T2K: >2 sigma preference for neutrino CP violation

In summary, the presentation at ICHEP discussed the results from the T2K experiment, which measured the CP phase of neutrino oscillations to be around -2 with 0 being unlikely. This result is not very precise yet, but T2K plans to collect more data in the next 10 years to improve the measurement. Other experiments will also contribute to this research. However, the current generation of experiments may not be able to exclude CP conservation at high confidence, but the next generation may have a better chance. Overall, the CP phase is a free parameter in all models of neutrino mixing.
  • #1
mfb
Mentor
Insights Author
37,137
13,982
Presentation at ICHEP
Report at university website

The main plot is on slide 18: ##\delta_{CP}## seems to be somewhere around -2, with 0 appearing unlikely. In other words, muon neutrinos oscillate more likely to electron neutrinos than anti-muon neutrinos oscillate to anti-electron neutrinos.

The measurement is not very precise yet, but unlike for most LHC measurements, there is no reason to expect 0 - the CP phase is a free parameter, it can be anything. T2K plans to collect 10 times more data within the next 10 years, so we will get more precise measurements in the not so distant future. Other experiments will contribute as well.
 
Physics news on Phys.org
  • #2
Well, let us not get over-excited with this. This result does not add a lot to what we already had from T2K and CP conservation is still essentially within the ##2\sigma## region. If there are only standard oscillations, the early T2K results in the neutrino channel would be a statistical fluctuation regardless of the parameters, just one that would be more likely in the case of maximal CP-violation.

This being said, T2K will continue to take data for some time still and NOvA as well. However, to me it appears unrealistic for the current generation of experiments to exclude CP-conservation at high confidence (##5\sigma +##). However, the next generation of experiments will stand a good chance of doing so and probing the mass ordering.
 
  • #3
Well, there is no prediction of δ_CP = 0, it can have any value. That makes the 2 sigma more relevant than "we saw a 2 sigma deviation from the standard model prediction".

The expected significance was a bit below 2 sigma, a naive scaling with the protons on target would lead to an expected significance close to 5 sigma in 2027 from T2K alone.
 
  • #4
So is the point here that it's a free parameter in the standard model, but not in certain BSM approaches?
 
  • #5
Neutrino mixing is beyond the standard model, and it is a free parameter in all models I am aware of.
 
  • Like
Likes Lord Crc and vanhees71

Related to T2K: >2 sigma preference for neutrino CP violation

What is T2K and why is it significant?

T2K, or Tokai to Kamioka, is an international collaboration of scientists conducting experiments to study neutrino oscillations. It is significant because it has provided evidence for the phenomenon of neutrino CP violation, which is a key piece of information in understanding the behavior of neutrinos and their role in the universe.

What is neutrino CP violation and why is it important?

Neutrino CP violation is the idea that neutrinos and their antiparticles, antineutrinos, behave differently. This is significant because it could potentially explain why there is more matter than antimatter in the universe, a fundamental question in physics.

What does ">2 sigma preference" mean in the context of T2K?

">2 sigma preference" refers to the level of significance of the data collected by the T2K experiment. In this case, it means that there is a 95% chance that the observed difference in behavior between neutrinos and antineutrinos is not due to random chance, but is a real phenomenon.

How was the T2K experiment conducted?

The T2K experiment involves sending a beam of neutrinos from the J-PARC accelerator in Japan to the Super-Kamiokande detector in Kamioka, Japan. The neutrinos travel 295 kilometers through the earth, allowing the scientists to observe any changes in their behavior. The experiment is ongoing and data is continuously being collected and analyzed.

What are the implications of the T2K results?

The T2K results provide strong evidence for the existence of neutrino CP violation, which has important implications for our understanding of the universe. It could potentially help us answer questions about the origins of matter and antimatter, and could also lead to further advancements in neutrino research and technology.

Similar threads

I T2K sees ~3 sigma evidence for neutrino CP violation
    • High Energy, Nuclear, Particle Physics
Replies
23
Views
4K
B Where Can I Find The New Daya Bay Results?
    • High Energy, Nuclear, Particle Physics
Replies
7
Views
1K
Neutrino oscillation - CP violation obscured by matter effect?
    • High Energy, Nuclear, Particle Physics
Replies
1
Views
2K
I Can Majorana Neutrinos Oscillate Between Neutrino and Antineutrino States?
    • Beyond the Standard Models
Replies
1
Views
2K
B Is CP Symmetry Violation the Key to Explaining Matter-Antimatter Imbalance?
    • Other Physics Topics
Replies
5
Views
1K
I New Constraints On The Higgs Boson Width
    • High Energy, Nuclear, Particle Physics
Replies
11
Views
1K
Do Neutrinos Violate Energy Conservation During Oscillation?
    • High Energy, Nuclear, Particle Physics
Replies
17
Views
5K
Helicity interactions of the Z0
    • High Energy, Nuclear, Particle Physics
Replies
2
Views
2K
I B -> s µµ decays: Current status
    • High Energy, Nuclear, Particle Physics
2
Replies
49
Views
9K
I How powerful would a collider have to be to observe a sphaleron?
    • High Energy, Nuclear, Particle Physics
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top