Supersymmetry and Unification of Fundamental Interactions

PREFACE.

CONFERENCE ORGANIZATION.

CONTENTS.

The Muon (g-2) Experiment (E821) at Brookhaven National Laboratory (BNL) started data taking in 1997. The latest result a_μ+ = 11659202(14)(6) × 10⁻¹⁰, based on statistics collected in 1999, is in good agreement with the previous measurement. With the precision of 1.3 ppm, the result shows the discrepancy with the Standard Model prediction a_μ(exp) − a_μ(SM) = 43(16) × 10⁻¹⁰.

The searches for supersymmetric particles with the data collected at LEP at centre-of-mass energies up to 209 GeV are reviewed. No signal has been found in any of the searched topologies and limits on the productions have been derived. Results were interpreted in “classical” neutralino LSP scenario, in the framework of Minimal Supersymmetric Standard Model (MSSM) with R-parity conserved. The results of the search have been translated into exclusion domains in the MSSM parameters space and indirect limit on the mass of lightest neutralino for any tanβ and sfermion mass are derived.

The search for the production of scalar leptons at LEP is presented. The results indicate that the data are in agreement with Standard Model predictions. A follow up to the reported excess of stau candidates in the 1999 LEP data is presented. It was found that was no coherent excess of stau candidates from data collected in 2000. In the absence of a signal, limits have been placed on the mass of the sleptons based on a 95% CL exclusion. The selectron mass has been excluded up to 99.4 GeV/c² for a mass of 40 GeV/c². Similarly, the smuon mass has been excluded to 95.4 GeV/c² and the stau mass has been excluded to 85.4 GeV/c².

We report on the result of a search for charginos and neutralinos in e⁺e⁻ collisions at centre-of-mass energies between 203 GeV and 208 GeV at LEP. No evidence for such particles is found in a data sample of 220 pb⁻¹. Improved upper limits for these particles are set on the production cross sections. New exclusion contours in the parameter space of the Minimal Supersymmetric Standard Model are derived, as well as new lower limits on the masses of these supersymmetric particles. Chargino masses below 103 GeV are excluded over large regions of the parameter space of the Minimal Supersymmetric Standard Model.

In the year 2000, the LEP e⁺e⁻ collider has been operated up to a centre-of-mass energy of 209 GeV. Each of the four LEP experiments, ALEPH, DELPHI, L3 and OPAL has collected an integral luminosity of about 220pb⁻¹. Particle searches have been performed covering a wide range of Supersymmetry models. This note describes the searches for charginos and neutralinos in case of some dedicated scenarios. The implications of the chosen scenario on the search strategy are explained and recent results^1,2,3,4 are presented.

This article presents the current experimental results of searches for Supersymmetry (SUSY) at the Collider Detector at Fermilab (CDF), using over 110 pb⁻¹ of proton-antiproton collision data with collected during the period 1992-1995. Since no signal was found, limits on the production of supersymmetric particles are derived. The prospects for supersymmetry searches at Run II of the Tevatron, that began in March 2001, are also discussed here.

At the ep collider HERA, events with high-P_t leptons and missing calorimeter energy are an ideal environment to search for signs of physics beyond the Standard Model. In this paper we will focus on the results by the H1 and ZEUS Collaborations on searches for lepton flavor violation (LFV) in both the μ and τ channels and single top production by flavor changing neutral currents (FCNC). Both processes produce striking final states which can be detected with high efficiency and negligible background, allowing the HERA experiments to set constraints on the relevant couplings which, in many cases, supersede previous results.

The first results of the search for the Standard Model Higgs boson by the four LEP collaborations and including all LEP data are described.

Results from 630 pb⁻¹ collected by each of the four LEP experiments have been derived for the Higgs bosons predicted by the extensions of the Standard Model with two Higgs-field doublets. Limits on the masses of the neutral Higgs bosons h⁰, A⁰, H⁰, the charged Higgs bosons H^±, and tan β, have been obtained by the LEP Higgs working group.

This proceeding is an overview of ATLAS capabilities on Higgs studies. After a short introduction on LEP and Tevatron searches on this subject, the ATLAS potential on a Standard Model and a Supersymmetric Higgs discovery are summarized. Last, a section presents the Higgs parameters measurement that will be possible at LHC.

