Electrons for neutrinos
Lead Research Organisation:
University of York
Department Name: Physics
Abstract
Neutrinos are ethereal particles which are extremely difficult to detect. They have a high abundance in the universe (around a trillion neutrinos pass through the average person every second), but having masses less than a millionth that of an electron and only interacting via the weak force and gravity, their probability of interaction is very small. In fact, neutrinos can pass through the entire diameter of the earth without interaction!
So how one can observe and study these ethereal particles at all in terrestrial experiments? The solution is to construct a detector that is made up of as large a volume of material as possible and to produce neutrino beams with incredibly intense flux. Such facilities are operational and exciting new facilities are planned. For example, in the Deep underground Neutrino Experiment (DUNE) under construction, neutrinos produced at Fermilab will pass 800 miles through the earths mantle to another laboratory in Sanford, where detectors comprise 40 tonnes of liquid Argon!
The rare interactions of neutrinos in detectors are obtained by examining the reaction products produced (usually with detection of a knocked-out proton) when a neutrino interacts with an atomic nucleus. The energy of the neutrino that produced the reaction is then inferred by nuclear reaction theoretical models. The problems stem from the fact that the atomic nuclei used for this purpose need to be large in order to get enough neutrino induced events; for example the Argon at Dune has 40 protons and neutrons in it's nucleus. A large nucleus is a very complicated object and the modelling of the reaction processes is very difficult with lots of outstanding questions: Can we suppress events where the knocked out nucleon scattered on it's way out of the nucleus? How well can we suppress contributions where the neutrino is absorbed on more than one nucleon and we only detect one? Producing a pion from a nucleon has a similar probability to knockout, but how well can we suppress these erroneous events in the experimental data? Can we get rid of processes where a pion (or pions) are initially produced in the nucleus and then reabsorbed to knock out nucleons? What about if we excite a nucleon in the reaction mechanism, and how do such excited nucleons behave in the nucleus? These are merely a small set of outstanding questions that directly impact the determination of the incident neutrino energy and flux.
In our programme we will use an analogous reaction to the neutrino-nucleus interactions: we will scatter electrons off the nuclei rather than neutrinos. This has the advantage that we get many orders of magnitude more events to test the models and very importantly, in a controlled way! By knowing the incident electron energy, all the assumptions in getting from nuclear fragments to the beam energy for a whole host of reactions and a wide range of nuclei becomes accessible. This data set is urgently needed to reduce errors in the theoretical modelling; these errors typically produce the largest systematic error for the neutrino experiments. By using common theoretical models for the neutrino- and electron-induced reactions we can challenge the models and improve the modelling of various processes at a level of details that was previously impossible. This then reduces significantly any systematic errors in extracting physics from the next generation neutrino facilities.
Progress requires a major programme of analysis of existing, as well as planned electron scattering experiments from nuclei with complex detector systems at Jefferson Laboratory (USA). We will construct a new analysis framework, which will be used to analyse and archive data in a form that makes it readily accessible and flexible for use by nuclear and particle communities for decades to come. The work will be carried out as part of a new collaborative network including colleagues at MIT, ODU, Jefferson Lab and Tel Aviv University.
So how one can observe and study these ethereal particles at all in terrestrial experiments? The solution is to construct a detector that is made up of as large a volume of material as possible and to produce neutrino beams with incredibly intense flux. Such facilities are operational and exciting new facilities are planned. For example, in the Deep underground Neutrino Experiment (DUNE) under construction, neutrinos produced at Fermilab will pass 800 miles through the earths mantle to another laboratory in Sanford, where detectors comprise 40 tonnes of liquid Argon!
