PASCOS 2004

PREFACE.

CONTENTS.

The origin of the galaxies represents an important focus of current cosmological research, both observational and theoretical. Its resolution involves a comprehensive understanding of star formation, galaxy dynamics, the cosmology of the very early universe, and the nature of the dark matter. In this review, I will focus on those aspects of dark matter that are relevant for understanding galaxy formation, and describe the outlook for detecting the most elusive component, non-baryonic dark matter.

Observations of the cosmic microwave background combined with large redshift surveys suggest that Ω_m ~ 0.3. Direct dynamical measurements combined with estimated of the universal luminosity density suggest Ω_m = 0.1 – 0.2. The apparent discrepancy may result from variations in the dark matter fraction with mass and scale. Traditional techniques already indicate that these variations are present. Gravitational lensing maps combined with large redshift surveys promise to measure the dark matter distribution. The Hectopsec Survey of a field in the Deep Lens Survey is a first approach to this kind of measurement.

There is now overwhelming observational evidence that our Universe is accelerating in its expansion. In these notes we discuss how modified gravitational theories can provide an explanation for this observed late-time cosmic acceleration. Specific low-curvature corrections to the Einstein-Hilbert action are examined. Many models generically contain unstable de Sitter solutions as well as late time accelerating attractor solutions.

Inspired by the current observations that the ratio of the abundance of dark energy Ω_Λ, and the matter density, Ω_m, is such that Ω_m/Ω_Λ ~ 0.37, we provide a string inspired phenomenological model where we explain this order one ratio, the smallness of the cosmological constant, and also the recent cosmic acceleration. We observe that any effective theory motivated by a higher dimensional physics provides radion/dilaton couplings to the standard model and the dark matter component with different strengths. Provided radion/dilaton is a dynamical field we show that Ω_Λ(t) tracks Ω_m(t) and dominates very recently.

The enormous red-shifting of the modes during the inflationary epoch suggests that physics at the very high energy scales may modify the primordial perturbation spectrum. Therefore, the measurements of the anisotropies in the Cosmic Microwave Background (CMB) could provide us with clues to understanding physics beyond the Planck scale. In this proceeding, we study the Planck scale effects on the primordial spectrum in the power-law inflation using a model which preserves local Lorentz invariance. While our model reproduces the standard spectrum on small scales, it naturally predicts a suppression of power on the large scales—a feature that seems to be necessary to explain deficit of power in the lower multipoles of the CMB.

For a large region of parameter space involving the cosmological constant and mass parameters, we discuss spacetime solutions that are effectively Minkowskian on large time and distance scales. A negative energy fluid is involved, resulting in a scale factor oscillating about a constant, with a frequency determined by the size of a negative cosmological constant. Gravity itself induces a coupling between the ghost-like and normal fields, and we find that this results in stochastic rather than unstable behavior. Ghosts could also allow for the existence of Lorentz invariant fluctuating solutions of finite energy density.

A self-consistent modular cosmology scenario and its testability in view of future CMB experiments are discussed. Particular attention is drawn to the enhanced symmetric points in moduli space which play crucial roles in our scenario. The running and moreover the running of running for the cosmic perturbation spectrum are also analyzed.

I present a new method for inferring the Cosmic Microwave Background(CMB) temperature quadrupole with accuracy better than cosmic variance. The method relies on measurements of the large angle CMB polarisation spectrum generated by a reionization epoch, exploiting the fact that CMB polarisation is sourced by the local quadrupole. It is generic enough and can be used to explicitly distinguish models that generate a low quadrupole from those that don’t.

The dynamics of the inflaton field is studied in the context of its interaction with bosonic and fermionic fields modeled by a minimal SUSY like model.

The first year Wilkinson Microwave Anisotropy Probe data favors primordial adiabatic fluctuation with a running spectral index with n_s > 1 on a large scale and n_s < 1 on a smaller scale. The model building of inflation that predicts perturbations with such a spectrum is a challenge. We give sensible particle physics models in supergravity that accommodate the desired running of the spectral index and discuss a method to discriminate those models.

We propose a simple model in which the MSSM plus neutrino mass term (LH_u)² is supplemented by a minimal flaton sector to drive the thermal inflation, and make two crucial assumptions: the flaton vacuum expectation value generates the μ-term of the MSSM and . The second assumption is particularly interesting in that it violates a well known constraint, implying that there exists a nearby deep non-MSSM vacuum, and provides a clear signature of our model which can be tested at future particle accelerators. We show that our model leads to thermal inflation followed by Affleck-Dine leptogenensis along the LH_u flat direction.

We discuss models of the accelerating universe where gravity is modified at infrared region. In particular, we consider the so-called Dvali-Gabadadze-Porrati (DGP) brane world model and an extension of the model. Interestingly, in some cases of the extended model, an enhanced big rip can occur. Some implications to observations of these models are also discussed.

The Pierre Auger Observatory is a major international effort aiming at high-statistics study of highest energy cosmic rays. A general description of the experimental set-up and overall performance of the detector at first light are presented.

The late infall of cold dark matter onto an isolated galaxy, such as our own, produces discrete flows and caustics in its halo. The set of caustics includes simple fold catastrophes located on topological spheres surrounding the galaxy, and a series of caustic rings in or near the galactic plane. The caustic rings are closed tubes whose cross-section is an elliptic umbilic catastrophe. The self-similar model of galactic halo formation predicts that the caustic ring radii a_n follow the approximate law a_n ~ 1/n. In a study of 32 extended and well-measured external galactic rotation curves evidence was found for this law. Also, the locations of ten sharp rises in the rotation curve of the Milky Way fit the prediction of the self-similar model at the 3% level. Moreover, a triangular feature in the IRAS map of the Galactic plane is consistent with the imprint of a ring caustic upon the baryonic matter. These observations imply that the dark matter in our neighborhood is dominated by a single flow. Estimates of that flow’s density and velocity vector are given.

