One of the main goals for hadron colliders is the study of the properties of the third generation quarks. We study the signatures for new TeV resonances that couple to top or bottom quarks both at the Tevatron Run II and at the CERN LHC. We find that in the simplest production processes of Drell-Yan type at the Tevatron, the signals are overwhelmed by QCD backgrounds. We also find that it is possible to study these resonances when they are produced in association with a pair of heavy quarks or in association with a single top at the LHC. In particular, with an integrated luminosity of $300{\mathrm{fb}}^{-1}$ at the LHC, it is possible to probe resonance masses up to around 2 TeV.

A quantum field theoretical model for the dynamics of the disoriented chiral condensate is presented. A unified approach to relate the quantum field theory directly to the formation, decay, and signals of the DCC and its evolution is taken. We use a background field analysis of the $O\left(4\right)\mathrm{}$ sigma model, keeping one-loop quantum corrections (quadratic order in the fluctuations). An evolution of the quantum fluctuations in an external, expanding metric which simulates the expansion of the plasma is carried out. We examine, in detail, the amplification of the low-momentum pion modes with two competing effects: the expansion rate of the plasma and the transition rate of the vacuum configuration from a metastable state into a stable state. We show the effect of DCC formation on the multiplicity distributions and the Bose-Einstein correlations.

We show that both small mixing in the quark sector and large mixing in the lepton sector can be obtained from a simple assumption of universality of Yukawa couplings and the right-handed neutrino Majorana mass matrix in leading order. We discuss conditions under which bilarge mixing in the lepton sector is achieved with a minimal amount of fine-tuning requirements for possible models. From knowledge of the solar and atmospheric mixing angles we determine the allowed values of $\sin {\theta }_{13}.$ If embedded into grand unified theories, the third generation Yukawa coupling unification is a generic feature while masses of the first two generations of charged fermions depend on small perturbations. In the neutrino sector, the heavier two neutrinos are model dependent, while the mass of the lightest neutrino in this approach does not depend on perturbations in the leading order. The right-handed neutrino mass scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as ${(m}_{\mathrm{top}}^2{/M}_{\mathrm{GUT}}){\sin }^2{\theta }_{23}{\sin }^2{\theta }_{12}$ in the limit $\sin {\theta }_{13}\simeq 0.$ Discussing symmetries we make a connection with hierarchical models and show that the basis independent characteristic of this scenario is a strong dominance of the third generation right-handed neutrino, $M_1{,M}_2<{10}^{-4}{M}_3,$ $M_3{=M}_{\mathrm{GUT}}.$

We discuss the impact of the true value of the CP phase on the mass hierarchy, CP violation, and CP precision measurements at neutrino superbeams and related experiments. We use a complete statistical experiment simulation including spectral information, systematics, correlations, and degeneracies to produce the results. However, since it is very complicated to understand the results in terms of a complete experiment simulation, we show the corresponding birate graphs as useful tools to investigate the CP phase-dependencies qualitatively. Unlike biprobability graphs, which are based upon oscillation probabilities, birate graphs use the total event rates of two measurements simultaneously as a function of the CP phase. Since they allow error bars for direct quantitative estimates, they can be used for a direct comparison with a complete statistical experiment simulation. We find that one can describe the CP phase dependencies of the mentioned measurements at neutrino superbeam setups, as well as one can understand the role of the $\mathrm{sgn}\left(\Delta m_{31}^2\right)$-degeneracy. As one of the most interesting results, we discuss the dependence of the CP precision measurement as a function of the CP phase itself, which leads to “CP patterns.” It turns out that this dependence is rather strong, which means that one has to be careful when one is comparing the CP precisions of different experiments.

