th / 9 80 90 09 v 1 3 S ep 1 99 8 Isospin breaking in the reaction np → dπ 0 at threshold
نویسنده
چکیده
The model for charge symmetry breaking in the reaction np → dπ applied earlier around the ∆ region is used to calculate the integrated forward-backward asymmetry of the cross section close to threshold. The mixing of the π and η mesons appears as strongly dominant at these energies. This contrasts elastic np scattering experiments, where the np mass difference in OPE dominates, or np → dπ closer to the ∆ region.
منابع مشابه
ar X iv : n uc l - ex / 0 51 10 27 v 1 1 5 N ov 2 00 5 Charge independence studied in NN → dπ reactions
We review to what extent charge independence breaking (CIB) in isospin related reactions of the type NN → dπ can or could be seen in existing data. In doing this we present fits to global and threshold cross sections including most recent data. Applying these we point out the probable impossibility to make model independent predictions even based solely on the different threshold energies and t...
متن کاملep - p h / 98 10 37 6 v 1 1 5 O ct 1 99 8 Light Quark Mass Difference and Isospin Breaking In Electromagnetic Pion Production ∗
It is demonstrated that there is a dynamic isospin breaking effect in the near threshold γ * N → πN reaction due to the mass difference of the up and down quarks, which also causes isospin breaking in the πN system. The photopion reaction is affected through final state πN interactions (formally implemented by unitarity and time reversal invariance). It is also demonstrated that the near thresh...
متن کاملar X iv : h ep - p h / 00 09 02 3 v 1 4 S ep 2 00 0 1 Isospin symmetry breaking and direct CP violation in B →
We discuss the isospin symmetry breaking quantity ∆ ±0 ≡ Γ(B ± → ρ ± γ)/2Γ(B 0 → ρ 0 γ)−1, and the direct CP violation in B ± → ρ ± γ within and beyond the standard model. After showing that the leading-order calculation would be a good approximation in such models, we argue that measurements of these quantities would be able to disentagle physics beyond the standard model.
متن کاملEffective field theory contribution to charge symmetry breaking NN scattering
The effect of isospin breaking pion s-wave rescattering is included in elastic NN scattering at low energies using effective field theory. Although this mechanism gave a large contribution to charge symmetry breaking in np → dπ, the effect is rather small in pp vs. nn scattering parameters and in the H-He binding energy difference. This smallness is caused by large cancellation of the up-down q...
متن کاملar X iv : n uc l - th / 9 30 90 09 v 1 8 S ep 1 99 3 MESON - EXCHANGE CURRENTS AND THE STRANGENESS RADIUS OF 4
Meson-exchange current contributions to the strangeness radius of He are computed in the one-boson exchange approximation. It is found that these contributions introduce a ∼10% correction to the one-body contribution. They should not, therefore, hamper the extraction of the nucleon strangeness radius from the parity-violating electron-He asymmetry.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1998