2,546 research outputs found
Two component theory and electron magnetic moment
The two-component formulation of quantum electrodynamics is studied. The
relation with the usual Dirac formulation is exhibited, and the Feynman rules
for the two-component form of the theory are presented in terms of familiar
objects. The transformation from the Dirac theory to the two-component theory
is quite amusing, involving Faddeev-Popov ghost loops of a fermion type with
bose statistics. The introduction of an anomalous magnetic moment in the
two-component formalism is simple; it is not equivalent to a Pauli term in the
Dirac formulation. Such an anomalous magnetic moment appears not to destroy the
renormalizability of the theory but violates unitarity.Comment: 17 pages, tex, gz-compressed tar fil
Perturbation Theory and Relative Space
The validity of non-perturbative methods is questioned. The concept of
relative space is introduced.Comment: 12 pages, report UM-TH-94-1
Muon anomalous magnetic moment due to the brane-stretching effect
We investigate the contribution of extra dimensions to the muon anomalous
magnetic moment by using an ADD-type 6-dimensional model. This approach
analyzes the extent of the influence of classical brane fluctuations on the
magnetic moment. When we consider that the brane fluctuations are static in
time, they add new potential terms to the Schr{\"o}dinger equation through the
induced vierbein. This paper shows that the brane fluctuation is responsible
for the brane-stretching effect. This effect would be capable of reproducing
the appropriate order for recent Brookhaven National Laboratory measurements of
the muon (g-2) deviation.Comment: 17 pages, 1 figure, minor changed, accepted for Phys. Rev.
Modelling postharvest quality behaviour as affected by preharvest conditions
Some hundred years ago, wise men decided that preharvest research and applications had to be regarded separated from the postharvest handling and behaviour. Over the years, both areas developed completely separated. Control over both areas was obtained by different companies and advisory boards, with mostly not too good means of communication between them. This decision hampered seriously the consistent and integral development of knowledge on food production and usage. Bridging the gap between all the knowledge and expertise available in the preharvest area of growing food and the postharvest area of storing and processing food, has become and is still becoming more and more important over the last couple of years. In this paper, based on theoretical considerations, on plausible (but unproven) mechanisms and applying the fundamental rules of chemical kinetics, a pathway to deduce general and generic models is developed towards a possible approach to integrate all available knowledge. Still the validity of this approach is not proven. However, a number of examples from both the applied as well as the fundamental point of view are elaborated to indicate such an interaction exists, and to indicate how to tackle the modelling problem. The examples range from physiological disorders like core brown, internal brown, chilling injury and the biological age of individual tomatoes in truss tomatoes as related to the maturity at harves
Supersymmetry in the Standard Model
We prove that the bosons and massless fermions of one generation of the
standard model are supersymmetric partners of each other. Except for one
additional auxilliary vector boson, there are no other SUSY particles.Comment: RevTex, 6 pages, uuencoded tar compressed fil
New Renormalization Group Equations and the Naturalness Problem
Looking for an observable manifestation of the so-called unnaturalness of
scalar fields we introduce a seemingly new set of differential equations for
connected Green functions. These equations describe the momentum dependence of
the Green functions and are close relatives to the previously known
renormalization group equations. Applying the new equations to the theory of
scalar field with interaction we identify a relation between the
four-point Green function and the propagator which expresses the unnaturalness
of the scalar field. Possible manifestations of the unnaturalness at low
momenta are briefly discussed.Comment: 12 revtex pages; a coefficient has been corrected in eq. (34), four
new references added; final version to appear in Phys. Rev.
Effective Field Theory of Gravity: Leading Quantum Gravitational Corrections to Newtons and Coulombs Law
In this paper we consider general relativity and its combination with scalar
quantum electrodynamics (QED) as an effective quantum field theory at energies
well below the Planck scale. This enables us to compute the one-loop quantum
corrections to the Newton and Coulomb potential induced by the combination of
graviton and photon fluctuations. We derive the relevant Feynman rules and
compute the nonanalytical contributions to the one-loop scattering matrix for
charged scalars in the nonrelativistic limit. In particular, we derive the
post-Newtonian corrections of order from general relativity
and the genuine quantum corrections of order .Comment: 14 pages, 12 figure
Extended Technicolor Models with Two ETC Groups
We construct extended technicolor (ETC) models that can produce the large
splitting between the masses of the and quarks without necessarily
excessive contributions to the parameter or to neutral flavor-changing
processes. These models make use of two different ETC gauge groups, such that
left- and right-handed components of charge quarks transform under the
same ETC group, while left- and right-handed components of charge -1/3 quarks
and charged leptons transform under different ETC groups. The models thereby
suppress the masses and relative to , and and
relative to because the masses of the quarks and charged leptons
require mixing between the two ETC groups, while the masses of the
quarks do not. A related source of the differences between these mass
splittings is the effect of the two hierarchies of breaking scales of the two
ETC groups. We analyze a particular model of this type in some detail. Although
we find that this model tends to suppress the masses of the first two
generations of down-type quarks and charged leptons too much, it gives useful
insights into the properties of theories with more than one ETC group.Comment: 14 pages, 4 figure
Implications of Dynamical Generation of Standard-Model Fermion Masses
We point out that if quark and lepton masses arise dynamically, then in a
wide class of theories the corresponding running masses exhibit
the power-law decay for Euclidean momenta
, where is a fermion of generation , and
is the maximal scale relevant for the origin of . We estimate
resultant changes in precision electroweak quantities and compare with current
data. It is found that this data allows the presence of such corrections. We
also note that this power-law decay renders primitively divergent fermion mass
corrections finite.Comment: 4 pages, late
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