{
  "_oai": {
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  "authors": [
    {
      "raw_name": "Hooman Davoudiasl", 
      "affiliations": [
        {
          "country": "USA", 
          "value": "Physics Department, Brookhaven National Laboratory, High Energy Theory Group, Upton, New York 11973, USA"
        }
      ], 
      "surname": "Davoudiasl", 
      "given_names": "Hooman", 
      "full_name": "Davoudiasl, Hooman"
    }, 
    {
      "raw_name": "Julia Gehrlein", 
      "affiliations": [
        {
          "country": "USA", 
          "value": "Physics Department, Brookhaven National Laboratory, High Energy Theory Group, Upton, New York 11973, USA"
        }
      ], 
      "surname": "Gehrlein", 
      "given_names": "Julia", 
      "full_name": "Gehrlein, Julia"
    }, 
    {
      "raw_name": "Robert Szafron", 
      "affiliations": [
        {
          "country": "USA", 
          "value": "Physics Department, Brookhaven National Laboratory, High Energy Theory Group, Upton, New York 11973, USA"
        }
      ], 
      "surname": "Szafron", 
      "given_names": "Robert", 
      "full_name": "Szafron, Robert"
    }
  ], 
  "titles": [
    {
      "source": "APS", 
      "title": "Is the <math><mrow><mover><mrow><mi>\u03b8</mi></mrow><mrow><mo>\u00af</mo></mrow></mover></mrow></math> Parameter of QCD Constant?"
    }
  ], 
  "dois": [
    {
      "value": "10.1103/PhysRevLett.129.161802"
    }
  ], 
  "publication_info": [
    {
      "journal_volume": "129", 
      "journal_title": "Physical Review Letters", 
      "material": "article", 
      "journal_issue": "16", 
      "year": 2022
    }
  ], 
  "$schema": "http://repo.scoap3.org/schemas/hep.json", 
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    "source": "APS", 
    "method": "APS", 
    "submission_number": "0184dc4049c511ed91f9a2b26b995c7b"
  }, 
  "page_nr": [
    6
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  "license": [
    {
      "url": "https://creativecommons.org/licenses/by/4.0/", 
      "license": "CC-BY-4.0"
    }
  ], 
  "copyright": [
    {
      "statement": "Published by the American Physical Society", 
      "year": "2022"
    }
  ], 
  "control_number": "73204", 
  "record_creation_date": "2022-10-11T14:30:03.288869", 
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  "collections": [
    {
      "primary": "HEP"
    }, 
    {
      "primary": "Citeable"
    }, 
    {
      "primary": "Published"
    }
  ], 
  "arxiv_eprints": [
    {
      "categories": [
        "hep-ph", 
        "astro-ph.CO"
      ], 
      "value": "2204.09694"
    }
  ], 
  "abstracts": [
    {
      "source": "APS", 
      "value": "Testing the cosmological variation of fundamental constants of nature can provide valuable insights into new physics scenarios. While many such constraints have been derived for standard model coupling constants and masses, the <math><mover><mi>\u03b8</mi><mo>\u00af</mo></mover></math> parameter of QCD has not been as extensively examined. In this Letter, we discuss potentially promising paths to investigate the time dependence of the <math><mover><mi>\u03b8</mi><mo>\u00af</mo></mover></math> parameter. While laboratory searches for <math><mrow><mi>C</mi><mi>P</mi></mrow></math>-violating signals of <math><mover><mi>\u03b8</mi><mo>\u00af</mo></mover></math> yield the most robust bounds on today\u2019s value of <math><mover><mi>\u03b8</mi><mo>\u00af</mo></mover></math>, we show that <math><mi>C</mi><mi>P</mi></math>-conserving effects provide constraints on the variation of <math><mover><mi>\u03b8</mi><mo>\u00af</mo></mover></math> over cosmological timescales. We find no evidence for a variation of <math><mrow><mover><mrow><mi>\u03b8</mi></mrow><mrow><mo>\u00af</mo></mrow></mover></mrow></math> that could have implied an \u201ciron-deficient\u201d Universe at higher redshifts. By converting recent atomic clock constraints on a variation of constants, we infer <math><mrow><mi>d</mi><mo>(</mo><msup><mrow><mover><mrow><mi>\u03b8</mi></mrow><mrow><mo>\u00af</mo></mrow></mover></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo><mo>/</mo><mi>d</mi><mi>t</mi><mo>\u2264</mo><mn>6</mn><mo>\u00d7</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>\u2212</mo><mn>15</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>yr</mi></mrow><mrow><mo>\u2212</mo><mn>1</mn></mrow></msup></mrow></math>, at <math><mn>1</mn><mi>\u03c3</mi></math>. Finally, we also sketch an axion model that results in a varying <math><mover><mi>\u03b8</mi><mo>\u00af</mo></mover></math> and could lead to excess diffuse gamma ray background, from decays of axions produced in high redshift supernova explosions."
    }
  ], 
  "imprints": [
    {
      "date": "2022-10-11", 
      "publisher": "APS"
    }
  ]
}