by Ian Randall. Published: 19 August 2011

This time, ALICE Matters interviewed Guy Paić, a long-time ALICE collaborator who works with the Institute for Nuclear Sciences at the National University of Mexico.

How long have you worked with ALICE?

Well, actually, I've been working in the heavy ion experiments since the very beginning at CERN, in 1986 - which makes for 25 years of life in heavy ion physics at CERN, and at RHIC in Brookhaven. I was one of the first collaborators in ALICE, and I’ve been here since the very inception. So, this makes almost a whole life, right?

In 2003 I left for Mexico’s National University, and I created there a group, from nothing; there was absolutely no experimental physics in this institute. Now we have a very nice group of young people, and we are starting to have a steady flow of PhD's and masters’ students, and so on. Actually, presently, here at CERN I have three students - one is a summer student, one is a student doing a PhD and the third one is a masters’ student.

In Mexico we have, also, a nice detector lab – so we have been collaborating on the possible upgrades of ALICE; in this case the Very High Momentum Particle Identification detector - since I was involved very actively in one of the other ALICE detectors, called the HMPID (the high momentum particle identification detector). In this we are contributing, from the side of Mexico.

How did you get into particle physics in the first place?

Originally, I was a low energy nuclear physicist. In the beginning of the eighties I saw that, actually, it was time to turn to higher energies and to new physics problems – and, so, this problem of studying the quark gluon plasma was something that looked to me to be quite reasonable and attractive.

Of course, one has to have the possibility to enter into a collaboration. Here I was lucky because, at that time, I was the head of a group in Croatia - because this was where I finished my schooling - and I was invited by Professor Stock to participate in the NA351 experiment at CERN.

This was how I started in this field, and I have always tried, since, to have two kinds of activities - one that is connected to development of new detectors and techniques, and the other connected with the interpretation of the physics and the results. I really enjoy having this ‘double persona’.

For instance: I’m working with one of my students on the development of the new detector, which is called JEM; and with another student, Antonio, I have a paper that is under review by the ALICE collaboration - which is, for a small lab, a big success, eh?

What are your plans for the future?

I am currently on sabbatical - since the first of February - and in a year, I am going back to Mexico. The good thing about Mexico – as it is like in the United States - there is no compulsory retirement age. So, as long as you feel fit and you enjoy what you are doing, you can stay: which is not necessarily the case in Europe.

So, from this point of view, I feel very well there, I learn Spanish and I'm enjoying myself very much.

So, I take it you really like your work?

This kind of work: if you don't like it, you’d better leave it. If you are not enjoying it, you should just jump off of the train.

It has been a very interesting time, since the beginning, and now we also have a whole lot of excellent data. In the machine, both the accelerators and the detectors are working in an impressive way and so it is clear that, with the flow of data that is coming, we will have to have some new insights. This is what is keeping me in - I would like to see these insights into these secrets of matter.

What advice would you give to a younger physicist that is just starting out?

Well, it is very difficult to give advice - it is better to show your own example, but, of course, the only advice that I would say is to question oneself all the time - Why do I do that? What is the finality of that? - because there is a lot of gruesome work - but one should have in front of that some kind of higher goal.

The initial difficulties should not put off the younger people - and, of course, the love for what they are doing. The people that are working in ALICE - especially the young ones -are putting in many hours of work to get good results - and it is not always easy. So that, to have this light, to see where you are going and like it - this is the right attitude.

How would you say ALICE has changed in your time with the collaboration?

When we started we all knew each other, all the collaboration - now there are a lot of new faces. You could reach everybody - now you don't see each other - it's all video conferences, there is not so much contact. It is clear that a collaboration of a hundred people is not the same as a collaboration of a thousand. This also requires different rules and so on, so everything gets a lot more organised than it was in the beginning - it was a bit hectic!.

Of course, there were several stages: the design, the planning, the construction and finally the data taking - they were all stages with different kinds of challenges and pleasures. One should enjoy all the stages - they are normal. The only thing is that, today, for the young people - they will, more-or-less, spend all their lives in one experiment, because the life of the LHC is about 20 years.

What hobbies do you enjoy?

Travelling. Primitive art: masks, things like that. I have a collection of African and Mexican art. I also like mountaineering, Skiing; and Tennis, in the summer.

  • 1. (IONS/STREAMER CH.) Study of Relativistic Nucleus - Nucleus Collisions