427 research outputs found
Instantaneous Interquark Potential in Generalized Landau Gauge in SU(3) Lattice QCD: A Linkage between the Landau and the Coulomb Gauges
We investigate in detail "instantaneous interquark potentials", interesting
gauge-dependent quantities defined from the spatial correlators of the temporal
link-variable , in generalized Landau gauge using SU(3) quenched lattice
QCD. The instantaneous Q potential has no linear part in the
Landau gauge, and it is expressed by the Coulomb plus linear potential in the
Coulomb gauge, where the slope is 2-3 times larger than the physical string
tension. Using the generalized Landau gauge, we find that the instantaneous
potential can be continuously described between the Landau and the Coulomb
gauges, and its linear part rapidly grows in the neighborhood of the Coulomb
gauge. We also investigate the instantaneous 3Q potential in the generalized
Landau gauge, and obtain similar results to the Q case. -length
terminated Polyakov-line correlators and their corresponding "finite-time
potentials" are also investigated in generalized Landau gauge
LEUKEMIA-ASSOCIATED TRANSPLANTATION ANTIGENS RELATED TO MURINE LEUKEMIA VIRUS : THE X.1 SYSTEM: IMMUNE RESPONSE CONTROLLED BY A LOCUS LINKED TOH-2
Two BALB radiation leukemias are strongly rejected by hybrids of BALB with certain other mouse strains, although BALB mice themselves exhibit no detectable resistance whatever. Hybrids immunized with progressively increased inocula are resistant to 200 x 106 or more leukemia cells; their serum is cytotoxic for the leukemia cells in vitro and protects BALB mice against challenge with these BALB leukemias. The antigenic system thus identified has been named X.1. In (BALB x B6) hybrids the major determinant of resistance was shown to be a B6 gene in the K region of H-2. This is likely to be the Rgv-1 (Resistance to gross virus) locus of Lilly, which may thus be identified in this case as an Ir (Immune response) allele conferring ability to respond to X.1 antigen on MuLV and leukemia cells, and so responsible for production of X.1 antibody and the rejection of X.1+ leukemia cells by hybrid mice. Immunoelectron microscopy with X.1 antiserum (from immunized hybrids) shows labeling both on the cell surface and on virions produced by the leukemia cells. It is not known whether X.1 comprises only one or more than one antigen. Three radiation-induced BALB leukemias, one A strain radiation-induced leukemia, and 15/15 AKR primary spontaneous leukemias were typed X.1+ by the cytotoxicity test. Several other leukemias, including one induced by passage A Gross virus and one long-transplanted AKR ascites leukemia carried in (B6 x AKR)F1 hybrids, were X.1-. Normal mice of strains with a high incidence of leukemia and one other strain (129) express X.1 antigen, but evidently in amounts too small for certain detection in vitro; by the method of absorption in vivo, however, these strains could be typed X.1+ and other strains X.1-. We ascribe the X.1 antigen system tentatively to a sub-type of MuLV that is not passage A Gross virus and is probably not the dominant sub-type in strains with a high incidence of leukemia. After repeated passage in hybrids, one of the BALB leukemias became relatively resistant to rejection by the hybrid, partially lost its sensitivity to X.1 antiserum in vitro, and in electron micrographs was seen to produce fewer virions. The serum of untreated (BALB x B6) hybrids often contains cytotoxic antibody against leukemia cells, some of it probably anti-X.1. But another commonly occurring antibody, which is cytotoxic for C57BL leukemia EL4, appears to belong to another (undefined) system
Gluon-propagator functional form in the Landau gauge in SU(3) lattice QCD: Yukawa-type gluon propagator and anomalous gluon spectral function
We study the gluon propagator in the Landau gauge in
SU(3) lattice QCD at = 5.7, 5.8, and 6.0 at the quenched level. The
effective gluon mass is estimated as MeV for fm. Through the functional-form analysis of
obtained in lattice QCD, we find that the Landau-gauge
gluon propagator is well described by the Yukawa-type
function with MeV for fm in the
four-dimensional Euclidean space-time. In the momentum space, the gluon
propagator with GeV is
found to be well approximated with a new-type propagator of ,
which corresponds to the four-dimensional Yukawa-type propagator. Associated
with the Yukawa-type gluon propagator, we derive analytical expressions for the
zero-spatial-momentum propagator , the effective mass ,
and the spectral function of the gluon field. The mass parameter
turns out to be the effective gluon mass in the infrared region of
1fm. As a remarkable fact, the obtained gluon spectral function
is almost negative-definite for , except for a positive
