International Journal of Modern Physics A

We report measurements of inclusive cross sections times branching ratios in electrons, muons or taus for W and Z bosons produced in collisions at 1.96 TeV using data collected with the DØ and CDF detectors in 2002-2004. Using the ratio of the cross sections times branching ratios for the W and Z bosons we also obtain constraints on the total decay width of the W boson.

In this talk we present a measurement of the ratio of inclusive cross sections at based on approximatly 180 pb^-1 of data collected with the DØ detector. Combining the Z → e⁺e^- and Z → μ⁺μ^- channels, the ratio was found to be 0.023 ± 0.004(stat) ± 0.002(syst).

The production of W bosons at large transverse momentum at the Tevatron is dominated by soft-gluon corrections. In this talk we present a calculation of these corrections at next-to-next-to-leading order. The corrections enhance the transverse momentum distribution of the W while reducing the scale dependence.

Using data from collisions at collected by the CDF and DØ detectors, we present measurements of the Drell-Yan inclusive differential cross section and forward-backward charge asymmetry as a function of invariant mass. We compare these measurements with Standard Model predictions, and present searches for new physics that could appear as deviations from the Standard Model in the Drell-Yan differential cross section.

It is shown that three scalar fields are dynamically generated after spontaneous symmetry breaking. Their masses are dynamically determined at about 10¹⁴GeV. They are ghosts. Unitarity of the SM is broken at 10¹⁴GeV.

This paper describes a direct measurement of the W boson total decay width Γ_W using the DØ detector at the Fermilab Tevatron Collider. The measurement uses an integrated luminosity of 177.3 pb^-1, collected during the 2002-2003 run. The width is determined by normalizing the predicted signal and background transverse mass distributions to 75,285 W → eν candidates in the transverse mass region 50 < M_T < 100 GeV and then fitting the predicted shape to the 625 candidates in the tail region 100 < M_T < 200 GeV. The W width is determined to be Γ_W = 2.011 ± 0.093 (stat) ± 0.107 (syst) GeV.

Using almost twice the luminosity of Run I, we present preliminary results on di-boson final states production at the Tevatron. These results include cross section measurements of most di-boson final states including the first measurement of WW cross section.

We present new results for two important heavy vector boson physics processes: (1), virtual corrections to hard bremsstrahlung which are relevant to precision predictions for the radiative return process in Z boson production at and beyond LEP2 energies; and, (2), electric charge screening effects in single W production with finite p_T, multiple photon radiation in high energy collider physics processes. In both cases we show that we improve the respective precision tag significantly. Phenomenological implications are discussed.

We present the results of a search for new particles with long lifetime that decay to a Z⁰ boson. A long-lived parent of the Z⁰ is predicted by several models in addition to being an experimentally clean channel. We vertex dimuons with invariant mass near the Z⁰ peak and study the decay length distribution. No evidence of a long-lived component is found, and cross-section limits are presented on a fourth generation quark model.

We present the prospects of searches for neutral, long-lived particles which decay to photons using their time of arrival measured with a newly installed EMTiming system at CDF. Using GMSB models we estimate the expected 95% confidence level exclusion regions as a function of the neutralino mass and lifetime. We find that a combination of single photon and diphoton analyses should allow the Tevatron in run II to easily extend the exclusion regions from ALEPH at LEP II, and cover parts of the theoretically favored GMSB parameter space.

The Collider Detector at Fermilab Collaboration has analyzed events with two photons in the central detector. The cross section is measured and compared to theoretical models. The diphoton mass spectrum is searched for anomalous narrow peaks and a search for gauge–mediated SUSY is performed with events with two photons and missing E_t.

A brief review of searches for physics beyond the Standard Model using single- and multi-photon events with missing energy at LEP is given here. These include searches for supersymmetry, large extra dimensions, and anomalous neutrino production. Recent results from all four LEP experiments are presented, including improved limits on the new scale of gravity for models with large extra dimensions and the most precise direct measurement of the number of light neutrino species. Status and prospects of the LEP combined searches are also discussed.

