Fluctuation and dissipation dynamics is examined at all temperature ranges for the general case of a background time evolving scalar field coupled to heavy intermediate quantum fields which in turn are coupled to light quantum fields. The evolution of the background field induces particle production from the light fields through the action of the intermediate catalyzing heavy fields. Such field configurations are generically present in most particle physics models, including grand unified and supersymmetry theories, with application of this mechanism possible in inflation, heavy ion collision, and phase transition dynamics. The effective evolution equation for the background field is obtained and a fluctuation-dissipation theorem is derived for this system. The effective evolution, in general, is nonlocal in time. Appropriate conditions are found for when these time nonlocal effects can be approximated by local terms. Here careful distinction is made between a local expansion and the special case of a derivative expansion to all orders, which requires analytic behavior of the evolution equation in Fourier space.

We propose a dark matter candidate with an “excited state” 1–2 MeV above the ground state, which may be collisionally excited and deexcites by $e^{+}{e}^{-}$ pair emission. By converting its kinetic energy into pairs, such a particle could produce a substantial fraction of the 511 keV line observed by the International Gamma-Ray Astrophysics Laboratory/SPI in the inner Milky Way. Only a small fraction of the dark matter candidates have sufficient energy to excite, and that fraction drops sharply with galactocentric radius, naturally yielding a radial cutoff, as observed. Even if the scattering probability in the inner kpc is $\ll 1\%$ per Hubble time, enough power is available to produce the $\sim 3\times {10}^{42}$ pairs per second observed in the galactic bulge. We specify the parameters of a pseudo-Dirac fermion designed to explain the positron signal, and find that it annihilates chiefly to $e^{+}{e}^{-}$ and freezes out with the correct relic density. We discuss possible observational consequences of this model.

We present a detailed analysis of meson-induced massive lepton (muon) Drell–Yan production for the process ${\pi }^{-}N\to {\mu }^{+}{\mu }^{-}X$, considering both an unpolarized nucleon target and longitudinally polarized protons. Using a QCD framework, we focus on the angular distribution of ${\mu }^{+}$, which is sensitive to the shape of the pion distribution amplitude, the goal being to test corresponding results against available experimental data. Predictions are made, employing various pion distribution amplitudes, for the azimuthal angle dependence of the ${\mu }^{+}$ distribution in the polarized case, relevant for the planned COMPASS experiment. QCD evolution is given particular attention in both considered cases.

We study the resummation of large logarithmic perturbative corrections to the single-inclusive jet cross section at hadron colliders. The corrections we address arise near the threshold for the partonic reaction, when the incoming partons have just enough energy to produce the high-transverse-momentum final state. The structure of the resulting logarithmic corrections is known to depend crucially on the treatment of the invariant mass of the produced jet at threshold. We allow the jet to have a nonvanishing mass at threshold, which most closely corresponds to the situation in experiment. Matching our results to available semianalytical next-to-leading-order calculations, we derive resummed results valid to next-to-leading-logarithmic accuracy. We present numerical results for the resummation effects at Tevatron and RHIC energies.

Elastic scattering amplitudes dominated by the Pomeron singularity which obey the principal unitarity bounds at high energies are constructed and analyzed. Confronting the models of double and triple (at $t=0$) Pomeron pole (supplemented by some terms responsible for the low energy behavior) with existing experimental data on $pp$ and $\overline{p}p$ total and differential cross sections at $\sqrt{s}\ge 5\mathrm{GeV}$ and $|t|\le 6{\mathrm{GeV}}^2$ we are able to tune the form of the Pomeron singularity. Actually the good agreement with the data is received for both models though the behavior given by the dipole model is more preferable in some aspects. The predictions made for the LHC energy values display, however, the quite noticeable difference between the predictions of models at $t\approx -0.4{\mathrm{GeV}}^2$. Apparently the future results of TOTEM experiment will be more conclusive to make a true choice.

We discuss some aspects of the search for $CP$ asymmetry in the three body $B$ decays, revealed through the interference among neighbor resonances in the Dalitz plot. We propose a competitive method to extract the CKM $\gamma$ angle combining Dalitz plot amplitude analysis of $B^{\pm }\to K^{\pm }{\pi }^{+}{\pi }^{-}$ and untagged $B^0$, ${\overline{B}}^0\to K_s{\pi }^{+}{\pi }^{-}$. The method also obtains the ratio and phase difference between the tree and penguin contributions from $B^0$ and ${\overline{B}}^0\to K^{*\pm }{\pi }^{\mp }$ decays and the $CP$ asymmetry between $B^0$ and ${\overline{B}}^0$. From Monte Carlo studies of 100 K events for the neutral mesons, we show the possibility of measuring $\gamma$.

We carefully analyze the renormalization group equations in the $\mathrm{\text{type}}\mathrm{I}+\mathrm{II}$ seesaw scenario in the extended standard model and the minimal supersymmetric standard model. Furthermore, we present analytic formulas of the mixing angles and phases and discuss the renormalization group effect on the different mixing parameters in the type II seesaw scenario. The renormalization group equations of the angles are independent of the Majorana phases. In addition, there is a contribution which is proportional to the mass squared difference for a hierarchical spectrum. This is in contrast to the inverse proportionality to the mass squared difference in the effective field theory case.

