757 research outputs found
Some Relations for Quark Confinement and Chiral Symmetry Breaking in QCD
We analytically study the relation between quark confinement and spontaneous
chiral-symmetry breaking in QCD. In terms of the Dirac eigenmodes, we derive
some formulae for the Polyakov loop, its fluctuations, and the string tension
from the Wilson loop. We also investigate the Polyakov loop in terms of the
eigenmodes of the Wilson, the clover and the domain wall fermion kernels,
respectively. For the confinement quantities, the low-lying Dirac/fermion
eigenmodes are found to give negligible contribution, while they are essential
for chiral symmetry breaking. These relations indicate no direct one-to-one
correspondence between confinement and chiral symmetry breaking in QCD, which
seems to be natural because confinement is realized independently of the quark
mass
Dirac spectrum representation of Polyakov loop fluctuations in lattice QCD
Dirac spectrum representations of the Polyakov loop fluctuations are derived
on the temporally odd-number lattice, where the temporal length is odd with the
periodic boundary condition. We investigate the Polyakov loop fluctuations
based on these analytical relations. It is semianalytically and numerically
found that the low-lying Dirac eigenmodes have little contribution to the
Polyakov loop fluctuations, which are sensitive probe for the quark
deconfinement. Our results suggest no direct one-to-one corresponding between
quark confinement and chiral symmetry breaking in QCD.Comment: 7 pages and 1 figure. Proceeding of the 33rd International Symposium
on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe International
Conference Center, Kobe, Japan. Also regarded as the Proceeding of the 4th
International Conference on new Frontiers in Physics (ICNFP 2015), 23-30
August 2015, Conference Center of the Orthodox Academy of Crete, Crete,
Greec
Relating Quark Confinement and Chiral Symmetry Breaking in QCD
We study the relation between quark confinement and chiral symmetry breaking
in QCD. Using lattice QCD formalism, we analytically express the various
"confinement indicators", such as the Polyakov loop, its fluctuations, the
Wilson loop, the inter-quark potential and the string tension, in terms of the
Dirac eigenmodes. In the Dirac spectral representation, there appears a power
of the Dirac eigenvalue such as , which behaves
as a reduction factor for small . Consequently, since this reduction
factor cannot be cancelled, the low-lying Dirac eigenmodes give negligibly
small contribution to the confinement quantities,while they are essential for
chiral symmetry breaking. These relations indicate no direct, one-to-one
correspondence between confinement and chiral symmetry breaking in QCD. In
other words, there is some independence of quark confinement from chiral
symmetry breaking, which can generally lead to different transition
temperatures/densities for deconfinement and chiral restoration. We also
investigate the Polyakov loop in terms of the eigenmodes of the Wilson, the
clover and the domain-wall fermion kernels, respectively, and find the similar
results. The independence of quark confinement from chiral symmetry breaking
seems to be natural, because confinement is realized independently of quark
masses and heavy quarks are also confined even without the chiral symmetry.Comment: 20 pages, 10 figures. arXiv admin note: text overlap with
arXiv:1611.0874
Neutrino Scattering on Glass: NuSOnG
These proceedings describe the physics goals and initial design for a new
experiment: NuSOnG -- Neutrino Scattering On Glass. The design will yield about
two orders of magnitude higher statistics than previous high energy neutrino
experiments, observed in a detector optimized for low hadronic energy and
electromagnetic events. As a result, the purely weak processes and (inverse muon decay)
can be measured with high accuracy for the first time. This allows important
precision electroweak tests and well as direct searches for new physics. The
high statistics also will yield the world's largest sample of Deep Inelastic
(DIS) events for precision parton distribution studies.Comment: Proceedings of NuFact0
MANX: A 6D Ionization-Cooling Experiment
Six-dimensional ionization cooling of muons is essential for muon colliders
and possibly beneficial for neutrino factories. An experiment to demonstrate
six-dimensional ionization cooling using practical apparatus is presented. It
exploits recent innovative ideas that may lead to six-dimensional muon-cooling
channels with emittance reduction approaching that needed for high-luminosity
muon colliders.Comment: 3 pages, 4 figures, to appear in Proceedings of the 9th International
Workshop on Neutrino Factories, Superbeams, and Betabeams (NuFact07), August