We present results on the searches for Extra Dimensions and Z′ Bosons conducted at the Tevatron's DØ Detector using dielectron, diphoton, and dimuon final states. The theoretical frameworks of Large Extra Dimensions (LED), Randall-Sundrum Extra Dimensions (RS), TeV^-1 Extra Dimensions, and Z′ bosons are explored in the dielectron and diphoton channels, while LED and Z′ bosons are also searched for in the dimuon final state. In the absence of signals we find lower 95% confidence level (CL) limits on the mass of a SM-like Z′ boson of 780 GeV and 680 GeV in the dielectron and dimuon channels, respectively. Furthermore, we find a lower 95% CL limit of 1.12 TeV on the TeV^-1 compactification scale (M_C) in the dielectron channel. In the diEM channel and LED framework we set a lower 95% CL limit of 1.43 TeV (GRW) on the fundamental Planck scale (M_S). Using a dimuon final state we find a lower 95% CL limit of 1.1 TeV (GRW) on M_S. We also find a lower 95% CL mass limit of 785 GeV on a RS graviton decaying into a dielectron or diphoton final state.

We report preliminary results of a search for substructure in quarks and leptons assuming a four-fermion contact interaction for dielectron pairs of large invariant mass. The search is based on dielectron data collected by the DØ detector in collisions at . The results agree well with predictions of the standard model and we obtain model-dependent lower limits at 95% confidence level on the compositeness scale of 3.6 to 9.1 TeV for different chiral models of the composite structure of quarks and electrons.

We present the results of a search for new particles decaying to tau pairs. Hypothetical particles, such as Z′ and MSSM Higgs boson A can potentially produce such pairs. The low-mass region, dominated by Z → ττ, is used as a control. No significant excess events over the estimated backgrounds is observed in the high-mass region, and we set upper limits on the cross section times branching ratio as a function of the Z′ and A mass.

The first search at a hadron collider for the production of excited and exotic electrons in association with a positron is presented. The excited electron decays to an electron and a photon with high transverse momentum yielding an electron+positron+photon final state signature. The search uses 202 pb^-1 of data collected in collisions at with the CDF II detector during 2001-2003. No excess of dielectron+photon events is observed. We present the e* sensitivity in the parameter space of the excited electron mass and the compositeness energy scale for both a gauge mediated and contact interaction model.

We present searches for new particles decaying into and produced in association with W^± bosons in collisions at . The searches focus on the Standard Model Higgs boson or Technicolor particle decaying into using approximately 162 pb^-1 of the dataset accumulated by the Collider Detector at Fermilab. The number of events and mass distribution are consistent with the Standard Model expectations and we set a 95% confidence level upper limit on the production cross section times branching ratio as a function of the new particle mass.

A search for the Higgs boson in the channels at DØ is described. The data, corresponding to an integrated luminosity of up to 177 pb^-1, are compared to theoretical predictions. No excess of events above the expected background is observed in any of the leptonic final states. Limits on the production cross-section times branching ratio, σ × BR(H → WW*), are therefore set at the 95% Confidence Level.

We present preliminary results of searches for technirho (ρ_T) and techniomega (ω_T) particles, using the decay channels (ρ_T), ω_T → e⁺e^- and , where , . These searches are based respectively on 200 pb^-1 and 238 pb^-1 of data collected in Run II of the Fermilab Tevatron. We select events with b–quark jets by identifying secondary vertices in the jets. We interpret our findings in terms of limits on the production of particles predicted by extended technicolor models. For the Wπ_T analysis, in the absence of an excess over standard model background, we compute a 95% C.L. upper limit on the techniparticle production cross section for the mass combination m(ρ_T) = 200 GeV and m(π_T) = 105 GeV of 6.4 pb. In the e⁺e^- channel, for certain model parameters, we exclude the existence of degenerate ρ_T and ω_T states with masses below 367 GeV; the most restrictive constraints on dilepton technicolor decays to date.

A search for non-SM light Higgs boson with an enhanced branching fraction into photons in collisions at the Fermilab Tevatron is presented using Run II DØ data taken between April 2002 and September 2003. We set 95% CL limits on the diphoton branching fraction as a function of Higgs msss for Fermiophobic and Topcolor Higgs scenarios.

Several theories predict the existence of light doubly charged Higgs bosons (H^±±). A search for the pair production of H^±± using the DØ detector is described, assuming a 100% branching ratio to muons. In the absence of signal, limits at 95% confidence level, of 118.4 GeV and 98.2 GeV are set for left-handed and right-handed doubly charged Higgs bosons respectively.

