International Journal of Modern Physics A

We construct a realistic model based on SUSY SO(10) with U(2) flavor symmetry. A set of symmetric mass textures give rise to very good predictions; 15 masses and 6 mixing angles are predicted by 11 parameters. Both the vacuum oscillation and LOW solutions are favored for the solar neutrino problem.

Recent neutrino parameter measurements place increasingly stringent on acceptable supersymmetric theories of flavor. A very fruitful approach is the application of non-Abelian discrete gauged flavor symmetries G_f. We discuss a highly successful model using G_f = T′ × Z₃ where T′ is a non-Abelian group based on the symmetries of a tetrahedron. This model reproduces the basic features of the U(2) model, and also predicts neutrino masses and mixing angles consistent with either the SMA or LMA scenarios.

A topcolor model is presented that contains both composite and fundamental scalar fields. Strong dynamics accounts for most of the top quark mass and part of the electroweak symmetry breaking scale. The fundamental scalar is weakly coupled and transmits its share of electroweak symmetry breaking to the light fermions. The model is allowed by the current experimental bounds, and can give a potentially large contribution to mixing.

I briefly describe two motivations, two mechanisms and two possible tests of the hypothesis that the physical parameters of the ground state of a theory can vary in different rerions of the universe.

An unconventional version of supersymmetry leads to the following highly teatable predictions: (1) the Higgs boson has an R-parity of -1, so it can only be produced as one member of a pair of superpartners. (2) The only superpartners are scalar bosons, so neutralinos etc. do not exist. (3) The most likely candidate for cold dark matter is therefore a sneutrino. (4) The Higgs and other bosonic superpartners have an unconventional equation of motion. These predictions are associated with new interpretations of Yukawa couplings, supersymmetry, gauge fields, and Lorentz invariance.

A geometric approach to the standard model in terms of the Clifford algebra Cℓ₇ is advanced. The gauge symmetries and charge assignments of the fundamental fermions and the higgs boson arise uniquely from a geometric model involving only four extra space-like dimensions. A key feature of the model is its use of double-sided operations on the algebraic spinors. The four added dimensions form a natural basis for the Higgs isodoublet field.

Padé-approximant treatments of the known terms of the QCD β-function are seen to develop possible infrared fixed point structure only if the number of fermion flavours is sufficiently large. This flavour threshold is seen to be between six and nine flavours, depending upon both the specific choice of approximant as well as on the presently-unknown five-loop β-function contribution. Below this flavour threshold, Padé approximants based upon the QCD β-function manifest the same infrared attractor structure as that which characterizes the exact NSVZ β-function of supersymmetric gluodynamics. Such infrared attractor structure is also seen to characterize Padé-approximant treatments of vector SU(N) gauge theory in the large N limit, suggesting common infrared dynamics for the strong and weak phases of this theory.

A geometrical model (GM) featuring a visualizable reduction of the elementary particles and interactions down to common elements has been developed. As a consequence, a taxonomy of particles and various interactions emerge, all in consonance with the Standard Model (SM) of particle physics. However, the GM goes well beyond the SM, incorporating a number of fundamental phenomena and issues for which the latter has no explanation. Since the GMs largely diagramatic development cannot be displayed in this brief paper, only a summary of its conceptual basis and consequences is presented herein.

Experimental results from π^-, K^-, Σ^- capture, and annihilations in liquid H₂ show that the fraction of captures and annihilations from atomic P states is less than 5% in agreement with theoretical expectations. However, an anomalously large fraction from P states by a factor of ten is inferred from the branching ratios for the reactions and at rest in liquid H₂ and liquid D₂ respectively. One explanation for this inconsistenct is that the reaction is occurring from an atomic S state of protnium, which is possible if the two π⁰'s are not identical. It should be noted that a second neutral pion (with different lifetime and decay properties) was observed in antinucleon-nucleon reactions in a 1964 experiment. We describe two experimental tests, one to determine whether can occur from an atomic S state, and another to search for the π⁰π⁰ decay mode of neutral vector mesons with J^PC = 1^--.

In this work I suggest that early twentieth century theoretical physicists did not have enough facts or experimental data to formulate a consistent atomic model and as a result the concept of the atom needs revised. I conclude that the new atomic model presented is based only on first principles, is easy to understand and visualize, and provides such a significant theoretical advance as to be a final theory.

In this talk, I discuss recent developments concerning the possibility of large extra space-ime dimensions and their relation to neutrino physics. After briefly reviewing how such dimensions can lower the fundamental GUT, Planck, and string scales, I then outline how these scenarios lead to a new higher-dimensional seesaw mechanism for generating neutrino oscillations — perhaps even without neutrino masses. I also discuss how neutrino flavor oscillations can occur in a higher-dimensional theory even if the Standard Model on the brane is flavor-diagonal, the bulk theory is flavor-neutral, and the brane/bulk couplings are flavor-blind. This talk reports on work done in collaboration with Emilian Dudas, Tony Gherghetta, and Ina Sarcevic.

We discuss the phenomenological consequences of theories which describe sterile neutrinos in large extra dimensions, in the so-called bulk. We briefly outline how the cumulative non-decoupling effect due to the tower of Kaluza-Klein singlet neutrinos may equivalently be described by a higher-dimensional effective theory with original order-unity Yukawa couplings. Based on this cumulative phenomenon, we obtain strong constraints on the fundamental quantum gravity scale and/or on the higher-dimensional Yukawa couplings.

A plausible explanation for the existence of additional light sterile neutrinos is that they correspond to modulini, fermionic partners of moduli, which propagate in new large dimensions. We discuss the phenomenological implications of such states and show that solar neutrino oscillation is well described by small angle MSW oscillation to the tower of Kaluza Klein States associated with the Modulini. We also consider how all oscillation phenomena can be explained in a model including bulk neutrino states.