The present results on R-parity violation searches performed by the four LEP experiments are presented. This concerns mainly the pair and single production of SUSY particles in the hypothesis of R-parity violation via explicit trilinear couplings (LLĒ, and ). The chargino pair production search in the spontaneaous R-parity violation by an effective bilinear term ε_i H_uL_i scenario is also presented.

Using data collected by the DØ experiment during the Run I of the Fermilab Tevatron, searches for supersymmetric signatures have been performed in the framework of R-parity violation. No deviations from standard model predictions have been observed. Limits on supersymmetric parameters are presented focusing on recent results as well as discovery potential of Run II.

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of events corresponding to 108.3 pb⁻¹ of data collected with the DØ detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, and , no evidence for signal is found. We derive cross-section limits as a function of stop, chargino , and sneutrino masses.

Supersymmetry has been searched for many years, but as it leads to numerous final states depending on the model and the set of parameters considered, only a small fraction of it has been explored. A quasi-model independent search is presented, which looks for any P_T excess in the data w.r.t standard model processes. This model has been validated and then applied to the 108 pb⁻¹ D0 Run I data collected between 1992 and 1996. No evidence for new high p_T physics was found.

The ALEPH search for the Standard Model Higgs boson in the year 2000 revealed an excess of signal-like events, consistent with a signal hypothesis m_h ≈ 115 GeV/c². Here we present the results after the analysis of all of the data collected during the year 2000, at collision energies up to 209 GeV, and which were published in November 2000.

The results of the searches for charged Higgs bosons at the four experiments at the LEP collider have been combined in order derive an exclusion limit using the largest possible data sample. This combined analysis excludes the existence of charged Higgs bosons with masses lower than 78.6 GeV/c² at 95% confidence level.

No abstract received.

Solar and atmospheric neutrino data strongly indicate the need for physics beyond the Standard Model. The neutrino oscillation interpretation of the atmospheric data is rather unambiguous, with more options still open for the solar data. After a brief summary of the latest global fits of neutrino data, I discuss theoretical neutrino mass models. This is done first from a top-bottom approach inspired by unification ideas involving a see-saw mechanism or high dimension operators. Then I consider bottom-up approaches, with especial emphasis on the idea that the origin of neutrino mass and mixing is intrinsically supersymmetric. Models involve effective bilinear breaking of R–parity. This allows for the possibility of probing the neutrino mixing also in the context of high–energy collider experiments such as the LHC.

I review a role played by baryon and lepton numbers and their discrete symmetries in determining the low energy effective theory relevant for TeV physics.

The SUSY contribution to the muon magnetic moment anomaly, , and the electron electric dipole moment, d_e, is discussed within the framework of a modified mSUGRA model where the magnitudes of the soft breaking masses are universal, but arbitrary phases are allowed. It is shown analytically how the cancellation mechanism can allow for large phases (i.e.θ_B ≲ 0.4) and still suppress the value of d_e below its current experimental bound. The dependence of on the CP violating phases are analytically examined, and seen to decrease it but by at most a factor of about two. This reduction would then decrease the upper bound on m_1/2 due to the lower bound of Brookhaven data, and hence lower the SUSY mass spectrum, making it more accessible to accelerators. At the electroweak scale, the phases have to be specified to within a few percent to satisfy the experimental bound on d_e, but at the GUT scale, fine tuning below 1% is required for lower values of m_1/2. This fine tuning problem will become more serious if the bound on d_e is decreased.

The weak scale spectrum of supersymmetric particles ought to reflect physical principles valid at much higher energy scales. The discovery of supersymmetric matter at collider experiments will not only verify weak scale SUSY, but will also test hypotheses associated with very high energy scales. The program ISAJET provides a link between a wide class of supersymmetric models and their experimental consequences. I describe the ISAJET SUSY models, and discuss some of their implications for experimental scrutinization at the Tevatron, LHC and linear e⁺e⁻ colliders.

A brief overview is given of recent developments in the analyses of large phases and CP violation in supersymmetric unified models. The problem of experimental electric dipole moment constraints and large phases is discussed. Implications of large phases on supersymmetric phenomena are reviewed. The possibility of generating a muon electric dipole moment much larger than implied by the scaling relation d_μ/d_e≃ m_μ/m_e from lepton flavor non-universality and within reach of the recently proposed Brookhaven experiment for a sensitive probe of d_μ is also discussed.

