Unbroken Supersymmetry Research Articles

Anomalous quadrupole moment of W in supersymmetry.

We consider the radiative corrections to the anomalous quadrupole moment of the charged gauge boson W in supersymmetric SU(2${)}_{L}$\ifmmode\times\else\texttimes\fi{}U(1${)}_{Y}$ theory. The results are finite and do not vanish contrary to the well-known result that radiative corrections to the lepton g-2 vanish identically in unbroken supersymmetry. Finally, the effects of spontaneously broken supersymmetry in a simple model with two Higgs doublets are discussed.

World-sheet instantons and the Peccei-Quinn symmetry

It is shown that world-sheets violate the Peccie-Quinn symmetries associated with some of the axions that arise in superstring compactification. In the case of unbroken low-energy supersymmetry, the Peccie-Quinn violating operators that arise are D terms of dimension six. One remaining axion is unaffected.

Dynamics of compositeW-bosons

We derive some constraints among the masses and couplings of theW-bosons and the vacuum condensates of some non-supersymmetric and supersymmetric theories where theW are composite particles. We deduce that in a theory where the value of the hypergluon condensate is much smaller than the value of the compositeness scale (like in the case of an unbroken supersymmetry), theW-bosons cannot be composite.

Radiative corrections in grand unified theories based on N=1 supergravity. II. Gauge theories.

The effect of radiative corrections in supersymmetric grand unified theories with soft- supersymmetry-breaking terms induced by N=1 supergravity is analyzed. It is shown that any mass hierarchy present in the limit of unbroken supersymmetry is stable under radiative corrections induced by soft-supersymmetry-breaking terms, provided the theory does not contain a light singlet field that transforms as a singlet under the unbroken subgroup of the theory below the grand-unification scale.

Supersymmetric electromagnetic moments and radiation zeros.

The radiative corrections to the electromagnetic moments of the charged gauge fermions and bosons (W\ifmmode \tilde{}\else \~{}\fi{} and W) of the vector superfields are studied in unbroken supersymmetry. We find that supersymmetry does not force such corrections to vanish as it does for the charged spinor members of chiral supermultiplets. The implications of these results for radiation zeros are discussed. As an example, in an appendix we calculate the cross section for the process \ensuremath{\gamma}e\ensuremath{\rightarrow}W\ifmmode \tilde{}\else \~{}\fi{}\ensuremath{\nu}${\ifmmode \tilde{}\else \~{}\fi{}}_{L}$ (which has been studied previously by two groups with differing results) with anomalous W\ifmmode \tilde{}\else \~{}\fi{} magnetic moment and show that radiation zeros exist in this process in the limit of vanishing anomalous W\ifmmode \tilde{}\else \~{}\fi{} moments.

Absence of radiative mass shifts for composite goldstone supermultiplets

A supersymmetric Dashen type formula is used to prove that there are no radiative mass corrections for Goldstone pion supermultiplets due to gauge interactions. In partivular, for unbroken supersymmetry the charged to neutral pion mass difference is shown to vanish to all orders in electromagnetism.

Color Singlet Composite Superfields Containing Massless Composite Fermions Obtained by the 't Hooft Equation -- Supermetacolor. II

Further study on supermetacolor, a supersymmetric extension of 't Hooft's metacolor, is made. In this scheme, both chiral symmetry and supersymmetry at the preon level are assumed to be taken over the composite level. As a consistency of this requirement, massless composite fermions should emerge and they should be members of chiral supermultiplets. In this paper, we develop a systematic prescription for finding superpartners of massless composite fermion. By making use of this method, superpartners of massless composite fermions are given explicitly in terms of original preon fields. In view of this result, it is argued that supermetacolor scheme is consistent one. At the same time this result leads to the suggestion that the above-mentioned symmetry realization (unbroken chiral symmetry and supersymmetry) is in fact possible.

