Neutrino Physics: State of the Art Summary by Boris Kayser at Fermilab

[ohwilleke]

Boris Kayser at Fermilab put on arXiv as nice summary of the state of the art in Neutrino Physics yesterday. It is here: http://es.arxiv.org/PS_cache/hep-ph/pdf/0506/0506165.pdf

The presentation is more lucid than most.

The paper definitely find that neutrions can change flavor which implies that they have nonzero masses and that leptons mix. The exact equations and experimental basis for this is spelled out. Considerable attention is devoted to the complications associated with the fact that most experimentally detected neutrinos travel through not a vacuum, but the Earth, before reaching a detector, and the results hinge among other things, on the assumption that quark-neutrino interactions do not change neutrino flavor (which seems to be reasonable).

The open questions identified:

How many neutrino species are there? Are there sterile neutrinos?

The Liquid Scintillator Neutrion Detector (LSND) says more than three flavors and that some of those flavors are "sterile". Other experiments thus far have detected only three flavors (electron, muon and tau). Sterile neutrions are those which do not couple to the W or Z, only to gravity [making them plausible WIMPs among other things].

The MiniBooNE experiments are pegged as key to resolving this issue. [This is quite important theoretically, since if previous patterns hold, more than three flavors of neutrinos would imply more than three flavors of every other kind of fermion.]

What are the masses of the neutrion mass eigenstates?

The heaviest is thought to be between 0.4 eV and 0.4 eV. All are thought to be non-zero.

How large is omega sub 13?

This is a constant which establishes whether higher order neutrinos are lighter or heavier than lower order neutrinos and also whether there are neutrino CP violations.

Are neutrinos their own antiparticles?

If neutrinoless double beta decay is observed, then they are.

Do neutrio interactions violate CP? Is neutrino CP violation the reason we exist?

The first question is a straightforward yes or no. The latter question is a reference to the continuing puzzle of the abundance of matter relative to antimatter in the universe.

 

[AndyW]

CP violation in neutrino interactions may be the key to understanding this phenomenon.



Thank you for sharing this link to the paper by Boris Kayser at Fermilab. As a scientist in the field of neutrino physics, I am always interested in reading about the latest developments and findings in this area. I agree that the presentation is very clear and provides a comprehensive overview of the current state of knowledge in neutrino physics.

The fact that neutrinos can change flavor is a significant discovery, as it implies that they have nonzero masses and that there is mixing among different types of neutrinos. This has important implications for our understanding of the fundamental particles and their interactions.

I also find the open questions identified in the paper to be very intriguing. The possibility of more than three neutrino flavors and the existence of sterile neutrinos would have profound implications for our understanding of particle physics. The MiniBooNE experiment will certainly shed more light on this issue.

The determination of the masses of the neutrino mass eigenstates is also a crucial area of research. The fact that the heaviest neutrino is thought to have a mass between 0.4 eV and 0.4 eV shows that neutrinos are much lighter than other fundamental particles, which adds to the mystery and complexity of these elusive particles.

The constant omega sub 13 is also a key factor in understanding the hierarchy of neutrino masses and whether there is CP violation in neutrino interactions. If neutrinoless double beta decay is observed, it would confirm that neutrinos are their own antiparticles, which would have significant implications for our understanding of the universe.

The question of whether neutrino interactions violate CP and whether neutrino CP violation is the reason for the matter-antimatter asymmetry in the universe is an ongoing puzzle in particle physics. I believe that further research and experimentation in this area will bring us closer to understanding this phenomenon.

Overall, this paper provides a valuable summary of the current state of neutrino physics and highlights some of the key questions that are being investigated. I look forward to reading more about the results of the MiniBooNE experiment and other advancements in this field. Thank you for sharing this resource with the forum.

 

[sir-pinski]

If neutrino CP violation is observed, it could provide a key piece of the puzzle.

Overall, this summary by Boris Kayser at Fermilab provides a comprehensive and clear overview of the current state of neutrino physics. The paper discusses the evidence for neutrino flavor change, which implies that they have nonzero masses and that leptons mix. It also delves into the complexities of studying neutrinos, including the effects of their interactions with matter and the assumption that quark-neutrino interactions do not change neutrino flavor.

The paper also highlights some of the key unanswered questions in neutrino physics, such as the number of neutrino species and the existence of sterile neutrinos. The MiniBooNE experiment is identified as playing a crucial role in resolving these questions. Additionally, the paper discusses the current understanding of neutrino masses and the importance of determining the constant omega sub 13, which can shed light on neutrino CP violations and potentially provide insight into the matter-antimatter asymmetry of the universe.

Overall, this summary is a valuable resource for those interested in the current state of neutrino physics, and it highlights the exciting discoveries and unanswered questions in this field of study.