Alignment in γ-hadron families of cosmic rays

Abstract

Alignment of main fluxes of energy in a target plane is found in families of cosmic ray particles detected in deep lead X-ray chambers. The fraction of events with alignment is unexpectedly large for families with high energy and large number of hadrons. This can be considered as evidence for the existence of coplanar scattering of secondary particles in interaction of particles with superhigh energy, E 0 > ∼ 10 16 eV. Data analysis suggests that production of most aligned groups occurs low above the chamber and is characterized by a coplanar scattering and quasiscaling spectrum of secondaries in the fragmentation region.The most elaborated hypothesis for explanation of alignment is related to the quark-gluon string rupture. However, the problem of theoretical interpretation of our results still remains open.

Emulsion chamber observations of Centauros, aligned events and the long-flying component

“…This phenomenon was first found by the Pamir Collaboration [27][28][29][30][31] and confirmed [23,24], in central Au+Au collisions at RHIC [25].…”

FANSY 1.0: a phenomenological model for simulation of coplanar particle generation in superhigh-energy hadron interactions

“…On the other hand, such a robust and transparent phenomenon is observed at these energies as a tendency for a coplanarity of most energetic cores of so called γ -ray-hadron families, i.e., groups of highest-energy (E n · 1 TeV) particles in EAS cores). The effect has been first found by the Pamir Collaboration in X-ray-emulsion chamber (XREC) experiments [1][2][3][4][5] and confirmed later in other mountain [6] and stratospheric [7][8][9][10] experiments. While assuming this observable effect to be produced by well-known elementary a e-mail: muhamed@sci.lebedev.ru particles, it is related to hadron-nucleus interactions at superhigh energies (E 0 10 16 eV [11], i.e., √ s 4 TeV) and can be characterized by large average transverse momenta, for instance, up to ∼ n × 10 GeV/c as early as at E 0 ∼ 10 16 eV [12,13].…”

“…Pamir (Pb-XREC) λ 4 ≥ 0.8, E γ ≥ 700 TeV 6 from 14 0.43 ± 0.13 [3] Pamir (C-XREC) λ 4 ≥ 0.8, E γ ≥ 700 TeV 5 from 35 0.15 ± 0.05 [5] Mt.Kanbala (Fe-XREC) λ 3 ≥ 0.8, E γ ≥ 500 TeV 6 from 12 0.5 ± 0.13 [6] the Strana λ 4 = 0.99, E γ 1500 TeV 1 1 [12,13] the JF2af2 the decascading algorithm with z c = 5 TeV·cm for Pamir's XRECs [11,28] Let us attempt to find estimates of probabilities, w i , to gain the real (or larger) experimental number of coplanar families in the framework of different FANSY's versions. Results are shown in Table 4.3.…”

“…Fig. 3.2 To analyze the coplanarity of interactions in terms usually applied in [1][2][3][4][6][7][8][9][10], the parameter λ N [1] decreasing from 1 (for N points disposed along a straight line) to −1/(N − 1) (in isotropic cases) is applied. As this parameter has been first defined for N points placed on a plane, coordinates of points of intersection of particles' trajectories with a target plane placed normally to the projectile particle direction are calculated.…”

Geometric structures in hadronic cores of extensive air showers observed by KASCADE

“…Therefore, it is not surprising that the observation of aligned structures in a number of emulsion chamber experiments has initiated considerable experimental and theoretical efforts over the last two decades [7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Aligned event structures were, for instance, reported by the PAMIR experiment [9,10]. An excess of events with substructure alignment above background fluctuations was found in the data for primary energies above an energy threshold of 8−10 PeV (see e.g.…”