Supersymmetry breaking by torsion and the Ricci-flat squashed seven-spheres

In eleven-dimensional supergravity, unbroken supersymmetries may survive spontaneous compactification to V4 × V7 only for Freund-Rubin solutions to the equations of motion. A torsion which renders V7 Ricci-flat and breaks supersymmetry can then be induced spontaneously. Two squashed seven-spheres with torsion are obtained in this way: the flattening torsion components are constant and given by the octonion multiplication table.

A note on supersymmetry breaking in 1+1 dimensions

The spontaneous breakdown of supersymmetry for a single chiral superfield in 1+1 dimensions is investigated and a number of puzzling features are resolved by noting that the loop expansion is not always valid. It is found that both broken and unbroken supersymmetry are stable with respect to radiative corrections.

Light composite supermultiplets

It is argued that in a wide class of massless strongly interacting supersymmetric gauge theories there exist confining phases with unbroken supersymmetry. We explain how to identify and interpret the light composite supermultiplet content of these phases.

Supersymmetry and positive temperature for simple systems

It has recently been argued by Girardello et al. that supersymmetry is automatically broken at positive temperature even when unbroken at T = 0, in the sense that the usual derivation of identities from unbroken supersymmetry does not automatically generalize to T > 0. Using as a guide simple examples with one bosonic and one fermionic degree of freedom, we study how supersymmetry reflects itself in the properties of excited states, in particular in the thermal properties at positive temperature. We derive a class of relations [see eq. 1.2)] which extend to all T the familiar consequences of unbroken supersymmetry for ground-state expectation values; these relations hold for unbroken and spontaneously broken supersymmetry. With Levine and Tomozawa we consider the algebra generated by the supercharges. In the case of two supercharges it can be reduced to the Clifford algebra of Pauli spin matrices, for which the eigenstates form irreducible doublets, except that a zero-energy eigenstate may be a singlet. The relations mentioned above are shown to hold for each doublet individually [see eq. (4,7)]. Some additional remarks are made on supersymmetry breaking at zero and positive temperatures.

More on cosmology for supersymmetric GUTS

Abstract It is argued that phase transitions which would occur at finite temperatures in supersymmetric grand unified theories (with supersymmetry unbroken at the tree level) proceed very slowly. In the simplest models, the universe would supercool in a phenomenologically unacceptable phase, essentially forever. Criteria which a supersymmetric GUT must satisfy to avoid this fate are briefly discussed.

Patterns of symmetry breaking in supersymmetric gauge theories

We give a group-theoretical analysis of the spontaneous breaking of the gauge group in supersymmetric Yang-Mills theories with unbroken supersymmetry.

Framed BPS states

We consider a class of line operators in $d = 4, \mathcal{N} = 2$ supersymmetric field theories, which leave four supersymmetries unbroken. Such line operators support a new class of BPS states which we call BPS These include halo bound states similar to those of $d = 4, \mathcal{N} = 2$ supergravity, where (ordinary) BPS particles are loosely bound to the line operator. Using this construction, we give a new proof of the Kontsevich-Soibelman wall-crossing formula (WCF) for the ordinary BPS particles, by reducing it to the semiprimitive WCF. After reducing on $S^1$, the expansion of the vevs of the line operators in the IR provides a new physical interpretation of the Darboux coordinates on the moduli space M of the theory. Moreover, we introduce a protected spin character (PSC) that keeps track of the spin degrees of freedom of the framed BPS states. We show that the generating functions of PSCs admit a multiplication, which defines a deformation of the algebra of holomorphic functions on $\mathcal{M}$. As an illustration of these ideas, we consider the sixdimensional (2, 0) field theory of $A_1$ type compactified on a Riemann surface $\mathcal{C}$. Here, we show (extending previous results) that line operators are classified by certain laminations on a suitably decorated version of $\mathcal{C}$, and we compute the spectrum of framed BPS states in several explicit examples. Finally, we indicate some interesting connections to the theory of cluster algebras.