6-11, 2007, Okayama University, Japa
Nuclear effects in Neutrino Nuclear Cross-sections
Nuclear effects in the quasielastic and inelastic scattering of
neutrinos(antineutrinos) from nuclear targets have been studied. The
calculations are done in the local density approximation which take into
account the effect of nucleon motion as well as renormalisation of weak
transition strengths in the nuclear medium. The inelastic reaction leading to
production of pions is calculated in a dominance model taking into
account the renormalization of properties in the nuclear medium.Comment: 4 pages,3 figures, Ninth International Workshop on Neutrino
Factories, Superbeams and Betabeams (NuFact07), August 6-11, 2007, Okayama
University, Okayama, Japa
Chiral Symmetry and Neutrino Pion Production off the Nucleon
The neutrino pion production off the nucleon is traditionally described in
the literature by means of the weak excitation of the Delta(1232) resonance and
its subsequent decay into N pi. Here, we present results from a model that
includes also some background terms required by chiral symmetry. We show that
the contribution of these terms is sizeable and leads to significant effects in
total and partially integrated pion production cross sections at intermediate
energies of interest for neutrino oscillation experiments. Finally, we discuss
parity-violating contributions to the pion angular differential cross section
induced by the interference of these non-resonant terms with the Delta piece.Comment: To appear in the proceedings of 9th International Workshop On
Neutrino Factories, Superbeams and Betabeams (NuFact07) August 6-11, 2007,
Okayama University, Japa
Global NLO Analysis of Nuclear Parton Distribution Functions
Nuclear parton distribution functions (NPDFs) are determined by a global
analysis of experimental measurements on structure-function ratios
F_2^A/F_2^{A'} and Drell-Yan cross section ratios
\sigma_{DY}^A/\sigma_{DY}^{A'}, and their uncertainties are estimated by the
Hessian method. The NPDFs are obtained in both leading order (LO) and
next-to-leading order (NLO) of \alpha_s. As a result, valence-quark
distributions are relatively well determined, whereas antiquark distributions
at x>0.2 and gluon distributions in the whole x region have large
uncertainties. The NLO uncertainties are slightly smaller than the LO ones;
however, such a NLO improvement is not as significant as the nucleonic case.Comment: 3 pages, LaTeX, 4 eps files, to be published in the AIP proceedings
of the 9th International Workshop on Neutrino Factories, Superbeams and
Betabeams (NuFact07), Okayama, Japan, August 6 - 11, 2007. A code for
calculating our nuclear parton distribution functions and their uncertainties
can be obtained from http://research.kek.jp/people/kumanos/nuclp.htm
Vector-axialvector mixing from a chiral effective field theory at finite temperature
We study the vector-axialvector mixing in a hot medium and its evolution
toward the chiral phase transition using different symmetry restoration
scenarios based on the generalized hidden local symmetry framework. We show
that the presence of the meson reduces the vector spectral function
around meson mass and enhances it around meson mass. The coupling
strength of to and vanishes at the critical temperature due
to the degenerate - masses. This feature holds rigorously in the
chiral limit and still stays intact to good approximation for the physical pion
mass.Comment: v2:11 pages, 6 figures, reorganized and expanded the text, new plots
and references added, main result and conclusions unchange
Paramagnetic‐Resonance Absorption of Ions with Spin 5/2: Mn++ in Calcite
The theory of the paramagnetic‐resonance absorption of ions with S = S=52 in crystalline fields of trigonal symmetry is presented. The case of manganous ions in calcite (CaCO3) is taken as an example. It is shown that the splitting of the fine‐structure satellites into doublets first reported by Hurd, Sachs, and Hershberger [Phys. Rev. 93, 373 (1954)] can be accounted for by assuming that the manganous ions can occupy the two nonequivalent Ca++ sites at random. The maximum splitting was measured at X band and K band and found to be 19.3±0.5 gauss. The value computed from the theory, assuming an ionic model, is 23.8 gauss. In addition, five pairs of weak lines were found, each pair occurring midway between adjacent hyperfine groups. The origin of these lines is uncertain. The applicability of the present theory to Al2O3:Fe, a zero‐field maser material, and to the photosensitive Fe+++ center in CdS is pointed out.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71145/2/JCPSA6-33-2-601-1.pd
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