We show that if the Standard Model gauge fields and fermions propagate in extra dimenions, a composite Higgs field with the correct quantum number can arise naturally as a bound state due to the strong gauge interactions in higher dimensions. The top quark mass and the Higgs mass can be predicted from the infrared fixed points of the renormalization group equations. The top quark mass is in good agreement with the experimental value, and the Higgs boson mass is predicted to be ~ 200GeV. There may be some other light bound states which could be observed at upcoming collider experiments.

We examine the structure of the Yukawa couplings in the 11 dimensional Horava-Witten M-theory based on non-standard embeddings. We find that the CKM and quark mass hierarchies can be explained in M Theory without introducing undue fine tuning. A phenomenological example is presented satisfying all CKM and quark mass data requiring the 5-branes cluster near the second orbifold plane, and that the instanton charges of the physical orbifold plane vanish. the latter condition is explicitly realized on a Calabi-Yau manifold with del Pezzo base dP₇.

We present metric solutions in six and higher dimensions with bulk cosmological constant, where gravity is localized on a 3-brane. The corrections to four-dimensional gravity from the bulk continuum modes are power-law suppressed. Furthermore, the introduction of a bulk "hedgehog" magnetic field leads to a regular geometry, and can localize gravity on the 3-brane with either positive, zero or negative bulk cosmological constant.

We consider the cosmology and hierarchy of scales in models with immersed in a five-dimensional curved spacetime subject to radion stabilization. The universe naturally find itself in the radiation-dominated epoch when the inter-brane spacing is static and stable, independent of the form of the stabilizing potential. We recover the standard Friedmann equations without assuming a specific form for the bulk energy-momentum tensor. We address the hierarchy problem in the context of a quartic and exponential stabilizing potential, and find that in either case the presence of a negative tension brane is required and that the string scale can be as low as the electroweak scale. In the situation of self-tuning branes (corresponding to an exponential potential) where the bulk cosmological constant is set to zero, the brane tensions have hierarchical values.

I review a heterotic-string solution in which the observable sector effective field theory just below the string scale reduces to that of the MSSM, with the standard observable gauge group being just SU(3)_C × SU(2)_L × U(1)_Y and the SU(3)_C × SU(2)_L × U(1)_Y - charged spectrum of the observable sector consisting solely of the MSSM spectrum. Associated with this model is a set of distinct flat directions of vacuum expectation values (VEVs) of fields that all produce solely the MSSM spectrum. Some of these directions only involve VEVs of non-Abelian singlet fields while others also contain VEVs of non-Abelian charged fields. The phenomenology of theses flat directions is summarized.

We review recent work on the application of the non-commutative geometric framework to an interpretation of the moduli space of vacua of marginal deformations of N = 4 super Yang-Mills theories. At rational values of couplings, different regions of moduli space may be associated with D5-branes of various topologies, and orbifold dual descriptions exist which may be accessed by T-duality. Singularities in the moduli space are associated with topology change.

Using Ads₇/CFT₆ correspondence we compute a subleading O(N) term in the scale anomaly of (2,0) theory describing N coincident M5 branes. The total scale anomaly extrapolated to N=1 is argued to be the same as the anomaly of a single free (2,0) tensor multiplet. This contribution is based on ref. ^1,2 where details and references may be found.

The spectrum of stable electrically and magnetically charged supersymmetric particles can change discontinously due to the decay of these particles as the vacuum on the Coulomb branch is varied. We show that this decay process is well described by semiclassical field configurations even when it occurs at strong coupling. the resulting picture of the stable supersymmetric spectrum is a generalization of the "string web" picture of these states found in string constructions.

We consider a bosonic CFT on a noncommutative orbifold Mⁿ/Sⁿ. To calculate three and four point functions of the twist operators on such an orbifold we perform a conformal map to the covering space and evaluate an appropriate Liouville action. We give an expression for the three point function for the case when the covering space is a sphere.

Periodic solutions of Bogomolny equation have novel Gravitational Instantons as their moduli spaces. String theory allows to identify these moduli spaces with moduli spaces of Hitchin systems as well as with Coulomb branches of Seiberg-Witten gauge theories on a space with one compact direction. We classify these Gravitatial Instantons. We also perform Nahm transform of Periodic Monopoles establishing the correspondence with Hitchin systems predicted by String Theory.

An outline of conformality approach to the gauge hierarchy is given including the use of non-abelian orbifolds to give unified model of the left-right type.

We consider compact four-dimensional Z_N × Z_M type IIB orientifolds, for certain values of N and M. We allow the additional feature of discrete torsion and discuss the modification of the consistency conditions arising from tadpole cancellation. We point out the differences between the cases with and without discrete torsion.

We develop a general algorithm, based on the standard method of partial resolution of Abelian orbifolds, to extract a consistent set of gauge theory data for an arbitrary toric variety whose singularity a D-brane probes. The discussions are based on the work: "D-Brane Gauge Theories from Toric Singularities and Toric Duality (hep-th/0003085)" with collaborators B. Feng and A. Hanany.

We show that the Randall-Sundrum brane-world may be realized in terms of a doubled D3-brane configuration of type IIB theory. We demonstrate the supersymmetry of this realization and indicate how it overcomes previous supersymmetric no-go theorems.

In this note we address the problem of solving for the positronium mass spectrum. We use front-form dynamics together with the method of flow equations. For a special choice of the similarity function, the calculations can be simplified by analytically integrating over the azimuthal angle. One obtains an effective Hamiltonian and we solve numerically for its spectrum. Comparing our results with different approaches we find encouraging properties concerning the cutoff dependence of the results.