DAMA is an observatory for rare processes based on the development and use of various kinds of radiopure scintillators. Several low background set-ups have been realized with time passing and many rare processes have been investigated. In particular, the DAMA/NaI set-up (≃ 100 kg highly radiopure NaI(Tl)) has investigated the model independent annual modulation signature for Dark Matter particles in the galactic halo. With the total exposure of 107731 kg × day, collected during seven annual cycles a model independent evidence at 6.3 σ C.L. has been achieved. At present the second generation DAMA/LIBRA is in operation deep underground.

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg-d of Ge net exposure after cuts for recoil energies between 10-100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using a standard dark matter halo distribution and nuclear-physics WIMP model, these data set the world’s lowest exclusion limits on the coherent WIMP-nucleon scalar cross-section for all WIMP masses above 13 GeV/c², ruling out a significant range of neutralino supersymmetric models. The best sensitivity at the minimum of the limit curve corresponds to a 90% C.L. cross-section exclusion of 4 × 10⁻⁴³ cm² at a WIMP mass of 60 GeV/c².

An alternative gravity and matter fields theory is studied where the consistency condition of equations of motion yields strong correlation between states of “primordial” fermion fields and local value of the dark energy. The same “primordial” fermion field at different densities can be either in states of regular fermionic matter or in states presumably corresponding to the dark fermionic matter. In regime of the fermion densities typical for normal particle physics, each of the primordial fermions splits into three generations identified with regular fermions. When restricting ourselves to the first two fermion generations, the theory reproduces general relativity and regular particle theory. When fermion energy density is comparable with vacuum energy density, the theory allows new type of states. The possibility of such Cosmo-Low Energy Physics (CLEP) states is demonstrated by means of solutions of the field theory equations describing FRW universe filled by homogeneous scalar field and uniformly distributed nonrelativistic neutrinos. Primordial neutrinos in CLEP state are drawn into cosmological expansion by means of dynamically changing their own parameters. Some of the features of the CLEP state in the late time universe: the mass of the primordial neutrino increases as a^3/2 (a = a(t) is the scale factor); its energy density scales as a sort of dark energy and approaches constant as a → ∞; this cold dark matter possesses negative pressure and its equation of state approaches that of the cosmological constant as a → ∞; the total energy density of such universe is less than it would be in the universe free of fermionic matter at all. The latter means that nonrelativistic neutrinos are able to produce expanding bubbles of the CLEP state playing the role of a true “cosmological vacuum” sorrounded by a “regular” vacuum.

This is a brief introduction to branon physics and its role in the dark matter problem. We pay special attention to the phenomenological consequences, both in high-energy particle physics experiments and in astrophysical and cosmological observations.

It is shown how high energy neutrino beams from very distant sources can be utilized to learn about some properties of neutrinos such as lifetimes, mass hierarchy, etc. Furthermore, even mixing elements such as U_e3 and the CPV phase in the neutrino mixing matrix can be measured in principle. Pseudo-Dirac mass differences as small as 10⁻¹⁸eV² can be probed as well.

In this talk we show how a natural neutrino mass hierarchy can follow from the type I see-saw mechanism, and a natural neutrino mass degeneracy from the type II see-saw mechanism, where the bi-large mixing angles can arise from either the neutrino or charged lepton sector. We also show that in such type II models the leptogenesis asymmetry parameter becomes proportional to the neutrino mass scale, in sharp contrast to the type I case, which leads to an upper bound on the neutrino mass scale, allowing lighter right-handed neutrinos and hence making leptogenesis more consistent with the gravitino constraints in supersymmetric models.

After a brief summary of the neutrino oscillation formalism and the solar neutrino sources and experiments I discuss the matter effect on solar neutrino oscillation. Then I discuss how the resulting alternative solutions are experimentally resolved in favour of the LMA solution, with particular emphasis on the SK, SNO and KL data.

The MiniBooNE E–898¹ experiment at Fermilab has been designed to confirm or dismiss the LSND observation by looking for ν_e appearance in a ν_µ beam. The experiment began taking beam data in September 2002. Here we describe the experiment, the first neutrino candidate events, and our expected sensitivity to a neutrino oscillation signal.

The Sudbury Neutrino Observatory (SNO) is an underground heavy-water Cherenkov detector designed to detect ⁸B solar neutrinos through neutral (NC) and charged (CC) current interactions on deuterons and elastic scattering on electrons. The results from the pure D₂O phase of the experiment confirmed solar model predictions and gave strong evidence for flavor change. In the second phase, 2 tonnes of NaCl were added to the heavy water, in order to enhance the detection of neutral current interactions. This allowed for precision, energy-unconstrained measurements of the solar neutrino flux that exclude maximal flavor mixing at a level of 5σ. The talk focused on the characterization of the detector response and the implications of the salt phase results on Neutrino Oscillation Physics. A status report was also given on the installation and commissioning work for the third phase of SNO, in which 40 ³He gas counters are deployed in the D₂O volume in order to detect the NC neutrons independently from the CC events.

The running of neutrino parameters in see-saw models and its implications for leptogenesis and for testing predictions of mass models with future precision experiments are discussed using analytical approximations as well as numerical results.

I present some selected parts of a recent analysis ¹ in which we explore (and combine together) all possible effects due to sterile neutrinos; I focus here on cosmology (BBN, CMB, LSS) and supernovæ.

