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    • Keywords


      Dijet, modified leading log approximation, coupling constant

    • Abstract


      Inclusive momentum distributions of charged particles are measured in dijet events. Events were produced at the AMY detector with a centre of mass energy of 60 ${\rm GeV}$. Our results were compared, on the one hand to those obtained from other $e^+ e^-$, $ep$ as well as CDF data, and on the other hand to the perturbative QCD calculations carried out in the framework of the modified leading log approximation (MLLA) and assuming local parton--hadron duality (LPHD). A fit of the shape of the distributions yields $\scr Q_{eff} = 263 \pm 13 {\rm MeV}$ for the AMY data. In addition, a fit to the evolution of the peak position with dijet mass using all data from different experiments gives $\scr Q_{eff} = 226 \pm 18 {\rm MeV}$. Next, αs was extracted using the shape of the distribution at the Z0 scale, with a value of 0.118 \pm 0.013. This is consistent, within the statistical errors, with many accurate measurements. We conclude that it is the success of LPHD + MLLA that the extracted value of $\alpha_{s}$ is correct. Possible explanations for all these features will be presented in this paper.

    • Author Affiliations



      1. Department of Physics, Ferdowsi University of Mashhad, 91775-1436, Mashhad, Iran
      2. Payesh Research Institute of Fundamental Physics, Mashhad, Iran
      3. Department of Physics, Payame Noor University, P.O. Box 19395-3697 Tehran, Iran
      4. Physics Department, Yazd University, 89195-741, Yazd, Iran
    • Dates

  • Pramana – Journal of Physics | News

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