Modern Physics Letters A

We review some recent efforts in determining the absolute neutrino mass scale in cosmology. We illustrate in particular how distance measurements such as the baryon acoustic oscillations and the galaxy weak lensing can break the degeneracy between the neutrino mass and dark energy equation of state parameters.

We consider a small, metastable maximum vacuum expectation value b₀ of order of a few eV, for a pseudoscalar Goldstone-like field, which is related to the scalar inflaton field ϕ in an idealized model of a cosmological, spontaneously-broken chiral symmetry. The b field allows for relating semi-quantitatively three distinct quantities in a cosmological context.

(a) A very small, residual vacuum energy density or effective cosmological constant of , for λ ~ 3×10^-14, the same as an empirical inflaton self-coupling.

(b) A tiny neutrino mass, less than b₀.

(c) A possible small variation downward of the proton to electron mass ratio over cosmological time. The latter arises from the motion downward of the b field over cosmological time, toward a nonzero value. Such behavior is consistent with an equation of motion.

We argue that hypothetical b quanta, potentially inducing new long-range forces, are absent, because of negative, effective squared mass in an equation of motion for b-field fluctuations. The assumed flatness of a potential maximum involves a small inverse-time parameter μ ≪ 1/t₀, where t₀ is the present age of the universe.

Cross sections of the colored scalar particle production in pp-collisions are calculated and differential and total cross sections of the corresponding parton subprocesses are obtained. The total cross section of scalar gluon production in pp-collisions at the LHC is estimated and the dominant decays of scalar gluons are discussed. The production cross section of scalar gluons F with masses m_F ≲ 1300 GeV is shown to be sufficient for the effective production of these particles at the LHC.

Recent results show that when nonlinear electrodynamics is considered, the no-scalar-hair theorems in the scalar–tensor theories (STT) of gravity, which are valid for the cases of neutral black holes and charged black holes in the Maxwell electrodynamics, can be circumvented.^1,2 What is even more, in the present work, we find new non-unique, numerical solutions describing charged black holes coupled to nonlinear electrodynamics in a special class of scalar–tensor theories. One of the phases has a trivial scalar field and coincides with the corresponding solution in General Relativity. The other phases that we find are characterized by the value of the scalar field charge. The causal structure and some aspects of the stability of the solutions have also been studied. For the scalar–tensor theories considered, the black holes have a single, non-degenerate horizon, i.e. their causal structure resembles that of the Schwarzschild black hole. The thermodynamic analysis of the stability of the solutions indicates that a phase transition may occur.

The Wilkinson Microwave Anisotropy Probe (WMAP) three-year results are used to constraint non-minimal inflation models. Two different non-minimally coupled scalar field potentials are considered to calculate the corresponding slow-roll parameters of non-minimal inflation. The results of numerical analysis of parameter space are compared with WMAP3 data to find the appropriate new constraints on the values of the non-minimal coupling.

The (1+1)-dimensional bosonized Schwinger model with a generalized gauge-invariant regularization has been studied in a noncommutative scenario. The original commutative model with the indicated regularization revealed the transition from confinement to deconfinement of the fermion.¹⁰ We show that though the introduction of spacetime noncommutativity gives rise to new features in the confinement scenario, it does not affect the deconfining limit.

Wilczek and his collaborators' anomaly cancellation approach is applied to the 3D Schwarzschild- and BTZ-like braneworld black holes induced by the generalized metrics in the Randall–Sundrum scenario. Based on the fact that the horizon of braneworld black hole will extend into the bulk spacetime, calculation is done from the bulk generalized metrics side and it is shown that this approach also reproduces the correct Hawking radiation for these braneworld black holes. Besides, since this approach does not involve the dynamical equation, it is also shown that the Hawking radiation is only a kinematic effect.