The consistent treatment of the propagation of neutrinos in randomly fluctuating media requires the use of quantum dynamical semigroups: they allow taking into account matter-induced, decoherence phenomena that go beyond the standard MSW effect. Within this framework, a widely adopted density fluctuation pattern is found to be inconsistent: it leads to transition probabilities that take unphysical negative values.

We present in this talk a model based on SO(10) × SU(2)_F having symmetric mass textures with 5 zeros constructed by us recently. The symmetric mass textures arising from the left-right symmetry breaking chain of SO(10) give rise to good predictions for the masses, mixing angles and CP violation measures in the quark and lepton sectors (including the neutrinos), all in agreement with the most up-to-date experimental data within 1 σ. Various lepton flavor violating decays in our model are also investigated. Unlike in models with lop-sided textures, our prediction for the decay rate of μ → eγ is much suppressed and yet it is large enough to be probed by the next generation of experiments. The observed baryonic asymmetry in the Universe can be accommodated in our model utilizing soft leptogenesis.

When the perturbations forming the acoustic peaks of the cosmic microwave background (CMB) reentered the universe horizon and interacted gravitationally with all the matter, neutrinos presumably comprised 41% of the universe energy. CMB experiments have already reached a capacity to probe this background of relic neutrinos. I discuss the imprints left by neutrinos on CMB anisotropy and polarization at the onset of the acoustic oscillations, the underlying physics, robustness or degeneracy of the imprints with changes of free cosmological parameters, and examples of non-minimal physics for decoupled relativistic species with detectable signatures in CMB.

Radiative corrections are calculated for antineutrino proton quasielastic scattering, neutrino deuteron scattering, and the asymmetry of polarised neutron beta decay from which G_A/G_V is determined. A particular emphasis is given to the constant parts that are usually absorbed into the coupling constants, and thereby those that appear in the processes that concern us are unambiguously tied among each other.

The search for phenomena arising from new physics was one of the central research topics of the LEP2 physics program. Below we discuss the search for the Standard Model Higgs boson, neutral Higgs bosons of the MSSM, searches for Supersymmetric particles, mass limit for the Neutralino LSP and effects from extra spatial dimensions.

We investigate the prospects for the discovery at the CERN Large Hadron Collider of a neutral Higgs boson produced with one bottom quark followed by Higgs decay into a pair of tau leptons. We work within the framework of the minimal supersymmetric model. The dominant physics background from the production of bτ⁺τ⁻, jτ⁺τ⁻ (j = g, u, d, s, c), , W + 2j and is calculated with realistic acceptance cuts and efficiencies. Promising results are found for the CP-odd pseudoscalar (A⁰) and the heavier CP-even scalar (H⁰) Higgs bosons with masses up to 1 TeV.

The collider Run II at Fermilab that started in March 2001 with upgraded accelerator complex and detectors is progressing extremely well. An integrated luminosity of 670 pb^-1 was delivered to the CDF and DØ experiments each, by the end of August 2004. Additional planned upgrades to the accelerators will result in an integrated luminosity of 4 - 8 fb^-1 for each experiment by the end of 2009. I present some preliminary electroweak and top quark physics measurements made by the DØ collaboration analyzing data sets corresponding to integrated luminosity in the range of 150-250 pb^-1.

This article presents selected experimental results on searches for Higgs and physics beyond the standard model (BSM) at the Collider Detector at Fermilab (CDF). The results are based on about 350 pb⁻¹ of proton-antiproton collision data at , collected during Run II of the Tevatron. No evidence of signal was found and limits on the production cross section of various physics processes BSM are derived.

We report preliminary results on searches for extra dimensions, new gauge bosons, and SUSY particles with the DØ detector at the Fermilab Tevatron collider. No evidence for such effects was found and we place limits on size of extra dimensions and the masses of new particles.

The H1 and ZEUS experiments collected about 110 pb⁻¹ of integrated luminosity in e⁺p collision and about 16 pb⁻¹ in e⁻p collision during HERA I data taking (1994-2000). Data were analysed searching for contact interactions, extra-dimensions, R-parity violating SUSY, lepton-flavor violating and flavor-changing neutral current interactions. Possible deviations from Standard Model were furthermore investigated studying events with isolated leptons and high missing transverse momentum, or with two or more isolated high transverse momentum objects (photons, leptons, jets or neutrinos). A summary of the results is given. The first results of HERA II (2003-2004 running period) are also shown.

In this article the most recent results from electroweak precision physics at LEP2 are reviewed and interpreted. Limits on the Higgs mass and constraints on the validity of the Standard Model (SM) are also derived via a fit to all electroweak results.

A review of the potential of the LHC experiments to discover and measure supersymmetric Dark Matter is presented. Different methods for sparticle mass spectrum reconstruction in the framework of R-Parity conserved mSUGRA model are discussed.

We present a unified picture of flavor and electroweak symmetry breaking based on a nonlinear sigma model spontaneously broken at the TeV scale. Flavor and Higgs bosons arise as pseudo-Goldstone modes. Explicit collective symmetry breaking yields stable vacuum expectation values and masses protected at one loop by the little-Higgs mechanism. The coupling to the fermions generates well-definite mass textures—according to a U(1) global flavor symmetry—that correctly reproduce the mass hierarchies and mixings of quarks and leptons. The model is more constrained than usual little-Higgs models because of bounds on weak and flavor physics. The main experimental signatures testable at the LHC are a rather large mass m_h⁰ = 317 ± 80 GeV for the (lightest) Higgs boson.

The masses of phenomenological scalar bosons are not protected against large contributions due to quantum loops involving the hypothetical very high energy theory that we assume is the true theory. Here I present a generalization of Yang-Mills theories that treats vector and scalar bosons on the same footing and results in Ward identities and current conservations that protect the masses of the scalars. It is remarkable that that the Standard Model obtains immediately upon choosing an appropriate gauge symmetry and allowing for one scalar field and one vector field to possess large vacuum expectation values. The Standard Model then appears as the unitary gauge of the chosen gauge symmetry. Due to the vectorial VEV there is a small breaking of the Lorentz invariance.

