118393051
On the many-field f(R) brane
Abstract We consider the Randall–Sundrum braneworld theory with a single extra dimension of infinite extent to investigate generalized f ( R ) braneworld models in the presence of several real scalar fields. In particular, we solve the modified Einstein equations for the case of flat brane, with zero cosmological constant, and for the case of bent brane, with a nonvanishing cosmological constant. In both cases we found explicit solutions for the scalar fields with analytical expressions for the respective warp factors.
118435943
Equivalence between supersymmetric self-dual and Maxwell–Chern–Simons models coupled to a matter spinor superfield
Abstract We study the duality of the supersymmetric self-dual and Maxwell–Chern–Simons theories coupled to a fermionic matter superfield, using a master action. This approach evades the difficulties inherent to the quartic couplings that appear when matter is represented by a scalar superfield. The price is that the spinorial matter superfield represents a unusual supersymmetric multiplet, whose main physical properties we also discuss.
119211852
Lorentz violation and the proper-time method
Abstract In this Letter, we apply the proper-time method to generate the Lorentz-violating Chern–Simons terms in the four-dimensional Yang–Mills and non-linearized gravity theories. It is shown that the coefficient of the induced Chern–Simons term is finite but regularization dependent.
118455730
Effective potential for a SUSY Lee–Wick model: The Wess–Zumino case
Using a superfield generalization of the tadpole method, we study the one-loop effective potential for a Wess–Zumino model modified by a higher derivative term, inspired by the Lee–Wick model. The one-loop Kahlerian potential is also obtained by other methods and compared with the effective potential.
118533824
Free energy of Lorentz-violating QED at high temperature
In this paper we study the one- and two-loop contribution to the free energy in QED with Lorentz symmetry breaking introduced via constant CPT-even Lorentz-breaking parameters at the high temperature limit. We find the impact of the Lorentz-violating term for the free energy and carry out a numerical estimation for the Lorentz-breaking parameter.
96444982
Horava-Lifshitz-like extensions of supersymmetric theories
Within the superfield approach, we formulate two different extensions of the Wess-Zumino model and super-QED with Horava-Lifshitz-like additive terms, discuss their quantum properties and calculate lower contributions to the effective action. In the case of the gauge theory, the one-loop effective potential turns out to be gauge independent.
119494597
X(3872): Hadronic molecules in effective field theory
Abstract We consider the implications from the possibility that the recently observed state X ( 3872 ) is a meson–antimeson molecule. We write an effective Lagrangian consistent with the heavy-quark and chiral symmetries needed to describe X ( 3872 ) . We explore the consequences of the assumption that X ( 3872 ) is a molecular bound state of D ∗ 0 and D ¯ 0 mesons for the existence of bound states in the D 0 D ¯ 0 and D ∗ 0 D ¯ ∗ 0 channels.
119297660
Primordial black holes and the observed Galactic 511 keV line
Abstract The observed 511 keV line from the Galactic Bulge is a real challenge for theoretical astrophysics: despite a lot of suggested mechanisms, there is still no convincing explanation and the origin of the annihilated positrons remains unknown. Here we discuss the possibility that a population of slowly evaporating primordial black holes with the mass around 10 16 –10 17 g ejects (among other particles) low-energy positrons into the Galaxy. In addition to positrons, we have also calculated the spectrum and number density of photons and neutrinos produced by such black holes and found that the photons are potentially observable in the near future, while the neutrino flux is too weak and below the terrestrial and extra-terrestrial backgrounds. Depending on their mass distribution, such black holes could make a small fraction or the whole cosmological dark matter.
9264360
Mixing and CP-violation in charm
The motivation most often cited in searches for D 0 − D 0 ¯ mixing and CP-violation in charm system lies with the possibility of observing a signal from new physics which dominates that from the Standard Model. We review recent theoretical predictions and experimental constraints on D 0 − D 0 ¯ mixing parameters. We also discuss the current status of searches for CP-violation in charmed meson transitions, as well as some recent theoretical ideas.
119219150
Black holes as antimatter factories
We consider accretion of matter onto a low mass black hole surrounded by ionized medium. We show that, because of the higher mobility of protons than electrons, the black hole would acquire positive electric charge. If the black hole's mass is about or below 1020 g, the electric field at the horizon can reach the critical value which leads to vacuum instability and electron-positron pair production by the Schwinger mechanism. Since the positrons are ejected by the emergent electric field, while electrons are back-captured, the black hole operates as an antimatter factory which effectively converts protons into positrons.
17946700
CP-violation in charm
I review recent results in theoretical and experimental analyses of CP-violation in charmed transitions, paying particular attention to constraints on parameters of beyond the Standard Model interactions.