In this work we have calculated the magnetic moment ${\mu }_{\nu }$ of a massive neutrino, to one-pion loop order. If $m_{\nu }$ varies between $\sim 3\mathrm{meV}$ and $\sim 3\mathrm{eV}$ and $m_{\pi }$ between 0 and $\sim 140\mathrm{MeV}$ one obtains values for ${\mu }_{\nu }$ which can compete with the Standard Model result in the chiral limit $m_{\pi }\to 0.$ The photon coupling to the $\pi \pi$-intermediate state leads to the presence of “chiral singularities” $[m_{\pi }^{-1}-$ and $\log {(m}_{\pi })$-terms]. There are no such terms for the $W^{-}{W}^{+}$-intermediate state of the Standard Model. As a result ${\mu }_{\nu }$ is particularly sensitive to the mass ratios ${(m}_{\pi }{/m}_{\mathcal{l}}{,m}_{{\nu }_{\mathcal{l}}}{/m}_{\mathcal{l}});$ this indicates to us that all electromagnetic properties of neutrinos $({\mu }_{\nu },〈r^2〉,$ etc.) are expected to change significantly in a dense or hot medium. Such medium modifications of ${\mu }_{\nu },〈r^2〉,$ etc. are entirely due to the $\pi \pi$-intermediate state which acts as a “doorway” state for the photon-neutrino coupling.

Nonradiative neutrino decay, which is not satisfactorily constrained, possibly and significantly changes the detected neutrino signal from galactic supernova explosions. We focus on the appearance of a sharp peak due to a neutronization burst in the time profile; this phenomenon would occur if the original ${\nu }_e,$ produced at the neutrinosphere and becoming ${\nu }_2$ or ${\nu }_3$ at the stellar surface, decays into a lighter antineutrino state such as ${\overline{\nu }}_1$ or ${\overline{\nu }}_2$ coupled to ${\overline{\nu }}_e.$ This is due to the fact that the signature of the neutronization burst is common to all numerical simulations, contrary to the spectral energy distribution of each flavor neutrino and antineutrino, which is still under intense debate. Therefore, the appearance of a neutronization peak in the ${\overline{\nu }}_e$ signal, if it were detected, would clearly indicate the nonstandard properties of neutrinos; the nonradiative neutrino decay would be one of the possible candidates. Using a newly developed formulation that includes flavor conversions inside the supernova envelope and neutrino decay during propagation in a vacuum, we calculate the expected neutrino signal at the detectors; the lifetimes of three modes ${\tau }_{12},{\tau }_{13},$ and ${\tau }_{23}$ are taken to be free parameters. We further introduce simple quantities, which represent a peak sharpness of the time profile and spectral hardness, and investigate the parameter dependence of these quantities. As the result, it is found that they are quite dependent on the relevant parameters, but it would be quite difficult to distinguish models using the signal obtained by the Super-Kamiokande detector; the future megaton-class detectors would have sufficient sensitivity. We also compare the neutrino decay model with another mechanism—i.e., resonant spin-flavor conversion—which also may give the appearance of a neutronization peak, and conclude that these two independent mechanisms give a very different signal and one can be distinguished from the other.

The effective Majorana neutrino mass $m_{\beta \beta }$ is evaluated by using the latest results of neutrino oscillation experiments. The problems of the neutrino mixing pattern, the absolute mass scale of neutrinos, and the effect of CP phases are addressed. A connection to the next generation of neutrinoless double beta decay $(0\mathrm{}\nu \beta \beta$ decay) experiments is discussed. The calculations are performed for ${}^{76}\mathrm{Ge},$${}^{100}\mathrm{Mo},$${}^{136}\mathrm{Xe},$ and ${}^{130}\mathrm{Te}$ by using the advantage of recently evaluated nuclear matrix elements with significantly reduced theoretical uncertainty. The importance of observation of the $0\nu \beta \beta$ decay of several nuclei is stressed.

We report a new measurement of the B-meson semileptonic decay momentum spectrum that has been made with a sample of 9.4 ${\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ data collected with the CLEO II detector at the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ resonance. Electrons from primary semileptonic decays and secondary charm decays were separated by using charge and angular correlations in ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ events with a high-momentum lepton and an additional electron. We determined the semileptonic branching fraction to be $\mathcal{B}\left(\overrightarrow{B}{\mathrm{Xe}}^{+}{\nu }_e\right)=(10.91\mathrm{}\pm 0.09\pm 0.24)\%$ from the normalization of the electron-energy spectrum. We also measured the moments of the electron-energy spectrum with minimum energies from 0.6 to 1.5 GeV.

