119407344
Bound States in Yukawa Theory
A generalization of the Gell-Mann–Low Theorem is applied to lowest nontrivial order to bound state calculations in Yukawa theory. We present the solution of the corresponding effective Schrödinger equation for two-fermion bound states with the exchange of a massless boson. The complete low-lying bound state spectrum is obtained for fine structure constants below one and different ratios of the constituent masses. The consistency of the nonrelativistic and one-body limits is explicitly verified.
118885765
Functional approaches to infrared Yang-Mills theory in the Coulomb gauge
We present the current status of ongoing efforts to use functional methods, Dyson-Schwinger equations and functional renormalization group equations, for the description of the infrared regime of nonabelian (pure) gauge theories. In particular, we present a new determination of the color-Coulomb potential with the help of the functional renormalization group that results in an almost linearly rising potential between static color charges at large spatial distances.
121014950
U(1) gauge theory on a spatial lattice: duality, photons, and shadow states
A bstractWe present a Hamiltonian approach to compact and noncompact (pure) U(1) gauge theory on a regular cubic spatial lattice in (2 + 1) and (3 + 1) dimensions. The diagonalization of the kinetic part of the Hamiltonian via Fourier transformation of the wave functionals induces an electromagnetic duality transformation. The dual variables are naturally associated with the dual lattice. The notation we borrow from algebraic topology suggests a straightforward generalization to irregular spatial lattices. We determine the states of the theory in the different representations in the strong- and weak-coupling limits, and compare the vacuum and the coherent states in the weak-coupling limit with the (shadow) states obtained some years ago by Varadarajan and Ashtekar and Lewandowski in an ultraviolet-regularized version of loop-quantized continuum U(1) gauge theory. Possible implications for the formulation of a nonperturbative renormalization group in loop-quantized theories and the description of confinement in non-abelian gauge theories are discussed.
209829221
GENERALIZED GELL-MANN–LOW THEOREM APPLIED TO A SCALAR MODEL
119193511
Hamiltonian Dyson‐Schwinger and FRG Flow Equations of Yang‐Mills Theory in Coulomb Gauge
A new functional renormalization group equation for Hamiltonian Yang‐Mills theory in Coulomb gauge is presented and solved for the static gluon and ghost propagators under the assumption of ghost dominance. The results are compared to those obtained in the variational approach.
122569817
Fermion damping and reaction rates in hot gauge theories
We examine the relation between the damping rate of a fermionic mode propagating in a hot QED or QCD plasma, and the corresponding reaction rate. We show that these two quantities should be equal provided the reaction rate is calculated using properly normalized wave functions for the mode in the medium. We use finite temperature cutting rules to identify the different terms in the expression for the damping rate with physical processes in the plasma.
25404962
Low background anti-neutrino monitoring with an innovative composite solid scintillator detector
The detection of anti-neutrinos from nuclear reactors at close stand-off is a challenging measurement. The requirements for a remote monitoring device that could be used for close stand-off reactor core monitoring is difficult to meet with standard liquid scintillator technologies. Due to the low rate of anti-neutrinos detectable within 10 m from research reactors the detection efficiency has to be as high as possible with a relatively compact and safe design. The more practical aspects of the system are usually difficult to meet because these systems have to be deployed at low overburden where reactor gamma-ray and neutron backgrounds are a few orders of magnitude higher than the anti-neutrino rate. Large and costly passive shielding is usually needed to reduce these backgrounds closer to the anti-neutrino rate (typically 10-4 Hz/tonne). A novel approach to measuring reactor anti-neutrinos was developed based on composite Polyvynil-Toluene and 6LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and MPPCs which enables accurate localization of the outgoing positron and neutron. This more precise imaging of the interaction help with discriminating backgrounds and thus limits the required passive shielding around the detector. We report the expected performance from a Geant4 Monte-Carlo simulation of the system and the test of a 8 kg active mass prototype deployed at the BR2 reactor in Mol, Belgium. Measurements of the reactor on and off backgrounds rates and energy spectrum of signal candidates are presented using data collected at BR2 during summer 2013.
123519082
MINOS the main injector neutrino oscillation search
Abstract MINOS is a neutrino experiment which uses a beam of neutrinos from the Fermilab main injector to determine the parameters of possible neutrino oscillations. It consists of two detectors: a near detector to measure the beam composition at the production site and a far detector 730 km away to re-measure the composition and detect any oscillation which may have occurred. MINOS is a tracking calorimeter build from solid plastic scintillators to measure all the neutrino interactions.
112402914
First results of the Trip-t based T2K front end electronics performance with GM-APD
The TRIP-t front end board (TFB) will read out Geiger-mode multi-pixel Avalanche Photo-Diodes (GM-APD) in several T2K detector systems. We report the first tests of the TFB electronics with GM-APD. Measurements of GM-APD charge spectra, energy and time resolution have been performed. Individual channel voltage trimming circuit functionality has also been tested. These results indicate very good performance of the TFB prototype with both 400 and 100 pixels GMAPD from Hamamatsu photonics.
122204341
New results from the MINOS experiment
MINOS is a long baseline neutrino oscillation experiment. Protons from the Fermilab main injector are used to generate an intense muon neutrino beam, which is directed at the Soudan underground laboratory in Northern Minnesota. The result from two years of running with a total exposure of 2.5 × 1020 protons on target from the NuMI beam is reported. We made a preliminary measurement by comparing the event rate and energy spectra of charge current muon neutrino interactions in the two detectors, which are 1 and 735 km from the neutrino production target. The data is consistent with vμ to v oscillation in the so-called atmospheric parameter range with δm2 = (2.38+0.20-0.16) × 10-3 eV2 and sin22Θ = 1-0.08.
119108691
Combining neutrino oscillation experiments with the Feldman–Cousins method
In this paper we describe how two or more experimental results can be combined within the procedure of Feldman and Cousins, to provide combined confidence limits on the physical parameters of interest. We demonstrate the technique by combining the recent electron neutrino appearance results from T2K and MINOS. Our best fit point is sin2 2θ13 = 0.08 (0.11) and δ = 1.1 (2.0)π; in addition we exclude sin2 2θ13 = 0 at 2.7σ (2.8σ) for the normal (inverted) neutrino mass hierarchy.