Results 41 to 50 of about 28,372 (160)
The evolving Planck mass in classically scale-invariant theories
Journal of High Energy Physics, 2017 We consider classically scale-invariant theories with non-minimally coupled scalar fields, where the Planck mass and the hierarchy of physical scales are dynamically generated.
K. Kannike +3 more
doaj +1 more source
New models and big bang nucleosynthesis constraints in f(Q) gravity
European Physical Journal C: Particles and Fields, 2023 The f(Q) theories of modified gravity arise from the consideration of non-metricity as the basic geometric quantity, and have been proven to be very efficient in describing the late-time Universe.
Fotios K. Anagnostopoulos +3 more
doaj +1 more source
Big bang nucleosynthesis with a varying fine structure constant and non-standard expansion rate [PDF]
Phys.Rev. D69 (2004) 123506, 2004 We calculate primordial abundances of light elements produced during big bang nucleosynthesis when the fine structure constant and/or the cosmic expansion rate take non-standard values. We compare them with the recent values of observed D, He4 and Li7 abundances, which show slight inconsistency among themselves in the standard big bang nucleosynthesis ...
arxiv +1 more source
Toward a self-consistent and unitary reaction network for big-bang nucleosynthesis
EPJ Web of Conferences, 2014 Unitarity, the mathematical expression of the conservation of probability in multichannel reactions, is an essential ingredient in the development of accurate nuclear reaction networks appropriate for nucleosynthesis in a variety of environments.
Paris Mark W. +8 more
doaj +1 more source
Non-universal scalar-tensor theories and big bang nucleosynthesis [PDF]
Phys.Rev.D79:103512,2009, 2008 We investigate the constraints that can be set from big-bang nucleosynthesis on two classes of models: extended quintessence and scalar-tensor theories of gravity in which the equivalence principle between standard matter and dark matter is violated. In the latter case, and for a massless dilaton with quadratic couplings, the phase space of theories is
arxiv +1 more source
Constraining axion dark matter with Big Bang Nucleosynthesis
Physics Letters B, 2014 We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD θ angle that redshifts in the early Universe, increasing the neutron–proton mass difference at neutron freeze-out.
Kfir Blum +3 more
doaj +1 more source
Big Bang Nucleosynthesis in Visible and Hidden-Mirror Sectors
Advances in High Energy Physics, 2014 One of the still viable candidates for the dark matter is the so-called mirror matter. Its cosmological and astrophysical implications were widely studied, pointing out the importance to go further with research.
Paolo Ciarcelluti
doaj +1 more source
Вісник Астрономічної школи, 2001 In the brief review the modern problems of the further evolution nuclides after formation of easiest of them H, D, 3He, 4He and, probably, 7Li in 100 seconds after the Big Bang are discussed.The possible ways of evolution nuclides in result are ...
N. S. Komarov
doaj +1 more source
Heavy Elements and Electromagnetic Transients from Neutron Star Mergers
Annalen der Physik, Volume 536, Issue 2, February 2024.Astro‐(physics) has made major leaps forward through the combined information provided by both gravitational waves and electromagnetic emission from the first detected neutron star merger event. This review provides an up‐to‐date overview of today's understanding of neutron star mergers and their electromagnetic emission and it discusses possible ...
Stephan Rosswog, Oleg Korobkin
wiley +1 more source
The Landscape, the Swampland and the Era of Precision Cosmology
Fortschritte der Physik, Volume 67, Issue 1-2, January-February 2019., 2019 Abstract We review the advanced version of the KKLT construction and pure de Sitter supergravity, involving a nilpotent multiplet, with regard to various conjectures that de Sitter state cannot exist in string theory. We explain why we consider these conjectures problematic and not well motivated, and why the recently proposed alternative string theory
Yashar Akrami +3 more
wiley +1 more source