Yesterday and today I have been spending time in Rome together with 600 Italian colleagues, at a symposium named "What Next". The idea is to discuss what should be the strategy of the institute to participate and support basic research in fundamental physics in the next few decades.

The format of the event is of short summary talks by ten "working groups" that examined different macro-areas: Precision SM Physics, Cosmic Ray Physics, Neutrino Physics, Flavour Physics, Gravitational Waves, Beyond the SM Physics, New Technologies, Fundamental Physics, and Dark Matter (I might have forgotten one). To each summary, delivered by two or three leaders of each working group, follows an open discussion that is allotted at least as much time as the presentations.

I really appreciate the idea of the symposium and I stand by it: INFN leaders have to take decisions on what to fund and how to allocate resources to present and future endeavours, and this appears very hard to do in the face of a generally constant or decreasing flow of funding, as well as a unclear experimental situation. Tough decisions have to be taken, and regardless of the excellent vision of our leaders, they do need to interrogate the "base" of hundreds of researchers that man the institution.

So I am trying to follow the discussion and provide my personal contribution to it, within the limits of my knowledge. Here, rather than trying to report on the many things that have been discussed today, I think I can offer my personal concerns on the future plans in the investigations of precision measurements of standard model properties.

After over forty years of investigations, the Standard Model remains a unbroken theory, which has withstood hundreds of tests and comparisons with experimental measurements of continuously increasing precision. We found a Higgs boson in 2012, and the theory appears totally self-consistent. So while our theorist friends insist arguing that the model is at most an effective theory, bound to break down at higher energy, and inconsistent in several respects, we have to reckon with the fact that there just could be nothing to discover by further increasing the precision of our experimental tests.

On the other hand, we have a new particle to study in detail now: the 125 GeV boson discovered by ATLAS and CMS has so far proven to be the particle we expected it to be, but we still know nothing on its self-interaction and on a number of other details. It would be a shame to avoid studying it in more detail in the future.

In this scenario, precision Standard Model physics appears a mandatory road to take. And of course, we have the means to do so. In particular, the Large Hadron Collider has a lot more to give than what has provided so far: a full exploitation of its potential requires a 20 year plan, what is called "High-Luminosity LHC". But there are other machines we can think of building: a linear collider, a muon collider, or a larger version of the LHC, which could reach 100 TeV in the center-of-mass of proton-proton collisions.

So if you talk to a particle physicist these days, you are unlikely to meet an opinion differing from the following: we need to complete the LHC program, and we need to build a new machine to measure Higgs boson couplings better than we can do at the LHC, as well as to push the reach for new particles to higher energy. At least, nobody ventured to hold a different view here in Rome today.

However, I made a point as I managed to grab a microphone during the discussion session. The problem I see is that bringing to full exploitation the LHC requires not just funding - which appears to be secured - but the constant dedication of a generation of young physicists. For sure, I argued, we cannot think that the data we collect in the next two decades will be analyzed by people of my generation. The same goes with the actual building of the upgrades of the detectors, their maintenance, and operation. But are we sure that, if we do not discover new physics with Run 2 of the LHC, we will be able to convince young physicists that their life should be invested in pushing a bit further the precision in the Standard Model parameters ?

We live in exciting times, as the February 11th announcement of the observation of gravitational waves has shown. I expect that more, exciting new discoveries will be made in the near future in astrophysics, neutrino physics, and cosmology. I am not at all sure that if I were a 25-year-old PhD student I would be as fascinated by subnuclear physics with accelerators as I was 25 years ago. I think I would take the road of astrophysics if I had to choose my path today. And I see this kind of reasoning being done by students in my University.

Whether we will be able to pass on to our students our enthusiasm for particle physics and particle detectors and for the physics we do with colliders, is to be seen. I would not be so sure we will succeed. And since I am even more doubtful that we will step on some form of new physics signal in the next few years, the risk that the HL-LHC and other even newer endeavours in accelerator physics get funded and remain disattended, or receive only the interest of developing world countries, is real. If INFN were to decide now on what to fund, it would be an impossible decision to take. But regardless of funding, there is a question to ask ourselves: what do we want to be working on in the next twenty years, really ? I am not so sure I know the answer.