It is pointed out that so far all theoretical estimates of coherent pion production off nuclei induced by neutrinos rely on the 'local approximation' well known in photonuclear physics. The effects of dropping this approximation are discussed. It is found that in a plane wave approximation for the pion the local approximation overestimates the coherent neutrino-induced pion production on nuclei.
Impulse approximation in the n p --> d pi^0 reaction reexamined
本文重新考察了n p -> d π ^0反应中的冲量近似（单体算符），重点是约化和反冲修正问题。当一个π介子交换包含在产生算符中时，证明了一个不一致性，然后通过引入“波函数修正”来解决，该修正对于静态核子传播子几乎为零。包括反冲修正的核子传播子被发现改变的幅度和符号的脉冲产生振幅，恶化与实验截面约30%的协议。一个截止是用来占外部波函数的唯象性质，并发现有一个显着的影响高达约2.5 GeV。
The J=1/2 iso-doublet double-$Λ$-hypernuclei, namely, ${}_{ΛΛ}^{5}$H and ${}_{ΛΛ}^{5}$He, are examined as the three-body cluster states, $ΛΛt$ ($t\equiv {}^3$H or triton) and $ΛΛh$ ($h\equiv {}^3$He or helion), respectively, in a model independent framework utilizing pionless halo effective theory. Both singlet and triplet states of the constituent $ΛT$ ($T\equiv t,h$) sub-system are used in the elastic channel for the study of $_Λ^4$H$-Λ$ and $_Λ^4$He$-Λ$ scattering processes. A prototypical leading order investigation using a sharp momentum cut-off regulator, irrespective of the type of the …
[Background] A quantitative understanding of neutrino interactions with nuclei is needed for precision era neutrino long baseline experiments (MINOS, NOvA, DUNE) which all use nuclear targets. Pion production is the dominant reaction channel at the energies of these experiments. [Purpose] Investigate the influence of nuclear effects on neutrino-induced pion production cross sections and compare predictions for pion-production with available data. [Method] The Giessen Boltzmann--Uehling--Uhlenbeck (GiBUU) model is used for the description of all incohrent channels in neutrino-nucleus reactions.…
Bremsstrahlung of photons emitted during the scattering of $π^{+}$-mesons off nuclei is studied for the first time. Role of interactions between $π^{+}$-mesons and nuclei in the formation of the bremsstrahlung emission is analyzed in details. We discover essential contribution of emitted photons from nuclear part of Johnson-Satchler potential to the full spectrum, in contrast to the optical Woods-Saxon potential. We observe unusual essential influence of the nuclear part of both potentials on the spectrum at high photon energies. This phenomenon opens a new experimental way to study and check …
For detailed explanation of the experimental results of lepton production cross section in hadronic collisions such as nucleon-nucleon or nucleon-nuclei, it is of great importance to use quarks and sea quarks distribution function inside free and bound nucleons. In this paper the role of pion cloud inside the nucleus in the structure function of Cu and Pt nuclei and the EMC ratio of these nuclei were investigated by using harmonic oscillator model.
We compute the medium-mass nuclei $^{16}$O and $^{40}$Ca using pionless effective field theory (EFT) at next-to-leading order (NLO). The low-energy coefficients of the EFT Hamiltonian are adjusted to experimantal data for nuclei with mass numbers $A=2$ and $3$, or alternatively to results from lattice quantum chromodynamics (QCD) at an unphysical pion mass of 806 MeV. The EFT is implemented through a discrete variable representation in the harmonic oscillator basis. This approach ensures rapid convergence with respect to the size of the model space and facilitates the computation of medium-mas…
We have applied the extended factorization scheme to investigate the electroweak pion production on nuclei. The ANL-Osaka model, which was obtained by analyzing the data of $πN$, $γN$, $N(e,e'π)$ and $N(ν,μ\,π) $ reactions up to invariant mass $W=$ 2 GeV, is used to generate the matrix elements of current operators relevant to pion-production off the nucleon. Medium effects on the $Δ$ (1232) component of meson-exchange current are included by using a $Δ$-nucleus potential determined from the previous $Δ$-hole model studies of pion-nucleus reactions. Nuclear correlations in the initial target s…
[Background] Long-Baseline experiments such as T2K, NOvA or the planned Deep Underground Neutrino Experiment (DUNE) require theoretical descriptions of the complete event in a neutrino-nucleus reaction. Since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. [Purpose] One of the dominant reaction channels in neutrino-nucleus interactions is pion production. This paper aims for a coherent view on all charged current charged pion production data that are avaible from the experiments MiniBooNE, the near detector experiment at T2K and MINERvA. [Methods] …
We study the pion-induced inclusive $Λ(1520)$ hyperon production from nuclei near threshold within a nuclear spectral function approach accounting for incoherent primary $π^-$ meson--proton ${π^-}p \to K^0Λ(1520)$ production processes. We calculate the absolute differential and total cross sections for the production of $Λ(1520)$ hyperons off carbon and tungsten nuclei at laboratory angles of 0$^{\circ}$--10$^{\circ}$, 10$^{\circ}$--45$^{\circ}$ and 45$^{\circ}$--85$^{\circ}$ by $π^-$ mesons with momentum of 1.7 GeV/c as well as their relative (transparency ratio) differential and integral yie…