The origin of quark and lepton masses is one of the outstanding problems of physics. As the experimental data becomes more and more accurate, testing theories of fermion masses requires greater care. In this talk we discuss a theoretical framework for testing those theories with a high energy desert. It is only with precision tests that we can hope to narrow the set of viable, beyond the standard model theories.

Present situation in the flavour mixing of quarks and leptons is briefly reviewed and a new approach called the Minimal Flavour Mixing (MFM) is considered in detail. According to MFM the whole of the flavour mixing is basically determined by the physical mass generation of the first family of fermions. So, in the chiral symmetry limit when the masses of the lightest quarks, u and d, vanish, all the weak mixing angle vanish. This minimal pattern is shown to fit extremely well the already established CKM matrix elements and to give fairly distinctive predictions for the as yet poorly known ones. Remarkably, together with generically small quark mixing it also leads to the large neutrino mixing thus giving adequate solution to the solar and atmospheric neutrino oscillation problem. The possible origin of this approach in the MSSM extended by a high-scale SU(3)_F chiral family symmetry is discussed.

I briefly review the cosmological constant problem and attempts toward its solution, and present the first nontrivial example for the self-tuning mechanism with a 1/H² term with the antisymmetric field strength H_MNPQ in a 5D RS-II setup.

New data on the anomalous magnetic moment of the muon together with the b → X_sγ decay rate and Higgs limits are considered within the supergravity inspired constrained minimal supersymmetric model. We perform a global statistical χ² analysis of these data and show that the allowed region of parameter space is bounded from below by the Higgs limit, which depends on the trilinear coupling and from above by the anomalous magnetic moment a_μ.

We consider the string models with dilaton domination in the intermediate string scale. After imposing the direct search limits on the lightest neutral Higgs and SUSY particle masses and the lightest neutralino LSP, the is predicted to be less than 55 × 10⁻¹⁰ for M_string = 3 × 10¹¹ GeV. If we further impose the B → X_sγ branching ratio, the predicted becomes lower to 35 × 10⁻¹⁰. The resulting LSP - proton scattering cross section is not larger than ~ 10⁻⁷ pb which is below the sensitivity of the current direct dark matter search experiments, but future experiments can cover this.

We systematically analyze neutron, electron, and mercury EDM constraints in SUSY models. We find that the addition of the mercury constraint practically rules out the EDM cancellation scenario and largely disfavors the decoupling scenario. On the other hand, models with approximate CP symmetry or off-diagonal CP violation remain attractive.

Direct detection of neutralino dark matter as well as its relic density are discussed within scenarios where relic neutralinos may make up the dominant bulk of the dark matter or only a small fraction of it.

Single production at hadron and photon colliders of gluinos and sneutrinos of super-symmetric models, as well as radions of the Randall-Sundrum model, is discussed. In the case of supersymmetry, R-parity breaking is needed in order to produce single susy particles. Resonant production of radions is considered at γγ collider.

Muon storage rings can act as copious sources of neutrinos, where many aspects of oscillation as well as non-oscillation physics can be studied. Non-oscillation effects, such as the violation of lepton flavor through R-parity violating supersymmetric (SUSY) interactions, can mimic neutrino oscillation signals in a long-baseline experiment at such a neutrino factory. We discuss ways of separating the (SUSY) non-oscillation effects, in particular with a near-site detector. It is also pointed out that b-quark production at a neutrino factory, especially in neutral current events, is a strong suggestion of lepton flavor violating interactions.

We investigate pair production of selectrons in e⁻e⁻ scattering with subsequent decay into an electron and the LSP including ISR and beamstrahlung. This process can be used at a linear collider to measure the selectron masses and the gaugino mass parameter M₁ very precisely.

Diagnostic signals of the minimal model of anomaly mediated supersymmetry breaking are discussed in the context of a e⁺e⁻ linear collider.

We show that the bosonic decays of the lighter top and bottom squarks, i.e. and , can be dominant in a wide range of the MSSM parameters. Compared to the fermionic decays, such as , these bosonic decays can have significantly different decay distributions. We also show that the effect of the supersymmetric QCD running of the quark and squark parameters on the and decay branching ratios is quite dramatic. These could have an important impact on the search for and and the determination of the MSSM parameters at future colliders.

