Neutrino trapping

Beta equilibrium, neutrino trapping, charge and color neutrality. The stellar matter in equilibrium has to obey the constraints of /3-equilibrium (d — u + e + ve,u + e — d + ve), expressed as... 

Cooling delay due to neutrino trapping. Estimates of the time interval after which an explosive effect of energy release like a GRB could be observed, depend on the possible structure of a compact object after the... 

Energy release due to (anti)neutrino untrapping. The configurations for the quark stars are obtained by solving the Tolman-Oppenheimer-Volkoff equations for a set of central quark number densities nq for which the stars are stable. In Fig. 13 the configurations for different antineutrino chemical potentials are shown. The equations of state with trapped antineutrinos are softer and therefore this allows more compact configurations. The presence of antineutrinos tends to increase the mass for a given central density. 

If the phase transition is somewhat stronger than we have discussed in the previous subsection, the initial temperature is higher, To 10 MeV. Neutrinos are trapped for a while in the interior of the newly formed quark star. For lower densities, where the quark matter contains trapped neutrinos the direct Urea process is operative and neutrino cooling is a surface effect. 

These same physicist astronomers, today called astroparticle physicists, are currently setting up and line-tuning traps for neutralinos, hypothesised particles of dark matter. These are just as subtle as neutrinos, but much rarer and much more massive. For the moment, the search has been fruitless, but patience is a virtue in the hunt for the invisible. 

Historically, chlorine was the first target used to trap neutrinos. Chlorine-37 is mainly sensitive to high-energy neutrinos emanating from marginal fusion reactions (2 out of 10000) which lead to production of boron-8. On rather rare occasions, under the impact of neutrinos, chlorine-37 is transformed into radioactive argon-37 which is easy to detect by its radiation. However, the myriads of low-energy neutrinos completely escape its notice. 

But quantitatively there is a disagreement between measurement and theory. The neutrinos actually caught in our traps are two or three times less numerous than the theory says they ought to be (Table 5.1). Naturally, this discrepancy is a challenge to the physicist. It does not seem to arise from any problem with the solar model itself, now that the Sun has been probed by its mechanical oscillations. 

Table 2. Pre-trapping neutrino detections predicted in SNO (heavy water) and Super Kamioka [99] with hardness ratios up to pm = 24.16 for indicated heavy nuclear e-capture matrix elements for 15 Mq Puller (1982) and 25 Mq WWF presupernova stars. Note the caveat in footnote 20...

Recently, experiments on nuclear decay have started to use MOTs as a source of cold, well-localized atoms. The low-energy recoiling nuclei can escape from the MOT and be detected in coincidence with, 3-decays to reconstruct information about the properties of the particles coming from the nuclear reactions. An example of such an experiment is a beta- neutrino correlation measurement on laser-trapped 38mj ... 

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