Many models of Electro-Weak symmetry breaking predict two Higgs doublets, and thus five Higgs bosons, three of which are neutral (h, H, A). The Minimal Supersymmetric extension of the Standard Model (MSSM) predicts the coupling of the bottom quark to the CP-odd scalar A to vary as tan β. The sum of the production of the CP-even scalars, h and H, is also proportional to tan² β. After searching for neutral Higgs bosons in multi-jet events containing three or more bottom-quark jets collected at the Tevatron by the DØ detector during Run II, we can exclude tan β > 80 – 120 for 90 GeV < m_A < 150 GeV.

We present the results of a search for a neutral MSSM Higgs boson decaying to a pair of tau leptons. The analyzed data sample corresponds to integrated luminosity of approximately 200 pb^-1 of collisions at . It was collected by the CDF detector during Run 2 of the Fermilab Tevatron. We select tau pairs in which one of the taus decays hadronically and the other to e or μ and neutrinos. We see no evidence of signal and perform a fit to the (partially) reconstructed di-tau mass to set limits on the product of Higgs production cross-section and its branching fraction to taus.

The electron mass is an intensive parameter on the distribution of formation intervals. The distribution is determined via a bridge connection defined by vectors existing across both parts of a direct product of such intervals. Particle mass and creation neutrinos form together. When mass exits coordinates are defined: mass and coordinates appear together. Bridge operators are determined for Maxwell, Einstein, and scale fields. Heavy particles are formed in an analogous way by putting them in groups.

We have searched for R-parity violating supersymmetry in final states with electrons and muons, assuming a single non-zero LLĒ or coupling, in particular λ₁₂₁, λ₁₂₂ or λ′₂₁₁. In the absence of an excess in the data, upper cross-section limits are set as a function of gaugino and slepton masses.

The searches are performed on data collected with the DØ detector in Run II, at a center of mass energy of 1.96 TeV and an integrated luminosity of up to 240 pb^-1. All limits are improving significantly compared to the DØ Run I results.

Searches have been performed for the trilepton decay signature from the associated production of the lightest chargino and the next-to-lightest neutralino in leptonic channels with (a) two electrons and a lepton, (b) an electron, a muon and a lepton (c) two muons and a lepton and (d) two like-sign muons. The searches use data taken with the DØ detector at the Fermilab Tevatron proton-antiproton collider at a center-of-mass energy of 1.96 TeV corresponding to an integrated luminosity of 147 pb^-1 to 249 pb^-1.

The apparent unification of gauge couplings around 10¹⁶ GeV is one of the strong arguments in favor of Supersymmetric extensions of the Standard Model (SM). In this contribution a new analysis, using the latest experimental data, is performed. The strong coupling α_s emerges as the key factor for evaluating the results of the fits, as the experimental and theoretical uncertainties in its measurements are substantially higher than for the electromagnetic and weak couplings. The present analysis pays special attention to numerical and statistical details. The results, combined with the current limits on the supersymmetric particle masses, favor a value for the SUSY scale ≲ 150 GeV and for α_s = 0.118 - 0.119.

The possible existence of a non-zero neutron electric dipole moment directly impacts our understanding of the nature of the electroweak and strong interactions. Experimental efforts over the past fifty years have increased the sensitivity to this very small quantity by eight orders of magnitude. An overview of a proposed experiment with the goal of a further two orders of magnitude increase in sensitivity to the level of 10^-28 e-cm is presented. Progress towards the solution of various technical challenges associated with the experiment is discussed, and a timeline for the experiment is outlined.

We give a brief introduction to the recent idea of Large eXtra Dimensions (LXDs). We give a motivation for the existence of a minimal length scale and show how to incorporate it into quantum theory. We derive first order corrections to high precision measurements such as transition frequencies in He⁺ and the muon gyromagnetic moment. The results clearly show that effects due to a minimal length have to be considered in models with LXDs.

The experimental precision of the anomalous magnetic moment of the muon has been improved to 0.5 part-per-million by the Brookhaven E821 experiment, similar to the theoretical uncertainty. In the same experiment, a new limit on the electric dipole moment of 2.8 × 10^-19e·cm (95% CL) was set. The experiment and plans to improve them are described.

I argue that muon lepton flavor violating (LFV) processes (such as μ → eγ and μ → e conversion in nuclei) provide a useful diagnostic tool to determine whether or not the effective neutrino mass can be safely extracted from the rate of neutrinoless double beta decay.

