30 Eylül 2024 Dergi makalesi Açık Erişim

CERN İşbirliği

Citation Style Language JSON

{
  "DOI": "10.1103/PhysRevLett.133.142301", 
  "abstract": "<p>A search for collective effects inside jets produced in proton-proton collisions is performed via correlation measurements of charged particles using the CMS detector at the CERN LHC. The analysis uses data collected at a center-of-mass energy of $\\sqrt{s}=13\\text{}\\text{}\\mathrm{TeV}$, corresponding to an integrated luminosity of $138\\text{}\\text{}{\\mathrm{fb}}^{-1}$. Jets are reconstructed with the anti-${k}_{T}$ algorithm with a distance parameter of 0.8 and are required to have transverse momentum greater than 550 GeV and pseudorapidity $|{\\eta }^{\\text{jet}}|&lt;1.6$. Two-particle correlations among the charged particles within the jets are studied as functions of the particles' azimuthal angle and pseudorapidity separations ($\\Delta {\\varphi }^{*}$ and $\\Delta {\\eta }^{*}$) in a jet coordinate basis, where particles' ${\\eta }^{*}$, ${\\varphi }^{*}$ are defined relative to the direction of the jet. The correlation functions are studied in classes of in-jet charged-particle multiplicity up to ${N}_{\\mathrm{ch}}^{j}\\approx 100$. Fourier harmonics are extracted from long-range azimuthal correlation functions to characterize azimuthal anisotropy for $|\\Delta {\\eta }^{*}|&gt;2$. For low-${N}_{\\mathrm{ch}}^{j}$ jets, the long-range elliptic anisotropic harmonic, ${v}_{2}^{*}$, is observed to decrease with ${N}_{\\mathrm{ch}}^{j}$. This trend is well described by Monte Carlo event generators. However, a rising trend for ${v}_{2}^{*}$ emerges at ${N}_{\\mathrm{ch}}^{j}\\gtrsim 80$, hinting at a possible onset of collective behavior, which is not reproduced by the models tested. This observation yields new insights into the dynamics of jet evolution in the vacuum.</p>", 
  "author": [
    {
      "family": "CERN \u0130\u015fbirli\u011fi"
    }
  ], 
  "container_title": "Physical Review Letters", 
  "id": "274677", 
  "issue": "14", 
  "issued": {
    "date-parts": [
      [
        2024, 
        9, 
        30
      ]
    ]
  }, 
  "title": "Observation of Enhanced Long-Range Elliptic Anisotropies Inside High-Multiplicity Jets in $pp$ Collisions at $\\sqrt{s}=13\\text{}\\text{}\\mathrm{TeV}$", 
  "type": "article-journal", 
  "volume": "133"
}