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Detecting Neutrinos

11 Claimed Neutrino Detections

This is section 11 of 13.

Results from the respective experiments are offered, when available.

11.1 Cowan–Reines neutrino experiment

The results from SNO were:

The first scientific results of SNO were published on 18 June 2001,  and presented the first clear evidence that neutrinos oscillate (i.e. that they can transmute into one another), as they travel from the Sun. This oscillation, in turn, implies that neutrinos have non-zero masses. The total flux of all neutrino flavours measured by SNO agrees well with theoretical predictions. Further measurements carried out by SNO have since confirmed and improved the precision of the original result.



The detection is simple. Deuterium nucleus ejected its neutron.

However, the experiment assumes only the deuterium nucleus is affected by a neutrino. The deuterium is in a water molecule with an oxygen atom which is a much bigger target when having more nucleons.

This is an inconsistent behavior for a neutrino. It can pass through Earth unaffected but it wiil be caught by only a deuterium atom having only 2 nucleons.

I disagree with these conclusions. There was nothing observed during this experiment to justify them. This is an indirect measurement by looking for results and assuming no other causes are present to explain those results.

Deuterium is an odd Z and odd N making it barely stable.

If the neutrino is claimed to have a non-zero mass then it must be measurable.
For example, the Moon can pass between the Sun and the SNO. The Moon has a substantial non-zero mass so the neutrino passing near the Moon must interact with the Moon, by at least changing the neutrino's path.
Therefore, SNO should see detections affected by the Moon at those times. The Moon's location is predictable.

Certainly, there is no justification of a confirmed change in flavour, unless one knows with certainty its flavour at its source.

It is impossible to measure a neutrino at its point of origin.

This experiment claims to detect the results of an encounter with something having no measurable attributes, other than an amount of energy it carries. For this book, this concidence is not sufficient to consider as evidence.

11.1.1 An Alternate Explanation

Every experiment is intentionally deep under the Earth's surface.

The reason is to limit contamination by events above the surface, like cosmic ray collisions in Eath's atmosphere.

Particles and electromagnetic radiation could be generated by this high velocity particle collider located high in the sky.

The dense matter in Earth's crust above the deep detectors is the desired shield for this possible contamination.

Unfortunately, when deeper toward Earth's core, the possibility of contamination from radioactive decay increases.

KAMLAND project confirmed what were called geoneutrinos from radioactivity near the detector..

11.2 The Kamioka Liquid-scintillator Anti-Neutrino Detector (KamLAND)

I found this web page,  from the US DOE, describing the KamLAND results

Results from KamLAND-Zen

In this data, the problematic 110m-Ag background peak identified in previous searches is reduced by more than a factor of 10.



Results were inconclusive.

The problematic 110m-Ag is a man-made isotope (the little m) which has a short half life.


I found this web page describing the HOMESTAKE results

Homestake gold mine experiment

It was wriiten by Davison E. Sopher at the University of Oregon in 2007.

His conclusion:

The result was that about 1/3 of the expected number of reactions occurred. This suggested three possibilities

1. The experiment was wrong.

2. The standard solar model was wrong.

It would be hard to get the number of neutrinos from p + p --> 2H + electron + neutrino wrong because this is the first step in the main energy producing reaction of the sun and we know how much energy is produced.
The experiment was not capable of seeing the p + p --> 2H + electron + neutrino because most of the neutrinos produced have too low energy to make the chlorine reaction occur.

The neutrinos that it could see result from a rare reaction in the sun.
It would be pretty easy to get the rate for this reaction wrong.

3. The standard picture of neutrinos was wrong. Electron neutrinos could oscillate to become muon neutrinos, which don't interact with chlorine.

At the time, it seemed that explanations 1 or 2 were most likely.



His page has more details to justify his conclusion.

I don't know where to find a list of elements which interact with neutrinos.

He states that chlorine does not. I looked,  but could not find such a list on--line.

11.4 OPERA

These were the results.

In total, five tau neutrinos were detected. On 31 May 2010, OPERA researchers observed the first tau neutrino candidate event in a muon neutrino beam. On 6 June 2012, OPERA announced the observation of a second tau neutrino event. On 26 March 2013, the experiment caught for the third time a muon neutrino oscillating into a tau neutrino during travel from CERN to LNGS. The fourth one was found in 2014, and the fifth was seen in 2015.



The number expected for the 5 detected is not identified.

I don't know one one can conclude that there was an oscillation of a hidden particle between the source and a claimed detection,

11.5 DONUT

this paper has its results.

Final tau-neutrino results from the DONuT experiment

This is from  its extract.

The DONuT experiment collected data in 1997 and published first results in 2000 based on four observed vt charged-current (CC) interactions. The final analysis of the data collected in the experiment is presented in this paper, based on 3.6x10^17 protons on target using the 800 GeV Tevatron beam at Fermilab. The number of observed vt  CC events is 9 with an estimated background of 1.5 events, from a total of 578 observed neutrino interactions.



They claimed 9 events.

The number expected is not identified.

The distinction between events and interactions (or neutrino detections) is not described

A background of 1.5 events suggests these numbers are from averages, not from the raw data.

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last change 04/04/2022