Measurement of flow harmonics with multi-particle cumulants in Pb+Pb collisions at $$\sqrt{s_{\mathrm {NN}}}=2.76$$ s NN = 2.76 TeV with the ATLAS detector
Bibliographic record
Abstract
ATLAS measurements of the azimuthal anisotropy in lead–lead collisions at $$\sqrt{s_{\mathrm {NN}}}=2.76$$ TeV are shown using a dataset of approximately 7 $$\upmu $$ b $$^{-1}$$ collected at the LHC in 2010. The measurements are performed for charged particles with transverse momenta $$0.5<p_{\mathrm {T}}<20$$ GeV and in the pseudorapidity range $$|\eta |<2.5$$ . The anisotropy is characterized by the Fourier coefficients, $$\mathrm {v}_n$$ , of the charged-particle azimuthal angle distribution for $$n = 2$$ –4. The Fourier coefficients are evaluated using multi-particle cumulants calculated with the generating function method. Results on the transverse momentum, pseudorapidity and centrality dependence of the $$\mathrm {v}_n$$ coefficients are presented. The elliptic flow, $$\mathrm {v}_2$$ , is obtained from the two-, four-, six- and eight-particle cumulants while higher-order coefficients, $$\mathrm {v}_3$$ and $$\mathrm {v}_4$$ , are determined with two- and four-particle cumulants. Flow harmonics $$\mathrm {v}_n$$ measured with four-particle cumulants are significantly reduced compared to the measurement involving two-particle cumulants. A comparison to $$\mathrm {v}_n$$ measurements obtained using different analysis methods and previously reported by the LHC experiments is also shown. Results of measurements of flow fluctuations evaluated with multi-particle cumulants are shown as a function of transverse momentum and the collision centrality. Models of the initial spatial geometry and its fluctuations fail to describe the flow fluctuations measurements.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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".