We present a measurement of the composition of B meson inclusive semileptonic decays using 9.4 ${\mathrm{fb}}^{\mathrm{-}1}$ of $e^{+}{e}^{-}$ data taken with the CLEO detector at the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ resonance. In addition to measuring the charged lepton kinematics, the neutrino four-vector is inferred using the hermiticity of the detector. We perform a maximum likelihood fit over the full three-dimensional differential decay distribution for the fractional contributions from the $\overrightarrow{B}{X}_c\mathcal{l}\nu$ processes with $X_c=D,$ $D^{*},$ $D^{**},$ and nonresonant $X_c,$ and the process $\overrightarrow{B}{X}_u\mathcal{l}\nu .$ From the fit results we extract the first and second moments of the $M_X^2$ and $q^2$ distributions with minimum lepton-energy requirements of 1.0 GeV and 1.5 GeV. We find $〈M_X^2-M_D^2〉=(0.456\mathrm{}\pm 0.014\pm 0.045\pm 0.109){\mathrm{GeV}}^2{/c}^4$ with a minimum lepton energy of 1.0 GeV and $〈M_X^2-M_D^2〉=(0.293\mathrm{}\pm 0.012\pm 0.033\pm 0.048){\mathrm{GeV}}^2{/c}^4$ with minimum lepton energy of 1.5 GeV. The uncertainties are from statistics, detector systematic effects, and model dependence, respectively. As a test of the HQET and OPE calculations, the results for the $M_X^2$ moment as a function of the minimum lepton energy requirement are compared to the predictions.

Measurements of the cross section for ${\overline{\nu }}_e{e}^{-}$ elastic scattering with unprecedented precision have recently been proposed. The impact of these experiments for detecting possible deviations from the standard electroweak theory is analyzed and compared with that of several other measurements.

The properties of the momentum space quark propagator in Landau gauge are examined for the overlap quark action in quenched lattice QCD. Numerical calculations are done on three lattices with different lattice spacings and similar physical volumes to explore the approach of the quark propagator toward the continuum limit. We have calculated the nonperturbative momentum-dependent wave-function renormalization function $Z({\zeta }^2;p)$ and the nonperturbative mass function $M\left(p\right)\mathrm{}$ for a variety of bare quark masses and perform an extrapolation to the chiral limit. We find the behavior of $Z({\zeta }^2;p)$ and $M\left(p\right)\mathrm{}$ are in reasonable agreement between the two finer lattices in the chiral limit, however the data suggest that an even finer lattice is desirable. The large momentum behavior is examined to determine the quark condensate.

We explore whether $“{\mathrm{f}}_0\mathrm{}\left(600\right)\mathrm{}$ or $\sigma ”$ exists as a pole in QCD, by a full lattice QCD simulation on the $8^3\times 16$ lattice using the plaquette action and Wilson fermions. It is shown that there exists a $\sigma$ pole, whose mass is as low as that of the $\rho ,$ owing to the disconnected diagram of the meson propagator. A discussion is given on the physical content of the $\sigma .$

We investigate the renormalization of the quark-mixing matrix in the electroweak standard model. The corresponding counterterms are gauge independent as can be shown using an extended BRS symmetry. Using rigid $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_{\mathrm{L}}$ symmetry, we prove that the ultraviolet-divergent parts of the invariant counterterms are related to the field renormalization constants of the quark fields. We point out that for a general class of renormalization schemes rigid $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_{\mathrm{L}}$ symmetry cannot be preserved in its classical form, but is renormalized by finite counterterms. Finally, we discuss a genuine physical renormalization condition for the quark-mixing matrix that is gauge independent and does not destroy the symmetry between quark generations.