The rare interactions of neutrinos in detectors are obtained by examining the reaction products produced (usually with detection of a knocked-out proton) when a neutrino interacts with an atomic nucleus. The energy of the neutrino that produced the reaction is then inferred by nuclear reaction theoretical models. The problems stem from the fact that the atomic nuclei used for this purpose need to be large in order to get enough neutrino induced events; for example the Argon at Dune has 40 protons and neutrons in it's nucleus. A large nucleus is a very complicated object and the modelling of the reaction processes is very difficult with lots of outstanding questions: Can we suppress events where the knocked out nucleon scattered on it's way out of the nucleus? How well can we suppress contributions where the neutrino is absorbed on more than one nucleon and we only detect one? Producing a pion from a nucleon has a similar probability to knockout, but how well can we suppress these erroneous events in the experimental data? Can we get rid of processes where a pion (or pions) are initially produced in the nucleus and then reabsorbed to knock out nucleons? What about if we excite a nucleon in the reaction mechanism, and how do such excited nucleons behave in the nucleus? These are merely a small set of outstanding questions that directly impact the determination of the incident neutrino energy and flux.
In our programme we will use an analogous reaction to the neutrino-nucleus interactions: we will scatter electrons off the nuclei rather than neutrinos. This has the advantage that we get many orders of magnitude more events to test the models and very importantly, in a controlled way! By knowing the incident electron energy, all the assumptions in getting from nuclear fragments to the beam energy for a whole host of reactions and a wide range of nuclei becomes accessible. This data set is urgently needed to reduce errors in the theoretical modelling; these errors typically produce the largest systematic error for the neutrino experiments. By using common theoretical models for the neutrino- and electron-induced reactions we can challenge the models and improve the modelling of various processes at a level of details that was previously impossible. This then reduces significantly any systematic errors in extracting physics from the next generation neutrino facilities.
Progress requires a major programme of analysis of existing, as well as planned electron scattering experiments from nuclei with complex detector systems at Jefferson Laboratory (USA). We will construct a new analysis framework, which will be used to analyse and archive data in a form that makes it readily accessible and flexible for use by nuclear and particle communities for decades to come. The work will be carried out as part of a new collaborative network including colleagues at MIT, ODU, Jefferson Lab and Tel Aviv University.
Planned Impact
The main near-term impact would be the development of an analysis framework which opens up user-friendly and straightforward access to a wealth of Jefferson Lab data. This will make possible a wider community of scientists to access the data, which will include MPhys and even undergraduate students at UoY and collaborating international institutions. This will have a direct impact on their learning opportunities including exposure to advanced techniques and methods (Monte Carlo, Machine Learning, GEANT4 simulations, etc) that are widely used in a variety of disciplines outside physics research, including medicine, engineering and finance. Students trained in Physics are in high demand by UK and international industry.
Further offshoots from pure research efforts to society as a whole usually take longer to realise, but we can point to the very successful track record the proposers and the UoY nuclear physics group have in identifying and commercialising opportunities arising from our pure research. This is discussed in our pathways to impact plan.
Further offshoots from pure research efforts to society as a whole usually take longer to realise, but we can point to the very successful track record the proposers and the UoY nuclear physics group have in identifying and commercialising opportunities arising from our pure research. This is discussed in our pathways to impact plan.
Organisations
- University of York (Lead Research Organisation)
- University of Glasgow (Collaboration)
- Florida International University (FIU) (Collaboration)
- University of New Hampshire (Collaboration)
- Ohio State University (Collaboration)
- Thomas Jefferson National Accelerator Facility (Collaboration)
- University of Virginia (UVa) (Collaboration)
- University of Richmond (Collaboration)
- University of Pennsylvania (Collaboration)
- Massachusetts Institute of Technology (Collaboration, Project Partner)
- Tel Aviv University (Collaboration)
- Old Dominion University (Project Partner)
Publications

Fegan, S.
(2023)
CLAS Note: Updating e2a fiducial cuts for e4nu

Khachatryan M
(2021)
Electron-beam energy reconstruction for neutrino oscillation measurements.
