Search results for "Variant"
showing 10 items of 1267 documents
Anomalies from nonfree action of the gauge group
1990
Abstract The question whether new anomalies appear, connected with the finite dimensional part of the gauge group isomorphic to the structure group of the theory, is investigated in a systematical way. The stability groups from the stratification of the gauge group on the space of connections lead to anomalies. The detection of these anomalies within the equivariant approach pursued here is extremely simple. For a large class of theories it is shown that no new anomalies appear.
An invariant analytic orthonormalization procedure with applications
2007
We apply the orthonormalization procedure previously introduced by two of us and adopted in connection with coherent states to Gabor frames and other examples. For instance, for Gabor frames we show how to construct $g(x)\in L^2(\Bbb{R})$ in such a way the functions $g_{\underline n}(x)=e^{ian_1x}g(x+an_2)$, $\underline n\in\Bbb{Z}^2$ and $a$ some positive real number, are mutually orthogonal. We discuss in some details the role of the lattice naturally associated to the procedure in this analysis.
Microscopic and translationally-invariant calculations with tensor forces and tensor correlations
1999
In this paper we discuss an approach to the ab initio study of ground states of light nuclei using realistic forces. The method constructs trial variational wavefunctions by superimposing state-dependent translationally-invariant pair correlations on a state-independent Jastrow-correlated wavefunction, with very promising results.
Translationally invariant coupled cluster method in coordinate space for nuclei
2002
We study a formulation of the translationally invariant coupled cluster method in coordinate space for finite nuclei. The new formulation remedies convergence problems that plagued previous calculations in configuration space. The method is applied to light nuclei using semi-realistic central interactions.
The calorimeter project for the Mu2e experiment
2013
The Mu2e experiment at Fermilab aims to measure the charged lepton flavor violating neutrinoless conversion of a negative muon into an electron. The conversion results in a monochromatic electron with an energy slightly below the rest mass of the muon (104.97 MeV). We expect to set a limit of ∼ 6×10^(−17) at 90% CL in three years of running, using an intense and clean pulsed μ^− beam providing ∼10^(18) stopped muons on target in three years of running. The experiment performs a strong suppression of potential background by gating off the prompts and performing precise momentum determination in conjunction with an highly efficient cosmic veto. The calorimeter should confirm that the candidat…
Jastrow-Correlated Configuration-Interaction Description of Light Nuclei
1999
This work describes recent progress of the UMIST-VALENCIA collaboration on the ab initio study of ground states of light nuclei using realistic forces. The method presented here constructs trial variational wave functions by superimposing a central Jastrow correlation on a state-dependent translationally invariant linearly correlated state, with very promising results.
Analysis of the B+→J/ψϕK+ data at low J/ψϕ invariant masses and the X(4140) and X(4160) resonances
2018
We have studied the $J/\ensuremath{\psi}\ensuremath{\phi}$ mass distribution of the ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\phi}{K}^{+}$ reaction from threshold to about 4250 MeV, and find that one needs the contribution of the $X(4140)$ with a narrow width, together with the $X(4160)$ which accounts for most of the strength of the distribution in that region. The existence of a clear cusp at the ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ threshold indicates that the $X(4160)$ resonance is strongly tied to the ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ channel, which finds a natural interpretation in the molecular picture of this resonance.
The Khuri-Jones Threshold Factor as an Automorphic Function
2013
The Khuri-Jones correction to the partial wave scattering amplitude at threshold is an automorphic function for a dihedron. An expression for the partial wave amplitude is obtained at the pole which the upper half-plane maps on to the interior of semi-infinite strip. The Lehmann ellipse exists below threshold for bound states. As the system goes from below to above threshold, the discrete dihedral (elliptic) group of Type 1 transforms into a Type 3 group, whose loxodromic elements leave the fixed points 0 and $\infty$ invariant. The transformation of the indifferent fixed points from -1 and +1 to the source-sink fixed points 0 and $\infty$ is the result of a finite resonance width in the im…
Motor strategies and adiabatic invariants: The case of rhythmic motion in parabolic flights
2021
The role of gravity in human motor control is at the same time obvious and difficult to isolate. It can be assessed by performing experiments in variable gravity. We propose that adiabatic invariant theory may be used to reveal nearly-conserved quantities in human voluntary rhythmic motion, an individual being seen as a complex time-dependent dynamical system with bounded motion in phase-space. We study an explicit realization of our proposal: An experiment in which we asked participants to perform $\infty-$ shaped motion of their right arm during a parabolic flight, either at self-selected pace or at a metronome's given pace. Gravity varied between $0$ and $1.8$ $g$ during a parabola. We c…
A covariant constituent-quark formalism for mesons
2014
Using the framework of the Covariant Spectator Theory (CST) [1] we are developing a covariant model formulated in Minkowski space to study mesonic structure and spectra. Treating mesons as effective $q\bar{q}$ states, we focused in [2] on the nonrelativistic bound-state problem in momentum space with a linear confining potential. Although integrable, this kernel has singularities which are difficult to handle numerically. In [2] we reformulate it into a form in which all singularities are explicitely removed. The resulting equations are then easier to solve and yield accurate and stable solutions. In the present work, the same method is applied to the relativistic case, improving upon the r…