“Hammer” events, neutrino energies, and nucleon-nucleon correlations
Background: Accelerator-based neutrino oscillation measurements depend on observing a difference between the expected and measured rate of neutrino-nucleus interactions at different neutrino energies or different distances from the neutrino source. Neutrino-nucleus scattering cross sections are comp...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2017
|
| Online Access: | http://hdl.handle.net/1721.1/109744 |
| _version_ | 1811072867614326784 |
|---|---|
| author | Weinstein, L. B. Piasetzky, Eli Chen, Or |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Weinstein, L. B. Piasetzky, Eli Chen, Or |
| author_sort | Weinstein, L. B. |
| collection | MIT |
| description | Background: Accelerator-based neutrino oscillation measurements depend on observing a difference between the expected and measured rate of neutrino-nucleus interactions at different neutrino energies or different distances from the neutrino source. Neutrino-nucleus scattering cross sections are complicated and depend on the neutrino beam energy, the neutrino-nucleus interaction, and the structure of the nucleus. Knowledge of the incident neutrino energy spectrum and neutrino-detector interactions are crucial for analyzing neutrino oscillation experiments. The ArgoNeut liquid argon time projection chamber (lArTPC) observed charged-current neutrino-argon scattering events with two protons back-to-back in the final state (“hammer” events) which they associated with short-range correlated (SRC) nucleon-nucleon pairs. The large volume MicroBooNE lArTPC will measure far more of these unique events.
Purpose: Determine what we can learn about the incident neutrino energy spectrum and/or the structure of SRC from hammer events that will be measured in MicroBooNE.
Methods: We simulate hammer events using two models and the well-known electron-nucleon scattering cross section. In the first model the neutrino (or electron) scatters from a moving proton, ejecting a π[superscript +], and the π[superscript +] is then absorbed on a moving deuteron-like np pair. In the second model the neutrino (or electron) scatters from a moving nucleon, exciting it to a Δ or N[superscript *], which then de-excites by interacting with a second nucleon: ΔN→pp.
Results: The pion production and reabsorption process results in two back-to-back protons each with momentum of about 500 MeV/c, very similar to that of the observed ArgoNeut events. These distributions are insensitive to either the relative or center-of-mass momentum of the np pair that absorbed the π. In this model, the incident neutrino energy can be reconstructed relatively accurately using the outgoing lepton. The Δp→pp process results in two protons that are less similar to the observed events.
Conclusions: ArgoNeut hammer events can be described by a simple pion production and reabsorption model. The hammer events that will be measured in MicroBooNE can be used to determine the incident neutrino energy but not to learn about SRC. We suggest that this reaction channel could be used for neutrino oscillation experiments to complement other channels with higher statistics but different systematic uncertainties. |
| first_indexed | 2024-09-23T09:18:09Z |
| format | Article |
| id | mit-1721.1/109744 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T09:18:09Z |
| publishDate | 2017 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1097442022-09-26T11:14:58Z “Hammer” events, neutrino energies, and nucleon-nucleon correlations Weinstein, L. B. Piasetzky, Eli Chen, Or Massachusetts Institute of Technology. Department of Physics Chen, Or Background: Accelerator-based neutrino oscillation measurements depend on observing a difference between the expected and measured rate of neutrino-nucleus interactions at different neutrino energies or different distances from the neutrino source. Neutrino-nucleus scattering cross sections are complicated and depend on the neutrino beam energy, the neutrino-nucleus interaction, and the structure of the nucleus. Knowledge of the incident neutrino energy spectrum and neutrino-detector interactions are crucial for analyzing neutrino oscillation experiments. The ArgoNeut liquid argon time projection chamber (lArTPC) observed charged-current neutrino-argon scattering events with two protons back-to-back in the final state (“hammer” events) which they associated with short-range correlated (SRC) nucleon-nucleon pairs. The large volume MicroBooNE lArTPC will measure far more of these unique events. Purpose: Determine what we can learn about the incident neutrino energy spectrum and/or the structure of SRC from hammer events that will be measured in MicroBooNE. Methods: We simulate hammer events using two models and the well-known electron-nucleon scattering cross section. In the first model the neutrino (or electron) scatters from a moving proton, ejecting a π[superscript +], and the π[superscript +] is then absorbed on a moving deuteron-like np pair. In the second model the neutrino (or electron) scatters from a moving nucleon, exciting it to a Δ or N[superscript *], which then de-excites by interacting with a second nucleon: ΔN→pp. Results: The pion production and reabsorption process results in two back-to-back protons each with momentum of about 500 MeV/c, very similar to that of the observed ArgoNeut events. These distributions are insensitive to either the relative or center-of-mass momentum of the np pair that absorbed the π. In this model, the incident neutrino energy can be reconstructed relatively accurately using the outgoing lepton. The Δp→pp process results in two protons that are less similar to the observed events. Conclusions: ArgoNeut hammer events can be described by a simple pion production and reabsorption model. The hammer events that will be measured in MicroBooNE can be used to determine the incident neutrino energy but not to learn about SRC. We suggest that this reaction channel could be used for neutrino oscillation experiments to complement other channels with higher statistics but different systematic uncertainties. United States. Department of Energy (Grants DE-FG02-96ER-40960) United States. Department of Energy (Grants DE-FG02-94ER40818) 2017-06-08T16:17:39Z 2017-06-08T16:17:39Z 2016-10 2016-07 2016-10-06T22:00:06Z Article http://purl.org/eprint/type/JournalArticle 2469-9985 2469-9993 http://hdl.handle.net/1721.1/109744 Weinstein, L. B., O. Hen, and Eli Piasetzky. “‘Hammer’ Events, Neutrino Energies, and Nucleon-Nucleon Correlations.” Physical Review C 94.4 (2016): n. pag. © 2016 American Physical Society en http://dx.doi.org/10.1103/PhysRevC.94.045501 Physical Review C Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Weinstein, L. B. Piasetzky, Eli Chen, Or “Hammer” events, neutrino energies, and nucleon-nucleon correlations |
| title | “Hammer” events, neutrino energies, and nucleon-nucleon correlations |
| title_full | “Hammer” events, neutrino energies, and nucleon-nucleon correlations |
| title_fullStr | “Hammer” events, neutrino energies, and nucleon-nucleon correlations |
| title_full_unstemmed | “Hammer” events, neutrino energies, and nucleon-nucleon correlations |
| title_short | “Hammer” events, neutrino energies, and nucleon-nucleon correlations |
| title_sort | hammer events neutrino energies and nucleon nucleon correlations |
| url | http://hdl.handle.net/1721.1/109744 |
| work_keys_str_mv | AT weinsteinlb hammereventsneutrinoenergiesandnucleonnucleoncorrelations AT piasetzkyeli hammereventsneutrinoenergiesandnucleonnucleoncorrelations AT chenor hammereventsneutrinoenergiesandnucleonnucleoncorrelations |