TY - JOUR

T1 - A counterexample to the a-'theorem'

AU - Shapere, Alfred D.

AU - Tachikawa, Yuji

PY - 2008

Y1 - 2008

N2 - We exhibit a renormalization group flow for a four-dimensional gauge theory along which the conformal central charge a increases. The flow connects the maximally superconformal point of an = 2 gauge theory with gauge group SU(N+1) and Nf = 2N flavors in the ultraviolet, to a strongly-coupled superconformal point of the SU(N) gauge theory with Nf = 2N massless flavors in the infrared. Our example does not contradict the proof of the a-theorem via a-maximization, due to the presence of accidental symmetries in the infrared limit. Nor does it contradict the holographic a-theorem, because these gauge theories do not possess weakly-curved holographic duals.

AB - We exhibit a renormalization group flow for a four-dimensional gauge theory along which the conformal central charge a increases. The flow connects the maximally superconformal point of an = 2 gauge theory with gauge group SU(N+1) and Nf = 2N flavors in the ultraviolet, to a strongly-coupled superconformal point of the SU(N) gauge theory with Nf = 2N massless flavors in the infrared. Our example does not contradict the proof of the a-theorem via a-maximization, due to the presence of accidental symmetries in the infrared limit. Nor does it contradict the holographic a-theorem, because these gauge theories do not possess weakly-curved holographic duals.

KW - Extended supersymmetry

KW - Supersymmetric gauge theory

KW - Supersymmetry and duality

UR - http://www.scopus.com/inward/record.url?scp=62649159892&partnerID=8YFLogxK

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U2 - 10.1088/1126-6708/2008/12/020

DO - 10.1088/1126-6708/2008/12/020

M3 - Article

AN - SCOPUS:62649159892

SN - 1126-6708

VL - 2008

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 12

M1 - 020

ER -