We present a recent BABAR search for lepton flavor violation in tau decays. The search for τ → ℓℓℓ(ℓ = e, μ) decays is based on a data sample of 91.6 fb^-1. No signal is found in any of six channels and 90% CL upper limits are set in the range of (1 - 3) × 10^-7. The search for τ → μγ decay is done with a 63 fb^-1 data sample. The number of observed events is consistent with expected background level and a preliminary upper limit is set at 2 × 10^-6 at 90% CL.

We report mainly on a search for lepton-flavor-violating τ decays involving π⁰/η/η′ final states using a sample of 153.8 fb^-1, which was recorded with the Belle detector at the KEKB e⁺e^- asymmetric-energy collider. We also present searches for other possible LFV tau decays, and discuss the relationship of our results to SUSY parameters.

Based on results of a search for the lepton-family-number-violating decay K⁺ → π⁺μ⁺e^- with data collected by experiment E865 in 1998 at the Alternating Gradient Synchrotron of Brookhaven National Laboratory we report an upper limit on the branching ratio at 2.2 × 10^-11 (90% C.L.). In combination with results based on the data collected in 1995, 1996, and a previous experiment, E777, an upper limit on the branching ratio of 1.2 × 10^-11 (90% C.L.) is obtained.

We present results for the production cross section of a Higgs boson with a pair of quarks, including next-to-leading order (NLO) QCD corrections.

The present constraints from electroweak radiative corrections suggest that the low mass region will be particularly interesting in future Higgs boson searches. In this paper, the discovery potential for a search of a low mass Standard Model Higgs boson, as well as the sensitivity to the lightest Higgs boson of the MSSM (h) are presented as a function of the collected luminosity, for the ATLAS experiment at the LHC.

We report an observation of a parity-violating asymmetry in fixed target electron-electron (Møller) scattering at a four-momentum transfer Q² = 0.03 (GeV/c)². This is a most precise measurement of parity nonconservation to date, and leads to a determination of the electron's weak charge and of the value of the effective weak mixing angle , which is consistent with the Standard Model expectation at the current level of precision. The comparison between the measurements of the weak mixing angle at Q² = 0.03 (GeV/c)² and at the Z⁰ pole establishes the running of sin²θ_W with 6.5σ significance.

Deconstruction is a powerful means to explore the rich dynamics of gauge theories in four and higher dimensions. We demonstrate that gauge symmetry breaking in a compactified higher dimensional theory can be formulated via deconstructed 4D moose theory with spontaneous symmetry breaking and without boundary condition. The proper higher-D boundary conditions are automatically induced in the continuum limit rather than being imposed. We identify and analyze the moose theories which exhibit delayed unitarity violation (effective unitarity) as a collective effect of many gauge groups, without resorting to any known 5D geometry. Relevant phenomenological constraints are also addressed.

We studied single Higgs boson production in γγ collisions proceeding via the hadronic content of the photon. For SM Higgs masses of current theoretical interest, the resolved photon contributions are non-negligible in precision cross section measurements. We found that production of the heavier Higgs bosons H⁰ and A⁰ of the MSSM can probe regions of the SUSY parameter space that will complement other measurements. Finally, we showed that associated tH^± production in γγ collisions can be used to make an accurate determination of tan β for low and high tan β by precision measurements of the γγ → H^±t + X cross section.

We describe the ILC detector simulation environment, which features a flexible GEANT4-based detector response program and a Java toolkit for full event reconstruction and analysis. The toolkit is currently being used for detector design and physics analysis for a future e⁺e^- linear collider. The reconstruction components are fully modular and are available for tasks from digitization of tracking detector signals through to cluster finding, pattern recognition, fitting, jetfinding, and analysis.

The development of a tracking algorithm for minimum ionizing particles based on the SiD detector design for a future e⁺e^- linear collider is described. Their identification and reconstruction, using the electromagnetic calorimeter alone, is an important step towards an Energy Flow algorithm which can play a key role in the measurement of the jet energy and the identification of long-lived particles. Implementation and possible future improvements of this algorithm are discussed.

