Studies of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>C</mml:mi> <mml:mi>P</mml:mi> <mml:mi>T</mml:mi> </mml:mrow> </mml:math> symmetry in positronium decays with the 192 plastic strip J-PET detector
Bibliographic record
Abstract
A direct test of the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:mi>C</a:mi> <a:mi>P</a:mi> <a:mi>T</a:mi> </a:mrow> </a:math> symmetry is performed for the electromagnetic decays of ortho-positronium using the Jagiellonian positron emission tomograph (J-PET). We present the precise measurement of the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>C</c:mi> <c:mi>P</c:mi> <c:mi>T</c:mi> </c:math> -sensitive angular correlation entailing the positronium spin and the momenta of its annihilation photons, surpassing previous studies utilizing the same detection system. Positrons originating from a <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mrow> <e:mmultiscripts> <e:mrow> <e:mi>Na</e:mi> </e:mrow> <e:mprescripts/> <e:none/> <e:mrow> <e:mn>22</e:mn> </e:mrow> </e:mmultiscripts> </e:mrow> </e:math> source are emitted from the detector’s center and subsequently form positronium atoms within the spherical chamber covered with porous material. Reconstruction of annihilation locations using the 192-strip J-PET detector makes it possible to determine the positronium emission direction, which defines the quantization axis along which positronium is polarized, without the application of external magnetic fields. The measurements were performed in total for 356 days resulting in an identification of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mrow> <g:mn>47.8</g:mn> <g:mo>×</g:mo> <g:msup> <g:mrow> <g:mn>10</g:mn> </g:mrow> <g:mrow> <g:mn>6</g:mn> </g:mrow> </g:msup> </g:mrow> </g:math> events with ortho-positronium decays into three photons. The results are consistent with the exactness of <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>C</i:mi> <i:mi>P</i:mi> <i:mi>T</i:mi> </i:math> symmetry with measured asymmetry amplitude <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mrow> <k:mo>−</k:mo> <k:mn>0.00029</k:mn> <k:mo>±</k:mo> <k:mn>0.00022</k:mn> </k:mrow> </k:math> (stat.) and with statistical error four times smaller than the previous best measurement.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".