Pattern Of Supersymmetry Breaking Research Articles

Elliptic Genera of Pure Gauge Theories in Two Dimensions with Semisimple Non-Simply-Connected Gauge Groups

In this paper we describe a systematic method to compute elliptic genera of (2,2) supersymmetric gauge theories in two dimensions with gauge group $$G/\Gamma $$ (for G semisimple and simply-connected, $$\Gamma $$ a subgroup of the center of G) with various discrete theta angles. We apply the technique to examples of pure gauge theories with low-rank gauge groups. Our results are consistent with expectations from decomposition of two-dimensional theories with finite global one-form symmetries and with computations of supersymmetry breaking for some discrete theta angles in pure gauge theories. Finally, we make predictions for the elliptic genera of all the other remaining pure gauge theories by applying decomposition and matching to known supersymmetry breaking patterns.

Partial breaking of arbitrary amount of d=3 supersymmetry

Among the solutions of string theory and supergravity which preserve some fraction of supersymmetry, the best known are those that leave one half of the supersymmetry unbroken, and there is a large number of field theory models with this pattern of supersymmetry breaking. However, a lot of brane configurations exist which preserve only $1/4$, $1/8$ or more exotic fractions of supersymmetry, and field theory side of these systems remains largely unexplored. To find whether the formalism of nonlinear realizations is useful in construction of models of this type, we consider the systems of some $N_0$ scalar and vector $N=1$, $d=3$ Goldstone supermultiplets. We find that it is possible to construct an $SO(N_0)$ invariant theory of $N_0$ scalar multiplets with $N_0$ broken supersymmetries. For $N_0=3$ or $N_0\geq 5$ its action is not of Nambu-Goto type and its structure remains universal for arbitrary $N_0$. The cases of $N_0=1,2$ correspond to the membranes in $D=4$ and $D=5$, respectively, while for $N_0=4$ some arbitrariness in the action remains, and with proper choice of parameters, it is possible to obtain the action of the membrane in $D=7$ in the bosonic limit. It is also shown that the $SO(N_0)$ invariant action of $N_0$ vector multiplets with $1/N_0$ pattern of supersymmetry breaking does not exist for arbitrary $N_0$.

Behaviors of two supersymmetry breaking scales in mathcal{N} = 2 supergravity

We study the supersymmetry breaking patterns in four-dimensional mathcal{N} = 2 gauged supergravity. The model contains multiple (Abelian) vector multiplets and a single hypermultiplet which parametrizes SO(4, 1)/SO(4) coset. We derive the expressions of two gravitino masses under general gaugings and prepotential based on the embedding tensor formalism, and discuss their behaviors in some concrete models. Then we confirm that in a single vector multiplet case, the partial breaking always occurs when the third derivative of the prepotential exists at the vacuum, which is consistent with the result of ref. [1], but we can have several breaking patterns otherwise. The discussion is also generalized to the case of multiple vector multiplets, and we found that the full ( mathcal{N} = 0) breaking occurs even if the third derivative of the prepotential is nontrivial.

A new approach to gauge coupling unification and proton decay

An analytical formalism, including RG running at two loop order, is used to link the supersymmetric and GUT spectra in any GUT model in which the three gauge couplings unify. In each specific GUT model, one can then fully explore the interplay between the pattern of supersymmetry breaking and the prediction for the proton lifetime. With this formalism at hand, we study three concrete GUT models: (i) Minimal SU(5) SUSY GUT, (ii) Missing Partner SU(5) SUSY GUT, and (iii) an orbifold SU(5) SUSY GUT. In each case we derive interesting conclusions about the possible patterns of the supersymmetric spectrum once the present limits on the proton lifetime are imposed, and vice versa, we obtain the predictions for the proton lifetime for specific viable choices of the SUSY spectrum.

Renormalization group invariants in supersymmetric theories: one- and two-loop results

We stress the potential usefulness of renormalization group invariants. Especially particular combinations thereof could for instance be used as probes into patterns of supersymmetry breaking in the MSSM at inaccessibly high energies. We search for these renormalization group invariants in two systematic ways: on the one hand by making use of symmetry arguments and on the other by means of a completely automated exhaustive search through a large class of candidate invariants. At the one-loop level, we find all known invariants for the MSSM and in fact several more, and extend our results to the more constrained pMSSM and dMSSM, leading to even more invariants. Extending our search to the two-loop level we find that the number of invariants is considerably reduced.

Supermembrane in D = 5: component action

Based on the connection between partial breaking of global supersymmetry, coset approach, which realized the given pattern of supersymmetry breaking, and the Nambu-Goto actions for the extended objects, we have constructed on-shell component action for N=1, D=5 supermembrane and its dual cousins. We demonstrate that the proper choice of the components and the use of the covariant (with respect to broken supersymmetry) derivatives drastically simplify the action: it can be represented as a sum of four terms each having an explicit geometric meaning.

