1,972 research outputs found
Gribov horizon and non-perturbative BRST symmetry in the maximal Abelian gauge
The non-perturbative nilpotent exact BRST symmetry of the Gribov-Zwanziger
action in the Landau gauge constructed in [ arXiv:1506.06995 [hep-th]] is
generalized to the case of Euclidean Yang-Mills theories quantized in the
maximal Abelian gauge. The resulting diagonal gluon propagator is evaluating in
dimensions D=4,3,2. In D=4,3 a decoupling type behavior is found in the
infrared region, while in D=2 a scaling type behavior emerges.Comment: Reviewed version with a new section and new references adde
Extracting convergent surface energies from slab calculations
The formation energy of a solid surface can be extracted from slab
calculations if the bulk energy per atom is known. It has been pointed out
previously that the resulting surface energy will diverge with slab thickness
if the bulk energy is in error, in the context of calculations which used
different methods to study the bulk and slab systems. We show here that this
result is equally relevant for state-of-the-art computational methods which
carefully treat bulk and slab systems in the same way. Here we compare
different approaches, and present a solution to the problem that eliminates the
divergence and leads to rapidly convergent and accurate surface energies.Comment: 3 revtex pages, 1 figure, in print on J. Phys. Cond. Mat
A non-perturbative study of matter field propagators in Euclidean Yang-Mills theory in linear covariant, Curci-Ferrari and maximal Abelian gauges
In this work, we study the propagators of matter fields within the framework
of the Refined Gribov-Zwanziger theory, which takes into account the effects of
the Gribov copies in the gauge-fixing quantization procedure of Yang-Mills
theory. In full analogy with the pure gluon sector of the Refined
Gribov-Zwanziger action, a non-local long-range term in the inverse of the
Faddeev-Popov operator is added in the matter sector. Making use of the recent
BRST invariant formulation of the Gribov-Zwanziger framework achieved in [Capri
et al 2016], the propagators of scalar and quark fields in the adjoint and
fundamental representations of the gauge group are worked out explicitly in the
linear covariant, Curci-Ferrari and maximal Abelian gauges. Whenever lattice
data are available, our results exhibit good qualitative agreement.Comment: 27 pages, no figures; V2, minor modifications, to appear in EPJ
Mantle geoneutrinos in KamLAND and Borexino
The KamLAND and Borexino experiments have observed, each at ~4 sigma level,
signals of electron antineutrinos produced in the decay chains of thorium and
uranium in the Earth's crust and mantle (Th and U geoneutrinos). Various pieces
of geochemical and geophysical information allow an estimation of the crustal
geoneutrino flux components with relatively small uncertainties. The mantle
component may then be inferred by subtracting the estimated crustal flux from
the measured total flux. To this purpose, we analyze in detail the experimental
Th and U geoneutrino event rates in KamLAND and Borexino, including neutrino
oscillation effects. We estimate the crustal flux at the two detector sites,
using state-of-the-art information about the Th and U distribution on global
and local scales. We find that crust-subtracted signals show hints of a
residual mantle component, emerging at ~2.4 sigma level by combining the
KamLAND and Borexino data. The inferred mantle flux slightly favors scenarios
with relatively high Th and U abundances, within +-1 sigma uncertainties
comparable to the spread of predictions from recent mantle models.Comment: Slight changes and improvements in the text & figures. Results
unchanged. To appear in Phys. Rev.
Desenvolvimento de cultivos iniciadores para o processamento de embutidos cárneos artesanais.
Projeto/Plano de Ação: 03.03.02.33.00
Geoneutrinos and reactor antineutrinos at SNO+
In the heart of the Creighton Mine near Sudbury (Canada), the SNO+ detector
is foreseen to observe almost in equal proportion electron antineutrinos
produced by U and Th in the Earth and by nuclear reactors. SNO+ will be the
first long baseline experiment to measure a reactor signal dominated by CANDU
cores (55\% of the total reactor signal), which generally burn natural
uranium. Approximately 18\% of the total geoneutrino signal is generated by the
U and Th present in the rocks of the Huronian Supergroup-Sudbury Basin: the
60\% uncertainty on the signal produced by this lithologic unit plays a crucial
role on the discrimination power on the mantle signal as well as on the
geoneutrino spectral shape reconstruction, which can in principle provide a
direct measurement of the Th/U ratio in the Earth.Comment: 7 pages including 2 figures and 1 table, in XIV International
Conference on Topics in Astroparticle and Underground Physics (TAUP 2015) IOP
Publishing , published on Journal of Physics: Conference Series 718 (2016)
06200
- …