in Nature
Description | The programme provides key nuclear physics data to better understand detection of the neutrino (through nuclar reactions induced in the detecting medium). The programme supported a body of work to constrain such reactions using electron beams at the Jefferson Laboratory in the USA. It catalysed interaction between nuclear physicists and neutrino physicists to address this key challenge for future research (e.g. the DUNE neutrino facility in the USA). The data from CLAS@JLAB has been published in nature. The key data will be obtained with the upgraded CLAS12@JLAB which will directly reach the kinematics of DUNE. The programme has developed into a core programme on our consolidated grant, with leadership catalysed by this award. |
Exploitation Route | The outcomes (and the continuing programme) will be key to reducing the systematic errror in key parameters to be detrermined at neutrino facilities (e.g. mass differences, mixing angles). The better understanding of nuclear reaction processes will provide data to improve modelling for many areas. The project has already instigated a new reserach direction - using next generation intense compact photon sources as a new method to produce (currently inaccessible) nuclei in the waiting points of the r-process path of nucleosynthesis. |
Sectors | Other |
Description | e4nu PhD funding |
Amount | £60,000 (GBP) |
Organisation | University of York |
Sector | Academic/University |
Country | United Kingdom |
Start | 11/2020 |
End | 04/2024 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | Florida International University (FIU) |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | Massachusetts Institute of Technology |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | Ohio State University |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | Tel Aviv University |
Country | Israel |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | Thomas Jefferson National Accelerator Facility |
Country | United States |
Sector | Public |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | University of Glasgow |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | University of New Hampshire |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | University of Pennsylvania |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | University of Richmond |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | Nuclear Data Mining Initiative for Jefferson Lab |
Organisation | University of Virginia (UVa) |
Country | United States |
Sector | Academic/University |
PI Contribution | We contributed to the successful grant application to the US Department of Energy (DOE) which underpins the data mining initiative. This had 20 named applicants. We used the data mining framework to access archived data from the CLAS spectrometer at Jefferson Lab. We found a new way to access previously unobserved nuclei on the r-process path. This programme will be developed in the future. Contributed to the writeup and analysis for the recent publication in Science (described below). We also have other active analyses. |
Collaborator Contribution | The partners setup the data analysis centres and framework to access archived data from Jefferson Lab. |
Impact | Analyses from the programme have been reported in the press and published in one of the leading scientific journals - Science http://www.dailypress.com/news/science/dp-nws-protons-neutrons-research-20141023-story.html http://www.sciencemag.org/content/346/6209/614.abstract?sid=8a24f19f-6ab9-406a-a97c-dce8fb08d61d |
Start Year | 2008 |
Description | e4nu |
Organisation | Massachusetts Institute of Technology |
Country | United States |
Sector | Academic/University |
PI Contribution | Data mining and analysis for electrons for neutrinos |
Collaborator Contribution | Data mining and analysis for electrons for neutrinos |
Impact | Papers and technical notes |
Start Year | 2019 |
Description | Binding Blocks A Level Masterclass Webinar |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | Presented a webinar "Using Electrons to Learn About Neutrinos" as part of the 'Binding Blocks' nuclear physics masterclass programme for A-level students |
Year(s) Of Engagement Activity | 2022 |
URL | https://sites.google.com/york.ac.uk/bindingblocks/home |
Description | Invited Seminar at Virginia Tech |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Professional Practitioners |
Results and Impact | Invited seminar at Virginia Tech, entitled "Electrons for Neutrinos at Jefferson Lab", November 10th, 2021. Delivered on Zoom with an audience drawn from the entire physics department at the host institution. |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.jlab.org/Hall-B/shifts/index.php?display=admin&task=speakers&deadline=2010-01-04 |
Description | Invited Seminar at the University of Glasgow |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Professional Practitioners |
Results and Impact | Invited seminar at the Univeristy of Glasgow, March 14th, 2022, entitled "Electrons for Neutrinos at Jefferson Lab", as part of the Nuclear and Hadron Physics group's regular series of seminars, attended by group members and PhD students |
Year(s) Of Engagement Activity | 2022 |
Description | Presentation by R. Williams at IoP Nuclear Physics Conference |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Keynote talk by Rhidian Williams at the IoP Nuclear Physics Conference, York, April 2023 |
Year(s) Of Engagement Activity | 2023 |
URL | https://iop.eventsair.com/np2023/keynote-speakers |
Description | UK national IOP nuclear physics conference |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Annual IOP nuclear physics conference 125 participants all over the UK. 3 days long event with a lot of presentations and informal discussions; plenary and parallel sessions |
Year(s) Of Engagement Activity | 2023 |
URL | https://www.iop.org/events/uk-nuclear-physics-conference-2023 |