相关论文: Constraining spacetime noncommutativity with primo…
The presence of light (m_a ~ 10^-6 ev) scalar fields in the early universe can modify the cosmology of neutrinos considerably by allowing their masses to vary on cosmological times. In this paper, we consider the effect of Planck-suppressed…
Recent work on increasing the effective number of neutrino species (Neff) in the early universe has focussed on introducing extra relativistic species (`dark radiation'). We draw attention to another possibility: a new particle of mass less…
We present a multi-epoch test of f(T) gravity with nonminimal torsion-matter coupling, combining early- and late-Universe observations. At the MeV scale, Big-Bang Nucleosynthesis constrains the fractional variation of the weak freeze-out…
The noncommutative QED (NCQED) has a non-Abelian nature due to the presence of 3- and 4-photon vertices in the lagrangian. Thus, NCQED predicts a new physics contribution to the $\gamma\gamma\rightarrow\gamma\gamma$ scattering already at…
We develop a string-inspired model for particle cosmology, based on a flipped SU(5)$\times$U(1) gauge group formulated in a no-scale supergravity framework. The model realizes Starobinsky-like inflation, which we assume to be followed by…
Big Bang Nucleosynthesis provides us with an observational insight into the very early Universe. Since this mechanism of light element synthesis comes out of the standard model of particle cosmology which follows directly from General…
We investigate the way how the total mass sum of neutrinos can be constrained from the neutrinoless double beta decay and cosmological probes with cosmic microwave background (WMAP 3-year results), large scale structures including 2dFGRS…
A new evaluation of the constraint on the number of light neutrino species (N_nu) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred…
The gauge-extended U(1)_C \times SU(2)_L \times U(1)_{I_R} \times U(1)_L model has the attractive property of elevating the two major global symmetries of the standard model (baryon number B and lepton number L) to local gauge symmetries.…
Primordial neutrino-antineutrino asymmetries can be constrained through big-bang nucleosynthesis (BBN) relic abundances and cosmic microwave background (CMB) anisotropies, both observables being sensitive to neutrino properties. The latter…
In this letter we propose a possible mechanism of left- and right-handed neutrino couplings to photons, which arises quite naturally in non-commutative gauge field theory. We estimate the predicted additional energy-loss in stars induced by…
We put bounds on the variation of the value of the fine structure constant $\alpha$, at the time of Big Bang nucleosynthesis. We study carefully all light elements up to $^7$Li. We correct a previous upper limit on $|\Delta \alpha /…
A critical review is given of the current status of cosmological nucleosynthesis. In the framework of the standard model with 3 types of relativistic neutrinos, the baryon-to-photon ratio, \eta, corresponding to the inferred primordial…
Dark sectors provide a compelling theoretical framework for thermally producing sub-GeV dark matter, and motivate an expansive new accelerator and direct-detection experimental program. We demonstrate the power of constraining such dark…
We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD $\theta$ angle that redshifts in the early universe, increasing the neutron-proton mass difference at…
Big Bang Nucleosynthesis imposes stringent bounds on light sterile neutrinos mixing with the active flavors. Here we discuss how altered dispersion relations can weaken such bounds and allow compatibility of new sterile neutrino degrees of…
We study effects of long-lived massive particles, which decay during the big-bang nucleosynthesis (BBN) epoch, on the primordial abundances of light elements. Compared to the previous studies, (i) the reaction rates of the standard BBN…
Big Bang nucleosynthesis in the presence of decaying relic neutral particles is examined in detail. All non-thermal processes important for the determination of light-element abundance yields of 2H, 3H, 3He, 4He, 6Li, and 7Li are coupled to…
We study strong coupling phenomena in U(1) gauge theory on the non-commutative plane. To do so, we make use of a T-dual description in terms of an $N\to\infty$ limit of U(N) gauge theory on a commutative torus. The magnetic flux on this…
It is shown that a subelectronvolt upper limit can be derived on the neutrino mass from the CMB data alone in the Lambda CDM model with the power-law adiabatic perturbations, without the aid of any other cosmological data. Assuming the…