Study group members

Please consult the spreadsheet below for the list of members for the TRISEP 2021 study groups.

https://drive.google.com/file/d/1vJ_SQmq47wCZQq9qanINY6HoXyh1SiqC/view

Ca Double Beta Decay detector

Design a double beta decay detector with calcium-doped liquid scintillator that will reach the normal hierarchy. Pick a location, design the detector, loading scheme, and run time. Consider the CaNDLES experiment as a starting point, and expand from there.  This paper https://arxiv.org/abs/2008.09288 will get you started. 

Cosmogenic activation

Effect of overburden of the rock with regards to the radioactive background and set threshold of overburden needed to stop cosmogenic activation. 

  • What process contribute to cosmogenic activation on material? 
  • What is the overburden needed to stop cosmogenic activation in materials? 
  • What is the effect on altitude on cosmogenic activation? can my detector material flight? 
  • What are the systematics in the cosmogenic activation estimates and what is their deviations? (neutron flux and production cross sections) 

Here are some papers to get you started: Ziegler_terrestrial_cosmic_rays46819Dongming_Mei_Cosmogenic_activation_2016-2

https://arxiv.org/abs/1708.07449

High Mass WIMPs Below the Neutrino Floor 

New proposed dark matter direct detection experiments such as Darwin and ARGO are proposing to go the neutrino “floor”. Of course it is not a floor, it is possible to search for weaker WIMP-nucleon couplings. What is your concept for an experiment that is sensitive to dark matter in the presence of, say 1 or 10, neutrino interactions in the target over your experiment? What kind of directionality do you need to reduce background? How well do you need to understand the neutrino background? 

What technologies cold you consider beyond that of Darwin and/or ARGO. These papers: https://arxiv.org/pdf/1307.5458.pdf https://arxiv.org/pdf/2104.07634.pdf and darwin-observatory.org will help you get started. 

Dark Sector & Dark Matter Production At SNOLAB 

Investigate the possibility of generating light dark matter candidates directly underground at the SNOLAB facility, using the rock surroundings the lab and a “small-scale” electron linear accelerator (e-linac).  

If we were to consider a e-linac  similar to what is being use for the ARIEL facility at TRIUMF (https://fiveyearplan.triumf.ca/teams-tools/e-linac-electron-linear-accelerator/), how big would the rock layer have to be in order to produce dark matter particles but shield from any possible secondary particles that could be a source of background for all other experiments in the lab?  

Conceptually design what would be an ideal detector (or detectors) to place downstream from the e-linac, optimized for light dark matter detection. Carefully explain the full process in your design idea and highlight/motivate any specific technology or technique that you would adopt. You can also consider modifying current experiments. Here some reference to help with this question: 

Looking for Long Lived Neutrals at Colliders 

Long lived neutral particles are an intriguing Beyond Standard Model (BSM) possibility. One could imagine models in which neutral particles are created that escape the detector before decaying to SM particles. The MATHUSLA collaboration has a letter of intent to study such particles. See arXiv:1811.00927. Other proposals include SHiP (https://arxiv.org/abs/1807.11737 ), CODEX, and FASER. 

Describe some BSM models that create LLPs (Long Lived Particles). What sort of models could you probe with a detector far from the interaction point at the proposed International Linear Collider? How do the different designs do this? How could you build a next-generation LLP detector at the LHC or ILC? Could you benefit by putting the detector underneath the ground? i.e. How do muons create backgrounds and can muons create backgrounds that look like they are coming up from the interaction point? (For this part of the question do not worry about cost. The LHC is 100 meters underground. If you like, assume the ILC is deeper than that but keep it reasonable.) 

Start with the Mathusla and SHiP arXiv articles listed above, but don’t stop there. What LLP detector at a collider would you like to see in 25 to 40 years? 

Measuring the Cosmic Neutrino Background

The cosmic microwave background has been studied very well and greatly increased our knowledge about the early Universe. There is also cosmic neutrino background at an even lower temperature, which still holds lots of secrets. Measuring cosmic neutrino background is very challenging and ideas of how to approach this measurement are necessary. How would you do that?  

  • What is cosmic microwave background?  
  • What is cosmic neutrino background and what can it tell us about the early Universe?  
  • What are the experimental challenges for this measurement?  
  • What kind of approach/detector technology has the best chance of being able to measure cosmic neutrino background?  

Remember: think on a 25 to 40 year time scale and do not worry about cost.   Optional question: Why is knowledge about the early Universe so interesting?  