Recently a new class of technicolor models are proposed, using technifermions of symmetric second-rank tensor. In the models, one can make reasonable estimates of physical quantities like the Higgs mass and the size of oblique corrections, using a correspondence to super Yang-Mills theory in the Corrigan-Ramond limit. The models predict a surprisingly light Higgs of mass, m_H = 150 ~ 500 GeV and have naturally small S parameter.

The Multiple Point Principle, according to which there exist many vacuum states with the same energy density, is put forward as a fine-tuning mechanism. By assuming the existence of three degenerate vacua, we derive the hierarchical ratio between the fundamental (Planck) and electroweak scales in the Standard Model. In one of these phases, 6 top quarks and 6 anti-top quarks bind so strongly by Higgs exchange as to become tachyonic and form a condensate. The third degenerate vacuum is taken to have a Higgs field expectation value of the order of the fundamental scale.

Recent results on CP violation and heavy flavor physics obtained by the Belle collaboration are reported. Time dependent CP violation in various b → s decay processes are measured with high luminosity (253fb⁻¹) and the average “sin2ϕ₁” value is found to be 2.4σ away from the world average for decays. Evidence for direct CP violation in B⁰ → K⁺π⁻ is found with 3.9σ significance. B → K^(*)l⁺l⁻ FCNC process is measured with high statistics, and a first look at the forward-backward asymmetry is presented.

We review our recent studies on the effects of CP-violating supersymmetric (SUSY) parameters on the phenomenology of neutralinos, charginos and third generation squarks. The CP-even branching ratios of the squarks show a pronounced dependence on the phases of A_t, A_b, μ and M₁ in a large region of the supersymmetric parameter space, which can be used to get information on these phases. In addition we have studied CP-odd observables, like asymmetries based on triple product correlations. In neutralino and chargino production with subsequent three-body decays these asymmetries can be as large as 20%.

Recently, we have presented [hep-ph/0408103] a variant of resonant leptogenesis in which the baryon asymmetry in the Universe is created by resonant lepton-to-baryon conversion of an individual lepton number, for example that of the τ-lepton. We briefly outline the phenomenological implications of this scenario for the production of sub-TeV heavy Majorana neutrinos at e⁺e⁻ linear colliders and for low-energy processes, such as 0νββ decay and μ → eγ.

In Lorentz-violating supergravity, sfermions have spin 1/2 and other unusual properties. If the dark matter consists of such particles, there is a natural explanation for the apparent absence of cusps and other small scale structure: The Lorentz-violating dark matter is cold because of the large particle mass, but still moves at nearly the speed of light. Although the R-parity of a sfermion, gaugino, or gravitino is +1 in the present theory, these particles have an “S-parity” which implies that the LSP is stable and that they are produced in pairs. On the other hand, they can be clearly distinguished from the superpartners of standard supersymmetry by their highly unconventional properties.

We examine a simple extension of the minimal renormalizable supersymmetric SO(10) grand unified theory by adding a 120-dimensional Higgs representation. This brings new antisymmetric contributions to the relevant quark and lepton mass sum rules and leads to a better fit of the measured values of lepton masses and mixings together with a natural completion of the renormalizable Higgs sector within the SUSY SO(10) framework.

Some rare decay processes are particularly sensitive to physics beyond the Standard Model (SM) because they have no SM tree contributions. We focus on one of these, B_d → ϕK_s. Our study is in terms of the high scale effective theory, and high scale models for the underlying theory, while previous studies have been focusing on the low scale effective Lagrangian. We show that models with family dependent Kähler potential can provide large non-SM CP effects to the B_d → ϕK_s process.

We present a systematic analysis of the decay at the leading log within the framework of Supersymmetry without R-parity. We point out some new contributions in the form of bilinear-trilinear combination of R-parity violating (RPV) couplings that are enhanced by large tan β. We also improve by a few orders of magnitude, bounds on several combinations of RPV parameters.

We extend the commonly used mSUGRA framework to allow complex soft terms. We show how these phases can induce large changes of the SUSY threshold corrections to the b quark mass and affect the neutralino relic density predictions of the model. We present some specific models with large SUSY phases which can accommodate the fermion electric dipole moment constraints and a neutralino relic density within the WMAP bounds.

The minimal SO(10) model with one 10 and one Higgs can fit the neutrino masses and mixing angles. Recently, a detailed analysis shows that the fit of solar, atmospheric mixing angles and mass ratios in this very predictive minimal model requires the Kobayashi-Maskawa phase to be either 0 (Type I seesaw) or to be much larger than 100°(Type II seesaw). In this talk, we propose a parity symmetric SO(10) model with an additional 120 Higgs multiplet. The parity symmetry makes the Yukawa matrices hermitian and all the parameters in Higgs sector are real. The model is more predictive since the number of parameters is less than the original minimal model. I will elaborate the predictions of this more minimal model.

Even without Grand Unification, proton decay can be a powerful probe of physics at the highest energy scales. Supersymmetric theories with conserved R-parity contain Planck-suppressed dimension 5 operators that give important contributions to nucleon decay. These operators are likely controlled by flavor physics, which means current and near future proton decay experiments might yield clues about the fermion mass spectrum. I present a thorough analysis of nucleon partial life-times in supersymmetric one-flavon Froggatt-Nielsen models with a single U(1)_X family symmetry which is responsible for the fermionic mass spectrum as well as forbidding R-parity violating interactions. Many of the models naturally lead to nucleon decay near present limits without any reference to grand unification.