We report the measurements of the $t\overline{t}$ production cross section and of the top quark mass using $1.02{\mathrm{fb}}^{-1}$ of $p\overline{p}$ data collected with the CDF II detector at the Fermilab Tevatron. We select events with six or more jets on which a number of kinematical requirements are imposed by means of a neural network algorithm. At least one of these jets must be identified as initiated by a $b$-quark candidate by the reconstruction of a secondary vertex. The cross section is measured to be ${\sigma }_{t\overline{t}}=8.3\pm 1.0(\mathrm{stat}{)}_{-1.5}^{+2.0}(\mathrm{syst})\pm 0.5(\mathrm{lumi})\mathrm{pb}$, which is consistent with the standard model prediction. The top quark mass of $174.0\pm 2.2(\mathrm{stat})\pm 4.8(\mathrm{syst})\mathrm{GeV}/c^2$ is derived from a likelihood fit incorporating reconstructed mass distributions representative of signal and background.

Numerical simulations of the bosonic sector of the $SU(2)\times U(1)$ electroweak standard model in $3+1$ dimensions have demonstrated the existence of an oscillon—an extremely long-lived, localized, oscillatory solution to the equations of motion—when the Higgs mass is equal to twice the $W^{\pm }$ boson mass. It contains total energy roughly 30 TeV localized in a region of radius 0.05 fm. A detailed description of these numerical results is presented.

We study gauge theories with/without an extra dimension at finite temperature, in which there are two kinds of order parameters of gauge symmetry breaking. One is the zero mode of the gauge field for the Euclidean time direction, and the other is that for the direction of the extra dimension. We evaluate the effective potential for the zero modes in the one-loop approximation and investigate the vacuum configuration in detail. Our analyses show that gauge symmetry can be broken only through the zero mode for the direction of the extra dimension, and no nontrivial vacuum configuration of the zero mode for the Euclidean time direction is found.

Non-Abelian strings for an Einstein-Yang-Mills-Higgs theory are explicitly constructed. We consider $N_f$ Higgs fields in the fundamental representation of the $U(1)\times SU(N_c)$ gauge group in order to have a color-flavor $SU(N_c)$ group remaining unbroken. Choosing a suitable ansatz for the metric, Bogomol’nyi-like first-order equations are found and rotationally symmetric solutions are proposed. In the $N_f=N_c$ case, solutions are local strings and are shown to be truly non-Abelian by parametrizing them in terms of orientational collective coordinates. When $N_f>N_c$, the solutions correspond to semilocal strings which, beside the orientational degrees of freedom, acquire additional collective coordinates parametrizing their transverse size. The low-energy effective theories for the correspondent moduli are found, showing that all zero modes are normalizable in presence of gravity, even in the semilocal case.

$S^3$ is a simple principle bundle which is locally $S^2\times S^1$. It has been shown that such a space can be constructed in terms of matrix models. It has also been shown that such a space can be realized by a generalized compactification procedure in the $S^1$ direction. We investigate the effective action of supersymmetric gauge theory on $S^3$ with an angular momentum cutoff and that of a matrix model compactification. Both cases can be realized in a deformed IIB matrix model with a Myers term. We find that the highly divergent contributions at the tree and 1-loop level are sensitive to the UV cutoff. However, the 2-loop level contributions are universal since they are only logarithmically divergent. We expect that the higher loop contributions are insensitive to the UV cutoff since 3-dimensional gauge theory is superrenormalizable.

We consider some scalar-coupled theories of gravity, including induced gravity, and study the Noether symmetries of Bianchi I, Bianchi III, and Kantowski-Sachs cosmological models for this theory. For various forms of coupling of the scalar field with gravity, some potentials are found in these cosmological models under the assumption that the Lagrangian admits Noether symmetry. The solutions of the field equations for the considered models are presented by using the results obtained from the Noether symmetry. We also find the explicit form of the scalar field in terms of the conformal time for Bianchi I, III, and Kantowski-Sachs models.

Bekenstein’s alternative to general relativity, TeVeS, reduces to modified Newtonian dynamics in the galactic limit. On cosmological scales, the ($\mathrm{\text{potential well}}\leftrightarrow \mathrm{\text{overdensity}}$) relationship is quite different than in standard general relativity. Here we investigate the possibility of cross-correlating galaxies with the cosmic microwave background (CMB) to probe this relationship. At redshifts of order 2, the sign of the CMB-galaxy correlation differs in TeVeS from that in general relativity. We show that this effect is detectable and hence can serve as a powerful discriminator of these two models of gravity.

The rates of multiparton collisions in high energy hadronic interactions provide information on the typical transverse distances between partons in the hadron structure. The different configurations of the hadron in transverse space are, on the other hand, at the origin of hadron diffraction. The relation between the two phenomena is explored in an eikonal model of hadronic interactions.

