Low-Scale String Resonances at the Large Hadron Collider

• Author / Creator

  Pourya Vakilipourtakalou

• If the large extra dimensions scenario [1, 2] is correct, the string scale Ms of string theory
  can be of the order of a few TeV; a theory known as low-scale string theory. In the D-brane
  [3, 4] formulation of low-scale string theory, string resonances (Regge excitations) can be produced
  in proton-proton collisions through 2-parton scatterings, and furthermore, in the limit
  Ms -> infinity, these scattering amplitudes match the tree-level scattering amplitudes derived in
  QCD. Using the cross-sections and decay widths of the string resonances, we write a Monte
  Carlo event generator, STRINGS-1.00, for the production and decay of the first and second
  string resonances, such that colour, quark flavour, baryon number, electric charge and total
  angular momentum are conserved. STRINGS is also capable of generating QCD tree-level
  scatterings in proton-proton collisions. We study the discovery potential of the first string
  resonance at the LHC (luminosity = 140 fb^-1) and the upcoming HL-LHC run (luminosity =
  3000 fb^-1) with a centre-of-mass energy of
  sqrt(s) = 13 TeV. This is done by using STRINGS to
  generate events for different string scales and studying the significance of the signals over the
  background in the dijet invariant mass distribution. For luminosities of 140 fb^-1 and 3000
  fb^-1, we find the maximum detectable string scales to be 8.4 TeV and 9.1 TeV, respectively.
  We also use results from an ATLAS paper [5] to set upper limits on the cross-section and
  lower limits on string scale of the first string resonance. We find with 95% confidence level
  that string resonances with string scales lower than 7.4 TeV do not exist in ATLAS results
  with an integrated luminosity of 37 fb^-1.

• Subjects / Keywords

  • String Resonances
  • String Phenomenology
  • Beyond Standard Model Physics

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-rn3h-d583

• License

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