TY - JOUR

T1 - New constraints on SO(10) model-building from string theory

AU - Dienes, Keith R.

N1 - Funding Information:
I would like to thankS . Barr, G. CleaverJ,. Erler, A. HananyC, . Kolda, J. Lykken, E Wilczek, and E. Witten for discussionsI . am particularlgy ratefutl o K.S. Babu, Z. KakushadzeE,. Kiritsis, and S.-H.H. Tye for manyi nsightfucl ommenttsh roughoutth e courseo f this work, and to J. March-Russelflo r collaboration\[s1 5,16\w] hichsupplied many of the generala rgumentws hich have been exploitedfo r the SO(IO) and E6 analysesp resentedin this paper.I also wish to thank the CERN Theory Group for hospitalityw hilep ortionso f this paperw erew ritten.T his work was supporteidn part by DOE GrantN o. DE-FG-0290ER40542.

PY - 1997/3/17

Y1 - 1997/3/17

N2 - A recent analysis of the methods by which higher-level gauge symmetries are realized in string theory has made it possible to systematically obtain new constraints on string GUT model-building. In this paper, we perform such a study for the case of SO(10) free-field string GUT models, and find a number of significant new results. First, we show that within the conventional string models using the so-called "diagonal" embeddings, all representations larger than the 16 must always transform as singlets under all gauge symmetries beyond SO(10). This includes the 45 and 54 representations, and holds regardless of the affine level at which SO(10) is realized. Furthermore, we show that such constructions can never give rise to the 120, 126, or 144 representations of SO(10) - again regardless of the affine level. We also perform a similar analysis for E6, and find that the adjoint 78 representation must always transform as a singlet under all gauge symmetries beyond E6; moreover, all representations beyond the 78 representation are prohibited. Taken together, these results thus severely limit the types of phenomenologically realistic field-theoretic SO(10) and E6 models that can be obtained using such string constructions. Finally, we also explore the possibility of using non-diagonal free-field embeddings, and show that in the SO(10) case such embeddings may have improved phenomenological prospects.

AB - A recent analysis of the methods by which higher-level gauge symmetries are realized in string theory has made it possible to systematically obtain new constraints on string GUT model-building. In this paper, we perform such a study for the case of SO(10) free-field string GUT models, and find a number of significant new results. First, we show that within the conventional string models using the so-called "diagonal" embeddings, all representations larger than the 16 must always transform as singlets under all gauge symmetries beyond SO(10). This includes the 45 and 54 representations, and holds regardless of the affine level at which SO(10) is realized. Furthermore, we show that such constructions can never give rise to the 120, 126, or 144 representations of SO(10) - again regardless of the affine level. We also perform a similar analysis for E6, and find that the adjoint 78 representation must always transform as a singlet under all gauge symmetries beyond E6; moreover, all representations beyond the 78 representation are prohibited. Taken together, these results thus severely limit the types of phenomenologically realistic field-theoretic SO(10) and E6 models that can be obtained using such string constructions. Finally, we also explore the possibility of using non-diagonal free-field embeddings, and show that in the SO(10) case such embeddings may have improved phenomenological prospects.

UR - http://www.scopus.com/inward/record.url?scp=0031575710&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031575710&partnerID=8YFLogxK

U2 - 10.1016/S0550-3213(96)00705-5

DO - 10.1016/S0550-3213(96)00705-5

M3 - Article

AN - SCOPUS:0031575710

VL - 488

SP - 141

EP - 158

JO - Nuclear Physics B

JF - Nuclear Physics B

SN - 0550-3213

IS - 1-2

ER -