Alf Pretzell | key arguments against the cosmic ray argument

If not otherwise indicated the citations are from Bietenholz 2008 (Cosmic Rays and the Search for a Lorentz Invariance Violation)

- 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 10^12 eV is around 10 primary particles per minute and m^², 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!

- The boost (the momentum / the velocity after transformation) 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 I do not cite here the literature because this correlation is canon in particle physics.

- 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.

- 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 (LIV) is known and precise laboratory experiments for small energies (gamma at 10^5) are available. However, at extremely high energies (10^17 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 Flys 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.

- Known physics might change drastically at energy densities making micro black holes possible as academically discussed in the meantime in higher dimensional space [Plaga 2009 http://arxiv.org/abs/0808.1415 ]. W. Bietenholz: ”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 - possible micro black hole production in colliders and the discussed effects at the Planck length - the comparison of the LHC collisions with cosmic ray events is additionally extremely questionable.

- The argumentation presented by Dar et al. 1999 (Will Relativistic Ion colliders…) commenting on symmetric head ons for the case of strangelets has to be inspected very carefully by experts and analyzed deeply extending the case to possible dangerous scenarios in general.

Concluding these arguments against operation and the calculations and considerations of even possibly dangerous scenarios of other academic colleagues are absolutely sufficient to enforce an independent, careful, public revision of the experiment and its discussed dangers before new experiments of any kind! The academic opinion clearly is not unambiguous as it would have to be the case amongst others for admissible operation.

The review by W. Bietenholz is written to give a summary of current research for cosmic rays and LIV - it is not intended to assess the LHC. My items against the argumention of CERN can be based on this review to a large extent.