Limitation on scalar neutrino masses from Tau decay

The apparent absence of the decay $\text{τ →}\text{ν}{}_{\mathrm{\tau }}\text{ν}{}_{\mathrm{?}}{}^1\text{?,}\text{where}\text{? =}\text{e or}\text{μ}\text{and}\text{ν}{}_{\mathrm{i}}$ is the spin-zero supersymmetric partner of ν_i, implies that the $\text{ν}{}_{\mathrm{i}}$ masses are sufficiently large that the decay is suppressed (assuming the supersymmetric partners exist). We give the resulting limits, which depend on the mass of the W? (the supersymmetric partner of the W) which mediates the decay, and on whether one or both $\text{ν}$ is massive. These are the only experimental limits on $\text{ν}$ masses.     

Cancellation of quantum correction for supersymmetric solitons in 1 + 1 dimensions

We show that the Bogomolny bound is saturated by supersymmetric solitons in 1 + 1 dimensions to all orders of the $\text{h}\text{?}$ expansion.     

Supersymmetric relics from the big bang

We consider the cosmological constraints on supersymmetric theories with a new, stable particle. Circumstantial evidence points to a neutral gauge/Higgs fermion as the best candidate for this particle, and we derive bounds on the parameters in the lagrangian which govern its mass and couplings. One favored possibility is that the lightest neutral supersymmetric particle is predominantly a photino $\text{～}\text{γ}$ with mass above $\text{1}\text{2}$ GeV, while another is that the lightest neutral supersymmetric particle is a Higgs fermion with mass above 5 GeV or less than O(100) eV. We also point out that a gravitino mass of 10 to 100 GeV implies that the temperature after completion of an inflationary phase cannot be above 10¹⁴ GeV, and probably not above 3 × 10¹² GeV. This imposes constraints on mechanisms for generating the baryon number of the universe.     

Supersymmetric regulators and supercurrent anomalies

The supercurrent anomalies of the supercurrent $\text{S}$_μ of the supersymmetric Yang-Mills theory in Wess-Zumino gauge are computed using the supersymmetric dimensional regulator of Siegel. It is shown that $\text{γ}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{=0}$ and $\text{?}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{≠0}$ in agreement with an earlier calculation based on the Adler-Rosenberg method. The problem of exhibiting the chiral anomaly and a regulator for local supersymmetry suggests that the interpretation of dimensional reduction in component language is incomplete.     

Dynamical supersymmetry breaking in supersymmetric QCD

The massless limit of supersymmetric QCD with $\text{N}{}_{\mathrm{?}}$ flavors and N colors is analyzed in detail. For $\text{N}{}_{\mathrm{?}}\text{< N}$ there is a unique superpotential which might be generated by non-perturbative effects. We show that it indeed appears, thus violating the non-renormalization theorems. For $\text{N}{}_{\mathrm{?}}\text{= N ? 1}$ instantons produce the superpotential. For $\text{N}{}_{\mathrm{?}}\text{< N ? 1}$ it is again generated, provided that a mild assumption about the dynamics of pure supersymmetric gauge theories is correct. For $\text{N}{}_{\mathrm{?}}\text{? N}$ no invariant superpotential exists; the classical vacuum degeneracy is a property of the full quantum theory. When a small quark mass term is added to the theory $\text{(}\text{for}\text{N}{}_{\mathrm{?}}\text{< N), N}$ supersymmetric ground states, identified with those found by Witten exist. As m → 0 these N vacua wander to infinity, leaving the massless theory without a ground state.     

Dimensional regularization and the two-loop axial anomaly in abelian,non-abelian and supersymmetric gauge theories

The two-loop corrections to the axial anomaly are calculated for a non-abelian gauge theory with fermions using both conventional and supersymmetric dimensional regularization. In both cases we find results consistent with the Adler-Bardeen theorem if we use non-anticommuting γ⁵ of 't Hooft and Veltman. Expectations (based on the supermultiplet structure of the anomalies) that there exists in N = 1 supersymmetric Yang-Mills theory an axial current J⁵ such that $\text{?·J}{}^5\text{～ β(g)F}\text{F}\text{?}$ are discussed.     

Spontaneous supersymmetry breaking in 1N leading order

We present a supersymmetric model, with only chiral superfields, invariant under an internal O(N) global symmetry. We show that, to leading order in $\text{1}\text{N}$, an auxiliary scalar field acquires a non-vanishing vacuum expectation value, that is, supersymmetry is spontaneously broken to this order of the approximation.     