We present the first evidence for the production of ${\rm Y}\mathrm{}\left(1D\right)\mathrm{}$ states in the four-photon cascade, ${\rm Y}\mathrm{}\left(3S\right)\mathrm{}\to \gamma {\chi }_b\mathrm{}\left(2P\right),$ ${\chi }_b\mathrm{}\left(2P\right)\mathrm{}\to \gamma {\rm Y}\mathrm{}\left(1D\right),$ ${\rm Y}\mathrm{}\left(1D\right)\mathrm{}\to \gamma {\chi }_b\mathrm{}\left(1P\right),$ ${\chi }_b\mathrm{}\left(1P\right)\mathrm{}\to \gamma {\rm Y}\mathrm{}\left(1S\right),$ followed by the ${\rm Y}\mathrm{}\left(1S\right)\mathrm{}$ annihilation into $e^{+}{e}^{-}$ or ${\mu }^{+}{\mu }^{-}.$ The signal has a significance of 10.2 standard deviations. The measured product branching ratio for these five decays, $(2.5\mathrm{}\pm 0.5\pm 0.5)\times {10}^{-5},$ is consistent with the theoretical estimates. The data are dominated by the production of one ${\rm Y}\mathrm{}\left(1D\right)\mathrm{}$ state consistent with the $J=2\mathrm{}$ assignment. Its mass is determined to be $(10161.1\mathrm{}\pm 0.6\pm 1.6)$ MeV, which is consistent with the predictions from potential models and lattice QCD calculations. We also searched for ${\rm Y}\mathrm{}\left(3S\right)\mathrm{}\to \gamma {\chi }_b\mathrm{}\left(2P\right),$ ${\chi }_b\mathrm{}\left(2P\right)\mathrm{}\to \gamma {\rm Y}\mathrm{}\left(1D\right),$ followed by either ${\rm Y}\mathrm{}\left(1D\right)\mathrm{}\to \eta {\rm Y}\mathrm{}\left(1S\right)\mathrm{}$ or ${\rm Y}\mathrm{}\left(1D\right)\mathrm{}\to {\pi }^{+}{\pi }^{-}{\rm Y}\mathrm{}\left(1S\right).$ We find no evidence for such decays and set upper limits on the product branching ratios.

Various dynamical regimes associated with confined monopoles in the Higgs phase of $\mathcal{N}=2\mathrm{}$ two-flavor QCD are studied. The microscopic model we deal with has the $\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}\times \mathrm{U}\mathrm{}\left(1\right)\mathrm{}$ gauge group, with a Fayet–Iliopoulos term of the U(1) factor, and large and (nearly) degenerate mass terms of the matter hypermultiplets. We present a complete quasiclassical treatment of the BPS sector of this model, including the full set of the first-order equations, derivations of all relevant zero modes, and derivation of an effective low-energy theory for the corresponding collective coordinates. The macroscopic description is provided by a ${\mathrm{CP}}^1$ model with or without twisted mass. The confined monopoles—string junctions of the microscopic theory—are mapped onto BPS kinks of the ${\mathrm{CP}}^1$ model. The string junction is $\frac{1}{4}$ BPS. Masses and other characteristics of the confined monopoles are matched with those of the ${\mathrm{CP}}^1$-model kinks. The matching demonstrates the occurrence of an anomaly in the monopole central charge in 4D Yang–Mills theory. We study what becomes of the confined monopole in the bona fide non-Abelian limit of degenerate mass terms where a global SU(2) symmetry is restored. The solution of the macroscopic model is known, e.g., from the mirror description of the ${\mathrm{CP}}^1$ model. The monopoles, aka ${\mathrm{CP}}^1$-model kinks, are stabilized by nonperturbative dynamics of the ${\mathrm{CP}}^1$ model. We explain an earlier rather puzzling observation of a correspondence between the BPS kink spectrum in the ${\mathrm{CP}}^1$ model and the Seiberg–Witten solution.

We investigate a four-dimensional world, embedded into a five-dimensional spacetime, and find the five-dimensional Riemann tensor via generalization of the Gauss(-Codacci) equations. We then derive the generalized equations of the four-dimensional world and also show that the square of the dilaton field is equal to Newton’s constant. We find plausible constant and nonconstant solutions for the dilaton.