Light-cone approach to field dynamics in AdS space-time is discussed.

Matrix algebra notation in introduced which extends Dirac abstract vector notation to explicitly describe standard hadrons, leptons and a specific type of 1-brane. The 3×3×3 matrix notation is easily used with the path integral approach to model both strong and weak interactions. The specific 1-brane, called a tripartite string (a type of orientifold), has three extra spatial dimensions and three extra curvature dimensions which are necessary to describe standard particles. The extra spatial dimensions compactify to one area-like metric which, when scaled according to the Randall-Sundrum approach, gives a mass metric which is orthogonal to fundamental particle quanta. A model of photons and the massive, oscillating neutrio is inherent to the tripartite string. R-S scaling is further employed in conjunction with complex gravity to produce a unique cosmological model which inherently explains the cosmological 'constant'. This model of the universe is cyclic in mass and time, where cosmological time is treated as an imaginary metric. It is further established that, for consistency with M/string theory, the 'singularity' of black hole is in fact finite; and that a tetrahedral structure qualitatively models the source of Galactic Annihilation Fountains.

Results from string theory strongly suggest that formation and evaporation of black holes is a unitary process. Thus we must find a flaw in the semiclassical reasoning that implies a loss of information. We propose a new criterion that limits the domain of classical gravity: the hypersurfaces of a foliation cannot be stretched too much.

The complete glueball spectrum for the AdS⁷ black hole supergravity dual of QCD is shown to bare a striking resemblance to the known lattice results despite the limitations of the strong coupling approximation. Further extensions of duality to couple hadronic matter to gravity in the Randall-Sundram brane world scenario are suggested.

Using the AdS/CFT correspondence, we show that the Anti-de Sitter (AdS) rotating (Kerr) black holes in five and seven dimensions provide us with examples of non-trivial field theories which are scale, but not conformally invariant. This is demonstrated by our computation of the actions and the stress-energy tensors of the four and six dimensional field theories residing on the boundary of the boundary of these Kerr-AdS black holes spacetimes.

We present results based on data taken in 1997 with the 302-PMT Antarctic Muon and Neutrino Detector Array-B10 ("AMANDA-B10") array. Atmospheric neutrinos created in the northern hemisphere are observed indirectly through their charged current interactions which produce relativistic, Cherenkov-light-emitting upgoing muons in the South Pole ice cap. The reconstructed angular distribution of these events is in good agreement with expectation and demonstrates the viability of this ice-based device as a neutrino telescope.

Ultra-high energy (E_ν>10¹⁵ eV) neutrinos interacting with Antarctic ice produce energetic electrons. The RICE project is designed to detect coherent radio emission from the electromagnetic cascades initiated by these electrons.. We describe the current status and the future plans of this radio effort

The High-Resolution Fly's Eye cosmic ray observatory has been operating in monocular (stereo) mode for about three years (one year), during which time we have observed extensive airshowers with an integrated aperture of ~ 1500 km²-sr-yr (~ 400 km-sr-yr) at 5×10¹⁹ eV. We describe the HiRes experiment and the nitrogen fluorescence technique, and present data taken in both monocular and stereo modes including preliminary energy spectra.

Cosmic rays with energies above 10²⁰ eV have been observed. The existence of these events presents us with a puzzle. The Greisen-Zatsepin-Kuzmin cutoff in the spectrum expected due to interactions with the cosmic background radiation is not observed. This constrains the origin of conventional particles responsible for these events to cosmologically-nearby distances (≪ 100 Mpc). Cosmic ray protons at these energies are deflected little by intergalactic magnetic fiels, so an association with likely sources on the sky is expected but has not been convincingly observed. Our understanding of the origin of these events is hampered by poor statistics and sky coverage, since the rate of cosmic rays above 10²⁰ eV is about one particle per km² per century. The Pierre Auger project has been formed to address this problem. Two 3000 km² observatory sites, one in each hemisphere, are planned to provide full sky coverage. Each site will include a hybrid detector consisting of a water Cerenkov detector array on the surface and air fluorescence 'eyes'. The southern observatory, located near the town of Malargue in Mendoza, Argentina, is now under construction.

We discuss BBN in the presence of a non-minimally coupled quintessence model. In some of these models, the gravitational constant and cosmic expansion rate are smaller than standard model predicts. The Helium abundance is then smaller, possibly resolve the marginal disagreement between theory and observation. Furthermore, the constraint on neutrino species may also be relaxed.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) project has been designed to detect gravitional waves directly using large interferometers at two widely separated sites. Construction of the observatory facilities is now complete, and commissioning of the interferometers is well underway. Following a series of engineering runs, science running is scheduled to begin in 2002. A parallel effort is underway to develop improved detector to achieve dramatically greater sensitivity in the future.

The amplitude of the second peak in the angular spectrum of the cosmic microwave background radiation is constrained to be small by recent experiments like Boomerang. This is surprising in the context of the ΛCDM model, which predicted a large second peak. However, this result is expected if CDM does not exist. The observed shape of the power spectrum was accurately predicted (before the fact) by a model motivated by the surprising recent successes of the modified dynamics (MOND) hypothesized by Milgrom.

We discuss massive and massless neutrino zero modes on electroweak strings. We argue that the eventual absence of the neutrino zero mode implies the existence of topogically stable strings where the required non-trivial topology has been induced by the fermionic sector.

We formulate the photon production from coherently oscillating pseudo Nambu-Goldstone bosonic fields in expanding space–time. It is then applied to calculate the photon production from axionic cold dark matter.