-functional peak at .Comment: 20 pages, 15 figure
Non-perturbative QCD effective charges
Using gluon and ghost propagators obtained from Schwinger-Dyson equations
(SDEs), we construct the non-perturbative effective charge of QCD. We employ
two different definitions, which, despite their distinct field-theoretic
origin, give rise to qualitative comparable results, by virtue of a crucial
non-perturbative identity. Most importantly, the QCD charge obtained with
either definition freezes in the deep infrared, in agreement with theoretical
and phenomenological expectations. The various theoretical ingredients
necessary for this construction are reviewed in detail, and some conceptual
subtleties are briefly discussed.Comment: Invited talk at Light Cone 2009: Relativistic Nuclear and Particle
Physics (LC2009), Sao Jose dos Campos, Brazil, 8-13 July, 200
Lattice QCD analysis for Faddeev-Popov eigenmodes in terms of gluonic momentum components in the Coulomb gauge
We analyze the relation between Faddeev-Popov eigenmodes and gluon-momentum
components in the Coulomb gauge using SU(3) lattice QCD. In the Coulomb gauge,
the color-Coulomb energy is largely enhanced by near-zero Faddeev-Popov
eigenmodes, which would lead to the confining potential. By the
ultraviolet-momentum gluon cut, the color-Coulomb energy and the Faddeev-Popov
spectrum are almost unchanged. In contrast to the ultraviolet insensitivity,
the color-Coulomb energy and the Faddeev-Popov eigenmodes drastically change by
infrared-momentum gluon cut. Without infrared gluons, the color-Coulomb energy
tends to become non-confining, and near-zero Faddeev-Popov eigenmodes vanish.
We also investigate the full FP eigenmodes, and find that infrared gluons
widely influence both high and low Faddeev-Popov eigenmodes.Comment: 8 pages, 5 figure
Lagrangian Floer superpotentials and crepant resolutions for toric orbifolds
We investigate the relationship between the Lagrangian Floer superpotentials
for a toric orbifold and its toric crepant resolutions. More specifically, we
study an open string version of the crepant resolution conjecture (CRC) which
states that the Lagrangian Floer superpotential of a Gorenstein toric orbifold
and that of its toric crepant resolution coincide after
analytic continuation of quantum parameters and a change of variables. Relating
this conjecture with the closed CRC, we find that the change of variable
formula which appears in closed CRC can be explained by relations between open
(orbifold) Gromov-Witten invariants. We also discover a geometric explanation
(in terms of virtual counting of stable orbi-discs) for the specialization of
quantum parameters to roots of unity which appears in Y. Ruan's original CRC
["The cohomology ring of crepant resolutions of orbifolds", Gromov-Witten
theory of spin curves and orbifolds, 117-126, Contemp. Math., 403, Amer. Math.
Soc., Providence, RI, 2006]. We prove the open CRC for the weighted projective
spaces using an equality between open
and closed orbifold Gromov-Witten invariants. Along the way, we also prove an
open mirror theorem for these toric orbifolds.Comment: 48 pages, 1 figure; v2: references added and updated, final version,
to appear in CM
Excited States in 52Fe and the Origin of the Yrast Trap at I=12+
Excited states in 52Fe have been determined up to spin 10\hbar in the
reaction 28Si + 28Si at 115 MeV by using \gamma-ray spectroscopy methods at the
GASP array. The excitation energy of the yrast 10+ state has been determined to
be 7.381 MeV, almost 0.5 MeV above the well known \beta+-decaying yrast 12+
state, definitely confirming the nature of its isomeric character. The mean
lifetimes of the states have been measured by using the Doppler Shift
Attenuation method. The experimental data are compared with spherical shell
model calculations in the full pf-shell.Comment: 9 pages, RevTeX, 7 figures include
Landau-Ginzburg/Calabi-Yau correspondence, global mirror symmetry and Orlov equivalence
We show that the Gromov-Witten theory of Calabi-Yau hypersurfaces matches, in
genus zero and after an analytic continuation, the quantum singularity theory
(FJRW theory) recently introduced by Fan, Jarvis and Ruan following ideas of
Witten. Moreover, on both sides, we highlight two remarkable integral local
systems arising from the common formalism of Gamma-integral structures applied
to the derived category of the hypersurface {W=0} and to the category of graded
matrix factorizations of W. In this setup, we prove that the analytic
continuation matches Orlov equivalence between the two above categories.Comment: 72pages, v2: Appendix B and references added. Typos corrected, v3:
several mistakes corrected, final versio
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