We analyze the CP asymmetry of the B → ϕK_S and B → η′K_S processes in general supersymmetric models. We adopt the QCD factorization method for evaluating the corresponding hadronic matrix elements. We show that chromomagnetic type of operator may play an important role in accounting for the deviation of the mixing CP asymmetry between B → ϕK_S and B → J/ψK_S processes observed by Belle and BaBar experiments. We also show that due to the different parity in the final states of these processes, their supersymmetric contributions from the R-sector have an opposite sign, which naturally explain the large deviation between their asymmetries.

We discuss the effects of the gravitino on the big-bang nucleosynthesis (BBN), paying particular attention to the hadronic decay mode of the gravitino. We will see that the hadronic decay of the gravitino significantly affect the BBN and, for the case where the hadronic branching ratio is sizable, very stringent upper bound on the reheating temperature after inflation is obtained.

We present a leptogenesis scenario through the decay of heavy triplets following smooth hybrid inflation within a moderate extension of the left-right supersymmetric gauge group SU(2)_L × SU(2)_R × U(1)_B−L. Baryon number conservation and the solution of the μ-problem are provided by additional symmetries. All the right handed neutrinos are heavier than inflatons. Then we have studied neutrino mass matrix generated by the triplet VEVs having the parameters constrained by leptogenesis and inflation scenario and found that the production of the required lepton asymmetry of the universe is not only right enough to be consistent with the neutrino mass and mixing angles predicted by the recent data but also can provide an estimate of b – τ unification in the context of a minimal susy SO(10) model.

We present the full three-loop β-functions for the MSSM generalised to include additional matter multiplets in 5, 10 representations of SU(5). We analyse the effect of three-loop running on the sparticle spectrum for the MSSM Snowmass Benchmark Points. We also consider the effect on these spectra of additional matter multiplets (the semi-perturbative unification scenario).

Abelian vector bosons can get massive through the Stueckelberg mechanism without spontaneous symmetry breaking via condensation of Higgs scalar fields. This appears very naturally in models derived from string theory and supergravity. The simplest scenarios of this type consist of extensions of the Standard Model (SM) or the minimal supersymmetric standard model (MSSM) by an extra U(1)_X gauge group with Stueckelberg type couplings. For the SM, the physical spectrum is extended by a massive neutral gauge boson Z′ only, while the extension of the MSSM contains a CP-even neutral scalar and two extra neutralinos. The new gauge boson Z′ can be very light compared to what one has in other models with U(1)′ extensions. Among the many new features of the Stueckelberg extension of MSSM, perhaps the most striking one in the possibility of a new lightest supersymmetric particle (LSP) which is mostly composed of Stueckelberg fermions. In this scenario the LSP of MSSM is unstable and decays into . Such decays alter the signatures of supersymmetry and have impact on searches for supersymmetry in accelerator experiments. Further, with R-parity invariance, is the new candidate for dark matter.

We present a supersymmetric SU(4)×SU(2)² × U(1)_X model of fermion masses with fundamental and antisymmetric tensor representations only. The up, down, charged lepton and neutrino Yukawa matrices are split by SU(4) and SU(2)_R Clebsch-Gordan coefficients. We obtain a hierarchical light neutrino mass spectrum with bi-large mixing. The condition that anomalies be cancelled by a Green-Schwarz mechanism consistent with gauge unification leads to fractional U(1)_X charges, which exclude B violation through dimension-4 and -5 operators.

We show that out-of-equilibrium plasma effects provide the conditions for the formation of embedded vortex-strings. The necessary conditions are an efficient dissipation mechanism for the field modes forming the string and a not too large scalar self-coupling right below the transition scale. We discuss the cosmological implications at the chiral, electroweak and GUT symmetry breaking scales.

Bright bursts of gamma rays from outer space have been puzzling Astronomers for more than thirty years and there is still no conceptually complete model for the phenomenon within the standard model of particle physics. Is it time to consider a supersymmetric (SUSY) origin for these bursts to add to the astronomical indications of supersymmetry from dark matter?

In theories with extra dimensions the Standard Model Higgs fields can be identified with internal components of bulk gauge fields (Higgs-gauge unification). The bulk gauge symmetry protects the Higgs mass from quadratic divergences, but at the fixed points localized tadpoles can be radiatively generated if U(1) subgroups are conserved, making the Higgs mass UV sensitive. We show that a global symmetry, remnant of the internal rotation group after orbifold projection, can prevent the generation of such tadpoles. In particular we consider the classes of orbifold compactifications T^d/ℤ_N (d even, N > 2) and T^d/ℤ₂ (arbitrary d) and show that in the first case tadpoles are always allowed, while in the second they can appear only for d = 2 (six dimensions).

The five dimensional version of the Green–Schwarz mechanism can be invoked to cancel abelian anomalies on the boundaries of brane world models. In five dimensions there are two dual descriptions that employ either a two–form tensor field or a vector field. We present the supersymmetric extensions of these dual theories using four-dimensional superspace. The vector formulation always contains singular boundary mass terms which are absent in the tensor formulation. This apparent inconsistency is resolved by showing that in either formulation the propagator of the anomalous U(1) gauge (super)field exhibits finite (non-local) boundary mass terms, which generically lead to a finite nonzero mass for the lowest lying Kaluza–Klein mode. Talk based on the work done in collaboration with T. Gherghetta and S. Groot-Nibbelink.

The anomaly-induced inflation (modified Starobinsky model) is based on the application of effective quantum field theory (QFT) approach to the Early Universe. We present a brief review of this model in relation to recent results concerning quantum field theory in curved space-time.

