Emergent Solution to the Strong 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:math>
 Problem

We investigate the impact of the QCD vacuum at nonzero θ on the properties of light nuclei, Big Bang nucleosynthesis, and stellar nucleosynthesis. Our analysis starts with a calculation of the θ-dependence of the neutron-proton mass difference and neutron decay using chiral perturbation theory. We then discuss the θ-dependence of the nucleon-nucleon interaction using a one-boson-exchange model and compute the properties of the two-nucleon system. Using the universal properties of four-component fermions at large scattering length, we then deduce the binding energies of the three-nucleon and four-nucleon systems. Based on these results, we discuss the implications for primordial abundances of light nuclei, the production of nuclei in stellar environments, and implications for an anthropic view of the universe.

show abstract

“…For further discussions related to this issue, see Refs. [10][11][12]. In the present paper we revisit this issue.…”

Section: Introductionmentioning

confidence: 92%

θ -dependence of light nuclei and nucleosynthesis

Lee

Meißner

Olive

et al. 2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…References [52][53][54][55][56][57] have considered resonances of graviton and fermion. Besides, Arakawa et al considered a massive vector field as a candidate of dark matter to explain the strong CP problem [58]. So, we will study the resonances of the five-dimensional vector field.…”

Section: The Resonant Character Ofâµmentioning

confidence: 99%

Generalized geometrical coupling for vector field localization on thick brane in asymptotic anti–de Sitter spacetime

et al. 2020

View full text Add to dashboard Cite

It is known that a five-dimensional free vector field AM cannot be localized on Randall-Sundrum (RS)-like thick branes, namely, the thick branes embedded in asymptotic Anti-de Sitter (AdS) spacetime. In order to localize a vector field on the RS-like thick brane, an extra coupling term should be introduced. In this paper, we generalize the geometrical coupling mechanism by adding two mass terms (αRg M N AM AN + βR M N AM AN ) into the action. We decompose the fundamental vector field AM into three parts: transverse vector partÂµ, scalar parts φ and A5. Then, we find that the transverse vector partÂµ decouples from the scalar parts. In order to eliminate the tachyonic modes ofÂµ, the two coupling parameters α and β should satisfy a relation. Combining the restricted condition, we can get a combination parameter as γ = 3 2 ± √ 1 + 12α. Only if γ > 1/2, the zero mode ofÂµ can be localized on the RS-like thick brane. We also investigate the resonant character of the vector partÂµ for the general RS-like thick brane with the warp factor A(z) = − ln(1 + k 2 z 2 )/2 by choosing the relative probability method. The result shows that, only for γ > 3, the massive resonant Kaluza-Klein modes can exist. The number of resonant Kaluza-Klein states increases with the combination parameter γ, and the lifetime of the first resonant state can be long enough as the age of our universe. This indicates that the vector resonances might be considered as one of the candidates of dark matter. Combining the conditions of experimental observations, the constrain shows that the parameter k has a lower limit with k 10 −17 eV, the combination parameter γ should be greater than 57, and accordingly, the mass of the first resonant state should satisfy m1 10 −15 eV.

show abstract

“…Similarly, the physics of early Universe phase transitions has become a popular topic in recent years, again driven by the prospect of observing gravitational waves from these phase transitions in upcoming experiments [28][29][30][31][32][33][34]. Besides significant advances in our understanding of the dynamics of these phase transitions [35][36][37][38][39] and in our computational techniques [40][41][42][43][44][45][46], phase transitions have been widely used as phenomenological tools, for instance to explain the baryon asymmetry of the Universe via electroweak baryogenesis [47][48][49][50][51][52][53][54][55][56][57][58][59] and other mechanisms [60][61][62][63][64][65][66], to form DM "nuggets" [67][68][69], or to set the abundance of particle dark matter [70][71][72][73]. Most r...…”

Section: Introductionmentioning

confidence: 99%