TY - JOUR

T1 - Metastable strings in Abelian Higgs models embedded in non-Abelian theories

T2 - Calculating the decay rate

AU - Shifman, M.

AU - Yung, Alexei V

PY - 2002

Y1 - 2002

N2 - We study the fate of U(1) strings embedded in a non-Abelian gauge theory with the hierarchical pattern of symmetry breaking Gv→U(1) v→ nothing, V≫v. While in the low-energy limit the Abrikosov-Nielsen-Olesen string (flux tube) is perfectly stable, when considered in the full theory it is metastable. We consider the simplest example: the magnetic flux tubes in SU(2) gauge theory with adjoint and fundamental scalars. First, the adjoint scalar develops a vacuum expectation value V breaking SU(2) down to U(1). Then, at a much lower scale, the fundamental scalar (quark) develops a vacuum expectation value v creating the Abrikosov-Nielsen-Olesen string. [We also consider an alternative scenario in which the second breaking, U(1)°→ to an adjoint field.] We suggest an illustrative Ansatz describing an "unwinding" in SU(2) of the winding inherent in the Abrikosov-Nielsen-Olesen strings in U(1). This Ansatz determines an effective 2D theory for the unstable mode on the string world sheet. We calculate the decay rate (per unit length of the string) in this Ansatz and then derive a general formula. The decay rate is exponentially suppressed. The suppressing exponent is proportional to the ratio of the monopole mass squared to the string tension, which is quite natural in view of the string breaking through the monopole-antimonopole pair production. We compare our result with the one given by Schwinger's formula dualized for describing monopole-antimonopole pair production in a magnetic field.

AB - We study the fate of U(1) strings embedded in a non-Abelian gauge theory with the hierarchical pattern of symmetry breaking Gv→U(1) v→ nothing, V≫v. While in the low-energy limit the Abrikosov-Nielsen-Olesen string (flux tube) is perfectly stable, when considered in the full theory it is metastable. We consider the simplest example: the magnetic flux tubes in SU(2) gauge theory with adjoint and fundamental scalars. First, the adjoint scalar develops a vacuum expectation value V breaking SU(2) down to U(1). Then, at a much lower scale, the fundamental scalar (quark) develops a vacuum expectation value v creating the Abrikosov-Nielsen-Olesen string. [We also consider an alternative scenario in which the second breaking, U(1)°→ to an adjoint field.] We suggest an illustrative Ansatz describing an "unwinding" in SU(2) of the winding inherent in the Abrikosov-Nielsen-Olesen strings in U(1). This Ansatz determines an effective 2D theory for the unstable mode on the string world sheet. We calculate the decay rate (per unit length of the string) in this Ansatz and then derive a general formula. The decay rate is exponentially suppressed. The suppressing exponent is proportional to the ratio of the monopole mass squared to the string tension, which is quite natural in view of the string breaking through the monopole-antimonopole pair production. We compare our result with the one given by Schwinger's formula dualized for describing monopole-antimonopole pair production in a magnetic field.

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U2 - 10.1103/PhysRevD.66.045012

DO - 10.1103/PhysRevD.66.045012

M3 - Article

AN - SCOPUS:0037104542

SN - 0556-2821

VL - 66

JO - Physical Review D

JF - Physical Review D

IS - 4

M1 - 045012

ER -