In this talk I will discuss the role of finite temperature quantum corrections in string cosmology and show that they can lead to a stabilization mechanism for the volume moduli. I will show that from the higher dimensional perspective this results from the effect of states of enhanced symmetry on the one-loop free energy. These states lead not only to stabilization, but also suggest an alternative model for ΛCDM. At late times, when the low energy effective field theory gives the appropriate description of the dynamics, the moduli will begin to slow-roll and stabilization will generically fail. However, stabilization can be recovered by considering cosmological particle production near the points of enhanced symmetry leading to the process known as moduli trapping.

The effect of NS 5 branes on an orientifold is studied. The orientifold is allowed to pass through a pile of k NS branes forming a regularized CHS geometry. Its effect on open strings in its vicinity is used to study the change in the orientifold charge induced by the NS branes.

When the 3-dimensional gravitational Chern-Simons term is reduced to two dimensions a dilaton-like gravity theory emerges. Its solutions involve kinks, which therefore describe 3-dimensional, conformally flat spaces.

This talk is about the planar equivalence between gluodynamics (super-Yang-Mills theory) and a non-supersymmetric “orientifold field theory.” We outline an “orientifold” large N expansion, analyze its possible phenomenological consequences in one-flavor massless QCD, and make a first attempt at extending the correspondence to three massless flavors. An analytic calculation of the quark condensate in one-flavor QCD starting from the gluino condensate in gluodynamics is thoroughly discussed.

Systems of tightly knotted, linked, or braided quantized flux tubes have a universal mass-energy spectrum, since the length of fixed radius flux tubes depend only on the topology of the configuration. We concentrate on the model of glueballs as knotted QCD flux tubes, but other applications are also briefly discussed.

The advent of phenomenological quantum gravity has ushered us in the search for experimental tests of the deviations from general relativity predicted by quantum gravity or by string theories, and as a by–product of this quest the possible modifications that some field equations, for instance, the motion equation of spin–1/2–particles, have already been considered. In the present work a modified Dirac equation, whose extra term embraces a second–order time derivative, is taken as mainstay, and two different experimental proposals to detect it are put forward. The novelty in these ideas is that two of them do not fall within the extant approaches in this context, to wit, red–shift, atomic interferometry, or Hughes–Drever type–like experiments.

I discuss a systematic method of analytically calculating the asymptotic form of quasi-normal frequencies. In the case of a four-dimensional Schwarzschild black hole, I expand around the zeroth-order approximation to the wave equation proposed by Motl and Neitzke. In the case of a five-dimensional AdS black hole, I discuss a perturbative solution of the Heun equation. The analytical results are in agreement with the results from numerical analysis.

Though QFT is well developed and successful in theoretical aspects and applications, there are some defects in QFT [1]. Ultraviolet divergences and infrared divergences are serious defects of QFT. The ultraviolet divergence will not be discussed in this article since it was discussed by Hung-Ming Tsai et al. in 2003 [2]. There are two approaches to remove the infrared singularities. The first part of this article is the mathematical proof of the existence of a positive lower bound of the energy of emitted photons or gluons. Therefore, the soft divergence is removed. The second part of this article is to show the existence of a regular basis of the solution space of the field equation. The second quantization is based on this regular basis. With this regular basis, the infrared divergences, both the soft divergence and the collinear divergence, are expected to be removed.

It is established the general structure of the Maxwell electromagnetic field for a 2+1 spacetime endowed with stationary and cyclic symmetries. The family of possible fields splits in two disjoint classes. The general solution for c ≠ 0 and its limiting cases are explicitly exhibited.

ATTENDEES.

PREFACE.

CONTENTS.

No abstract received.

We examine the gravitational forces in a brane-world scenario felt by point particles on two 3-branes bounding a 5-dimensional AdS space with S¹/Z₂ symmetry. The particles are treated as perturbations on the vacuum metric and coordinate conditions are chosen so that no brane bending effects occur. We make an ADM type decomposition of the metric tensor and solve Einstein’s equations to linear order in the static limit. While no stabilization mechanism is assumed, all the 5D Einstein equations are solved and are seen to have a consistent solution. We find that Newton’s law is reproduced on the Planck brane at the origin while particles on the TeV brane a distance y₂ from the origin experience an attractive force that has a growing exponential dependence on the brane position.

A short review of the problems with the action for massive gravitons is presented. We show that consistency problems could be resolved by employing spontaneous symmetry breaking to give masses to gravitons. The idea is then generalized by enlarging the SL(2,ℂ) symmetry to SL(2N,ℂ) × SL(2N,ℂ) which is broken to SL(2,ℂ) spontaneously through a non-linear realization. The requirement that the space-time metric is generated dynamically forces the action constructed to be a four-form. It is shown that the spectrum of this model consists of two sets of massive matrix gravitons in the adjoint representation of SU(N) and thus are colored, as well as two singlets, one describing a massive graviton, the other being the familiar massless graviton.

In this article major recent advances in the physics of massive neutrinos are reviewed and pathways to future precision measurements are outlined.

Results from studies of effective Lagrangians for gaugino condensation are summarized and re-examined with an eye to previously neglected one-loop quadratically divergent corrections.

SUSY breaking and its mediation are among the most important problems of supersymmetric generalizations of the standard model. The idea of gravity-mediated SUSY breaking, proposed in 1982 by Arnowitt, Chamseddine and Nath, and independently by Barbieri, Ferrara and Savoy, fits naturally into superstring theory, where it can be realized at both classical as well as quantum levels. This talk is dedicated to Pran Nath on his 65th birthday.

No abstract received.

