TY - CHAP
T1 - Strings on orbifolds
AU - Choi, Kang Sin
AU - Kim, Jihn E.
N1 - Funding Information:
* Research supported m part by NSF Grant PHY80-19754 Supported by an NSF Graduate Student Fellowship
PY - 2006
Y1 - 2006
N2 - As discussed in the previous chapter, the heterotic string possesses very rich symmetries. It naturally describes SO(32) and E8 ×E8 gauge group, by assigned charges along the string. Also it has sixteen real (N = 4 in four dimension) supersymmetries. However, these symmetries are too large from the phenomenological point of view, by the criteria discussed in Chap. 2. Namely, in weakly coupled string theories, unless the fortuitous appearance of family structure results from the twisted sector as we will see it is better for a big gauge group is given already so that the standard model(SM) gauge group of rank 4 can be embedded there. In addition, as emphasized in Chap. 2, the group must allow "spinor representation" of SO(10). This leads to the E8 ×E′8 heterotic string as the first choice. In a strongly coupled string, nonperturbative effects may produce defects and we have to consider branes also. Compactification of strongly coupled strings are briefly sketched in Appendix B.2.
AB - As discussed in the previous chapter, the heterotic string possesses very rich symmetries. It naturally describes SO(32) and E8 ×E8 gauge group, by assigned charges along the string. Also it has sixteen real (N = 4 in four dimension) supersymmetries. However, these symmetries are too large from the phenomenological point of view, by the criteria discussed in Chap. 2. Namely, in weakly coupled string theories, unless the fortuitous appearance of family structure results from the twisted sector as we will see it is better for a big gauge group is given already so that the standard model(SM) gauge group of rank 4 can be embedded there. In addition, as emphasized in Chap. 2, the group must allow "spinor representation" of SO(10). This leads to the E8 ×E′8 heterotic string as the first choice. In a strongly coupled string, nonperturbative effects may produce defects and we have to consider branes also. Compactification of strongly coupled strings are briefly sketched in Appendix B.2.
UR - http://www.scopus.com/inward/record.url?scp=33749165733&partnerID=8YFLogxK
U2 - 10.1007/3-540-32764-9_6
DO - 10.1007/3-540-32764-9_6
M3 - Chapter
AN - SCOPUS:33749165733
SN - 3540327630
SN - 9783540327639
T3 - Lecture Notes in Physics
SP - 149
EP - 183
BT - Quarks and Leptons From Orbifolded Superstring
ER -