Description Of Final-state Interactions Research Articles

New model comparison for semi-inclusive charged-current electron and muon neutrino scattering by Ar40 in the energy range of the MicroBooNE experiment

In this work we present a comparison of semi-inclusive muon and electron neutrino cross sections with Ar40 target measured by the MicroBooNE collaboration with the predictions of an unfactorized model based on the relativistic distorted wave impulse approximation (RDWIA) and the SuSAv2-MEC model implemented in the neutrino event generator GENIE. The predictions based on the RDWIA approach, with a realistic description of the initial state and a phenomenological relativistic complex optical potential for the description of final state interactions, better describe the measured cross sections than GENIE-SuSAv2 and RDWIA with a purely real potential. Published by the American Physical Society 2024

Quasi-two-body decays in perturbative QCD* *Supported by the National Natural Science Foundation of China (11347030), the Program of Science and Technology Innovation Talents in Universities of Henan Province, China (14HASTIT037), and the Natural Science Foundation of Henan Province, China (232300420116)

In this work, we investigate the quasi-two-body decays with using the perturbative QCD (PQCD) approach. The description of final state interactions of the pair is achieved through the two-meson distribution amplitudes (DAs), which are normalized to the time-like form factor. The PQCD predictions on the branching ratios of the quasi-two-body decays show an obvious hierarchy: and . From the invariant mass -dependence of the decay spectrum for each channel, one can find that the branching fraction is concentrated in a narrow region around the pole mass. Thus, one can obtain the branching ratios for the corresponding two-body decays under the narrow-width approximation. We find that the branching ratios of the decays are consistent with the previous PQCD calculations within errors. These predictions will be tested in future experiments.

Benchmarking intranuclear cascade models for neutrino scattering with relativistic optical potentials

The description of final-state interactions (FSI) in the large phase space probed in neutrino experiments poses a great challenge. In neutrino experiments, which operate under semi-inclusive conditions, cascade models are commonly used for this task, while under exclusive conditions FSI can be treated with relativistic optical potentials (ROP). We formulate conditions under which the ROP approach and cascade model can be directly compared. We feed the NEUT cascade with events from a relativistic distorted-wave impulse approximation calculation that uses the real part of an optical potential. Cuts on the missing energy of the resulting events are applied to define a set of events that can be directly compared to RDWIA calculations with the full optical potential. The NEUT cascade and ROP agree for proton kinetic energies $T_p > 150$ MeV for carbon, oxygen and calcium nuclei when a realistic nuclear density is used to introduce events in the cascade. For $T_p < 100$ MeV the ROP and NEUT cross sections differ in shape and differences in magnitude are larger than 50 \%. Single transverse variables allow to distinguish different approaches to FSI, but due to a large non-QE contribution the comparison to T2K data does not give an unambiguous view of FSI. We discuss electron scattering and argue that with a cut in missing energy FSI can be studied with minimal confounding factors in e.g. $e4\nu$. The agreement of the ROP and NEUT for T2K conditions lends confidence to these models as a tool in oscillation analyses for sufficiently large nucleon kinetic energies. These results urge for caution when a cascade model is applied for small nucleon energies. The assessment of model assumptions relevant to this region are strongly encouraged. This paper provides novel constraints on cascade models from proton-nucleus scattering that can be easily applied to other neutrino event generators.

Lorentz-boosted description of a heavy quarkonium

In this paper we study the relation between the light-front (infinite momentum) and rest-frame descriptions of quarkonia. While the former is more convenient for high-energy production, the latter is usually used for the evaluation of charmonium properties. In particular, we discuss the dynamics of a relativistically moving system with nonrelativistic internal motion and give relations between rest frame and light-front potentials used for the description of quarkonium states. We consider two approximations, first the small coupling regime, and next the nonperturbative small binding energy approximation. In both cases we get consistent results. Our results could be relevant for the description of final state interactions in a wide class of processes, including quarkonium production on nuclei and plasma. Moreover, they can be extended to the description of final state interactions in the production of weakly bound systems, such as for example the deuteron.

Scaling ideas in neutrino scattering reactions: application to the MiniBooNE experiment

An exhaustive analysis of the world data on electron scattering has shown that scaling and superscaling properties are fulfilled with great accuracy. The relativistic impulse approximation (RIA) yields a satisfactory description of experimental data. Not only scaling and superscaling behavior emerge, but also the specific asymmetric shape of the experimental scaling function is reproduced. In this work two relativistic approaches are considered to evaluate the neutrino-nucleus cross sections. One, based on the relativistic impulse approximation, relies on the microscopic description of nuclear dynamics using relativistic mean field theory, and incorporates a description of final state interactions. The second is based on the superscaling behavior exhibited by electron scttering data and its applicability, due to the universal character of the scaling function, to the analysis of neutrino scattering reactions. The role played by the vector meson-exchange currents in the two-particle two-hole sector is also incorporated and the results obtained are compared with the recent data for neutrinos measured by the MiniBooNE Collaboration.

Relativistic models for quasielastic electron and neutrino-nucleus scattering

Relativistic models developed within the framework of the impulse approximation for quasielastic (QE) electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI) in the inclusive scattering are compared. In the relativistic Green’s function (RGF) model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF) model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE) MiniBooNE cross sections.

Models for quasielastic electron and neutrino-nucleus scattering

Models developed for the exclusive and inclusive quasielastic electron-nucleus scattering have been extended to quasielastic neutrino-nucleus scattering. Different descriptions of final-state interactions are compared. For the inclusive electron scattering the relativistic Green's function model is compared with a model based on the use of relativistic purely real mean field potentials in the final state. Both approaches lead to a redistribution of the strength but conserving the total flux. Results for electron and neutrino scattering are presented and discussed in different conditions and kinematics. The results of the relativistic Green's function and of the relativistic mean field models are compared with the double-differential charged-current quasielastic neutrino cross sections recently measured by the MiniBooNE collaboration using a carbon target.

Bridging two ways of describing final-state interactions in A(e,e′p) reactions

We outline a relativistic and unfactorized framework to treat the final-state interactions in quasi-elastic A(e,e'p) reactions for four-momentum transfers Q$^{2} \gtrsim 0.3$ (GeV/c)$^{2}$. The model, which relies on the eikonal approximation, can be used in combination with optical potentials, as well as with the Glauber multiple-scattering method. We argue that such a model can bridge the gap between a typical ``low'' and ``high-energy'' description of final-state interactions, in a reasonably smooth fashion. This argument is made on the basis of calculated structure functions, polarization observables and nuclear transparencies for the target nuclei $^{12}$C and $^{16}$O.