12,409 research outputs found
A Field-Theoretic Approach to Connes' Gauge Theory on
Connes' gauge theory on is reformulated in the Lagrangian
level. It is pointed out that the field strength in Connes' gauge theory is not
unique. We explicitly construct a field strength different from Connes' one and
prove that our definition leads to the generation-number independent Higgs
potential. It is also shown that the nonuniqueness is related to the assumption
that two different extensions of the differential geometry are possible when
the extra one-form basis is introduced to define the differential
geometry on . Our reformulation is applied to the standard model
based on Connes' color-flavor algebra. A connection between the unimodularity
condition and the electric charge quantization is then discussed in the
presence or absence of .Comment: LaTeX file, 16 page
Mass Shift and Width Broadening of J/psi in hot gluonic plasma from QCD Sum Rules
We investigate possible mass shift and width broadening of J/psi in hot
gluonic matter using QCD sum rule. Input values of gluon condensates at finite
temperature are extracted from lattice QCD data for the energy density and
pressure. Although stability of the moment ratio is achieved only up to T/Tc ~
1.05, the gluon condensates cause a decrease of the moment ratio, which results
in change of spectral properties. Using the Breit-Wigner form for the
phenomenological side, we find that mass shift of J/psi just above Tc can reach
maximally 200 MeV and width can broaden to dozens of MeV.Comment: 4 pages, 5 figures, version to appear in Physical Review Letter
Reconstruction of the spontaneously broken gauge theory in non-commutative geometry
The scheme previously proposed by the present authors is modified to
incorporate the strong interaction by affording the direct product internal
symmetry. We do not need to prepare the extra discrete space for the color
gauge group responsible for the strong interaction to reconstruct the standard
model and the left-right symmetric gauge model(LRSM). The approach based on
non-commutative geometry leads us to presents many attractive points such as
the unified picture of the gauge and Higgs field as the generalized connection
on the discrete space; Minkowski space multipied by N-points discrete space.
This approach leads us to unified picture of gauge and Higgs fields as the
generalized connection. The standard model needs N=2 discrete space for
reconstruction in this formalism. \lr is still alive as a model with the
intermediate symmetry of the spontaneously broken SO(10) grand unified
theory(GUT). N=3 discrete space is needed for the reconstruction of LRSM to
include two Higgs bosons and which are as usual transformed as
(2,2*,0)$ and (1,3,-2) under left-handed SU(2)x right-handed SU(2)x U(1),
respectively. xi is responsible to make the right handed-neutrino Majorana
fermion and so well explains the seesaw mechanism. Up and down quarks have the
different masses through the vacuum expectation value of phi.Comment: 21 page
Concept to standardize space vehicle piggyback experiment modules
Study investigates the use of spent launch vehicle stages and modules to support earth orbital operations and functions after successful completion of the primary mission. Emphasis is placed primarily on determination of those uses that afford the greatest utility with minimum possibility of degradation to the primary mission
Critical behavior of charmonia across the phase transition: A QCD sum rule approach
We investigate medium-induced change of mass and width of J/psi and eta_c
across the phase transition in hot gluonic matter using QCD sum rules. In the
QCD sum rule approach, the medium effect on heavy quarkonia is induced by the
change of both scalar and twist-2 gluon condensates, whose temperature
dependences are extracted from the lattice calculations of energy density and
pressure. Although the stability of the operator product expansion side seems
to break down at T > 1.06Tc for the vector channel and T>1.04Tc for the
pseudoscalar channel, we find a sudden change of the spectral property across
the critical temperature Tc, which originates from an equally rapid change of
the scalar gluon condensate characterized by e-3p. By parameterizing the ground
state of the spectral density by the Breit-Wigner form, we find that for both
J/psi and eta_c, the masses suddenly decrease maximally by a few hundreds of
MeV and the widths broaden to ~100 MeV slightly above Tc. Implications for
recent and future heavy ion experiments are discussed.
We also carry out a similar analysis for charmonia in nuclear matter, which
could serve as a testing ground for observing the precursor phenomena of the
QCD phase transition. We finally discuss the possibility of observing the mass
shift at nuclear matter at the FAIR project at GSI.Comment: 18 pages, 21 figures, 2 figures are added and discussion on effect of
dynamical quarks is extended. version to appear in Phys.Rev.
Pion Interferometry From A Relativistic Fluid With A First Order Phase Transition In CERN-SPS 158 GeV/A Pb+Pb Collisions
We investigate pion source sizes through the Yano-Koonin-Podgoretski\u{\i}
(YKP) parametrization for the Hanbury-Brown Twiss (HBT) effect in the CERN-SPS
158 GeV/A central collisions. We calculate two-particle correlation functions
numerically based on a (3+1)-dimensional relativistic hydrodynamics with a
first order phase transition and analyze the pair momentum dependence of the
HBT radii extracted from the YKP parametrization in detail. We find that even
in the case of a first order phase transition, expansion and the surface
dominant freeze-out make the source in the hydrodynamical model opaque
significantly. Consequently, the interpretation of the temporal radius
parameter as the time duration becomes unavailable for the hydrodynamical
model.Comment: 5 pages, LaTeX with six eps figures, Contribution to 'International
Workshop XXVIII on Gross Properties of Nuclei And Nuclear Excitations'.
Hirchegg, Austria, Jan 16-22, 200
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