3,842 research outputs found
Higgs Mass in the Standard Model from Coupling Constant Reduction
Plausible interrelations between parameters of the standard model are
studied. The empirical value of the top quark mass, when used in the
renormalization group equations, suggests that the ratio of the colour SU(3)
gauge coupling , and the top coupling is independent of the
renormalization scale. On the other hand, variety of top-condensate models
suggest that the Higgs self-coupling is proportional to .
Invoking the requirement that the ratio is independent of
the renormalization scale , fixes the Higgs mass. The pole mass of the Higgs
[which differs from the renormalization group mass by a few percent] is found
to be GeV for the one-loop equations and GeV for the
two-loop equations.Comment: 17 pages RevTeX including 7 figure
General relativistic gravitational field of a rigidly rotating disk of dust: Solution in terms of ultraelliptic functions
In a recent paper we presented analytic expressions for the axis potential,
the disk metric, and the surface mass density of the global solution to
Einstein's field equations describing a rigidly rotating disk of dust. Here we
add the complete solution in terms of ultraelliptic functions and quadratures.Comment: 5 pages, published in 1995 [Phys. Rev. Lett. 75 (1995) 3046
1/N_c Corrections to the Hadronic Matrix Elements of Q_6 and Q_8 in K --> pi pi Decays
We calculate long-distance contributions to the amplitudes A(K^0 --> pi pi,
I) induced by the gluon and the electroweak penguin operators Q_6 and Q_8,
respectively. We use the 1/N_c expansion within the effective chiral lagrangian
for pseudoscalar mesons. In addition, we adopt a modified prescription for the
identification of meson momenta in the chiral loop corrections in order to
achieve a consistent matching to the short-distance part. Our approach leads to
an explicit classification of the loop diagrams into non-factorizable and
factorizable, the scale dependence of the latter being absorbed in the
low-energy coefficients of the effective theory. Along these lines we calculate
the one-loop corrections to the O(p^0) term in the chiral expansion of both
operators. In the numerical results, we obtain moderate corrections to
B_6^(1/2) and a substantial reduction of B_8^(3/2).Comment: 32 pages, LaTeX, 8 eps figures. One reference added, to appear in
Phys. Rev.
A relativistic calculation of super-Hubble suppression of inflation with thermal dissipation
We investigated the evolution of the primordial density perturbations
produced by inflation with thermal dissipation. A full relativistic analysis on
the evolution of initial perturbations from the warm inflation era to a
radiation-dominated universe has been developed. The emphasis is on tracking
the ratio between the adiabatic and the isocurvature mode of the initial
perturbations. This result is employed to calculate a testable factor: the
super-Hubble suppression of the power spectrum of the primordial perturbations.
We show that based on the warm inflation scenario, the super-Hubble suppression
factor, , for an inflation with thermal dissipation is at least 0.5. This
prediction does not depend on the details of the model parameters. If is
larger than 0.5, it implies that the friction parameter is larger than
the Hubble expansion parameter during the inflation era.Comment: 22 pages, 3 figures, use RevTex, accepted by Class. Quant. Gra
General Relativistic Description of the Observed Galaxy Power Spectrum: Do We Understand What We Measure?
We extend the general relativistic description of galaxy clustering developed
in Yoo, Fitzpatrick, and Zaldarriaga (2009). For the first time we provide a
fully general relativistic description of the observed matter power spectrum
and the observed galaxy power spectrum with the linear bias ansatz. It is
significantly different from the standard Newtonian description on large scales
and especially its measurements on large scales can be misinterpreted as the
detection of the primordial non-Gaussianity even in the absence thereof. The
key difference in the observed galaxy power spectrum arises from the real-space
matter fluctuation defined as the matter fluctuation at the hypersurface of the
observed redshift. As opposed to the standard description, the shape of the
observed galaxy power spectrum evolves in redshift, providing additional
cosmological information. While the systematic errors in the standard Newtonian
description are negligible in the current galaxy surveys at low redshift,
correct general relativistic description is essential for understanding the
galaxy power spectrum measurements on large scales in future surveys with
redshift depth z>3. We discuss ways to improve the detection significance in
the current galaxy surveys and comment on applications of our general
relativistic formalism in future surveys.Comment: accepted for publication in Physical Review
Neutrino masses and mixings
We propose a novel theoretical understanding of neutrino masses and mixings,
which is attributed to the intrinsic vector-like feature of the regularized
Standard Model at short distances. We try to explain the smallness of Dirac
neutrino masses and the decoupling of the right-handed neutrino as a free
particle. Neutrino masses and mixing angles are completely related to each
other in the Schwinger-Dyson equations for their self-energy functions. The
solutions to these equations and a possible pattern of masses and mixings are
discussed.Comment: LaTex 11 page
Anomalous Chiral Behavior in Quenched Lattice QCD
A study of the chiral behavior of pseudoscalar masses and decay constants is
carried out in quenched lattice QCD with Wilson fermions. Using the modified
quenched approximation (MQA) to cure the exceptional configuration problem,
accurate results are obtained for pion masses as low as 200 MeV. The
anomalous chiral log effect associated with quenched loops is studied
in both the relation between vs. and in the light-mass
behavior of the pseudoscalar and axial vector matrix elements. The size of
these effects agrees quantitatively with a direct measurement of the
hairpin graph, as well as with a measurement of the topological susceptibility,
thus providing several independent and quantitatively consistent determinations
of the quenched chiral log parameter . For with
clover-improved fermions all results are consistent with
.Comment: 51 pages, 20 figures, Late
Running-phase state in a Josephson washboard potential
We investigate the dynamics of the phase variable of an ideal underdamped
Josephson junction in switching current experiments. These experiments have
provided the first evidence for macroscopic quantum tunneling in large
Josephson junctions and are currently used for state read-out of
superconducting qubits. We calculate the shape of the resulting macroscopic
wavepacket and find that the propagation of the wavepacket long enough after a
switching event leads to an average voltage increasing linearly with time.Comment: 6 pages, 3 figure
Thermodynamics of the superconducting state in Calcium at 200 GPa
The thermodynamic parameters of the superconducting state in Calcium under
the pressure at 200 GPa were calculated. The Coulomb pseudopotential values
() from 0.1 to 0.3 were taken into consideration. It has been
shown, that the specific heat's jump at the critical temperature and the
thermodynamic critical field near zero Kelvin strongly decrease with
. The dimensionless ratios and
significantly differ from the predictions based on the BCS model. In
particular, decreases from 2.64 to 1.97 with the Coulomb
pseudopotential; whereas increases from 0.140 to 0.157. The numerical
results have been supplemented by the analytical approach.Comment: 7 pages, 6 figure
Quenched Chiral Artifacts for Wilson-Dirac Fermions
We examine artifacts associated with the chiral symmetry breaking induced
through the use of Wilson-Dirac fermions in lattice Monte Carlo computations.
For light quark masses, the conventional quenched theory can not be defined
using direct Monte Carlo methods due to the existence of nonintegrable poles in
physical quantities. These poles are associated with the real eigenvalue
spectrum of the Wilson-Dirac operator. We show how this singularity structure
can be observed in the analysis of both QED in two dimensions and QCD in four
dimensions.Comment: 32 pages (Latex) including 13 figures (EPS
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