Heavy quarks rare decays t → cZ, t → cγ, t → cg, b → cγγ are investigated in the SM and MSSM. The branching ratio of these decays are calculated.

No abstract received.

Supersymmetric standard models coupled to superconformal theory is studied. Within this framework, hierarchical Yukawa couplings are generated. It is shown at the same time we can obtain degenerate sfermion masses.

We summarized our report on neutrino masses and μ → e γ in the generic supersymmetric standard model, emphasizing on the much overlooked scalar masses contributions from R-parity violation.

We discuss the embedding of R-Parity preserving Minimal Left Right Supersymmetric models into Pati-Salam and SO(10) GUTs.

We investigate squark and gluino pair production at LHC(CMS) for the case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in events depends rather strongly on the relation between LSP, gluino and squark masses and it decreases with the increase of LSP mass. For relatively heavy LSP mass close to squark or gluino masses it is possible to detect SUSY for .

We point out that axino can be a natural candidate for sterile neutrino which would accomodate the LSND data with atmospheric and solar neutrino oscillations. It is shown that the so called 3 + 1 scheme can be easily realized when supersymmetry breaking is mediated by gauge interactions and also R-parity is properly broken. Among the currently possible solutions to the solar neutrino problem, only the large angle MSW oscillation is allowed in this scheme. The weak scale value of the Higgs μ parameter and the required size of R-parity violation can be understood by means of spontaneoulsy broken Peccei-Quinn symmetry.

The scalar top discovery potential has been studied with a full-statistics background simulation at and for the TESLA project. The beam polarization is very important to measure the scalar top mixing angle and to determine its mass. The latest estimation of the beam polarization parameters is applied. This study includes e⁺ polarization, which improves the sensitivity. For a 180 GeV scalar top at minimum production cross section, we obtain Δm = 0.8 GeV and in the neutralino decay channel, and Δm = 0.5 GeV and in the chargino decay channel.

We discuss corrections to ΔM_Bd, ΔM_Bs and to the CP violation parameter ε in two examples of (generalized) minimal flavour violation models: 2HDM and MSSM in the large tan β limit. We show that for H⁺ not too heavy, ΔM_Bs in the MSSM with heavy sparticles can be substantially smaller than in the SM due the charged Higgs box contributions and in particular due to the growing like tan⁴ β contribution of the double penguin diagrams involving neutral Higgs boson exchanges.

I discuss the sensitivity of kaon experiments to the scale of supersymmetry breaking in models with light sgoldstinos.

The restrictions on the lightest Higgs boson mass in the minimal supersymmetric models are briefly reviewed. The particle spectrum is considered in the framework of the simplest modification of NMSSM that allows to avoid the domain wall problem and to get the self-consistent solution in the strong Yukawa coupling limit. The lightest Higgs boson mass in the investigated model can reach 125 GeV at values of tan β ≥ 1.9 and does not exceed 130.5 ± 3.5 GeV.

We investigated the possibility of a heavy SM Higgs via relaxation of the electroweak precision bound. We also illustrated the effects of a relatively low supersymmetry mediation scale on the prediction of light CP-even Higgs mass in MSSM.

No abstract received.

Finite Unified Theories (FUTs) are N = 1 supersymmetric GUT's which are all-loop finite beyond the unification point. They also have impressive predictive power. The new characteristic predictions of FUTs are: 1) The lightest Higgs boson mass is predicted to be in the window 115-130 GeV, in case the LSP is a neutralino. 2) The s-spectrum starts above several hundreds of GeV.

We construct SU(5) SUSY GUT in 5D compactified on S¹/Z₂ orbifold where the matter fields are living in the five dimensional bulk. SU(5) symmetry is broken down to the Standard Model gauge group by the orbifold projection which automatically ensures stability of proton in all orders of perturbation theory. The model predicts extra mirror quark-lepton families which along with the GUT particles and the excitations of extra dimensions could be observable at high energy colliders providing the unification scale is in the TeV range.

We report on a preferred region of supersymmetric parameter space by t, b, τ Yukawa unification. We find a narrow region survives for μ > 0 (suggested by b → sγ and the anomalous magnetic moment of the muon) with A₀ ~ −2m₁₆, m¹⁶ ≥ 1200 GeV, μ,M_1/2 ≪ m₁₆ and tan β ~ 50 ± 2. Demanding Yukawa unification thus makes definite predictions for Higgs and sparticle masses.