We study the brane world motion in non-static bulk by generalizing the second Randall-Sundrum scenario Explicitly, we take the bulk to be a Vaidya-AdS metric, which describes the gravitational collapse of a spherically symmetric null dust fluid in Anti-de Sitter spacetime. We point out that during an inflationary phase on the brane, black holes will tend to be thermally nucleated in the bulk We analyze the thermodynamical properties of this brane-world. We point out that during an inflationary phase on the brane, black holes will tend to be thermally nucleated in the bulk. Thermal equilibrium of the system is discussed. We calculate the late time behavior of this system, including 1-loop effects. We argue that at late times a sufficiently large black hole will relax to a point of thermal equilibrium with the brane-world environment. This result has interesting implications for early-universe cosmology.

Recent measurements of the cosmic microwave background (CMB) anisotropies by BOOMERANG and MAXIMA collaborations have tightened the observational constraints on theories of structure formation. They disagree with the predictions of conventional topological defect models. Considering the fact that topological defects are predicted by the majority of realistic particle physics models, the exact nature of the constraints imposed by the recent data on the population and the properties of the defects must be fully understood. We show that the predictions of current cosmic string models can be brought into a closer agreement with the observations by choosing a closed universe with Ω = 1.3 and by including the effects of the small-scale structure and radiation products of the strings. These alone, however, are not sufficient for obtaining a good fit to the measured shape of the angular power spectrum. To fit the data cosmic strings would either have to be correlated on large (perhaps superhorizon) scales or would have to possess a higher degree of coherence, i.e. be more "time-correlated".

A relic particle X which annihilates with its antiparticle into electromagnetically-interacting particles, e.g. , γγ, etc., will lead to a distortion in the spectrum of the cosmic microwave background (CMB). The magnitude of this effect is calculated and compared with known limits on the deviations of the CMB from a Planck spectrum. Limits which can be placed on such a particle are found to be competitive with similar limits from Big Bang nucleosynthesis.

A particular kind of quintessence is considered with equation of motion p_Q/ρ_Q = -1, corresponding to a cosmological term with the time-dependece Λ(t) = Λ(t₀) (R(t₀)/R(t))^P and we examine how values of Ω_m and Ω_Λ depend on P.

The pulsating model is briefly reviewed. The main idea is that a new tensor is introduced as a replacement for the cosmological term. The model predicts that the universe cannot be presently accelerating, and hence is in disagreement with the Type Ia supernovae results.

After a long shutdown in 1999, the CLEO Collaboration at Cornell University's Wilson Laboratory began taking data in 2000 using its third generation detector, CLEO III. Several improvements to the detector system have been made in order to take advantage of the possibility of unprecedented luminosities of well over 2×10³³ expected from CESR, and to explore new territory in the physics of B mesons. These improvements include a new drift chamber, a four layer silicon vertex detector and a RICH detector. These features will be described, and its performance will be presented.

BTeV is an experiment being constructed at the Fermilab collider, designed to study mixing, CP violation, and rare decays of beauty and charm hadrons. The detector covers the forward region (10-300 mrad), components include silicon pixels, tracking, RICH, PdWO₄ electromagnetic calorimeter, and muon system. Brief description of individual detector elements are presented.

The status of the Run II upgrade to the CDF detector will be reviewed and the future schedule summarized.

The status of the D0 upgrade project is summarized, including a discussion of all subdetectors, the trigger system as well as plans for further upgrades in view of the Tevatron high luminosity phase Run IIb.

Na59 Experiment at CERN-SPS aims for obtaining circularly polarized high energy photons (~100GeV) starting from an unpolarized electron beam. The basic principle of operation was predicted in 1962 by Cabbibo and has remained untested up to now. Among other physics goals, Na59 collaboration investigates usage of crystals for high energy photon polarimetry. This paper presents the experiment and summarizes some of the results obtained as of Autumn 2000.

Robust tracking is an essential tool to address the full range of physics which can be accessed at LHC. The CMS Collaboration has chosen the detector technology for the Si-licon Strip tracking system. Over the last few years considerable progress has been made in the understanding of the operation of silicon strip detector in the harsh environment of the LHC. An overview of recent results is given with particular emphasis on resistivity and crystal orientation of the substrate, strip capacitance and breakdown voltage.

A new silicon microvertex detector (MVD) will be installed in the ZEUS experiment during the 2000 HERA luminosity upgrade. Such a high precision detector will improve the global tracking system and allow to identity events with secondary vertices originating from the decays of long-lived states. It will be placed in the proximity to the beam pipe to surround the interaction region. The barrel part is a 60 cm long cylinder consisting of three double layers of single-sided silicon detectors, the forward part is made of four double shaped layers, called wheels, extending 42 cm along the beam. A test beam has been setup in order to characterize the performance of the detector modules and readout electronics (i.e. track position resolution, signal to noise ratio, detection efficiency). The detector layout and some selected test beam results are presented.

The upgrade of the CLEO detector has finished with the installation of the new silicon detector in February 2000. The detector is a four layer barrel-style device with double-sided silicon detectors. It spans the radial distance from 2.5 cm to 10.2 cm and cover 93% of the solid angle surrounding the interaction region. The innermost layer is 16 cm, the outermost is 55 cm long. Important features of the new design are a very small radiation length of the detector material and new front-end electronics to deal with the capacitive load of the long silicon wafer chains. First results of the detector performance will be presented.

We discuss the design, implementation and performance of the radiation monitoring and protection system used by the Silicon Vertex Tracker (SVT) in the BaBar detector. Using 12 reverse-biased PIN photodiodes mounted around the beampipe near the IP, we are able to provide instantaneous radiation dose rates, absorbed dose integrals, and active protection that aborts the circulating beams in the PEP-II storage ring when radiation levels exceed user-defined thresholds. The systems has reliably protected the SVT from excessive radiation damage and has also served as a key diagnostic tool in understanding radiation backgrounds at PEP-II.