We discuss the ATLAS physics programme for the first year of LHC operation. The layout of the initial (staged) detector will be described, as well as the impact of staging on the physics reach. The main data samples and strategies which will be used to calibrate, align and understand the detector response will be presented. Finally, the physics channels which will be addressed in the first months of operation will be discussed. These include a low-mass Higgs boson, for which a striking signal might be observed after only a few months of data taking. The impact of a realistic non-optimal detector performance, as expected at the beginning, will be illustrated in some cases.

The large number of events that will be produced at LHC, will allow very precise measurements of the properties of the top quark, which may also reveal New Physics. The mass of the top quark will be measured with a precision of about one GeV. Rare decays of the top quark can be probed for branching ratios as small as 10^-4. Finally, the detailed study of three different mechanisms of electroweak single top production will allow precise measurements of the CKM matrix element V_tb.

The Large Hadron Collider(LHC) is a proton proton collider being built at CERN, Geneva which will collide two 7 TeV proton beams giving a center of mass energy of 14 TeV. The Compact Muon Solenoid (CMS) is a multi-purpose detector at the LHC which is designed to discover the Higgs boson over the mass range of 90 to 1000 GeV. Since LEP searches have put a 95% C.L. lower bound on (standard model) Higgs mass of 114.4 GeV and theory excludes mass above about 1 TeV, CMS should discover the Higgs if it exists. In this paper, we will review CMS's Higgs-discovery potential both in the Standard Model and the Minimal Supersymmetric Standard Model for Higgs bosons produced in gluon-gluon fusion and in vector boson fusion mechanisms. Particular emphasis will be placed on discovery in the early years of running with luminosity of about 2 × 10³³cm^-2/s.

We discuss the status of preparations for SUSY searches at ATLAS. This includes inclusive techniques designed for discovery of SUSY via missing energy signatures, and prospects for measurements of SUSY model parameters such as sparticle masses. Results of the analysis of 5 fb^-1 of fully simulated Monte Carlo data are shown.

In 2007, the Large Hadron Collider (LHC) will circulate and collide proton-proton beams at an expected center-of-mass energy of 14 TeV. The Compact Muon Solenoid (CMS) is one of four experiments at the LHC and has been designed with particular attention to selecting and reconstructing muons with high redundancy. This paper briefly describes the CMS Muon System and provides an overview of CMS preparations for new physics searches involving lepton final states during the early phases of running at the LHC.

The direct s-channel coupling to Higgs bosons is 40000 times greater for muons than electrons; the coupling goes as mass squared. High precision scanning of the lighter h⁰ and the higher mass H⁰ and A⁰ is thus possible with a muon collider. The H⁰ and A⁰ are expected to be nearly mass degenerate and to be CP even and odd, respectively. A muon collider could resolve the mass degeneracy and make CP measurements. The origin of CP violation in the K⁰ and B⁰ meson systems might lie in the the H⁰/A⁰ Higgs bosons. If large extra dimensions exist, black holes with lifetimes of ~ 10^-26 seconds could be created and observed via Hawking radiation at the LHC. Unlike proton or electron colliders, muon colliders can produce black hole systems of known mass. This opens the possibilities of measuring quantum remnants, gravitons as missing energy, and scanning production turn on. Proton colliders are hampered by parton distributions and CLIC by beamstrahlung. The ILC lacks the energy reach.

It is possible that superstrings, as well as other one-dimensional branes, could have been produced in the early universe and then expanded to cosmic size today. I discuss the conditions under which this will occur, and the signatures of these strings. Such cosmic superstrings could be the brightest objects visible in gravitational wave astronomy, and might be distinguishable from gauge theory cosmic strings by their network properties.

Tree-level gluon scattering amplitudes in Yang-Mills theory frequently display simple mathematical structure which is completely obscure in the calculation of Feynman diagrams. We describe a novel way of calculating these amplitudes, motivated by a conjectured relation to twistor space, in which the problem of summing Feynman diagrams is replaced by the problem of solving a certain set of algebraic equations.

We write down two supercharges in the matrix string theory at the leading order, following previous works relating the matrix string theory to the light-cone superstring field theory. We check the supersymmetry algebra at this order and also discuss the problems of higher order contact terms.

We investigate the time-dependent behaviour of brane-antibrane orbital systems, mainly concentrating on the stability of the "Branonium" configuration.