In the context of SUSY SU(5) GUT we explore the possibility of interaction of the Higgs 24-plet (Σ), which breaks GUT symmetry, with matter and Higgs (H₂) 5-plets. This coupling violates the -parity and is related to an appearance of the bi-linear -parity violating terms. A consistency with phenomenological bounds leads to non-trivial restriction on the Yukawa couplings of the model. We identify symmetries which lead to desirable values of parameters.

The huge freedom in the SM fermionic mass matrices allows for large RH and LH quark rotations. This is a natural possibility in view of the observed large leptonic mixing. Proton decay and especially its gauge mediated decay is sensitive also to those mixing angles which are non-relevant in the SM. A model with realistic mass matrices and large rotations is presented. It is shown that the large leptonic mixing leads to enhancement of the proton decay branching ratios involving muons.

It is shown that a realistic SUSY SU(6) GUT can dynamically generate the GUT scale and solve at the same time the doublet-triplet splitting problem. The cos-mological implications of such a model are briefly reviewed.

Mechanism for generation of suppressed neutrino masses, within low scale theories, is considered. The mechanism do not have extradimensional nature and is realized through extended SU(2)_L scalar multiplets. Latters, in some cases, are also crucial for successful low scale unification.

In this talk, we discuss two non-minimal models with singlet neutrino in large extra dimensions: (1) singlet neutrino in a sub-space of the bulk and (2) Dirac mass for singlet with lepton number violating Yukawa couplings. The motivation is to obtain the mass scale relevant for atmospheric neutrino oscillations with a quantum gravity scale M_* ~ a few TeV and with at most O(1) higher-dimensional couplings. In both non-minimal models, such a low M_* can be consistent with the limit on BR(μ → eγ) (unlike in the minimal model). We also show that in this scenario, with 2 Higgs doublets, the decay of charged Higgs into left-handed τ can be significantly enhanced, with O(1) branching ratio, due to the large number of Kaluza-Klein states of the right-handed neutrino.

I briefly describe the recent construction of the first specific string D-brane models yielding just the SM massless fermion spectrum. One of the most remarkable facts predicted by these constructions is that the global symmetries of the SM like Baryon and Lepton numbers as well as the axial U(1)_A are gauged symmetries whose anomalies are canceled by a Green-Schwarz mechanism only in the case of three quark-lepton generations. Proton stability and the Dirac nature of neutrino masses are thus a prediction of these theories. This is work done in collaboration with Fernando Marchesano and Raul Rabadán.

We summarize some recent progress in constructing four-dimensional supersymmetric chiral models from Type II orientifolds. We present the construction a supersymmetric Standard-like Model and a supersymmetric GUT model to illustrate the new features of this approach and its connection to M theory on compact, singular G₂ holonomy spaces. The Standard-like model presented is the first example of a three-family supersymmetric orientifold model with the Standard Model as part of the gauge structure. We also discuss the connection of how chiral fermions arise in this class of models with recent results of M theory compactified on G₂ holonomy spaces.

We discuss physical implications of the four-dimensional effective supergravity, that describes low-energy physics of the Randall-Sundrum model with moduli fields in the bulk and charged chiral matter living on the branes. Cosmological constant can be cancelled through the introduction of a brane Polonyi field and a brane superpotential for the 4d dilaton. We deduce a generalization of the effective 4d action to the case of a general, not necessarily exponential, warp factor. We note, that breakdown of supersymmetry in generic warped models may lead to the stabilization of the interbrane distance.

We review a recent progress in constructing low-energy effective action in super Yang-Mills theories. Using harmonic superspace approach we consider SYM in terms of unconstrained superfield and apply background field method to finding effective action for SU(N) SYM broken down to U(1)^N−1. General structure of leading low-energy corrections to effective action is discussed.

We discuss a mechanism of partial breaking supersymmetry by brane solitons and describe properties of effective field theories which arise as a result of this phenomenon.

We present a new ultra-violet finite noncommutative supersymmetric gauge theory.

A ten-dimensional supersymmetric E₈ gauge theory is compactified over six-dimensional coset spaces. We find that the resulting four dimensional theory is a softly broken supersymmetric gauge theory in case the coset space is non-symmetric.

