Axions and the Strong CP Problem
By Jihn E. Kim, G. Carosi. The Ideas of Particle Physics, 2008
589 citations recorded by the source corpus.
Current upper bounds on the neutron electric dipole moment constrain the physically observable quantum chromodynamic (QCD) vacuum angle $|\overline{\ensuremath{\theta}}|\ensuremath{\lesssim}{10}^{\ensuremath{-}11}$. Since QCD explains a great deal of experimental data from the $100\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ to the TeV scale, it is desirable to explain this smallness of $|\overline{\ensuremath{\theta}}|$ in the QCD framework; this is the strong $CP$ problem. There now exist two plausible solutions to this problem, one of which leads to the existence of a very light axion. The axion decay constant window, ${10}^{9}\ensuremath{\lesssim}{F}_{a}\ensuremath{\lesssim}{10}^{12}\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ for an $O(1)$ initial misalignment angle ${\ensuremath{\theta}}_{1}$, has been obtained from astrophysical and cosmological data. For ${F}_{a}\ensuremath{\gtrsim}{10}^{12}\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ with ${\ensuremath{\theta}}_{1}lO(1)$, axions may constitute a significant fraction of the dark matter of the universe. The supersymmetrized axion solution of the strong $CP$ problem introduces its superpartner the axino, which might have affected the evolution of the Universe significantly. The very light axion (theory, supersymmetrization, and models) using recent particle, astrophysical, and cosmological data, and present prospects for its discovery is reviewed here.
View Paper: https://www.semanticscholar.org/paper/0ce4d58d47655110b190716429714502c5869641
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
Citations in the corpus
- Flavor structures of charged fermions and massive neutrinos (2019, background): “There are a number of theoretical solutions to this long-standing problem [239, 240, 247], among which the most popular ones are the Peccei-Quinn mechanism [156, 157] and its variations”
- Axions (2003, unknown): “Carosi [6] (take a deep breath before).”
- The Simons Observatory: science goals and forecasts (2018, background): “…the strong CP problem (Peccei and Quinn 1977; Weinberg 1978; Wilczek 1978; Abbott and Sikivie 1983; Ipser and Sikivie 1983; Moody and Wilczek 1984; Kim and Carosi 2010), however we consider here not the QCD axion with mass ∼ 10−7 eV but its much lighter cousin, the ULA, with masses between 10−33…”
- The landscape of QCD axion models (2020, background): “In models of the Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) type [109, 110] the anomaly is carried by SM quarks (as in the WW model), while models of the Kim-Shifman-Vainshtein-Zakharov (KSVZ) type [111, 112] require new colored fermions.”
- Search for New Physics with Atoms and Molecules (2017, background): “IX and also the reviews by Kim and Carosi (2010) and Graham et al. (2015a)].”
- Gravitational probes of dark matter physics (2017, background): “(43) With mF in the range of 10 6 − 1011 GeV, the gravitino masses can range from ∼ 100 eV up to 100 TeV.”
- Recent Progress in the Physics of Axions and Axion-Like Particles (2020, background): “In the following, we present the low energy axion couplings relevant for our subsequent discussion of axion phenomenology [1, 3].”