Traditional smearing or blocking techniques serve well to increase the overlap of operators onto physical states but allow for links orientated only along lattice axes. Recent attempts to construct more general propagators have shown promise at resolving the higher spin states but still rely on iterative smearing. We present a new method of superlink construction which creates smeared links from (sparse) matrix multiplications, allowing for gluonic propagation in arbitrary directions. As an application and example, we compute the positive-parity, even-spin glueball spectrum up to spin 6 for pure gauge SU(2) at $\beta =6$, $L=16$, in $D=2+1$ dimensions.

We study the single-transverse-spin asymmetry for dijet production in hadronic collisions in both the collinear QCD factorization approach and the Brodsky-Hwang-Schmidt model. We show that a nonvanishing asymmetry is generated by both initial-state and final-state interactions, and that the final-state interactions dominate. We find that in the leading kinematic region where the transverse momentum imbalance of the two jets, ${\overrightarrow{q}}_{\perp }={\overrightarrow{P}}_{1\perp }+{\overrightarrow{P}}_{2\perp }$, is much less than the momentum of either jet, the contribution from the lowest nontrivial perturbative order to both the spin-averaged and the spin-dependent dijet cross sections can be factorized into a hard part that is a function only of the averaged jet momentum ${\overrightarrow{P}}_{\perp }=({\overrightarrow{P}}_{1\perp }-{\overrightarrow{P}}_{2\perp })/2$, and perturbatively generated transverse momentum dependent (TMD) parton distributions. We show that the spin asymmetry at this nontrivial perturbative order can be described by the TMD parton distributions defined in either semi-inclusive deep inelastic scattering or the Drell-Yan process. We derive the same hard parts from both the collinear factorization approach and in the context of the Brodsky-Hwang-Schmidt model, verifying that they are not sensitive to details of the factorized long-distance physics.

We investigate the isospin-violating mixing of the light scalar mesons $a_0(980)$ and $f_0(980)$ within the unitarized chiral approach. Isospin-violating effects are considered to leading order in the quark mass differences and electromagnetism. In this approach both mesons are generated through meson-meson dynamics. Our results provide a description of the mixing phenomenon within a framework consistent with chiral symmetry and unitarity, where these resonances are not predominantly $q\overline{q}$ states. Amongst the possible experimental signals, we discuss observable consequences for the reaction $J/\Psi \to \varphi {\pi }^0\eta$ in detail. In particular, we demonstrate that the effect of $a_0$–$f_0$ mixing is by far the most important isospin-breaking effect in the resonance region and can indeed be extracted from experiment.

We point out that the precision measurements of the pseudo observables $R_b^0$, ${\mathcal{A}}_b$, and $A_{\mathrm{FB}}^{0,b}$ performed at the CERN LEP and the Stanford Linear Collider suggest that in models with minimal-flavor violation the sign of the $Z$-penguin amplitude is identical to the one present in the standard model. We determine the allowed range for the nonstandard contribution to the Inami-Lim function $C$ and show, by analyzing possible scenarios with positive and negative interference of standard model and new physics contributions, that the derived bound holds in each given case. Finally, we derive lower and upper limits for the branching ratios of $K^{+}\to {\pi }^{+}\nu \overline{\nu }$, $K_L\to {\pi }^0\nu \overline{\nu }$, $K_L\to {\mu }^{+}{\mu }^{-}$, $\overline{B}\to X_{d,s}\nu \overline{\nu }$, and $B_{d,s}\to {\mu }^{+}{\mu }^{-}$ within constrained minimal-flavor violation, making use of the wealth of available data collected at the $Z$ pole.

We calculate the shear modulus of crystalline color superconducting quark matter, showing that this phase of dense, but not asymptotically dense, three-flavor quark matter responds to shear stress like a very rigid solid. To evaluate the shear modulus, we derive the low-energy effective Lagrangian that describes the phonons that originate from the spontaneous breaking of translation invariance by the spatial modulation of the gap parameter $\Delta$. These massless bosons describe space- and time-dependent fluctuations of the crystal structure and are analogous to the phonons in ordinary crystals. The coefficients of the spatial derivative terms of the phonon effective Lagrangian are related to the elastic moduli of the crystal; the coefficients that encode the linear response of the crystal to a shearing stress define the shear modulus. We analyze the two particular crystal structures which are energetically favored over a wide range of densities, in each case evaluating the phonon effective action and the shear modulus up to order ${\Delta }^2$ in a Ginzburg-Landau expansion, finding shear moduli which are 20 to 1000 times larger than those of neutron star crusts. The crystalline color superconducting phase has long been known to be a superfluid—by picking a phase its order parameter breaks the quark-number $U(1{)}_B$ symmetry spontaneously. Our results demonstrate that this superfluid phase of matter is at the same time a rigid solid. We close with a rough estimate of the pinning force on the rotational vortices which would be formed embedded within this rigid superfluid upon rotation. Our results raise the possibility that (some) pulsar glitches could originate within a quark matter core deep within a neutron star.