Alf Pretzell | cosmic rays versus colliding beams

• - The composition of cosmic rays even at our time is not entirely clear: “[…], but many aspects of the energy dependent composition are controversial” and “the identification is not easy at all, and in practice the criteria are not always consistent". Also ultra high energy cosmic rays are rare events:"Note that the flux above 10¹² eV is around 10 primary particles per minute and m², but above 10^18.5 eV it drops to O(1) particle/(km² year) […], so the search for UHECR takes patience". The reason for construction of colliders is the imprecise configuration in observing natural cosmic rays. Only limited insight into the physics of cosmic rays is possible up to now - experiments for further clarification are currently prepared!
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• - The boost (the momentum / the velocity) of the products in a cosmic collision might be higher in the rest frame of the earth than the minimum momentum of the collider products (whatever heavy products). This results in other cross sections of these products with the matter of earth (or the atmosphere or moon) and other subsequent reactions due to the different energies. Not only are the products important but also their momentum when further reactions have to be considered. I do not cite here the literature because this correlation is canon in particle physics.
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• - The conditions in the collider (collision in the vacuum near to a solid) are different from the environment in the atmosphere (collision in gas) or on the moon (collision in a solid). Respective implications (reactions, life times, …) have to be analyzed in detail.
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• - To be able to compare the reactions a Lorentz transformation has to be applied: In the LHC two protons with equal velocities shall collide head on in the lab - in the cosmic case an extremely fast proton is assumed to meet a resting proton (relative to the earth). Up to now no violation of this transformation is known and precise laboratory experiments for small energies (gamma at 10⁵) are available. However, at extremely high energies (10¹⁷ eV of LHC after transformation or more) experimental evidence is rare (Auger, HiRes, neutrinos) and neither fully exact nor unambiguous: “This observation [AGASA] disagrees, however, with the data of the HiRes (High Resolution Fly’s Eye) observatory". Lorentz invariance violation in this context is discussed in the literature: “On the other hand, the sizable number of super-GZK cosmic rays asks for an explanation and keeps the door open for speculations” and “This is a very active field of research with exciting open questions. We may expect enlightening new data in the near future. They could lead to new insight in outstanding issues like LIV — or to new puzzles and perhaps to evidence for new physics.” More than 100 physical parameters subjected to the transformation are discussed: “Kostelecky ́et al. have identified more than 100 LIV parameters in this way, including CPT breaking terms". Not all are checked by the cutoff seen in Auger but could play a role in LHC experiments.
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• - Known physics might change drastically at energy densities making micro black holes possible as academically discussed in the meantime [Plaga http://arxiv.org/abs/0808.1415 ]. W. Bietenholz: “Based on the uncertainty relations (3.14), the identification of a as the Planck length now leads to a consistent picture of the space-time uncertainty range as the event horizon of a mini black hole [142]. In fact, a (hypothetical) measurement of a length of O(LPlanck) requires (according to the Heisenberg uncertainty) an enormous energy density, which gives rise to such an event horizon — the notion of detectable events then requires inequalities (3.14) to hold with a ∼ LPlanck. This Gedankenexperiment suggests that points should indeed be washed out over a range of O(LPlanck ). If several directions are involved, as in relation (3.14), this is practically equivalent to non-commutativity. […] Thus we have the case of an “active LIV”” Within this context comparison of the LHC collisions with cosmic ray events are additionally extremely questionable.