by Virginia Greco. Published: 16 April 2018

Andrea Dainese is Deputy Physics Coordinator of the ALICE experiment as of January 2017 and he is fully involved in the detector upgrade and in the definition of ion programmes at the future CERN accelerators. We talked with him to learn about his scientific activity and interests.

Andrea Dainese, Deputy Physics Coordinator of the ALICE experiment, is also Chair of the Steering Committee of the Quark Matter 2018 Conference, which will be held In Venice (Italy), 13-19 May.

 

Not many twists, but a steady way up characterized the career of Andrea Dainese, who is now researcher at the Italian National Institute of Nuclear Physics (INFN) in the same city (Padua, Italy) in which he grew up and studied and Deputy Physics Coordinator of ALICE, the experiment he has been working on for almost 18 years.

After completing his Master at the University of Padua, with a research project on the NA57 experiment at the CERN SPS, in 2000 he enrolled for a PhD and entered the ALICE Collaboration. For his doctoral thesis, he performed simulation studies about physics measurements that involve the Silicon Pixel Detector (SPD) – which was being designed in Padua and other institutes at the time –, such as the reconstruction of charm hadron decays. He continued working on these topics after receiving his PhD and became an expert of heavy flavour physics, so that over the years he covered various roles in the ALICE working group dedicated to this research area. He also took part in the task force that defined the strategy for the upgrade of the experiment and that wrote its Letter of Intent, approved in 2012.

Since then, Andrea has been dedicating a major fraction of his time to the upgrade. He coordinated the physics studies for the new Inner Tracking System (ITS) and then took the lead of the ALICE group in INFN Padua, which also contributed to the hardware developments for the new ITS and its mechanical support. Later, he took over the coordination of the performance studies for the whole upgrade of ALICE and became the reference person for it within the Physics Board. This meant acting as a link between the physics groups and the teams working on the detector construction and simulations. Since January 2017, he is deputy physics coordinator, together with Andreas Morsch.

In this capacity, Andrea follows the work carried out by all physics working groups, the approval process of preliminary results and the preparation results for scientific papers. “Marco, Andreas and I work in a collegial way,” he explains. “We discuss and analyse together the ongoing activities and the issues that need actions and decisions. Of course, each of us has some specific expertise that is taken into account. Just to make an example, I contribute more on hard probes physics and upgrade-related studies, while Andreas has a lot of insight on correlations and is our expert on simulation aspects. Marco has a broad view of all topics and he leads discussions within the physics board, of which he is chairman.”

Not only is Andrea in charge of matters related to the experiment upgrade, but he also plays a role in the various groups discussing future heavy-ion programmes, both at relatively-short and long term. In fact, if from one side the plan for the next 10 years has been already approved, decisions have to be taken for the following decades and about future accelerators.

The heavy-ion programme at the LHC might be extended beyond Run 4, which will end in 2029,” Andrea explains, “hence, the experiments together with the theory community are evaluating what direction to give to future research. For example, colliding lighter ions is an option on the table, which would allow studying a system smaller than Pb-Pb collisions, but not as small as the pp one.” Intermediate conditions, though, can be produced with lead ions as well, in non-central and p-Pb collisions, thus it is not clear yet if injecting lighter ions would really provide relevant information. “Anyway, they could offer an advantage in terms of luminosity, since this quantity in LHC is limited by bound-free pair production and electromagnetic dissociation of nuclei, which increase respectively with the seventh and fourth powers of Z – the atomic number,” Andrea clarifies. “Therefore, colliding nuclei with smaller Z would reduce this effect and guarantee higher luminosity.” New contributions to this discussion will be certainly brought in by the analysis of the 8-hour xenon run of last year, the results of which will be presented at the Quark Matter 2018 conference, to be held in Venice, Italy, from 13 to 19 May.

For the last four years, Andrea has also coordinated – together with Silvia Masciocchi and Urs Wiedemann– the group that has performed physics studies on heavy-ion collisions at the Future Circular Collider (FCC). Some interesting measurements that could be done only with such a machine, which would deliver collisions at a luminosity more than 10 times higher and an energy 7 times higher than the ones foreseen for the High Luminosity LHC (HL-LHC), have been singled out. “In such conditions, we would be able to investigate physics phenomena using new probes,” Andrea explains. “For example, some analysis has shown that the top quark and its decay chain (top quark –> W boson + bottom quark) can allow to study the density of the QGP as a function of time, since the interaction of the products of the decay of the top quark and of the W boson starts some instants later than when the QGP is created. This research cannot be carried out at the HL-LHC, because the top quark has a very low rate of production, thus in order to have good statistics we need high energy and luminosity”. 

There is another interesting aspect that could be investigated at the FCC,” continues Andrea. “The initial temperature of the system could reach close 1 GeV, so that pairs of charm-anticharm quarks can form thermally in the QGP by interaction of quarks and gluons. The study of this thermal generation can give us indications on how the system temperature evolves in time.”

The coordination of and participation in so many groups fill up Andrea’s agenda, leaving him not much spare time. “I have two daughters as well who keep me busy,” he adds, “nevertheless, I try to find the time for some mountain biking, which I really enjoy!