@article{dbe30edd85cf4eacb2ff35b214311e25,
title = "String theory and the path to unification: A review of recent developments",
abstract = "This is a pedagogical review article surveying the various approaches towards understanding gauge coupling unification within string theory. As is well known, one of the major problems confronting string phenomenology has been an apparent discrepancy between the scale of gauge coupling unification predicted within string theory, and the unification scale expected within the framework of the Minimal Supersymmetric Standard Model (MSSM). In this article, I provide an overview of the different approaches that have been taken in recent years towards reconciling these two scales, and outline some of the major recent developments in each. These approaches include string GUT models; higher affine levels and non-standard hypercharge normalizations; heavy string threshold corrections; light supersymmetric thresholds; effects from intermediate-scale gauge and matter structure beyond the MSSM; strings without supersymmetry; and strings at strong coupling.",
author = "Dienes, {Keith R.}",
note = "Funding Information: T. Damour, A. Faraggi, E. Kiritsis, J. March-Russell, R. Myers, Y. Nir, A. Sagnotti,a nd S.-H.H. Tye for careful preliminary readings of this article, and for numerous comments and suggestions.T his article originally grew out of an invited review talk given at the Conference “Unification: J;rom the Weak Scale to the Planck Scale” which was held at the Institute for Theoretical Physics in Santa Barbara, California, in October 1995, and I benefittedg reatly from conversationsw ith many participants both at this conference and at the workshop that precededi t. My greatestd ebt, however, is to my collaboratorsf rom whom I have learnedm uch of this subject, and who were co-authorso n some of the work described herein. These include Alon Faraggi (with whom I collaborated on portions of the material presentedi n Sections 5-8); John March-Russell (portions of Sections 4 and 5); and Moshe Moshe and Robert Myers (portions of Section 9). Indeed, many of the ideas in this review have been drawn from the papers that resulted from these collaborations,a nd I thank my co-authors for their extraordinary indulgence in this regard. This work was supportedi n part by DOE Grant No. DE-FG-0290ER40542.",
year = "1997",
month = aug,
doi = "10.1016/S0370-1573(97)00009-4",
language = "English (US)",
volume = "287",
pages = "447--525",
journal = "Physics Report",
issn = "0370-1573",
publisher = "Elsevier B.V.",
number = "6",
}