Here are some excellent articles on the subject to get you started:  

MSW effect in long baseline

Neutrino oscillations for neutrinos passing through matter (e.g. the Earth) are influenced by the MSW effect due to interactions with particles in the medium they are passing through.  Because the Earth consists of matter rather than anti-matter, the MSW effect is asymmetric for neutrinos and antineutrinos.  Though the MSW effect has been experimentally observed in solar neutrinos, it should also play a role in long baseline experiments, where neutrinos pass through the Earth’s crust and mantle, but long baseline experiments to date have not had the sensitivity to detect these effects.  The PDG’s article on neutrino oscillation goes through the derivation of the MSW effect and shows how it affects oscillations, see section 14.5: https://pdg.lbl.gov/2020/reviews/rpp2020-rev-neutrino-mixing.pdf

1. How would you design a long baseline experiment that would be able to observe the difference between neutrino and antineutrino oscillations caused by the MSW effect?  Keep in mind that asymmetry between neutrinos and antineutrinos can also arise from CP violation if δCP is non-zero. Here is an article to get you started – you can find more by searching arxiv.org: https://arxiv.org/pdf/hep-ph/0411309.pdf

2. The MSW effect could provide a probe of the neutrino mass hierarchy, as discussed here: https://arxiv.org/pdf/1708.05495.pdf.  What would be the requirements for a long baseline experiment to not only observe the MSW effect but to measure it well enough to distinguish normal from inverted hierarchy?

 A Muon Collider to Solve muon (g-2)?

The anomalous magnetic moment of the muon is a hot topic now. For this question, design a muon collider that will measure the Beyond Standard Model (BSM) physics of muon (g-2) if the discrepancy is BSM physics. 

  • How does it work? ie what interactions can you measure that are relevant to muon (g-2)? 
  • What sort of beam energies are needed? What sort of luminosities? 
  • What is your concept for a detector to make the measurements at the collider? 
  • Remember: think on a 25 to 40 year time scale and do not worry about cost.  
  • Optional question: What is the neutrino flux from such a muon collider like? Is this neutrino flux physically dangerous to humans? 

This excellent article on the subject will get you started: https://arxiv.org/pdf/2101.10334.pdf 

Neutrino detector in space

Ignoring the obvious practical difficulties, if a large neutrino detector could be constructed anywhere in the solar system, where would you place it and what measurement(s) could you make with it?

This is a very open-ended question, and you can be creative in your answer, but you should back up your idea with numbers.  Show how this detector could perform better at your chosen measurement than the same detector on Earth.  To generate ideas, you might start by thinking about how neutrino fluxes and background rates will vary in different parts of the solar system.

An Experiment to explore normal hierarchy for double beta decay? 

Current and near future double beta decay experiments are aiming to reach sensitivity in the inverted hierarchy. In order to reach the normal hierarchy mass ranges, detectors either will have to be very large or a new technology is needed.  

  • What is the detailed mechanism for double beta decay?  
  • What is meant by mass hierarchy?  
  • What are the experimental conditions that need to be met for a double beta decay?  
  • Why is it so hard to reach the normal hierarchy ranges and what will be needed?  
  • Remember: think on a 25 to 40 year time scale and do not worry about cost.   
  • Optional question: Would discovering neutrinoless double beta decay clearly tell us the mass of the neutrino?  

This excellent article on the subject will get you started: Neutrinoless Double-Beta Decay: Status and Prospects (annualreviews.org) 

Radon implantation and Surface screening

Radon implantation depth in material, with help of SRIM/TRIM simulation. Code easily downloadable via http://srim.org/ and you can run it online. 

  • What is the mean path for an alpha particle? Understand the dE/dx of alpha particle. 
  • Why can Radon222 be problematic for low background experiments? What is alpha energy? Which energy region of interest for rare event searches?  
  • What is the probability that radon stick on the surface? 
  • Simulate implantation depth profile of radon on different materials- Ge, Cu, Si. (via trim). 
  • How can we estimate alpha surface activity on materials? What techniques are available and what would be needed for the next generation low-background experiments? (energy resolution, surface area, PSD) 

Some articles to get you started: 

Clemenza2011_Article_Radon-inducedSurfaceContaminat
Matthew_Stein_Dark_Matter_2017-3

Using supernova neutrinos to learn about neutrino mass and hierarchy

Supernova (SN) neutrinos from a close-by galactic supernova can tell us a lot about both the supernova and the neutrino properties. One can use a time-of-flight (TOF) method to learn about the neutrino mass. Of course these events are very rare – with only 1-3 per century. SN produce all types of neutrinos and by using different detection mechanism, one can also learn more about the neutrino mass hierarchy. So, if you could have no financial constraints, what set of detectors would you need to be well prepared for a galactic SN event.  

  • What types of neutrinos, how many and in what ratio are produced by a SN event?  
  • How does the TOF method work and allow us to learn about neutrino mass?  
  • What are the experimental conditions/targets that are useful here?  
  • How can SN neutrino measurement contribute to the knowledge about mass hierachy?  
  • Remember: think on a 25 to 40 year time scale and do not worry about cost.   
  • Optional question: Is there a difference between neutrinos and antineutrinos coming from a SN?  

Here are some excellent articles on the subject to get you started:  

Sterile neutrinos at JUNO

If you could change the direction of Fermilab’s neutrino beam to point at JUNO instead of DUNE, what would be Juno’s sensitivity to the sterile neutrino problem?