Pion production

Afnan I. R. and Thomas A. W. Faddeev approach to pion production and pion-deuteron scattering, Phys. Rev. C 10, 109-125 (1974)... 

The typical size of the pion production region in the case of short lived sources is 14-3 fm which is much smaller than the Bohr radius of the 7r+7r atom tb = 387 fm). Thus the Coulomb interaction in the final state was taken into account multiplying (F) with the Coulomb factor Ac (3) [71] which depends on the relative velocity 0 of the 7r+7r pair in its c.m.s. ... 

Nuclear and pion related 7-rays provide important information about the spectra of protons and ions accelerated in solar flares [e.g. Hua and Lingen-felter, 1987 Murphy et al., 1987 Lockwood et al., 1997 Hua et al., 2002], However, nuclear 7-ray lines probe the proton spectrum only up to 40 MeV, while 7-rays from pion decays are only observed in the most intense flares. In addition, any spectral break in the proton spectrum is likely to he below the pion production threshold. Neutrons produced at the solar surface over a wide range of energies may provide important information from the 50-300 MeV regime, complementing 7-ray observations. Due to the long neutron thermal-ization time ( 100 s) the 2.223 MeV neutron capture line is only a limited measure of neutron production. The spectrum of accelerated and interacting protons can be deduced more reliably from direct neutron measurements. 

Fig. 1 illustrates the importance of the various energy ranges of the energetic flare particles, in particular for the neutron production. A typical solar proton production spectrum d J/dE E 2-5 (A) is folded with the cross-sections for the neutron (B), 7-ray line (C and D) and pion production (E), and weighted by the elemental abundances of the target material [Lockwood et al., 1997],... 

Mesonenerzeugung s. Pionenerzeugung, meson production see pion production. 

Pionenerzeugung, pion production 513, 532f. Pionenreaktionen mit Kernen, pion reactions with nuclei 534f. 

The starting point for muon experiments is the production of pions (it) in a nuclear reaction initiated by energetic protons (e.g., Be + p — l Be + ir ). Threshold energies for pion production are > 150 MeV but the cross sections peak in the "intermedi-... 

A model estimate of the difference, is what will be calculated. Since the intention is to study predictions of the optical potential for energies as high as 1 GeV, one needs a model of the NN interaction which extends well above the pion production threshold. The nucleon-isobar coupled channels model of [Ra 87] can be used for these calculations. This model is summarized in section 3.6.1. Based on g-matrix results, s expected to be small at intermediate energies (but not negligible) therefore, the initial calculations [Ra90] used the local, factorized on-shell tp" form of the optical potential to estimate this quantity. More sophisticated calculations remain to be done in the future. 

We have shown that the vector mesons in the CFL phase have masses of the order of the color superconductive gap, A. On the other hand the solitons have masses proportional to F%/A and hence should play no role for the physics of the CFL phase at large chemical potential. We have noted that the product of the soliton mass and the vector meson mass is independent of the gap. This behavior reflects a form of electromagnetic duality in the sense of Montonen and Olive [29], We have predicted that the nucleon mass times the vector meson mass scales as the square of the pion decay constant at any nonzero chemical potential. In the presence of two or more scales provided by the underlying theory the spectrum of massive states shows very different behaviors which cannot be obtained by assuming a naive dimensional analysis. 

We do not find it productive to involve our analysis into further speculations that will include the decay processes of muons and pions, and their mean lives in order to find out which version is more acceptable, that with muons or with pions. It is well known that the muon s mean life changes as a function of its velocity however, there are no data regarding what happens with decay processes with particles that reach velocities v > c [11]. 

The spectrum-weighted moment Zp n(a) depends both on the physics of production of the secondary pion and on the value of the differential spectral index a. 

The approach by Judge and Nash uses as input the production spectra of parent pions and kaons and calculates the flux resulting from pion and kaon... 

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