynamics and partial decay widths with different approaches [1][2][3][4][5][6]. However, no absolute branching fractions (BFs) of η 0 decays have yet been measured due to the difficulty of tagging its inclusive decays.…”

“…The precision of our measurements is a factor 2 to 4 better than that of CLEO. The comparisons of the decay widths of η 0 → ηπ þ π − and η 0 → ηπ 0 π 0 with different theoretical approaches, including the chiral unitary approach [1], the chiral perturbation theory [5] and the chiral effective field theory [4], are presented in Table III. Here the measured decay widths are obtained using the η 0 total decay width Γðη 0 Þ ¼ 0.196 AE 0.009 MeV [7].…”

Three-body Calculation of Total Cross Sections of the p d → 3 H e η Reaction From Chiral Dynamics

“…If i s are found such that the divergences of the one loop Green functions moreover divergences of the tree level diagrams of L 2 S vanished, then we're renormalization amplitude at this order, see Ref. [15] for more details. The results for the L r i s and i s are given in Table 1.…”

“…where the renormalized coupling constants N r i and D r i are measurable numbers and the constants i are i are chosen to absorb the one-loop divergences in the amplitudes [15], and given by …”

“…The search for the η and η mesic nucleus is exciting and there are plans to continue this investigations in the future. Recently, with the use of Chiral Perturbation Theory(ChPT), we have studied the η in to 3π and 2π [15] and η → 3π [16] decays, after performing these reactions. The Scattering amplitude and decay width are calculated for different modes up to NLO.…”