We study mesons in an super Yang-Mills theory with fundamental matter from its dual string theory on AdS₅ × S⁵ with a D7-brane probe. For quarks with a finite mass m_q, the meson spectrum is discrete and exhibits a mass gap of order . The spectrum of mesons with large spin J is obtained from semiclassical rotating open strings attached to the D7-brane. It displays Regge behaviour for whereas for it corresponds to that of two non-relativistic quarks bound by a Coulomb potential. We calculate 〈TrF²〉 around an isolated quark, to gain insight into the Regge behaviour of the spinning mesons.

Recent progress in the construction of time dependent solutions of supergravity theories corresponding to so called spacelike branes will be reviewed.

We argue that many models of inflation in string theory require the usual ten-dimensional compactification geometry to be modified during inflation. Based on arguments from the four-dimensional effective theory, we propose a modified ten-dimensional geometry in which the four-dimensional effective theory is just consistent. We also discuss the implications of the light modes in reheating, following inflation. (Based on work in progress with Anupam Mazumdar and Robert Myers.)

We summarize an explicit construction of a duality cycle for geometric transitions in type II and heterotic theories. We emphasize that the manifolds with torsion constructed with this duality cycle are crucial for understanding different phenomena appearing in effective field theories.

In recent years there had been a growing interest in analog models of general relativity, with certain superfluid solutions simulating black hole solutions of Einstein's gravitational field equation. The quantization of a superfluid, composed of discrete particles (helium atoms), treated as a nonrelativistic many body problem does not lead to divergencies as the quantization of Einstein's field equations. Quantization of gravity is possible in string theory, but only if one introduces the daring hypothesis of higher dimensions. But if the gravitational field is made up of discrete elements as superfluid helium is made up of helium atoms, then gravity can be quantized without difficulty in three space and one time dimension. Such a hypothesis, of course, implies that Lorentz invariance is a dynamic symmetry caused by real rod and clock deformations, as it was assumed in the pre-Einstein theory of relativity by Lorentz and Poincaré, which required the existence of an aether. Making the hypothesis that this aether is a kind of superfluid plasma made up of positive and negative Planck mass particles interacting with the Planck force over a Planck length, one obtains an analog of the standard model, including gravity, which can be quantized as a nonrelativistic many body problem. In this model nonrelativistic vortex rings in three space dimensions and one time dimension simulate the relativistic theory of closed strings in ten space-time dimensions. But because in the vortex lattice, one obtains a large dimensionless number conceivably advancing our understanding of the finestructure constant.

We consider model A dynamics for a quench from the disordered into the ordered phase of SU(3) lattice gauge theory and the analogue 3d 3-state Potts model. For the gauge model this corresponds to a rapid heating from the confined to the deconfined phase. The exponential growth factors of low-lying structure function modes are numerically calculated. The linear theory of spinodal decomposition is used to determine the critical modes. This allows for the Debye screening mass estimation in an effective phenomeno-logical model. The quench leads to competing vacuum domains, which make the equilibration of the QCD vacuum after the heating non-trivial. The influence of such domains on the gluonic energy density is studied.

We use lattice QCD to fully determine the CKM matrix. |V_cd|, |V_cs|, |V_ub|, |V_cb| and |V_us| are, respectively, directly determined with our lattice results for form factors of semileptonic D → πlν, D → Klν, B → πlν, B → Dlν and K → πlν decays. The accuracy is comparable to that of the Particle Data Group averages. In addition, |V_ud|, |V_tb|, |V_ts| and |V_td| are determined by using unitarity of the CKM matrix and the experimental result for sin (2β). In this way, we obtain all 9 CKM matrix elements, where the only theoretical input is lattice QCD.

We present a lattice calculation of the scattering phase shift for the I = 2S-wave pion-pion system in the continuum limit with two-flavor dynamical effect. Calculations are made at three lattice spacings, using the finite volume method proposed by Lüscher in the center of mass system, and its extension to the laboratory system by Rummukainen and Gottlieb.

In the present work we show that it is possible to arrive at a Ginzburg-Landau (GL) like equation from pure SU(2) gauge theory. This has a connection to the dual superconducting model for color confinement where color flux tubes permanently bind quarks into color neutral states. The GL Lagrangian with a spontaneous symmetry breaking potential, has such (Nielsen-Olesen) flux tube solutions. The spontaneous symmetry breaking requires a tachyonic mass for the effective scalar field. Such a tachyonic mass term is obtained from the condensation of ghost fields.

