19006666
Convergence of the optimized delta expansion for the connected vacuum amplitude: Anharmonic oscillator.
The convergence of the linear $\delta$ expansion for the connected generating functional of the quantum anharmonic oscillator is proved. Using an order-dependent scaling for the variational parameter $\lambda$, we show that the expansion converges to the exact result with an error proportional to $\exp(-cN^{1/3})$.
18922676
On the phase structure of the 3D SU(2)-Higgs model and the electroweak phase transition
Abstract The phase structure of the 3D SU (2)-Higgs model, the dimensionally reduced effective theory for the electroweak model at finite temperature, is analysed on the lattice using a variant of the linear δ-expansion. We develop a systematic variational cumulant expansion for general application to the study of gauge-invariant operators in 3D gauge-Higgs models, with emphasis on the symmetric phase. In particular, the technique is not restricted to finite lattice volumes, and application to the fundamental 3D SU (2)-Higgs model allows the discontinuity of certain observables across the first-order transition to be observed directly for small 4I) Higgs masses. The resulting phase structure agrees well with Monte Carlo simulations for small Higgs masses, but, at least to the order calculated, the technique is less sensitive to the expected evolution of the transition to a crossover for Higgs masses above 80 GeV.
120279229
Evaluation of Feynman diagrams in the logarithmic approach to quantum field theory
The techniques necessary to compute the O(δ2) contributions to the Green’s functions of a scalar field theory with self‐interaction λ(φ2)1+δ in d‐dimensional space‐time are developed. The resulting expressions are evaluated explicitly for d=1, 0, and some negative even dimensions. For d=3 and 4 we calculate their leading behavior in terms of a spatial cutoff a.
118106812
Groups, Representations and Physics
General properties of groups and mappings group representations properties of irreducible representations physical applications continuous groups SO(N) further applications the SU(N) groups and particle physics representations of the Poincare group gauge groups.
42992493
Interpolating Lagrangians and SU(2) gauge theory on the lattice.
We apply the linear {delta} expansion to non-Abelian gauge theory on the lattice, with SU(2) as the gauge group. We establish an appropriate parametrization and evaluate the average plaquette energy {ital E}{sub {ital P}} to {ital O}({delta}). As a check on our results, we recover the large-{beta} expansion up to {ital O}(1/{beta}{sup 2}), which involves some {ital O}({delta}{sup 2}) contributions. Using these contributions we construct a variant of the 1/{beta} expansion which gives a good fit to the data down to the transition region.
118655103
Comment on New ansatz for metric operator calculation in pseudo-Hermitian field theory
In a recent Brief Report by Shalaby, a new first-order perturbative calculation of the metric operator for an $i{\ensuremath{\phi}}^{3}$ scalar field theory is given. It is claimed that the incorporation of derivative terms in the ansatz for the metric operator results in a local solution, in contrast to the nonlocal solution previously obtained by Bender, Brody, and Jones. Unfortunately, Shalaby's calculation is not valid because of sign errors.
34597488
Left-right asymmetry in neutrino-produced hadron jets.
In an experiment (E546) to study interactions of {l angle}{ital E}{r angle}=100 GeV and {l angle}{ital Q}{sup 2}{r angle}=17 GeV{sup 2} neutrinos in the Fermilab 15-foot bubble chamber, we have looked for a left-right asymmetry in the azimuthal angle {phi} of individual hadrons about the direction of the lepton momentum transfer ({ital q} vector). Significant asymmetry is found for forward positive hadrons; for {ital x}{sub {ital F}}{gt}0.10, we find {l angle}cos{phi}{r angle}={minus}0.029{plus minus}0.008, where {ital x}{sub {ital F}} is the Feynman {ital x} variable. Negative hadrons with {ital x}{sub {ital F}}{gt}0.10 show no asymmetry, {l angle}cos{phi}{r angle}=0.004{plus minus}0.011. A model which includes parton intrinsic transverse momentum {ital k}{sub {ital t}} reproduces the asymmetry of combined positive and negative hadrons with {ital x}{sub {ital F}}{gt}0.10, {l angle}cos{phi}{r angle}={minus}0.018{plus minus}0.0065, if {l angle}{ital k}{sub {ital t}}{sup 2}{r angle}=0.065{plus minus}0.024 GeV{sup 2}/c{sup 2}. But the model predicts almost equal asymmetries for positive and negative hadrons. The model also agrees poorly with the observed dependence on the kinematic variables {ital x} and {ital Q}{sup 2} if the {ital k}{sub {ital t}} distribution is assumed to be independent of kinematic variables.
29593010
Pion absorption above the Delta (1232) resonance.
Two-proton and three-proton inclusive [pi][sup +] absorption cross sections were measured for incident pion energies from 250 to 500 MeV on targets of [sup 12]C, [sup 58]Ni, [sup 90]Zr, [sup 118]Sn, and [sup 208]Pb using a large solid angle bismuth germanate detector array. Pion absorption events leading to three or more protons in the final state were observed to become more significant with increasing incident pion energy and were dominant at 500 MeV. The total absorption cross sections were inferred from analyses of the data with uncertanties of approximately 25%.
124266533
Observation of mu e Events in anti-neutrino and Neutrino Interactions in the Fermilab 15-Foot Neon-H Bubble Chamber
125143796
An Exposure of the 15 foot bubble chamber with a neon - hydrogen mixture to a wideband neutrino beam from the Tevatron
125826043
Study of Hadronic Systems Produced in electron-neutrino (anti-electron-neutrino) n e Interactions