A low Fermi scale from a simple gaugino-scalar mass relation

In supersymmetric extensions of the Standard Model, the Fermi scale of electroweak symmetry breaking is determined by the pattern of supersymmetry breaking. We present an example, motivated by a higher-dimensional GUT model, where a particular mass relation between the gauginos, third-generation squarks and Higgs fields of the MSSM leads to a Fermi scale smaller than the soft mass scale. This is in agreement with the measured Higgs boson mass. The mu parameter is generated independently of supersymmetry breaking, however the mu problem becomes less acute due to the little hierarchy between the soft mass scale and the Fermi scale as we will argue. The resulting superparticle mass spectra depend on the localization of quark and lepton fields in higher dimensions. In one case, the squarks of the first two generations as well as the gauginos and higgsinos can be in the range of the LHC. Alternatively, only the higgsinos may be accessible at colliders. The lightest superparticle is the gravitino.

Partial breaking of global supersymmetry and super particle actions

We argue the conjecture that the on-shell component super particle actions have a universal form, in which the physical fermions enter the action through the ein-bein and the space-time derivatives of the matter fields, only. We explicitly constructed the actions for the super particles in $D=3$ realizing the $N=4\cdot 2^{k} \rightarrow N=2\cdot 2^k$ pattern of supersymmetry breaking, and in $D=5$ with the $N=16$ supersymmetry broken down to the $N=8$ one. All constructed actions have indeed a universal form, confirming our conjecture. Our construction is strictly based on the assumption that in the system we have one half breaking of the global supersymmetry, and on the very special choice of the superspace coordinates and component fields.

The heterotic MiniLandscape and the 126 GeV Higgs boson

Abstract The MSSM candidates arising from the heterotic MiniLandscape feature a very constrained supersymmetry breaking pattern. This includes a fully predictable gaugino mass pattern, which is compressed compared to the CMSSM, and an inverted sfermion hierarchy due to distinct geometric localisation, featuring stops as light as 1 TeV. The observed Higgs mass sets a lower bound $ {m_{{\widetilde{g}}}}>1.2\;\mathrm{TeV} $ on the gluino mass. The electroweak fine-tuning is reduced by a UV relation between the scalar mass of the two heavy families and the gluino mass. While large parts of the favoured parameter space escape detection at the LHC, the prospects to test the MiniLandscape models with future dark matter searches are very promising.

Implications of different supersymmetry breaking patterns for the spectrum and decay of neutralinos and charginos

We consider different patterns of supersymmetry breaking gaugino masses, and implications of these patterns for the phenomenology of neutralinos and charginos in models of low energy supersymmetry. We outline a general procedure for obtaining approximate values for the neutralino masses relevant for our analysis, and describe the constraints on the gaugino mass parameters which follow from the present experimental limits on the mass of the lightest chargino. We evaluate an upper bound on the mass of the lightest neutralino that follows from the structure of the mass matrix in different models for the gaugino mass parameters. Using the experimental lower limit for the chargino mass, we examine the lower bound for the neutralino masses. Using a sum rule for the squared masses of charginos and neutralinos, we discuss how to distinguish between different models for the supersymmetry breaking scenarios. We discuss in detail the decay modes of neutralinos and charginos in different models of supersymmetry breaking. Our analysis shows that by measuring the masses and decay properties of the neutralinos, one can distinguish between different patterns of supersymmetry breaking in the gaugino sector. We then compare the dark matter characteristics that arise in different models of supersymmetry breaking.

Dynamical supersymmetry breaking in intersecting brane models

In this paper we study dynamical supersymmetry breaking in absence of gravity with the matter content of the minimal supersymmetric standard model. The hidden sector of the theory is a strongly coupled gauge theory, realized in terms of microscopic variables which condensate to form mesons. The supersymmetry breaking scalar potential combines F, D terms with instanton generated interactions in the Higgs-mesons sector. We show that for a large region in parameter space the vacuum breaks in addition to supersymmetry also electroweak gauge symmetry. We furthermore present local D-brane configurations that realize these supersymmetry breaking patterns.

Induced superstring cosmologies and moduli stabilization

We extend the analysis of the recently obtained stringy cosmological solutions induced by thermal and quantum effects, once space–time supersymmetry is spontaneously broken by geometrical fluxes. Cases in which more than one modulus participating in the supersymmetry breaking mechanism are investigated. The free energy is obtained at the full string level. In the intermediate cosmological region where the temperature and the supersymmetry breaking scale are sufficiently smaller than the Hagedorn temperature, the quantum and thermal corrections are under control and calculable. The reason is that the contributions to the effective potential of the moduli that are not participating in the supersymmetry breaking are exponentially suppressed. The backreaction on the initially flat background results in many cases into cosmological evolutions, where the dynamics of all complex structure moduli is frozen. The solutions describe effectively a radiation dominated era, where thermal effects are never negligible, even if the temperature tends to zero at late times. We analyze several types of supersymmetry breaking patterns and examine the stability of the corresponding radiation era.

Neutralino dark matter and trilepton searches in the MSSM

Searches for supersymmetry are among the most exciting physics goals at run II of the Tevatron. In particular, in supersymmetric models with light charginos, neutralinos, and sleptons, associated chargino-neutralino production can potentially be observed as multilepton events with missing energy. We discuss how, in the generic TeV-scale minimal supersymmetric standard model (MSSM), the prospects for these chargino-neutralino searches are impacted by cosmological considerations, namely, the neutralino relic abundance and direct detection limits. We also discuss what an observation of chargino-neutralino production at the Tevatron would imply for the prospects of future direct dark-matter searches without assuming specific patterns of supersymmetry breaking.