We present the overview of the production and testing of the DØ Silicon Microstrip Tracker. Final assembly and anticipated performance of the deterctor are also discussed in this context.

The CDF Layer 00 detector consists of single-sided silicon sensors assembled on the beampipe, forming the innermost of eight silicon layers in the CDF detector for Run II of the Fermilab Tevatron. Radiation tolerant p-in-n silicon with 25(50) μm implant(readout) pitch are mounted on a lightweight, cooled support structure and connect to electronics outside the tracking volume via long, fine-pitch cables. Layer 00 will significantly improve the impact parameter resolution and enhance the longevity of the silicon system, benefitting a large portion of the physics program for Run II.

The upgraded silicon tracker for the Collider Detector at Fermilab has 722,432 strips. These strips are instrumented with SVX3D ASICs fabricated in the Honeywell 0.8 μm radiation hard CMOS process. We describe test setup and procedures used to screen production chips and to ensure reliability of the silicon system front-end electronics.

Results on tests conducted on real SVXII ladders using cosmic rays and beta source data are presented. These results include charge collection and signal to noise ratio.

The ATLAS experiment is now in the process of finalizing the development of the design of silicon pixel sensors for use in the pixel detector. The sensors will be operated in a severe LHC radiation enviroment with bias voltages at the end of lifetime up to 600 V while maintaining a good signal-to-noise ratio and charge collection efficiency, small cell size and minimal multiple scattering. The radiation hardness issues and quality assurance procedures are discussed.

An optical package of novel design has been developed for the ATLAS pixel detector. The package contains two VCSELs and one PIN diote to transmit and receive optical signals. The design is based on a simple connector-type concept and is made of radiation-hard material. Several packages have been fabricated and show promising results.

We present results on the performance of diamond pixel detectors using the highest quality available Chemical Vapor Deposition (CVD) diamond. CVD diamond has been discussed extensively as an alternate sensor material for use very close to the interaction region of the LHC where extreme radiation conditions exist. Devices with the pixel patterns of both the ATLAS and CMS experiments have been tested with their respective electronics. The results presented include pulse height spectra, spatial resolution, and plans for future studies.

Results from a large scale test performed on the Micro-Strip Gas Chambers developed for the CMS experiment are reported. Irradiation, close to the expected LHC background, was provided by a low energy (350MeV), high rate (6kHz/mm²) pion beam at PSI. Excellent performance of the detectors was obtained using solutions specific to the demanding radiation environment.

We have evaluated the performance of a short-wavelength enchanced type APD as a photosensor for a 3-m long scintillating fiber. By cooling the APD down to -40^°C or below, the detection efficiency for a minimum ionizing particle reached nearly 100%.

CLEO III upgrade was completed with the integration of Ring Imaging CHerenkov(RICH) detector for charged particle identification. The design of this cylindrical detector consists of LiF' crystal radiators and multi-wire proportional chamber photon detectors coupled through a N₂ filled expansion gap. Early performance on K/π separation is presnted.

A Time-of-Flight detector (TOF), with a technique based on plastic scintillators and finemesh photomultipliers, has been added to the CDF-II experiment. The main physics motivation is to improve neutral B meson flavor determination by K^± identification. The expected time resolution is 100 ps, which provides at least two standard deviations separation between K^± and π^± for momenta p < 1.6 Gev/cand better than 1.2 standard deviations separation over all momenta when combining TOF identification with dE/dx identification using the new drift chamber.

In the next decade, high energy physicists will use very sophisticated equipment to record unprecedented amounts of data in the hope of making major advances in our understanding of particle phenomena. Some of the signals of new physics will be small, and the use of advanced analysis techniques will be crucial for optimizing signal to noise ratio. I will discuss new directions in data analysis and some novel methods that could prove to be particularly valuable for finding evidence of any new physics, for improving precision measurements and for exploring parameter spaces of theoretical models.

A laser-based calibration and monitoring system for the plug upgrade calorimeter is described. A pulsed nitrogen ultraviolet laser excites all of the about 1000 photomultiplier tubes (PMTs) in each plug calorimeter. The light is focused into a quartz fiber and routed first to a primary distributor (PD) and from there to 12 secondary distributors (COWs), which feed the individual PMTs. The system will be used as a debugging tool during calorimeter rigging and will help the wire source calibration system in initially equalizing the PMT gains. In addition, an LED imbedded in each COW can set a continuous DC level on each PMT, allowing for PMT burn-in and gain conditioning.

The DØ preshower detector has been tested with cosmic ray muons. We report results on the light yields for minimum ionizing particles and the spatial resolution. The detection efficiency and noise contamination are also investigated.

The status is given of the lead tungstate electromagnetic crystal calorimeter for the CMS detector at the Large Hadron Collider: calorimeter design, development of calorimeter components and results obtained in particle beams are discussed.

Resistive Plate Chambers (RPC) have been chosen as dedicated trigger detectors for the CMS experiment at the LHC. The expected severe operating conditions have required an intense research and development activity on these detectors over the past years. Experimental results on overall performance of large chambers, rate capability, ageing and photon sensitity are reviewed. In all of these tests the detector has proven to achieve good enough performance for successful use at the LHC.

The possibility of triggering on muons at higher luminosities and smaller bounch spacings has been preserved in the central region and ectended to the forward (η < 1.5) by constructing new scintillation counters and refurbishing existing ones. The new counters are made of polystyrene - based scintillator produced by Monokristall under JINR supervision and employ a readout technique which is based on the use of wavelength-shifting fiber coupled to a miniature photomultilier tube produced by Hamamatsu. The tecnique, which was developed at Pisa and JINR, was optimized for long transmission lengths. This makes it particularly suitable for use with the long (3.2m) counters needed to complete coverage of the central region. The counters are also very compact. The use of a similar technique to refurbish aging PVT-based muon counters affords a striking demonstration of how this method may be used to solve problems related to long transmission lengths and(or) poor transmission properties of scintillation counters.

