All SM fundamental fermions have chirtality.valenumr said:This a confusing point for me. If neutrinos have mass, can they have chirality? And another point... Right handed neutrinos "don't exist" because they don't interact in EW theory. At least that is my understanding.
Yes, in principle, we are waiting for ∼ 0.5 eV. It was predicted at the end of the year 2023. But here, this prediction was repeated; maybe the update is close.Vanadium 50 said:So, we have two possibilities.
(A) The KATRIN experiment has chosen to update its results by presenting them at an obscure conference, with absolutely no explanation of what has changed. Indeed, the citation is to the older number.
(B) Some who gave the talk rounded a number differently in their presentation.
And you are asking us to go with Option A.
Vanadium 50 said:And you are asking us to go with Option A.
Wow. Just wow.exponent137 said:Yes,
The actual published paper rounds to 0.8 eV.mfb said:What's unclear?
And the next data release happened, half a year later after it was promised:exponent137 said:By the end of year 2023 KATRIN will release their results (page 26): https://indico.in2p3.fr/event/29681.../attachments/76424/110930/04-TLasserre-v1.pdf
And then in 2025.
"next data release by end 2023 (<0.5 eV sensitivity)
target sensitivity: m < 0.2-0.3 eV by 2025"
The fiends! Imagine the chutzpah of waiting until the analysis was complete before going public with it! The nerve! What kind of scientists are they?exponent137 said:And the next data release happened, half a year later after it was promised:
I thought nothing negative with this sentence. Only for evidence, I gave 1/2 year. It is a natural law, it seems.Vanadium 50 said:I wonder if they can be criminally charged with waiting until they were sure of a result rather than publishing something fish on your preferred schedule. Hang 'em high! Stake them to anthills!
This pushes the limit on the sum of the three neutrino masses to 1.41 eV in a normal hierarchy and 1.46 eV in an inverted hierarchy, when considered together with neutrino oscillation observations.exponent137 said:And the next data release happened, half a year later after it was promised:
https://arxiv.org/pdf/2406.13516
The new upper bound is mν<0.45 eV.
Was this paper the first announcement?
Cosmological neutrino mass bounds are becoming increasingly stringent. The latest limit within ΛCDM from Planck 2018+ACT lensing+DESI is ∑mν < 0.072eV at 95% CL, very close to the minimum possible sum of neutrino masses (∑mν > 0.06eV), hinting at vanishing or even ''negative'' cosmological neutrino masses.
In this context, it is urgent to carefully evaluate the origin of these cosmological constraints. In this paper, we investigate the robustness of these results in three ways: i) we check the role of potential anomalies in Planck CMB and DESI BAO data; ii) we compare the results for frequentist and Bayesian techniques, as very close to physical boundaries subtleties in the derivation and interpretation of constraints can arise; iii) we investigate how deviations from ΛCDM, potentially alleviating these anomalies, can alter the constraints.
Daniel Naredo-Tuero, et al., "Living at the Edge: A Critical Look at the Cosmological Neutrino Mass Bound" arXiv:2407.13831 (July 18, 2024).From a profile likelihood analysis, we derive constraints in agreement at the ∼10% level with Bayesian posteriors. We find that the weak preference for negative neutrino masses is mostly present for Planck 18 data, affected by the well-known "lensing anomaly". It disappears when the new Planck 2020 HiLLiPoP is used, leading to significantly weaker constraints. Additionally, the pull towards negative masses in DESI data stems from the z=0.7 bin, which is in ∼3σ tension with Planck expectations. Without these outliers, and in combination with HiLLiPoP, the bound relaxes to ∑mν<0.11eV at 95% CL. The recent preference for dynamical dark energy alleviates this tension and further weakens the bound. As we are at the dawn of a neutrino mass discovery from cosmology, it will be very exciting to see if this trend is confirmed by future data.
ohwilleke said:The best take on the cosmology bound in light of DESI is that:
Daniel Naredo-Tuero, et al., "Living at the Edge: A Critical Look at the Cosmological Neutrino Mass Bound" arXiv:2407.13831 (July 18, 2024).
I've seen the paper and blogged it yesterday. In that post, I discussed some assumptions from the body text that this new cosmology based neutrino mass limitation is based upon, among other things. I stated that:exponent137 said:There is a new release of data. The upper limit of the sum of neutrino masses is still ever 0,07 eV? Namely, according to the Naredo paper, there should be some outliers in data.
https://arxiv.org/pdf/2411.12022
Before consideration of the full-shape data from DESI and without the limitation of an assumed zero mass bound, the DESI experiment had exhibited a weak preference for negative neutrino masses, and there was a fair amount of discussion in the wake of that about why it did so, which I discussed in this blog post about Daniel Naredo-Tuero, et al., "Living at the Edge: A Critical Look at the Cosmological Neutrino Mass Bound" arXiv:2407.13831 (July 18, 2024) which notes a key outlier in the DESI data that drives some of this result.The DESI collaboration has found that the sum of the three neutrino masses should be less than 0.071 eV at 95% confidence (assuming as a prior only that the sum of the neutrino masses is greater than zero). This disfavors an inverted neutrino hierarchy the demands roughly a minimum of a 0.100 eV sum of neutrino masses, while a normal neutrino hierarchy requires a minimum sum of neutrino masses of only about 0.059 eV. The preference for a normal hierarchy is only about two sigma, however. This estimate is heavily dependent upon the assumed dark energy model, however, and assumes a fixed cosmological constant.
Cosmological neutrino mass bounds are becoming increasingly stringent. The latest limit within ΛCDM from Planck 2018+ACT lensing+DESI is ∑mν < 0.072eV at 95% CL, very close to the minimum possible sum of neutrino masses (∑mν > 0.06eV), hinting at vanishing or even ''negative'' cosmological neutrino masses.
In this context, it is urgent to carefully evaluate the origin of these cosmological constraints. In this paper, we investigate the robustness of these results in three ways: i) we check the role of potential anomalies in Planck CMB and DESI BAO data; ii) we compare the results for frequentist and Bayesian techniques, as very close to physical boundaries subtleties in the derivation and interpretation of constraints can arise; iii) we investigate how deviations from ΛCDM, potentially alleviating these anomalies, can alter the constraints.
I didn't see a discussion of the z=0.7 bin outlier in the most recent paper whose preprint was made available on arXiv yesterday, although it is possible that I missed it as I read only the parts of the paper that were most interesting to me, rather than reading it cover to cover, carefully and in depth.From a profile likelihood analysis, we derive constraints in agreement at the ∼10% level with Bayesian posteriors. We find that the weak preference for negative neutrino masses is mostly present for Planck 18 data, affected by the well-known "lensing anomaly". It disappears when the new Planck 2020 HiLLiPoP is used, leading to significantly weaker constraints. Additionally, the pull towards negative masses in DESI data stems from the z=0.7 bin, which is in ∼3σ tension with Planck expectations. Without these outliers, and in combination with HiLLiPoP, the bound relaxes to ∑mν<0.11eV at 95% CL. The recent preference for dynamical dark energy alleviates this tension and further weakens the bound. As we are at the dawn of a neutrino mass discovery from cosmology, it will be very exciting to see if this trend is confirmed by future data.