String threshold corrections in models with spontaneously broken supersymmetry

Jul, 1998
59 pages
Published in:
  • Nucl.Phys.B 540 (1999) 87-148
e-Print:
Report number:
  • CERN-TH-97-44,
  • NEIP-97-007,
  • IOA-97-08,
  • LPTENS-97-11,
  • CPTH-S499-0397,
  • CPTH-S499.0397

Citations per year

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Abstract: (Elsevier)
We analyse a class of four-dimensional heterotic ground states with N = 2 space-time supersymmetry. From the ten-dimensional perspective, such models can be viewed as compactifications on a six-dimensional manifold with SU (2) holonomy, which is locally but not globally K 3 × T 2 . The maximal N = 4 supersymmetry is spontaneously broken to N = 2. The masses of the two massive gravitinos depend on the ( T, U ) moduli of T 2 . We evaluate the one-loop threshold corrections of gauge and R 2 couplings and we show that they fall in several universality classes, in contrast to what happens in usual K 3 × T 2 compactifications, where the N = 4 supersymmetry is explicitly broken to N = 2, and where a single universality class appears. These universality properties follow from the structure of the elliptic genus. The behaviour of the threshold corrections as functions of the moduli is analysed in detail: it is singular across several rational lines of the T 2 moduli because of the appearance of extra massless states, and suffers only from logarithmic singularities at large radii. These features differ substantially from the ordinary K 3 × T 2 compactifications, thereby reflecting the existence of spontaneously broken N = 4 supersymmetry. Although our results are valid in the general framework defined above, we also point out several properties, specific to orbifold constructions, which might be of phenomenological relevance.
Note:
  • 59 pages, Latex2e, final version to appear in Nucl. Phys. B
  • supersymmetry: spontaneously broken
  • threshold: correction
  • string model
  • universality
  • ground state: heterotic
  • moduli space
  • compactification
  • coupling
  • bibliography