Three researchers working in the new field of astroparticle physics argue the case for making the data from astroparticle experiments public.
Making astronomical data from the telescopes in space or on Earth freely available is common practice. A first step in this direction for particle physics data has been undertaken recently with QUAERO, a scheme developed at Fermilab to make high-energy data from the D0 experiment generally available (CERN Courier November 2001 p8, Abazov et al. 2001). This kind of “experimental transparency” allows any physicist in the world to test a new theoretical idea or evaluation algorithm. However, the practice does not exist for data taken from dark-matter experiments, although the most natural approach for this relatively new cross-disciplinary field of astroparticle physics should be that the data do not remain the private property of each experimental collaboration, but become public, as in the case of astronomical data.
We do not believe that the continuing secrecy in experimental astroparticle physics has been introduced intentionally. On the contrary the reason most probably lies in the lack, as yet, of any direct signature for dark-matter particles, which are believed to dominate the gravitational mass of the universe strongly. This situation has existed for decades, but despite this the challenging experimental question of the nature of dark matter is now fascinating more and more physicists across different disciplines. To our knowledge, there is no other similar example in the past.
As long as dark-matter physicists believe they have a zero result with their data, they will focus on improving detector performance to stay at the forefront of their field of research. Who then, has the time and the courage to consider releasing data collected over several years, which have become downgraded at best to measurements of background? There is no lack of data coming out of the underground dark-matter experiments worldwide, but these data have already been quasi disqualified because they do not fit the widely accepted picture of dark-matter interactions at the Earth.
However, in the past even dark-matter data have been re-evaluated following a new (theoretical) approach from inside as well as outside the collaboration, and this is exactly why astroparticle physicists should release their data. Most, if not all, dark-matter experiments are not complex, and their data can easily be formatted for non-experts. Scientific problems know no frontiers, and certainly not those as defined by a collaboration, even an international one. The dark-matter problem itself might also require some kind of synergism, or even a cross-correlation, between different experiments that have been declared – or even not declared – as dark-matter experiments.
As in particle physics, astroparticle physics theory is far ahead of experimental performance. However, it could be that the generally accepted theoretical picture does not point the experimentalists in the right direction. After all, there have been plenty of unanticipated discoveries in the past. For example, if the recently widely discussed theory of extra dimensions reflects reality, at least some of the approaches of the dark-matter searches must be revised because the particles they are aiming to detect have completely different properties from those assumed so far. Obviously, we must be sure that a signature in dark-matter data from previous experiments has not been overlooked, otherwise the broken dreams of dark-matter physicists will become their nightmares.
Making the data from astroparticle physics public will certainly promote scientific collaboration and will increase the many numbers of “amateurs” working in this field. Scientific transparency can only be beneficial to the science we are supposed to serve, and we have therefore suggested to the astroparticle physics community that it releases its data (Hoffmann et al. 2003). CERN, with its astroparticle physics programme, could once more be the pioneer of a new approach.
V M Abazov et al. 2001 Phys. Rev. Lett. 87 231801.
D H H Hoffmann, J Jacoby, K Zioutas 2003 Astroparticle Physics (in press).