Measurements and theories of the King–Perkins–Chudakov effect

On the Chudakov effect for the most probable value of high-energy electron-positron pair ionization loss in thin targets

“…Therefore, it is more accurate to use the calculated value of E MP , rather than E AV , for comparison with experimental results obtained with the use of thin detectors. Particularly, it is shown that although this does not completely remove the discrepancy between the results of the experiment [22,23] and the theory, it provides a much better coincidence in the part of the investigated region of parameters where the Chudakov effect is the most significant.…”

“…The Chudakov effect has been studied experimentally with the use of cosmic ray photons for pair production in emulsions [13,16,17], which showed a fairly good agreement with the theories of this effect for the mean ionization loss of the pair [12,[18][19][20][21]. In [22,23] there was reported the first proof-of principle experiment of this kind, where the photons were generated by high-energy electrons in an accelerator. It was noted that such an approach allows for much more precise determination of the pair energy and achievement of better statistics.…”

“…1 shows the examples of struggling functions of e + e − pairs in silicon targets of various thickness calculated on the basis of (11) and (24). The example of a target with x = 16 µm is chosen since a silicon detector of this thickness has been applied in the experiment [22,23] discussed above. We see that, like in the case of single particles, in thin targets the distribution (24) is broader than (11).…”

The influence of non-parallelism of electron and positron velocities upon high-energy e+e− pair ionization loss in thin plate

“…Let us also note that the problem statement considered in [11] and [14] probably better corresponds to the experimental situation of the first accelerator-based investigation of pair ionization loss [9,10] in which the pairs loss was measured in thin silicon detector situated on different distances from golden foils in which the pairs were created by high-energy photons. Taking into account the contribution from transition radiation leads to somewhat better description of the obtained here results than the one provided by theories of pair ionization loss in boundless medium [1][2][3][4][5].…”

“…Ionization energy loss of an ultra relativistic electron-positron pair created by a high-energy photon in substance has been studied in series of works both theoretically [1][2][3][4][5] and experimentally [6][7][8][9][10]. Its main peculiarity is associated with existence of socalled Chudakov effect which consists in reduction of pair ionization loss in the vicinity of its creation point comparing to the sum of losses of electron and positron which traverse the substance separately one from another.…”