Spontaneous breaking of supersymmetry in a hidden sector, communicated gravitationally to the visible world of the Minimal Supersymmetric Standard Model (MSSM) gives rise to soft supersymmetry breaking. In string theoretic models with D-branes, the MSSM gauge and matter fields originate from open strings localized on these branes, while the hidden sector is given by closed string excitations or other distant branes. To obtain chiral non-abelian gauge symmetries with semirealistic properties, we consider intersecting or magnetized D-branes, for which a computable low energy Lagrangian is known, giving rise to a specific pattern of soft breaking parameters. Since in D-brane models the universality of gravity is partly violated, gauge coupling unification is usually negated, and one can put bounds from experiments on the parameters that characterize the model, which are however not very restrictive and model dependent. A possible source of supersymmetry breaking is the presence of background fluxes in the compactification, which allows a combined approach to moduli stabilization and supersymmetry breaking.

We review the prospects for SUSY searches at the LHC and at electron positron linear colliders in light of recent constraints on the relic density of cold dark matter as well as those from the determination of muon anomalous magnetic moment and rare decays of bottom mesons, using the mSUGRA model to guide our thinking. The WMAP measurement requires a neutralino relic density somewhat lower than the typical model value, so that efficient neutralino annihilation is required. We find several qualitatively different regions of the mSUGRA parameter space that are favoured by the WMAP data: unless tan beta is very large, experiments at the LHC should be able to probe most of these regions. An important exception is the region with small mu and large values of universal scalar and gaugino masses, where the LSP has a considerable higgsino component and is close in mass to the chargino. We find that linear colliders should be able to probe parts of this region not accessible at the LHC.

The minimal supergravity model (mSUGRA) was established by Pran Nath and others over 20 years ago, and serves as the paradigm model for supersymmetry phenomenology. A standard prediction is that the lightest neutralino comprises the bulk of dark matter in the universe. I outline expectations for indirect detection of neutralino dark matter via neutralino annihilation in the solar core, and in the galactic halo. These rates are compared to direct detection rates and also to prospects for supersymmetry detection at the Fermilab Tevatron, CERN LHC and a 0.5-1 TeV linear e⁺e⁻ collider.

We present the status of the search for dark matter particles. The different methods include cryogenic detectors and liquid Noble gas detectors such as Xenon (ZEPLIN, etc.). We review the evidence for Dark Matter in the galaxy and the method to detect particle dark matter. The current limits on the search for dark matter are reviewed and some possibility to evade these limits using dark matter flows. The possible future one ton detectors are discussed as is the range of sensitivity of these detectors.

A brief review is given of the ways of testing SUGRA unified models and a class of string models using data from precision electroweak experiment, Yukawa unification constraints, and constraints from dark matter experiment. Models discussed in detail include mSUGRA, extended SUGRA model with non-universalities within SO(10) grand unification, and effective theories with modular invariant soft breaking within a generic heterotic string framework. The implications of the Hyperbolic Branch including the focus point and inversion regions for the discovery of supersymmetry in collider experiments and for the detection of dark matter in the direct detection experiments are also discussed.

We compute the supersymmetric QCD corrections to the quark-squark-chargino and quark-squark-neutralino interactions in the presence of SUSY CP phases. The analysis includes one loop diagrams arising from the exchange of gluinos, charged Higgs and neutral Higgs. We then apply the effective lagrangian to investigate the effect of CP phases on the fermionic decay of the third generation squarks into charginos and neutralinos. We find that the CP phases can increase or decrease the decay rates. The inclusion of radiative corrections can bring new phase dependences of the decay rates which were absent in the tree level analysis. One of these phases is ξ₃ of the SUSY QCD sector. In the region of the parameter space studied we found that the numerical size of the corrections can be as large as 50%. The variation of the corrected decay rates with ξ₃ is found to be significant. The EDM constraints are satisfied using the cancellation mechanism.

The effective Lagrangian including one loop corrections is deduced for the couplings of the charged Higgs with squarks and sleptons, and with charginos and neutralinos. The effect of the one loop corrections is found to be quite significant in a number of sectors. The effective Lagrangian is then used to analyze the decay of the charged Higgs into a number of decay channels. Specifically we consider the decay of H⁺(H⁻) into the decay modes , , and (i=1,2; j=1-4). The loop corrections to these decay modes are also found to be quite significant lying in the range 20-30% in significant regions of the parameter space of the SUGRA model. The effects of CP phases on the effective Lagrangian and on the branching ratios are also analysed and these effects found to be important.

A review is given of a recently developed technique for the analysis of SO(2N) invariant couplings which allows a full exhibition of the SU(N) invariant content of couplings involving the SO(2N) semi-spinors |Ψ_± > with chiralilty ± and tensor representations. We discuss the Basic Theorem used in the analysis and then exhibit the technique by illustrative examples for the computation of the trilinear and quartic couplings for the SO(10) case involving three generations of 16 plets of matter.

The use of the AdS/CFT correspondence to arrive at quiver gauge field theories is discussed. An abelian orbifold with the finite group Z_p can give rise to a nonsupersymmetric G = U(N)^p gauge theory with chiral fermions and complex scalars in different bi-fundamental representations of G. The precision measurements at the Z resonance suggest the values p = 12 and N = 3, and a unifications scale M_U ~ 4 TeV. Dedicated to the 65th birthday of Pran Nath.

