Axions

Consumer products require expensive magazine advertisements and television commercials. This can amount to 30% or 40% of the selling price. If a new laundry product is introduced, a large amount of money must be spent to convince supermarkets and/or mass distribution outlets to grant it shelf space. They must be convinced it will sell before they will put it on their shelves. They are only interested in items that will move. In 1968 Colgate introduced its new pre-soak, Axion . In the first 9 months it spent over 3,000,000 for advertisements alone- 640,000 for newspaper ads, 865,000 for network television, 886,000 for spot local radio commercials, 800,000 for spot local television commercials, and 199,000 for magazine ads.8 Airwick spent over 7,000,000 to introduce a new disinfectant-deodorant spray in 1973.7... 

In a cryogenic experiment, one or several detectors are used for a definite goal for which they have been optimized. For example, in CUORE experiment described in Section 16.5, the sensors are the Ge thermistors, i.e. thermometers used in a small temperature range (around 10 mK). One detector is a bolometer made up of an absorber and a Ge sensor. The experiment is the array of 1000 bolometers arranged in anticoincidence circuits for the detection of the neutrinoless double-beta decay. Note that the sensors, if calibrated, could be used, as well, as very low-temperature thermometers. Also the array of bolometers can be considered a single large detector and used for different purposes as the detection of solar axions or dark matter. 

FIGURE 11.16. A possible mechanism for the ortho-hydroxy aXion of phenol over copper acetate dimers. 

Another important classification of particle dark matter rests upon its production mechanism. Particles that were in thermal equilibrium in the early Universe, like neutrinos, neutralinos, and most other WIMPs (weakly interacting massive particles), are called thermal relics. Particles which were produced by a non-thermal mechanism and that never had the chance of reaching thermal equilibrium in the early Universe are called non-thermal relics. There are several examples of non-thermal relics axions emitted by cosmic strings, solitons produced in phase transitions, WIMPZILLAs produced gravitationally at the end of inflation, etc. 

We will discuss three cold dark matter candidates which are well-motivated , i.e. that have been proposed to solve problems in principle unrelated to dark matter and whose properties can be computed within a well-defined particle physics model. The three candidates we discuss are (1) a heavy active neutrino with standard model interactions, (2) the neutralino in the minimal super-symmetric standard model, and (3) the axion. Examples of other candidates that can be included in this category are a sterile neutrino (See e.g. Abazajian, Fuller, Patel (2001)) and other supersymmetric particles such as the grav-itino (See e.g. Ellis et al.(1984)) and the sneutrino (see, e.g.,Hall, Moroi Murayama( 1998)). 

Figure 16.6. Laboratory, as-trophysical, and cosmological constraints on the axion mass mi, The inflation scenario and the string scenario are referred in the text as the vacuum alignment scenario and the string emission scenario, respectively, /a is the axion decay constant, which is inversely related to rriA The axion is a good dark matter candidate for 1 /reV Ss rriA Ss 1 meV. (Figure from Raffelt in Review of Particle Physics, Hagiwara et al.(2002).)...

Axion Our third and last example of a well-motivated cold dark matter candidate is the axion. 

In a cosmological context, axions, contrary to neutrinos and neutralinos, are generally produced non-thermally (although thermal axion production is sometimes considered, as are non-thermal neutrino and neutralino productions). The two main mechanisms for non-thermal axion production are vacuum alignment... 

Figure 16.7. Experimental constraints on the density of axions in the galactic halo near the Sun as a function of the axion mass (upper scale) and cavity frequency (lower scale). The regions above the curves marked DFSZ and KSVZ are excluded fro the respective axion models. The currently accepted value for the local dark halo density is 0.45 GeV/cm3, which is approximately the extension of the excluded region for the KSVZ axion. (Figure from Asztalos et al.(2004).)...

Current cosmological data imply the existence of non-baryonic dark matter. We have discussed some of the most popular candidates and shown that none of the candidates known to exist, i.e. the active neutrinos, can be non-baryonic cold dark matter. Hence to explain the nature of cold dark matter we need to invoke hypothetical particles that have not been detected yet. Some of these hypothetical particles have been suggested for reasons different than the dark matter problem (such as sterile neutrinos, neutralinos, and axions), some others have been proposed mainly as a solution to the cold dark matter problem (e.g., self-interacting dark matter, WIMPZILLAs, etc.). Although most studies focus on the first category of candidates, especially neutralinos and axions, we should keep an open mind. 

Zhitnitsky, A. R. 1980. On possible suppression of the axion hadron interactions, Sov. J. Nucl. Phys. 31, 260... 

Many discussions have been in the literature about the nature of this new particle. Some have assumed that it was the axion others have ruled out the standard axion, but have not ruled out non-standard axions. In fact, the particle physicists concluded that they had ruled out a new elementary particle. It seems rather improbable now that such a particle exists at all. [20]... 

Axions arising from Peccei-Quinn symmetry (1977) as a cure for the strong CP violation problem (46). 

Within the year, all the best people (48, 49) were including cold dark matter (CDM) in their models for galaxy formation. From then to now, speakers and writers of the CDM words generally mean WIMPs and their ilk, though axions and a few other candidates behave in much the same way during structure formation. "Bias," the idea that luminous baryons will be more tightly clustered than the CDM (presumably because they are dissipative) dates from the same period. 

Axions come out of a sort of Bose-Einstein condensation in the early universe rather than from a state of thermal equilibrium, and so will be cold no matter how small their masses. Kolb and Turner in their 1990 duograph (59) gave them a whole chapter (chapter 10), and nothing seems to have happened since to make them a less serious candidate, though the masses must now be in the smaller of the two ranges then possible, near 1 O 5 eV, to keep decay products below detectability (ApOl, Sect. 12.5). Laboratory searches are in progress, and if they find something persuasive, you won t need me to tell you about it. 

Axions need a big box by particle standards. Have you ever worried about a Heisenberg uncertainty size for something with a mass of 1 O 5 eV at T = 3K We get 2.2 mm. And they have such a box, a big chunk of a Reviews of Modem Physics (66). 

In the early 1980s two-in-one detergent softener compositions such as Bold 3, Axion 2, and Dynamo 2 were on sale on the European market. Fab Total, the latest generation, was still available in Latin America a few years ago. 

Axion solution pH 8.0. e Weight loss of solid samples, 1%. 

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