Between 5 and 6th February, INFN met the delegations from the American Department of Energy (DOE) and the National Science Foundation (NSF) in order to establish a new scientific cooperation among Italy and USA. We talked about this meeting with Antonio Masiero, the INFN Deputy Director. “The collaboration between these two countries is excellent,” says Masiero, “and at the moment it involves four research projects, which are the topics we have discussed two weeks ago in Washington.”
The first project concerns the neutrino physics and takes place at Fermilab. It is composed by two experiments involving Italian physicists: a short baseline experiment and a long baseline experiment, which are respectively the first and the second phase of the project. The American interest in a collaboration with INFN is due to the Italian knowledge around liquid argon and its use as a target for particle detectors. “In Italy we have worked largely with liquid argon at Gran Sasso Laboratories, under the guide of Carlo Rubbia,” explains Masiero. “Our experiment is called ICARUS and it represents the best example of using liquid argon as a target for particle detectors. Thus, Americans need our know-how.”
The second context that attracted the American interest, especially the NSF participation, are the Gran Sasso Laboratories themselves. In particular, these laboratories work with American teams in four experiments: BOREXINO, CUORE, XENON and DARK SIDE. BOREXINO studies neutrinos, in particular solar neutrinos and geo neutrinos, which come from the Earth's crust. The second one, called CUORE works on a special type of radioactive decay, named double beta decay. “This experiment is very important concerning the fundamental research,” says Masiero, “because it tries to answer the question on the nature of the neutrinos mass, in detail if they have Dirac mass or Majorana mass.”
But not only neutrinos interest American researchers. XENON, the third experiment involving both Italy and USA, explores the mysterious world of dark matter, trying to discover the role of WIMPs, which are one of the main candidates as dark matter components. “XENON is the second more detailed experiments in the world concerning dark matter,” explains Masiero. “The first place is occupied by the American LUX.” As suggested by its name, this experiment uses xenon as target, instead of liquid argon. Until now, researchers have used a 10 liters target of xenon and 100 liters, but the goal is using a 1T target. Finally, the experiment called DARK SIDE is related to WIMPs detection too, but differently from XENON, it uses a liquid argon target.
The third field that has been discussed two weeks ago in Washington is space, and the projects involved are two. The first is called FERMI, which is a satellite for studying gamma-rays, but it has also the role of antimatter detector. “Space offers a great advantage if compared to the Earth because we have not the filter represented by the atmosphere,” says Masiero. “Even if at the same time on Earth we can make observations on bigger surfaces and for a longer time.” FERMI is working for three years but it has already achieved a significant goal: it confirmed the results of a previous experiment, PAMELA, on the unexpected behavior of positrons over a certain energy. In fact, if the energy increases, the number of positrons on space would be expected to decrease, but actually this number seems to increase too. “Is it caused by dark matter annihilation?” asks Masiero. “We don't know yet, but the incoming results are suggesting us a new scenario.” This hypothesis is confirmed also by AMS experiment, led in collaboration with NASA, which is focused on antimatter, in particular on the positron flux. AMS shows the same results concerning the increasing number of positrons at high energy – while for antiprotons it has not been observed any anomaly – thus scientists are studying the possible astrophysical origin of this phenomenon.
The last topic that has been presented in Washington meeting was the international cooperation on big projects like the LHC upgrade or AUGER, an experiment built in Argentina for studying cosmic radiation and cosmic swarms that by hitting the atmosphere produce sets of particles that can be studied on Earth.
Even if good results are more, we cannot ignore the difficulties that this kind of international cooperation must suffer in this historical moment. “We are living in a difficult moment for basic research in most Western countries like US, Italy, but also France and UK, where scientific research is traditionally recognized as a valuable asset,” says Masiero. “In countries like the US or Italy, it is hard to make a medium or long-term planning of the research activities since we have to rely on annual budgets which may vary, hence making uncertain the destiny of large projects that require significant investments in terms of human and financial resources.”
Another problem that emerged is represented by globalization in cooperation on big projects. “On one hand such a need for global efforts in major scientific enterprises in our field represents an opportunity, since it obliges different communities from different countries or continents to make a common effort finding an important synergy in their work; on the other hand, globalization in scientific research dictates new rules and demands a different way of approaching the scientific, technical and economic issues. It is a formidable challenge that we have to face and to win.”