The HEIDELBERG-MOSCOW experiment operating 11kg of enriched ⁷⁶Ge in the GRAN SASSO Underground Laboratory, is one of the long-running underground experiments. It is the most sensitive double beta decay experiment since more than ten years. The analysis of the data taken from 2 August 1990 - 20 May 2003, is presented here. The collected statistics is 71.7 kg y. The background achieved in the energy region of the Q value for double beta decay is 0.11 events/ kg y keV. The two-neutrino accompanied half-life is determined on the basis of more than 100 000 events to be . The confidence level for the neutrinoless signal has been improved to a 4.2σ level. The half-life is . Fundamental consequences of this first evidence for neutrinoless double beta decay is that total lepton number is not conserved, and that the neutrino is a Majorana particle, and further, that only a degenarate neutrino mass model is allowed. The effective neutrino mass deduced is (0.2 - 0.6) eV (99.73% c.l.). The HEIDELBERG-MOSCOW experiment yields sharp restrictions also for other beyond standard model physics. These include SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass, test of special relativity and equivalence principle in the neutrino sector and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc.

This talk provides a brief summary of the status of lattice QCD calculations of the light quark masses and the kaon bag parameter B_K. Precise estimates of these four fundamental parameters of the standard model, i.e., m_u, m_d, m_s and the CP violating parameter η, help constrain grand unified models and could provide a window to new physics.

An attempt is made to interrelate (i) fermion masses, (ii) neutrino oscillations, (iii) CP and flavor violations, and (iv) baryogenesis via leptogenesis, within supersymmetric grand unification, based on an effective symmetry which is either G(224) = SU(2)_L × SU(2)_R × SU(4)^c or SO(10). Reviewing the framework proposed in this context by Babu, Pati and Wilczek (BPW), which successfully describes fermion masses and neutrino oscillations, a recent work by Babu, Rastogi and me is presented. It is shown that the BPW framework can be extended rather simply to include CP violation that is intimately linked to fermion masses and neutrino oscillations. Including SM and SUSY contributions, it is found that the extension can correctly account for the observed flavor and/or CP violations in Δm_K, Δm_Bd, S(B_d → J/ψK_S) as well as ∊_K, while retaining the successes of the BPW framework as regards fermion masses and neutrino oscillations. While SUSY contribution is small (≲ few%) for the first three quantities, that to ∊_K is sizable (~ 20-25%) and negative (as desired) compared to that of the SM. The model predicts S(B_d → ϕK_S) to be in the range +(0.65-0.73), close to the SM prediction. The model yields Re(∊′/∊)_SUSY ≈ +(4 – 14) × 10⁻⁴; the relevance of this contribution can be assessed only when the associated matrix elements are known reliably. The model also predicts that the electric dipole moments of the neutron and the electron, as well as the rare processes μ → eγ and τ → μγ, should be discovered with improvements in the current limits by factors of 10 to 100. Last but not the least, the model naturally leads to baryogenesis via leptogenesis in good accord with observation.

We review recent results (hep-th/0405194, hep-th/0405129, and hep-th/0404198) on the BPS multi-wall solutions in supersymmetric U(N_C) gauge theories in five dimensions with N_F(> N_C) hypermultiplets in the fundamental representation. Total moduli space of the BPS non-Abelian walls is found to be the complex Grassmann manifold SU(N_F)/[SU(N_C) × SU(N_F - N_C) × U(1)]. Exact solutions are obtained with full generic moduli for infinite gauge coupling. A 1/4 BPS equation is also solved, giving vortices together with the non-Abelian walls and monopoles in the Higgs phase attached to the vortices. The full moduli space of the 1/4 BPS solutions is found to be holomorphic maps from a complex plane to the wall moduli space.

We describe some recent investigation about the structure of generic D = 4, 5 theories obtained by generalized dimensional reduction of D = 5, 6 theories with eight supercharges. We relate the Scherk-Schwarz reduction to a special class of N = 2 no-scale gauged supergravities.

We argue that the study of the statistics of the landscape of string vacua provides the first potentially predictive – and also falsifiable – framework for string theory. The question of whether the theory does or does not predict low energy supersymmetry breaking may well be the most accessible to analysis. We argue that low energy – possibly very low energy – supersymmetry breaking is likely to emerge, and enumerate questions which must be answered in order to make a definitive prediction.

Recent measurements of the values of gauge coupling constants as well as neutrino properties support the idea of a grand unified (GUT) description of particle physics at a large scale of M_GUT ~ 10¹⁶ GeV. We discuss a strategy to incorporate this picture in the framework of superstring theory. In such a scheme successful predictions of GUTs can be realized while some of the more problematic aspects of grand unification might be avoided. The most promising models are expected in the framework of the heterotic E₈ × E₈ string theory.

Possible sources of neutrinos with energies > 1 TeV, and fluxes which yield signals above atmospheric background at large neutrino detectors are identified and discussed. An interesting candidate for a Galactic source lies in the Cygnus-OB2 region of star formation, with neutrinos resulting from neutron decay following nuclear photodisintegration on the ambient photon sea. Possible extragalactic sources are Fanaroff-Riley I radio galaxies similar to Centaurus A, in which cumulative burst activity can be integrated over the Hubble sphere to provide a positive neutrino signal at IceCube.

We describe, for arbitrary dimensions the construction of a covariant and supersymmetric constraint for the massless super Poincaré algebra and we show that the constraint fixes uniquely the representation of the algebra. For the case of finite mass and in the absence of central charges we discuss a similar construction, which generalizes to arbitrary dimensions the concept of the superspin Casimir. Finally we discuss briefly the modifications introduced by central charges, both scalar and tensorial.

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This is an overview of the contributions of Pran Nath, Matthews Distinguished Professor of Physics at Northeastern University, to the development of particle theory. The underlying theme in the work of Professor Nath since the mid-1960s has been the unification of elementary particle interactions. This work includes development of local supersymmetry (SUSY), supergravity grand unification (mSUGRA), proposals regarding the discovery of supersymmetry at colliders and in dark matter, and the use of effective Lagrangians to explore the consequences of current algebra.

Selected Works of Pran Nath.

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