We discuss a novel form of the variational approach in Quantum Field Theory in which the trial quantum configuration is represented directly in terms of relevant expectation values rather than, e.g., increasingly complicated structure from Fock space. The quantum algebra imposes constraints on such expectation values so that the variational problem is formulated here as an optimization under constraints. As an example of application of such approach we consider the study of ground state and critical properties in a variant of nonlinear sigma model.

In this talk we present a field theoretical model constructed in Minkowski superspace with a deformed supercoordinate algebra. Our study is motivated in part by recent results from super-string theory, which show that in a particular scenario in Euclidean superspace the spinor coordinates θ do not anticommute. Field theoretical consequences of this deformation were studied in a number of articles. We present a way to extend the discussion to Minkowski space, by assuming non-vanishing anticommutators for both θ, and . We give a consistent supercoordinate algebra, and a star product that is real and preserves the (anti)chirality of a product of (anti)chiral superfields. We also give the Wess-Zumino Lagrangian that gains only Lorentz-invariant corrections due to non(anti)commutativity within our model. The Lagrangian in Minkowski superspace is also always manifestly Hermitian.

We present the elements of resummed quantum gravity, a new approach to QG based on the work of Feynman using the simplest example of a scalar field as the representative matter. We show that we get a UV finite quantum correction to Newton's law.

The first result from BNL E949 for the rare kaon decay is described. One candidate event was seen with a signal-to-noise ratio of 0.9. Combined with the two events previously reported by E787, the best estimate of the branching ratio is .

We report on a new result from the Fermilab HyperCP experiment, which is searching for CP violation by comparing the proton and antiproton angular distributions in Ξ^- → Λπ^- → pπ^-π^- and decays. This result represents a greatly increased sensitivity over previous measurements.

Measurement of the B_s oscillation frequency via B_s mixing analyses provides a powerful constraint on the CKM matrix elements. The study of B_d oscillations is an important step towards B_s mixing and preliminary measurements of Δm_d have been made with ~250 pb^-1 of data collected with the upgraded Run II DØ detector. Different flavor tagging algorithms have been developed and are being optimized for use on a large set of B_s mesons that have been reconstructed in different semileptonic decay modes.

The CDF Collaboration has made a preliminary measurement of B_d mixing as a first step toward measuring mixing in the B_s system. Flavor tagging using opposite-side jets and muons as well as same-side tagging schemes have been applied. Results agree well with precise results from the B-factories. We use these results to estimate CDF's B_s mixing range using the present data set (~250pb^-1) and extrapolate to the potential from larger data sets in future running.

We present results on time-dependent CP asymmetries in neutral B decays. The amplitude of the CP asymmetry, sin2β in the Standard Model, is derived from decay-time distributions from events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B⁰ or from its decay products. Using data collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure sin2β = 0.722 ± 0.040(stat) ± 0.023(syst) and , determining the sign of cos2β to be positive at 86% CL.

We present new measurements of CP-violation parameters in B⁰ → ϕK⁰, , , , , , and decays based on a sample of pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e⁺e^- collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the decay modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. All results are preliminary.

We present results on time-dependent CP asymmetries in and B⁰ → K⁺K^-K⁰. The measurements use a data sample consisting of approximately and 227(B⁰ → K⁺K^-K⁰) million B-meson pairs recorded at the ϒ(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. From a time-dependent maximum likelihood fit, we measure for : the mixing-induced CP violation parameter and the direct CP violation parameter C_f0K = -0.24 ± 0.31 (stat) ± 0.15 (syst). From a simultaneous fit to and decays, we find: and C_ϕK = 0.00 ± 0.23 (stat) ± 0.05 (syst). For decays with decays excluded, we find: and . From the decays with decays excluded, we extract the fraction of CP-even final states from angular moments f_even = 0.89 ± 0.08 ± 0.06.

Final-state rescattering effects on direct CP violation in charmless hadronic B decays and on the polarization anomaly in B → ϕK* are discussed.

We report a study of the modes B^± → DK^± and B^± → D*K^± where D^(*) decays to CP eigenstates. The data sample used contains 274 million events collected at the ϒ(4S) resonance with the Belle detector at KEKB. Measurements are made of and , the magnitudes of the CP asymmetries for D_CPK and for .

