The influence of nuclear isospin mixing on parity-violating elastic electron scattering is studied for the even-even, N=Z nuclei 12C, 24Mg, 28Si, and 32S. Their ground-state wave functions have been obtained using a self-consistent axially-symmetric mean-field approximation with density-dependent effective two-body Skyrme interactions. Some differences from previous shell-model calculations appear for the isovector Coulomb form factors which play a role in determining the parity-violating asymmetry. To gain an understanding of how these differences arise, the results have been expanded in a spherical harmonic oscillator basis. Results are obtained not only within the plane-wave Born approximation, but also using the distorted-wave Born approximation for comparison with potential future experimental studies of parity-violating electron scattering. To this end, for each nucleus the focus is placed on kinematic ranges where the signal (isospin-mixing effects on the parity-violating asymmetry) and the experimental figure-of-merit are maximized. Strangeness contributions to the asymmetry are also briefly discussed, since they and the isospin mixing contributions may play comparable roles for the nuclei being studied at the low momentum transfers of interest in the present work.
We systematically calculate the isospin violating decay, $D_s^*\to D_sπ^0$, with the heavy meson chiral perturbation theory up to $\mathcal{O}(p^3)$ including the loop diagrams. The $\mathcal{O}(p^3)$ tree level amplitudes contain four undetermined LECs. We use two strategies to estimate them. With the nonanalytic dominance approximation, we get $Γ[D_s^\ast\to D_sπ^0]=(3.38\pm0.12)$ eV. With the naturalness assumption, we give a possible range of the isospin violating decay width, $[1.11-6.88]$ eV. We find that the contribution of the $\mathcal{O}(p^3)$ corrections might be significant.
In this work, we revisit the isospin violating decays of $X(3872)$ in a coupled-channel effective field theory. In the molecular scheme, the $X(3872)$ is interpreted as the bound state of $\bar{D}^{*0}D^0/\bar{D}^0D^{*0}$ and $D^{*-}D^+/D^-D^{*+}$ channels. In a cutoff-independent formalism, we relate the coupling constants of $X(3872)$ with the two channels to the molecular wave function. The isospin violating decays of $X(3872)$ are obtained by two equivalent approaches, which amend some deficiencies about this issue in literature. In the quantum field theory approach, the isospin violating …
Time reversal invariance violating parity conserving (TVPC) effects are calculated for elastic proton deuteron scattering with proton energies up to $2~$MeV. Distorted Wave Born Approximation is employed to estimate TVPC matrix elements, based on hadronic wave functions, obtained by solving three-body Faddeev-Merkuriev equations in configuration space with realistic potentials.
Two parity violating asymmetries from $n p \to d γ$ in pionless effective field theories
我们考虑过程$\vec n p\to d γ$和$ np \to d \overset {\circlearrowleft}γ$的宇称破坏观测量。我们使用无介子有效场论进行计算，有和没有明确的二重子场。在将这些结果与我们已经获得的关于$\vec NN$散射中宇称违反不对称性的结果相结合之后，实验输入原则上允许提取在宇称违反拉格朗日量中出现的所有五个参数。
The effects of charge symmetry breaking in nucleon electromagnetic form factors on parity- violating elastic electron-12C scattering is studied, and found to be much smaller than other known effects. The analysis of a planned experiment is discussed.
Isospin-violating dark matter (IVDM), which couples differently with protons and neutrons, provides a promising mechanism to ameliorate the tension among recent direct detection experiments. Assuming DM is non-interacting bosonic asymmetric IVDM, we investigate how the existence of old neutron stars limits the DM-proton scattering cross-section $σ_{\rm p}$, especially the effects of the isospin violating DM-nucleon interactions and the symmetry energy in the equation of state of isospin asymmetric nuclear matter. Our calculations are completely based on general relativity and especially the st…
