62 research outputs found
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
Electrodisintegration of Deuteron into Dark Matter and Proton Close to Threshold
We discuss an investigation of the dark matter decay modes of the neutron,
proposed by Fornal and Grinstein (Phys. Rev. Lett. 120 191801 (2018)) and
Ivanov et al. ( arXiv:1806.10107 [hep-ph]) for solution of the neutron lifetime
anomaly problem, through the analysis of the electrodisintegration of the
deuteron d into dark matter fermions chi and protons p close to threshold. We
calculate the triple-differential cross section for the reaction e^- + d ->\chi
+ p + e^- and propose to search for such a dark matter channel in coincidence
experiments on the electrodisintegration of the deuteron e^- + d -> n + p + e^-
into neutrons n and protons close to threshold with outgoing electrons, protons
and neutrons in coincidence. A missing of neutron signals should testify a
detection of dark matter fermions.Comment: 7 pages, 1 figure, the paper is revised, according to a revision of
1806.10107v2 [hep-ph
Radiative corrections of order O(alpha E_e/m_N) to Sirlin's radiative corrections of order O(alpha/pi) to neutron lifetime
We calculate the radiative corrections of order O(alpha E_e/m_N) as
next-to-leading order corrections in the large nucleon mass expansion to
Sirlin's radiative corrections of order O(alpha/pi) to the neutron lifetime.
The calculation is carried out within a quantum field theoretic model of strong
low-energy pion--nucleon interactions described by the linear sigma-model (LsM)
with chiral SU(2)xSU(2) symmetry and electroweak hadron-hadron, hadron-lepton
and lepton-lepton interactions for the electron-lepton family with SU(2)_L x
U(1)_Y symmetry of the Standard Electroweak Model (SEM). Such a quantum field
theoretic model is some kind a hadronized version of the Standard Model (SM).
From a gauge invariant set of the Feynman diagrams with one-photon exchanges we
reproduce Sirlin's radiative corrections of order O(alpha/pi), calculated to
leading order in the large nucleon mass expansion, and calculate
next-to-leading corrections of order O(alpha E_e/m_N). This confirms Sirlin's
confidence level of the radiative corrections O(alpha E_e/m_N). The
contributions of the LsM are taken in the limit of the infinite mass of the
scalar isoscalar sigma-meson. In such a limit the LsM reproduces the results of
the current algebra (Weinberg, Phys. Rev. Lett. {\bf 18}, 188 (1967)) in the
form of effective chiral Lagrangians of pion-nucleon interactions with
non--linear realization of chiral SU(2)xSU(2) symmetry. In such a limit the
LM is also equivalent to Gasser-Leutwyler's chiral quantum field theory
or chiral perturbation theory (ChPT) with chiral SU(2)xSU(2)symmetry and the
exponential parametrization of a pion-field (Ecker, Prog. Part. Nucl. Phys.
{\bf 35}, 1 (1995)).Comment: 50 pages, 7 figures. arXiv admin note: text overlap with
arXiv:1805.0970
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