It is shown that renormalization of the Fayet-Iliopoulos term in softly broken SUSY gauge theory, in full analogy with all the other soft terms renormalizations, is completely defined in a rigid or unbroken theory. However, contrary to the other soft renormalizations, there is no simple differential operator that acts on the renormalization functions of a rigid theory and allows one to get the renormalization of the F-I term.

We consider degeneracy of sfermion masses in the supersymmetric models leading to hierarchical Yukawa couplings through interaction with SCFTs. We show the IR sum rules among sfermion masses in general softly broken SCFTs, and that the sfermion masses are made degenerate by coupling to a certain class of SCFTs. It is found, however, that flavor dependence in the squark/slepton masses remains due to the standard model gauge interactions.

We consider a class of models with infinite extra dimension, where bulk space does not possess SO(1,3) invariance, but Lorentz invariance emerges as an approximate symmetry of the low-energy effective theory. A peculiar feature of our scenario is that there are no truly localized modes. All four-dimensional particles are resonances with finite widths. The latter depends on the energy of the particle and is naturally small at low energies.

The role of associativity or WDVV equations in effective supersymmetric quantum theories is discussed and it is demonstrated that for wide class of their solutions when residue formulas are valid the proof of associativity equations can be reduced to solving the system of ordinary linear equations and depends only upon corresponding matching and nondegeneracy conditions. The covariance of WDVV equations upon generic duality transformations and the role of associativity equations in general context of quasiclassical integrable systems is also discussed.

The story how the long standing paradox with counting vacua in SUSY Yang-Mills is reviewed.

We consider interaction of two lumps corresponding to 0-branes in noncommutative gauge theory.

We apply a harmonic superspace approach to study quantum aspects of noncommutative supersymmetric field theories. The structure of low-energy effective actions of the models of noncommutative q-hypermultiplet and vector multiplet is studied using the background field method in harmonic superspace.

The superdiffeomorphisms invariant description of N - extended spinning particle is constructed in the framework of the approach of nonlinear realizations. The action is universal for all values of N. The form of this action coincides with the one-dimensional version of the gravity action, analogous to Trautman's one.

We present an example of N = 4 SUSY mechanics on the Kähler manifold which can be viewed as a mechanical counterpart of N = 2 supersymmetruc sigma model by Alvarez-Gaume and Freedman.

The full analysis of the number of preserved supersymmetries in the model of N = 1 D = 4 superparticle with tensorial central charges, which are constructed with unique even spinor, has been carried out. The operator quantization of the model has been fulfilled.

We discuss non-renormalization properties of some composite operators in supersymmetric Yang-Mills theory.

It is shown that two definitions for the exterior differential in superspace, giving the same exterior calculus, when applied to the Poisson bracket lead to the different results.

We consider the problem of supersymmetry breaking in 5 dimensional N = 1 supersymmetric models with S¹/Z₂ compactification.

We consider soliton-like solutions to supergravity based on the Kerr BH solution. We show that near the BH core gravity can mediate a phase transition forming a superconducting bag described by supersymmetric domain wall model.

It is a brief survey of the superextended Born-Infeld theories with partially spontaneously broken supersymmetries.

Proceeding from the concept of the partial breaking of global supersymmetry, we derive the worldsheet superfield action of the string in super AdS₃ background.

In this talk I report the results of two recent papers concerning the realization of the N = 8 supersymmetry from the division algebra of the octonions. At first I discuss a Sugawara realization for the “Non-associative N = 8 SCA” in terms of a superaffinization of the algebra of octonions. Next, I discuss the fact that the N = 8 SCA provides a generalized Poisson brackets structure for an N = 8 super-KdV.

We analyze superfield representations of BPS-conditions for the self-dual static solutions of D = 4, N = 2 supersymmetric Yang-Mills theory.

We analyze the reasons of appearing the different sets of fields entering into the T-duality transformations and discuss a possibility to construct the uniform T-duality rules.

We discuss W-algebras related to Toda-type integrable systems.

We consider a large-N supersymmetric model and find that the nonequilibrium evolution tends, at high energies, towards a massless phase.

TALKS NOT INCLUDED INTO THE VOLUME.

LIST OF PARTICIPANTS.

CONFERENCE PHOTOGRAPHS.