Azimuthal Modulations in Photon-Induced Processes
Bibliographic record
Abstract
We review recent theoretical developments and experimental measurements of azimuthal modulations in photon-induced processes, covering both ultra-peripheral heavy-ion collisions (UPCs) and $e^+e^-$ colliders. The azimuthal asymmetries $\cos(nϕ)$ ($n=1,2,3,4$) serve as precision diagnostics that probe the linear polarization of coherent photons, final-state soft radiation effects, and quantum interference phenomena at the femtometer scale. In UPCs, we discuss dilepton production, diffractive dijet and vector meson production, where theoretical predictions show excellent agreement with STAR, ALICE, and CMS measurements. The unique double-slit interference effect in nucleus-nucleus collisions plays a crucial role in describing experimental observations. At $e^+e^-$ colliders, $γγ\toππ$ azimuthal asymmetries enable the direct extraction of helicity amplitude phases, with important implications for hadronic light-by-light scattering and the muon anomalous magnetic moment. Azimuthal modulations establish a powerful tool for multi-dimensional nuclear imaging and precision QED/QCD tests.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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".