We describe a system for control and readout of scintillation conters, in the CDF Muon Upgrade for Run II, that use a miniature (low again) photomultiplier tube coupled to a high voltage generator. In the system, we mount on each counter an electronics module that amplifies counter signals, sets tube gain, discriminates signals, sets tube gain, discrimates signals with an adjustable threshold, and drives a light source. A 48 channel control unit distributes power, gain and thereshold settings, light source triggers, and receives counter signals on tristed pair cables, stretches and transmits the signals to remote time digitizers. Also, we describe a scintillation counter design that integrates the scintillator, filesn, and electronics modules into a sturdy packega.

A hybrid system consisting of a photon calorimeter, a magnetic spectrometer and an electron calorimeter designed to measure accurately the luminosity collected by the ZEUS detector after the HERA upgrade is presented.

We have made an observation of 45 MeV electron beam bunches using the nondestructive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with the optical beam path distance from the electron beam. The risetime of the signal was bandwidth limited by our detection system to ~ 70 ps. An EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. The EO technique may be ideal for the measurement of bunch structure with femtosecond resolution of relativistic charged particle beam bunches.

A coherent and complete suite of triggers and data compression stages for the BTeV experiment has been designed and prototyped. Level 1 considers all crossings, finds primary vertices, and searches for detached tracks from these primary vertives using only the pixel vertex detector. Muons with a relatively high transverse momentum will also be identified at that stage. Level 1 runs on dedicated processors. Level 2 selects events based on the pixel and the forward tracking systems, and will run on a conventional processor farm. Level 3 will use the complete BTeV detector information to reduce the background by a factor of factor 2 to 5 and to reduce significantly the event size.

We have constructed a high-p_T trigger for the HERA-B experiment at DESY. The HERA-B experiment produces B mesons by inserting wire targets into the halo of the proton beam circulating in HERA. The high-pt trigger records events that contain tracks that have high transverse momentum with respect to the beam. Such a trigger is efficient for recording B → π⁺π^-, B → K^- π⁺, B_s → K⁺ K^-, , and other topical hadronic B decays. These decays provide sensitivity to the internal angles alpha and gamma of the CKM unitarity triangle, and they also can be used to measure or constrain the mixing parameter x_s.

The decay J/ψ → μ⁺ μ^- is one of the main trigger channels in the HERA-B experiment. The muon deterctor and the trigger hardware are described. Results are reported from the initial trigger commissioning that includes the Muon Pretrigger and Second Level Trigger. A J/ψ mass peak with good signal to background ratio is obtained.

We describe the Level 1 muon trigger system for Run II of the colliding beam experiment at the Fermilab Tevatron. The muon trigger logic makes use of tracks from the central fiber tracker and hits from muon detector elements which include both scintillator and drift tube arrays. Details of the FPGA trigger logic and trigger simulation results are given. Extensive use is made of Gbit/s serial links in order to transmit data to the Level 1 muon trigger system. Results on error rates from these Gbit/s serial links using up to 200 feet of coaxial cable are presented.

The D0 Level 2 trigger (L2), a subsystem of the three-stage D0 trigger, reduces event rates from 10 KHz to 1 KHz. The system is organized as a global processor and preprocessors for the calorimeter, muon, tracker, and preshower subsystems. Preprocessors digest information from a single detector system and produce a list of the objects. The global processor receives the object lists, matches across detectors, and applies selection criteria to the objects. The system can buffer 16 events. The L2 design has been guided by extensive queuing simulations. The system is presently being commissioned, with all components available as either pre-production or production boards.

Run II at the Tevatron is scheduled to start in March 2001. The accelerator complex and collider detectors are undergoing substantial upgrades. This has motivated a complete redesign of the online-trigger system for the Collider Detector at Fermilab (CDF). The CDF trigger system has a three-level architecture that will reduce the 7.6 MHz crossing rate to 50 Hz written to tape. Using a pipelined and buffered system, the trigger is designed to be "deadtimeless". The structure of the trigger will be flexible and programmable in order to respond to changing beam conditions or physics goals. This paper will review the structure of the CDF trigger system and give a status report on construction and commissioning of the system.

In the upcoming Fermilab Tevatron collider run, collisions will occur at 132 ns intervals, and the CDF II trigger system requires that information about drift chamber tracks be provided within 2.2 μs of every collision, so that tracking information can be used in conjunction with data from other detector components to trigger on physics objects with little background. We have developed a fast online track processor for locating high-momentum tracks in the chamber. The design is highly parallel, and is implemented in programmable logic devices. We describe the design of the system and performance tests.

The DOIM (Dense Optical-electrical Interface Modules) is a custom-designed optical data transmission module employed in the upgrade of Silicon Vertex Detector of CDF experiment at Fermilab. Each DOIM module consists a transmitter(TX) converting electrical differential input signals to optical outputs, a middle segment of jacketed fiber ribbon cable, and a receiver (RX) which senses the light inputs and converts them back to electrical signals. The targeted operational frequency is 53 MHz, and higher rate is achievable. This article outlines the design goals, implementation methods, production test results, and radiation hardness tests of these modules.

We report on the development and performance of a novel track-finding processor for the Level-1 trigger of the CMS endcap muon system. The processor links track segments identified in the cathode-strip chambers of the endcap muon system into complete three-dimensional tracks. It then measures the momentum of the best track candidates from the sagitta measured between three muon chambers in the endcap fringe field. The processor is pipelined at 40 MHz, and has an overall latency of 400 ns. The logic for the prototype is implemented in high-density FPGAs and SRAM memory. It receives approximately 3 gigabytes of data every second from a custom backplane operating at 280 MHz. Test results of the prototype are consistent with expectation.

