By Markus Kuster, Georg Raffelt, Berta Beltrán
Axions are bizarre hypothetical debris which could either clear up the CP challenge of quantum chromodynamics and whilst account for the darkish topic of the universe. according to a sequence of lectures by way of international specialists during this box held at CERN (Geneva), this quantity presents a pedagogical advent to the idea, cosmology and astrophysics of those interesting debris and offers an up to date account of the prestige and prospect of ongoing and deliberate experimental searches. rookies and practitioners of astroparticle physics will locate during this publication either a concise creation and a present reference paintings to a show off subject that connects the “inner area” of the trouble-free particle international with the “outer house” of the universe at large.
Read Online or Download Axions: Theory, Cosmology, and Experimental Searches PDF
Best cosmology books
This can be the compelling, first-hand account of Alan Guth’s paradigm-breaking discovery of the origins of the universeand of his dramatic upward thrust from younger researcher to physics celebrity. Guth’s startling theorywidely considered as the most very important contributions to technological know-how through the 20th centurystates that the massive bang was once set into movement by way of a interval of hyper-rapid inflation,” lasting just a billion-trillion-billionth of a moment.
No sleek astronomer made a extra profound contribution to our figuring out of the cosmos than did Edwin Hubble, who first conclusively validated that the universe is increasing. Basing his thought at the remark of the swap in distanct galaxies, referred to as pink shift, Hubble confirmed that this can be a Doppler impact, or alteration within the wavelength of sunshine, due to the swift movement of celestial items clear of Earth.
Cosmologist Alex Vilenkin attracts on rising medical study to supply a brand new idea in regards to the production, growth, and eventual death of the universe. summary: Cosmologist Alex Vilenkin attracts on rising medical study to supply a brand new concept concerning the production, enlargement, and eventual dying of the universe
- The Ultimate Fate of the Universe
- Understanding the Universe: From Quarks to the Cosmos
- The Barbarian Principle: Merleau-Ponty, Schelling, and the Question of Nature
- Lucifer's Legacy: The Meaning of Asymmetry
- Gravitational waves in Einstein's theory
- Death from the Skies!: These Are the Ways the World Will End...
Additional resources for Axions: Theory, Cosmology, and Experimental Searches
However, pop. II axions may get gravitationally bound to miniclusters later on. It seems rather diﬃcult to model this process reliably. A discussion is given in . It is concluded there that the accretion of pop. II axions results in miniclusters that have an inner core of pop. I axions with density of order 10−18 g cm−3 and a fluﬀy envelope of pop. II axions with density of order 10−25 g cm−3 . When a minicluster falls onto a galaxy, tidal forces are apt to destroy it. If a minicluster falls through the inner parts of the Galaxy (r < 10 kpc), where the density is of order 10−24 g cm−3 , its fluﬀy envelope of pop.
107) where η is the fraction of cold axions that are pop. I. We assume that all pop. 100, Case 2) to estimate ̺a (teq ). 102), we find for pop. II ℓf,II ∼ q ln ℓmc teq t3 ≃ 42 q . 103) and assuming the range γ ∼ 7–60, suggested by the numerical simulations , we conclude that pop. II axions do homogenize and hence the axion energy density has a smooth component at teq . However, pop. II axions may get gravitationally bound to miniclusters later on. It seems rather diﬃcult to model this process reliably.
We will assume that the initial value of a is suﬃciently small that fa sin(a/fa ) ≃ a. Let us define ψ by a(t) ≡ t−3/4 ψ(t) . 41) 3 . 42) 16 t2 For t > t1 , we have d ln ω/dt ≪ ω ≃ ma . That regime is characterized by the adiabatic invariant ψ02 (t) ω(t), where ψ0 (t) is the changing oscillation amplitude of ψ(t). 43) where C is a constant. Hence a(t) = A(t) cos with A(t) = t C ma (t) dt′ ω(t′ ) , t−3/4 . 45) Hence, during the adiabatic regime, A2 (t) ma (t) ∝ t−3/2 ∝ R(t)−3 . 46) The zero-momentum mode of the axion field has energy density ̺a = 1 2 2 2 ma A and describes a coherent state of axions at rest with number density na = 12 ma A2 .
Axions: Theory, Cosmology, and Experimental Searches by Markus Kuster, Georg Raffelt, Berta Beltrán