The quantum dynamics of heterotic vortex strings

We study the quantum dynamics of vortex strings in = 1 SQCD with U(Nc) gauge group and Nf = Nc quarks. The classical worldsheet of the string has = (0, 2) supersymmetry, but this is broken by quantum effects. We show how the pattern of supersymmetry breaking and restoration on the worldsheet captures the quantum dynamics of the underlying 4d theory. We also find qualitative matching of the meson spectrum in 4d and the spectrum on the worldsheet.

String theoretic QCD axion with stabilized saxion and the pattern of supersymmetry breaking

String theoretic axion is a prime candidate for the QCD axion solving the strong CP problem. For a successful realization of the QCD axion in string theory, one needs to stabilize moduli including the scalar partner (saxion) of the QCD axion, while keeping the QCD axion unfixed until the low energy QCD instanton effects are turned on. We note that a simple generalization of KKLT moduli stabilization provides such set-up realizing the axion solution to the strong CP problem. Although some details of moduli stabilization are different from the original KKLT scenario, this set-up leads to the mirage mediation pattern of soft SUSY breaking terms as in the KKLT case, preserving flavor and CP as a consequence of approximate scaling and axionic shift symmetries. The set-up also gives an interesting pattern of moduli masses which might avoid the cosmological moduli, gravitino and axion problems.

Stability of flux compactifications and the pattern of supersymmetry breaking

We extend the KKLT approach to moduli stabilization by including the dilaton and the complex structure moduli into the effective supergravity theory. Decoupling of the dilaton is neither always possible nor necessary for the existence of stable minima with zero (or positive) cosmological constant. The pattern of supersymmetry breaking can be much richer than in the decoupling scenario of KKLT.

The two-dimensional Wess-Zumino model in the Hamiltonian lattice formulation

We investigate a Hamiltonian lattice version of the two-dimensional Wess-Zumino model, with special emphasis to the pattern of supersymmetry breaking. Results are obtained by Quantum Monte Carlo simulations and Density Matrix Renormalization group techniques.

Low-energy brane-world effective actions and partial supersymmetry breaking

As part of a programme for the general study of the low-energy implications of supersymmetry breaking in brane-world scenarios, we study the nonlinear realization of supersymmetry which occurs when breaking N=2 to N=1 supergravity. We consider three explicit realizations of this supersymmetry breaking pattern, which correspond to breaking by one brane, by one antibrane or by two (or more) parallel branes. We derive the minimal field content, the effective action and supersymmetry transformation rules for the resulting N=1 theory perturbatively in powers of kappa = 1/M_{Planck}. We show that the way the massive gravitino and spin-1 fields assemble into N=1 multiplets implies the existence of direct brane-brane contact interactions at order O(kappa). This result is contrary to the O(kappa^2) predicted by the sequestering scenario but in agreement with recent work of Anisimov et al. Our low-energy approach is model independent and is a first step towards determining the low-energy implications of more realistic brane models which completely break all supersymmetries.

Phenomenological constraints on patterns of supersymmetry breaking

Specific models of supersymmetry breaking predict relations between the trilinear and bilinear soft supersymmetry breaking parameters A0 and B0 at the input scale. In such models, the value of tanβ can be calculated as a function of the scalar masses m0 and the gaugino masses m1/2, which we assume to be universal. The experimental constraints on sparticle and Higgs masses, b→sγ decay and the cold dark matter density ΩCDMh2 can then be used to constrain tanβ in such specific models of supersymmetry breaking. In the simplest Polonyi model with A0=(3−3)m0=B0+m0, we find 11≲tanβ≲20 (tanβ≃4.15) for μ>0 (μ<0). We also discuss other models with A0=B0+m0, finding that only the range −1.9≲A0/m0≲2.5 is allowed for μ>0, and the range 1.25≲A0/m0≲4.8 for μ<0. In these models, we find no solutions in the rapid-annihilation ‘funnels’ or in the ‘focus-point’ region. We also discuss the allowed range of tanβ in the no-scale model with A0=B0=0. In all these models, most of the allowed regions are in the χ−τ̃1 coannihilation ‘tail’.

Lepton flavor violation and neutrino mixings in a3×2seesaw model

We study the predictions for BR(mu-> e+gamma) and BR(tau-> e,mu+gamma) in a class of recently proposed horizontal SU(2) model that leads to a 3 X 2 seesaw model for neutrino masses. We consider two such models and obtain the correct bi-large mixing pattern for neutrinos. In these models, the effective low energy theory below the SU(2)_H scale is the MSSM. Assuming a supersymmetry breaking pattern as in the minimal SUGRA models, we find that consistent with present g-2, b->s+gamma and WMAP dark matter constraints on the parameters of the model, the BR(mu-> e+gamma) prediction is accessible to the proposed MEG experiment at PSI making this class of models testable in the near future.