The MINOS long baseline neutrino oscillation experiment will consists of two magnetized tracking calorimeters one on the Fermilab site and one in Minnesota. This paper summarizes the design, magnetic performance, and status of the MINOS magnets.

The Main Injector(MI) and the Recycler Ring (RR) are newly built synchrotrons in the Fermilab Accelerator complex. Many new features have been incorporated in their design and are tested. MI has already served as a 150 GeV proton injector to the Tevatron during the final stages of 1998-1999 800 GeV fixed target HEP experiments. Presently, MI is in use for collider Run-II commissioning. The MI and the RR will play major roles in the future HEP programs at Fermilab.

The international TESLA collaboration proposes a 500-800 GeV center-of-mass linear collider based on super-conducting 1.3 GHz cavities. This technology promises a luminosity of 3.4×10³⁴ cm^-2 s^-1. Results from the cavity R&D program at the TESLA test facility and details of the collider design will be presented.

An electron/positron linear collider with a center-of-mass energy between 0.5 and 1 TeV would be an important complement to the physics program of the LHC in the next decade. The Next Linear Collider (NLC) is being designed by a US collaboration (FNAL, LBNL, LLNL, and SLAC) which is working closely with the Japanese collaboration that is designing the Japanese Linear Collider (JLC). This paper will discuss the technical difficulties encountered as well as the changes that have been made to the NLC design over the last year. These changes include improvements to the X-band rf system as well as modifications to the beam delivery system. The net effect has been to reduce the length of the collider from about 32 km to 25 km and to reduce the number of klystrons and modulators by a factor of two. Together these lead to significant cost savings.

Superconducting magnets are the underlying technology for all existing and future hadron colliders. A vigorous national R&D effort has been launched to improve magnet performance and reduce costs. Various designs are being considered including a low-field superferric magnet that could be the first step in a staged construction of a Very Large Hadron Collider. High-field magnets are being developed based on cosine-theta, block, and common-coil arrangements using both wind-and-react and react-and-wind fabrication techniques. A review of the different magnet R&D programs and the status of each is presented. An important part of the national effort is an R&D program to improve the performance and lower the cost of Nb₃Sn superconducting wire.

I derive the overlap Dirac operator starting from the overlap formalism, discuss the numerical hurdles in dealing with this operator and present ways to overcome them.

Supersymmetry, like Poincaré symmetry, is softly broken at finite lattice spacing provided the gaugino mass term is strongly suppressed. Domain wall fermions provide the mechanism for suppressing this term by approximately imposing chiral symmetry. We present the first numerical simulations of supersymmetric SU(2) Yang-Mills on the lattice in d=4 dimensions using domain wall fermions.

Several lattice calculations which probe the chiral and topological structure of QCD are discussed. The results focus attention on the low-lying eigenmodes of the Dirac operator in typical gauge field configurations.

The numerical technique of discrete light-cone quantization (DLCQ) is applied to a single-fermion truncation of Yukawa theory in four dimensions. The truncated theory is regulated by three Pauli-Villars bosons, which are introduced directly in the DLCQ Fock-state basis. A special form of the Lanczos diagonalization algorithm is used to handle the indefinite metric. Renormalization is done nonperturbatively.

QCD and QED exhibit an infinite set of three-point Green's functions that contain only OZI rule violating contributions, and (for QCD) are subleading in the large N_c expansion. We prove that the QCD amplitude for a neutral hybrid 1^-+ exotic current to create ηπ⁰ only comes from OZI rule violation contributions under certain conditions, and is subleading in N_c.

We describe how one can use chiral perturbation theory to obtain results for physical quantities, such as quark masses, using partially quenched simulations.

The canonical formalism in classical theory of QCD is developed on a space-like hypersurface. The Poisson bracket on the space-like hypersurface is defined and it plays an important role to describe every algebraic relation in the canonical formalism into Lorentz covariant form. By converting the Poisson bracket on the hypersurface to four-dimensional commutator, we can pass over to QCD in the Heisenberg picture without spoiling the Lorentz covariance.

Most past work on weak nonleptonic decays has mixed dimensional regularization in the weak operator product expansion with some form of a cutoff regularization in the evaluation of the matrix elements. Even with the usual technique of matching the two schemes, this combination misses physics at short distance which can be described by dimension eight (and higher dimension) operators. I describe some recent work with V. Cirigliano and E. Golowich which clarifies these effects and provides a numerical estimate suggesting that they are important.

We use a space-time asymmetric O(a) improved fermion action and fix the asymmetry non-perturbatively to restore the relativistic dispersion relation. We compute spectra and matrix elements of quarkonia and heavy-light mesons and compare with results obtained using a symmetric action with the Fermilab interpretation i.e. that the physics of heavy lattice quarks depends solely on their kinetic mass. We provide additional evidence to support this.

The principle of flux quantization of gauge fields is used to define a new Quantum Chromodynamic (QCD) theory. Calculated mass spectra results are presented for 26 different baryons. Variations are within 2% of the measured values.

We propose a new method to compute amplitudes of electroweak processes in the strong background magnetic field, using γ → e⁺ e^- as an example. We show that the moments of γ → e⁺e^- width are proportional to the derivatives of photon polarization function at the zero energy. Hence, the pair-production width can be easily calculated from the latter by the inverse Mellin transform. The prospects of our approach are commented.

The contemporary use of Dyson-Schwinger equations in hadronic physics is exemplified via applications to the calculation of pseudoscalar meson masses, and inclusive deep inelastic scattering with a determination of the pion's valence-quark distribution function.

