27,096 research outputs found
Non-Relativistic Approximation of Dirac Equation for Slow Fermions Coupled to the Chameleon and Torsion Fields in the Gravitational Field of the Earth
We analyse a non-relativistic approximation of the Dirac equation for slow
fermions, coupled to the chameleon field and torsion in the spacetime with the
Schwarzschild metric, taken in the weak gravitational field of the Earth
approximation. We follow the analysis of the Dirac equation in the curved
spacetime with torsion, proposed by Kostelecky (Phys. Rev. D69, 105009 (2004)),
and apply the Foldy--Wouthuysen transformations. We derive the effective
low-energy gravitational potentials for slow fermions, coupled to the
gravitational field of the Earth, the chameleon field and to torsion with
minimal and non-minimal couplings.Comment: 12 page
Non-Relativistic Approximation of the Dirac Equation for Slow Fermions in Static Metric Spacetimes
We analyse the non-relativistic approximation of the Dirac equation for slow
fermions moving in spacetimes with a static metric, caused by the weak
gravitational field of the Earth and a chameleon field, and derive the most
general effective gravitational potential, induced by a static metric of
spacetime. The derivation of the non-relativistic Hamilton operator of the
Dirac equation is carried out by using a standard Foldy-Wouthuysen (SFW)
transformation. We discuss the chameleon field as source of a torsion field and
torsion-matter interactions.Comment: 8 page
Standard Electroweak Interactions in Gravitational Theory with Chameleon Field and Torsion
We propose a version of a gravitational theory with the torsion field,
induced by the chameleon field. Following Hojman et al. Phys. Rev. D17, 3141
(1976) the results, obtained in Phys. Rev. D90, 045040 (2014), are generalised
by extending the Einstein gravity to the Einstein-Cartan gravity with the
torsion field as a gradient of the chameleon field through a modification of
local gauge invariance of minimal coupling in the Weinberg-Salam electroweak
model. The contributions of the chameleon (torsion) field to the observables of
electromagnetic and weak processes are calculated. Since in our approach the
chameleon-photon coupling constant beta_(gamma) is equal to the
chameleon-matter coupling constant beta, i.e. beta_(gamma) = beta, the
experimental constraints on beta, obtained in terrestrial laboratories by T.
Jenke et al. (Phys. Rev. Lett. 112, 115105 (2014)) and by H. Lemmel et al.
(Phys. Lett. B743, 310 (2015)), can be used for the analysis of astrophysical
sources of chameleons, proposed by C. Burrage et al. (Phys. Rev. D79, 044028
(2009)), A.-Ch. Davis et al. (Phys. Rev. D80, 064016 (2009), and in references
therein, where chameleons induce photons because of direct chameleon-photon
transitions in the magnetic fields.Comment: 26 pages, 8 figure
On kaonic deuterium. Quantum field theoretic and relativistic covariant approach
We study kaonic deuterium, the bound K^-d state A_(K d). Within a quantum
field theoretic and relativistic covariant approach we derive the energy level
displacement of the ground state of kaonic deuterium in terms of the amplitude
of K^-d scattering for arbitrary relative momenta. Near threshold our formula
reduces to the well-known DGBT formula. The S-wave amplitude of K^-d scattering
near threshold is defined by the resonances Lambda(1405), Sigma(1750) and a
smooth elastic background, and the inelastic channels K^- d -> NY and K^- d ->
NY pion, with Y = Sigma^(+/-), Sigma^0 and Lambda^0, where the final-state
interactions play an important role. The Ericson-Weise formula for the S-wave
scattering length of K^-d scattering is derived. The total width of the energy
level of the ground state of kaonic deuterium is estimated using the
theoretical predictions of the partial widths of the two-body decays A_(Kd) ->
NY and experimental data on the rates of the NY-pair production in the
reactions K^-d -> NY. We obtain Gamma_{1s} = (630 +/-100) eV. For the shift of
the energy level of the ground state of kaonic deuterium we predict
epsilon_(1s) = (353 +/-60)eV.Comment: 73 pages,10 figures, Latex, We have slightly corrected the
contribution of the double scattering. The change of the S-wave scattering
length of K^-d scattering does not go beyond the theoretical uncertainty,
which is about 18
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