We consider a Friedmann-Roberston-Walker cosmological model with some exotic perfect fluid with spin known as the Weyssenhoff fluid. The possibility that the dark energy may be described in part by the Weyssenhoff fluid is discussed. The observational constraint coming from supernovae type Ia observations is established. This result indicates that, whereas the cosmological constant is still needed to explain current observations, the model with a spin fluid is admissible. For high redshifts $z>\mathrm{}1\mathrm{}$ the differences between the model with spin fluid and the cold dark matter model with a cosmological constant become detectable observationally for the flat case with ${\Omega }_{\mathrm{m},0\mathrm{}}=\mathrm{0.3.}\mathrm{}$ From the maximum likelihood method we obtain the value of ${\Omega }_{\mathrm{s},0\mathrm{}}=0.004\mathrm{}\pm \mathrm{0.016.}$ This gives us the limit ${\Omega }_{\mathrm{s},0\mathrm{}}>-0.012$ at the $1\sigma$ level. While the model with “brane effects” is preferred by the supernovae Ia data, the model with a spin fluid is statistically admissible. For comparison, the limit on the spin fluid coming from cosmic microwave background anisotropies is also obtained. The uncertainties in the location of a first peak give the interval $-1.4\times {10}^{-10}<{\Omega }_{\mathrm{s},0\mathrm{}}<-{10}^{-10}.$ From big bang nucleosynthesis we obtain the strongest limit, ${\Omega }_{\mathrm{s},0\mathrm{}}\gtrsim -{10}^{-20}.$ The interconnection between the model considered and brane models is also pointed out.

If the narrow exotic baryon resonances ${\Theta }^{+}\mathrm{}\left(1540\right)\mathrm{}$ and ${\Xi }_{3/2}\mathrm{}\left(1862\right)\mathrm{}$ are members of the $J^P={\frac{1}{2}}^{+}$ antidecuplet with $N^{*}\mathrm{}\left(1710\right),$ the octet-antidecuplet mixing is required not only by the mass spectrum but also by the decay pattern of $N^{*}\mathrm{}\left(1710\right).$ This casts doubt on the validity of the ${\Theta }^{+}$ mass prediction by the chiral soliton model. While all pieces of the existing experimental information point to a small octet-decuplet mixing, the magnitude of mixing required by the mass spectrum is not consistent with the value needed to account for the hadronic decay rates. The discrepancy is not resolved even after the large experimental uncertainty is taken into consideration. We fail to find an alternative $\mathrm{SU}\left(3\right)\mathrm{}$ assignment even with a different spin-parity assignment. When we extend the analysis to mixing with a higher $\mathrm{SU}\left(3\right)\mathrm{}$ multiplet, we find one experimentally testable scenario in the case of mixing with a 27-plet.

We present predictions for ρ-meson form factors obtained from the analysis of QCD sum rules in next-to-leading order of perturbation theory. The radiative corrections turn out to be sizeable and should be taken into account in rigorous theoretical analysis.

In the limit of flavor SU(3) symmetry, the amplitudes for $B_d^0\to {\pi }^{+}{\pi }^{-}$ and $B_s^0\to K^{+}{K}^{-}$ are related to one another. Taking the values of the weak phases $\beta$ and $\gamma$ from independent measurements, the ratio $R_d^s\equiv {BR(B}_s^0\to K^{+}{K}^{-}{)/BR(B}_d^0\to {\pi }^{+}{\pi }^{-})$ and the two $B_d^0\to {\pi }^{+}{\pi }^{-}$ CP asymmetries ${\mathcal{A}}_{\mathrm{dir}}$ and ${\mathcal{A}}_{\mathrm{mix}}$ depend on only two quantities. By measuring these three observables, one can test for the presence of physics beyond the standard model. In this paper, using present data, and including theoretical uncertainties due to SU(3) breaking, we perform such an analysis. The experimental errors are still very large, but with improved measurements from Babar, Belle and CDF this will be a useful method to search for new physics.