We discuss a method called quasi-sparse eigenvector diagonalization which finds the most important basis vectors of the low energy eigenstates of a quantum Hamiltonian. It can operate using any basis, either orthogonal or non-orthogonal, and any sparse Hamiltonian, either Hermitian, non-Hermitian, finite-dimensional, or infinite-dimensional. The method is part of a new computational approach which combines both diagonalization and Monte Carlo techniques.

Using product integrals we review the unambiguous mathematical representation of Wilson line and Wilson loop operators, including their behavior under gauge transformations and the non-abelian Stokes theorem. Interesting consistency conditions among Wilson lines are also presented.

We present non-perturbative methods to calculate accurately the renormalized quantities for Dyson's Hierarchical Model. We apply this method and calculate the critical exponent γ with 12 and 4 significant digits in the high and low temperature phases, respectively. We report accurate values for universal ratios of amplitudes and preliminary results concerning the comparison with perturbative results.

Recent results for two boson interferometry from CERN experiment NA44 are presented. Experiment NA44 is a focussing spectrometer with both excellent momentum resolution and particle identification. The most recent results shown will be two-pion and two-kaon correlations from 158 GeV/nucleon Pb+Pb running. The systematics of the NA44 two-boson results are described rather well by a final-state rescattering model.

We implement the dynamical renormalization group (DRG) using the hard thermal loop (HTL) approximation for the real-time nonequilibrium dynamics in hot plasmas. The focus is on the study of the relaxation of gauge and fermionic mean fields and on the quantum kinetics of the photon and fermion distribution functions. As a concrete physical prediction, we find that for a QGP of temperature T~200 MeV and lifetime 10≤t≤ 50 fm/c there is a new contribution to the hard (k~T) photon production form off-shell bremsstrahlung (q→qγ and at just O(α) that grows logarithmically in time and is comparable to the known on-shell Compton scattering and pair annihilation at O(αα_s).

PHOBOS is one of the four experiments at the Relativistic Heavy Ion Collider that started colliding gold nuclei at a center of mass energy of √s_NN = 56 and 130 GeV per pair of colliding nucleons in June 2000. The pseudorapidity density of primary charged particles in central collisions has been measured near mid-rapidity.

I argue that a reliable computation of the color-superconducting gap parameter in cold, dense quark matter requires knowledge of the gluon self-energy in a color superconductor. As a first step to determine the gluon self-energy, I report calculations of the Debye and Meissner masses in two- and three-flavor color superconductors.

The Bethe-Salpeter equations for spin zero diquark composites in the color superconducting phase of N_f = 2 and N_f = 3 cold dense QCD are studied. The explicit form of the spectrum of the diquarks with the quantum numbers of the (pseudo-) Nambu-Goldstone bosons is derived.

I present an analysis of the relaxation rate for long-wavelength fluctuations of the order parameter in an O(N) scalar theory near the critical point. Our motivation is to model the non-equilibrium dynamics of critical fluctuations near the chiral phase transition in QCD. In the next-to-leading order in the large N expansion we find a critical slowing down regime, i.e. an increasing of the relaxation time of long wavelengths fluctuations. This result suggests, for near critical systems, relevant deviations from thermal equilibrium for the distribution functions of low-energy particles and could have important phenomenological consequences in Heavy Ions Collision and in the Early Universe Cosmology.

I present a method for self-consistently including the effects of screening in finite-temperature field theory calculations. The method reproduces the perturbative limit in the weak-coupling limit and for intermediate couplings this method has much better convergence than standard perturbation theory. The method relies on a reorganization of perturbation theory accomplished by shifting the expansion point used to calculate quantum loop corrections. I will present results from a three-loop calculation within this formalism for scalar λϕ⁴.

The quantum kinetics of photons in hot QED plasmas is studied directly in real time by implementing the dynamical renormalization group. In contrast to conventional approach, the dynamical renormalization group method consistently includes off-shell (energy non-conserving) effects and accounts for time-dependent collisional kernel. To lowest order we find that in the relaxation time approximation the semihard photon distribution function relaxes with a power law.

We show how hydrodynamics of relativistic system with broken continuous symmetry can be constructed using the Poisson bracket technique. We illustrate the method on the example of relativistic superfluids.

In quantum field theory, heavy particles with mass M much greater than the temperature T give not only effects suppressed by the Boltzmann factor e^-M/T, but also effects suppressed by powers of T/M. We show that power-suppressed terms in equilibrium observables arise from effective interactions among light particles due to virtual heavy particles. We study a model introduced by Matsumoto and Yoshimura in which heavy bosons interact only through a term that allows pair annihilation into light particles. We construct an effective Lagrangian for the light field by integrating out the heavy field, and use it to calculate the leading power-suppressed terms in the energy density. The thermal average of the Hamiltonian density for the heavy field includes a term proportional to T⁶/M², but we show that this term can be eliminated by a field redefinition and therefore cannot have any physical significance.

We study the viscosity corrections to the growth rate of nucleating bubbles in a slightly supercooled first order phase transition. We propose a microscopic approach that leads to the nonequilibrium equation of motion of the coordinate that describes small departures from the critical bubble and allows to extract the growth rate consistently in a weak coupling expansion and in the thin wall limit. In 3+1 dimensions we recognize model independent long-wavelength hydrodynamic fluctuations that describe surface waves. The coupling of this coordinate to these hydrodynamic modes results in the largest contribution to the viscosity corrections to the growth rate. The growth rate was calculated for a ϕ⁴ scalar field theory to lowest order in the coupling constant.

The PHENIX experiment is one of two large detectors at Brookhaven's Relativistic Heavy Ion Collider. The detector that was operated in the first RHIC run in the summer of 2000 is described. Several million Au-Au collisions were recorded during the first run.