We present measurements of branching fractions and CP asymmetries of several B^- → D^(*)0K^(*)- decays, with the D^(*)0 decaying to CP-even, CP-odd, and flavor eigenstates, that can constrain the CP angle γ as well as the amplitude ratio r_b = A(B → u)/A(B → c), using methods proposed by Gronau, London and Wyler or Atwood, Dunietz and Sony¹. We use data collected with the BABAR detector at the PEP-II asymmetric energy e⁺e^- collider at SLAC.

The Belle experiment has measured branching fractions and CP asymmetries for the charmless decays B⁰ → π⁺π^- and B⁰ → ρ^±π^∓. From these measurements, constraints upon the CKM angle ϕ₂ can be obtained. These constraints indicate that ϕ₂ is around 100°.

We present the preliminary measurement of CP-violating asymmetries in B⁰ → (ρπ)⁰ → π⁺π^-π⁰ decays using a time-dependent Dalitz plot analysis. The results are obtained from a data sample of 213 million decays, collected by the BaBar detector at the PEPII asymmetric-energy B-Factory at SLAC. We measure 16 coefficients of the bilinear form factor terms occurring in the time-dependent decay rate of the B⁰ meson with the use of a maximum-likelihood fit. The physically relevant CP parameters are derived from these coefficients.

Relative branching fractions of decays (where h, h′ = K or π) and the direct CP asymmetry in the mode are measured with 179 ± 11 pb^-1 of data collected at using the CDF II detector at the Fermilab Tevatron collider. The first branching-fraction measurement of a meson to two pseudoscalars, , and a search for the baryon mode are also presented, in addition to branching-fraction limits on the rare channels , , and .

We present preliminary results of maximum-likelihood Dalitz plot analyses performed by the BABAR Collaboration of the charmless hadronic decays B⁰ → K⁺π^-π⁰, B⁺ → K⁺π^-π⁺, and B⁺ → π⁺π^-π⁺. We report inclusive decay rates, as well as fractions and phases for intermediate resonant decays. We also report CP-violating charge asymmetries for intermediate resonant decays of neutral B mesons.

We present preliminary measurements of branching fractions and direct CP violating asymmetries in charmless twobody B decays, obtained with the BABAR detector using a sample of 227 M decays. We report the first observation of and the first observation of direct CP violation in B⁰ → K⁺π^- decays.

We determine the weak phases and the amplitudes by proposing an parametrization to each topologies of amplitudes in power of Wolfenstein parameter λ ~ 0.22. Comparing this parametrization with the experimental data, we can obtain the phase ϕ₃ from the B → Kπ data up to theoretical uncertainty of O(λ³) ~ 5%. We find that these solutions indicate a large color-suppressed tree amplitude. The extraction of the phase ϕ₂ and ϕ₃ are consistent with the global unitarity triangle fit.

We present measurements of B → PV and VV decays based on 140 fb^-1 of data recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e⁺e^- storage ring. Branching fractions of B → ηK*, ηρ⁺, ρπ⁰, and ρ⁺K* are measured; while upper limits of B → ηρ⁰ and ρ⁰K* decays are given. The polarization study of B → ϕK* is also updated.

Using a data sample of 122 million decays collected with BABAR detector at the PEP-II asymmetric B factory at SLAC, we measure the time-dependent-asymmetry parameters of the longitudinally polarized component in the B⁰ → ρ⁺ρ^- decay as C_L = -0.23 ± 0.24 (stat) ± 0.14 (syst) and S_L = -0.19 ± 0.33 (stat) ± 0.11 (syst). The B⁰ → ρ⁰ρ⁰ decay mode is also searched for in a data sample of about 227 million pairs. No significant signal is observed, and an upper limit of 1.1 × 10^-6 (90% C.L.) on the branching fraction is set. The penguin contribution to the CKM angle α uncertainty is measured to be 11°. All results are preliminary.

We present results for measurements of the decays to charmless final states of B⁰ meson to ηK⁰, ηω, with , and of B⁺ to ηρ⁺, η′π⁺. Analyses are based on data taken with the BABAR detector at the PEP-II asymmetric e⁺e^- collider at SLAC. We measure the following branching fractions in units of , , , , and . The charge asymmetries are and . First error is statistical, the second systematic. All results are preliminary.