A calculation of Z0 → 2 gluinos

We report the results of a one-loop calculation of $\text{Z}{}^0\text{→}\text{gg}$, where $\text{g}$ is a gluino, the proposed supersymmetric partner of a gluon. Depending on the masses of the scalar quarks and of the top quark, the branching ratio for the decay is in the 10^?5 to 10^?4 range for gluino mass below about 40 GeV. The signature for gluinos should allow detection in this range.     

Squark production at the pp collider

The recently observed $\text{p}\text{p}$ collider events with large missing P_T are analysed in terms of a supersymmetric model with a light photino and scalar quarks with mass in the range 20 to 35 GeV. A lower bound of O(60 GeV) on the gluino mass in this scenario is found.     

Squark and gluino production at the pp collider

We present detailed calculations of the missing energy and jet signatures for squark and gluino pair-production at the CERN $\text{p}\text{p}$ collider, incorporating three improvements over previous analyses. These include smearing in transverse momentum at production, the fragmentation of supersymmetric partons into supersymmetric hadrons, and the hadronization of their decay products as well as of the residual jets. We find that previous estimates of supersymmetric signatures are not substantially altered by the inclusion of smearing and fragmentation. We present rapidity and transverse momentum distributions for both primary and secondary jets, and discuss variations in the trigger conditions which could increase the number of two-jet events and help discriminate between different models for the monojet events. We find that gluinos give fatter jets than do squarks of the same mass, although it is not easy to understand the thinness of the observed monojets if they are due to squarks of mass O(40) GeV. We emphasize that the key feature to clarify the supersymmetric interpretation of missing p_T events is the study of secondary jet production in mono- and dijet events.     

Supersymmetry and weak,electromagnetic and strong interactions

We study a possible way to construct supersymmetric theories which could be considered as realistic, excepted that the problem of mass generation for electron, muon and quarks remains. There is a new class of leptons which includes charged ones, and a “photonic neutrino”. Spin $\text{1}\text{2}$-gluons and heavy spin 0- quarks are associated with ordinary vector gluons and quarks.     

The Weinberg angle in the supersymmetric Weinberg-Salam model

The gauge theory based on the graded Lie group $\text{SU(}\text{2}\text{1}\text{)}$ (the so-called supersymmetric Weinberg-Salam model) attracted the attention of theorists some time ago, and attempts are now being made to incorporate this model into grand unified theories. Using a consistent normalization of the group generators, we wish to point out that the model predicts $\text{sin}{}^2\text{θ}{}_{\mathrm{<mtext>w</mtext>}}\text{=}\text{1}\text{2}$.     

Supersymmetric three-jets in electron-positron annihilation

The bremsstrahlung of gluons and gluinos off quarks and squarks is studied in e⁺e^? annihilation for longitudinally polarized beams. The contribution of a given supersymmetric state is found to be 11–27% of the conventional gluon bremsstrahlung. With all supersymmetric channels open this adds up to 90–100% of the q$\text{q}$g contribution. Dalitz-plot and angular distributions are investigated. A pronounced forward-backward asymmetry is found for gluino bremsstrahlung. Characteristic features are also exhibited by the angular distribution of the normal to the event plane.     

Instantons and condensates in supersymmetric CPN−1 models

The partition function in the multi-instanton background for the supersymmetric CP^N?1 model is calculated and is shown to be supersymmetry invariant. This is used to calculate Green's function involving N pairs of $\text{ψ}\text{ψ(x}{}_{\mathrm{i}}\text{)}$, and this turns out to be independent of the positions. A possible interpretation is that the composite field $\text{ψ}\text{ψ}$ acquires a vacuum expectation value. The results are in agreement with those obtained in the 1/N expansion.     

Polyakov's spinning string from canonical point of view

We give a canonical formulation of Polyakov's modified spinning string theory. This means that we start with the lagrangian , where $\text{L}$₁ is a counter term derived from the general form of the trace anomaly. In the superconformal gauge $\text{L}$₁ reduces to the supersymmetric Liouville lagrangian. A general solution of the supersymmetric Liouville equation is derived as well as appropriate boundary condutions for the Neveu-Schwarz (NS) and Ramond models. Under the assumption that the exact quantization of the Liouville theory does not yield any additional anomalies. We show that relativistic invariance requires the constant C to be $\text{C=}\text{10?D}\text{8π}$, in agreement with Polyakov's result. For D<10 the string acquires longitudinal modes. A semiclassical quantization of the Liouville theory is then performed with the result that the mass spectrum starts with $\text{m}{}^2\text{?}\text{1}\text{2}\text{α′}\text{and}\text{m}{}^2\text{= 0}$ in the NS and Ramond models in any dimension D?10. The longitudinal excitations are determined by a simple harmonic oscillator expression. It is shown that a consistent exact quantization could remove the tachyon state in the NS model.