Farewell to Gianpaolo Bellini, protagonist of neutrino physics and creator of the Borexino experiment.

Internationally renowned physicist Gianpaolo Bellini, former full professor at the University of Milan and scientist emeritus at the INFN, passed away on August 12th at his home in Foresto Sparso, in the province of Bergamo, at the age of 91. His work left a profound mark on the study of neutrinos and on the development of the INFN, making a significant contribution to establishing the Gran Sasso National Laboratories as one of the world’s leading centers of astroparticle physics research, thanks in particular to the Borexino experiment, which he conceived, together with physicists Frank Calaprice and Raju Raghavan, and led for over 20 years.

Under his leadership, the experiment achieved results that marked the history of the discipline: from the measurement of neutrinos emitted by the main nuclear reactions in the Sun, to the first direct observation of neutrinos produced by the CNO cycle, fundamental to understanding the fusion processes in the Sun’s most massive stars. Both discoveries were included among the British Institute of Physics’ “Top Ten Breakthroughs” in 2014 and 2020, respectively. Borexino was also the first experiment to detect geoneutrinos, opening a new window onto the energy production processes occurring in the Earth’s core.

“Today we lose a great scientist who made fundamental contributions to the study of solar neutrinos and to understanding the reactions that power the Sun and stars,” recalls Antonio Zoccoli , president of the INFN. “For his pioneering studies, he would certainly have deserved to have his career crowned with the Nobel Prize. Thank you, Gianpaolo!”

“Gianpaolo’s passing is a tremendous loss, both personally and scientifically,” commented Marco Pallavicini , member of the INFN Executive Board and co-spokesperson for the Borexino Scientific Collaboration. “I was fortunate to share the Borexino adventure with him for almost thirty years. Gianpaolo was a great scientist and a powerful leader throughout the collaboration, capable of resolutely addressing the major scientific and technological challenges that accompanied the experiment’s implementation. He worked on the experiment with great enthusiasm and dedication until the very end. We will miss him deeply.”

“Gianpaolo’s passing represents a grave loss for the entire scientific community and, in particular, for the Gran Sasso National Laboratories,” said Ezio Previtali , director of the INFN Gran Sasso National Laboratories. “Gianpaolo was among the founders of our laboratories and dedicated a significant portion of his scientific career to proposing, developing, and leading the Borexino experiment. His strong personality and decisive approach contributed to the development of the scientific lines he promoted and allowed him to overcome the numerous difficulties associated with conducting an experiment as complex as Borexino. His scientific legacy will be a point of reference for future generations of physicists and for many of the experiments that will arise from the ideas he proposed.”

“I shared a very long stretch of scientific activity with Gianpaolo, centered on the absolutely unique and exhilarating adventure of Borexino,” recalls Gioacchino Ranucci , INFN researcher and co-spokesperson for the Borexino Scientific Collaboration. “The experiment’s success is due to the solid scientific guidance of Gianpaolo, who, as a great scientist and a highly capable manager, brought it to a brilliant conclusion, overcoming difficulties and obstacles. Not only will we, my colleagues at Borexino, never forget Gianpaolo, but the scientific legacy of the experiment’s results will remain as a testament to his extraordinary human and scientific experience. Today, I mourn not only my colleague, but also my older brother, with whom I shared a deep and sincere friendship.”

The value of his scientific contributions has been recognized by numerous prestigious international awards. In 2016, Bellini received the Bruno Pontecorvo Prize from the Joint Institute for Nuclear Research in Dubna, “for his outstanding contributions to the development of low-energy neutrino detection methods, their implementation in the Borexino detector, and the important results on solar neutrinos and geo-neutrinos obtained by this experiment.” And in 2017, he was awarded the Enrico Fermi Prize from the Italian Physical Society, “for his crucial contributions to neutrino physics and astrophysics at the Gran Sasso underground laboratory.”

Before the Borexino adventure, Bellini had already made fundamental contributions to high-energy physics. Between the late 1960s and the 1990s, he led joint teams from the University of Milan and the INFN engaged in experiments at CERN, the Institute for High Energy Physics in Protvino, Russia, and Fermilab.

His career has been deeply intertwined with the growth of the INFN. A member of the Board of Directors from 1973 to 1983, he served as its Vice President from 1983 to 1989, and chaired the institution’s National Computing Committee between 1981 and 1983. He also coordinated the national program on superconductivity applied to the LEP2 and LHC accelerators, contributing to the development of technologies for large international research infrastructures.

At the University of Milan, where he has been a full professor since 1976, he has trained generations of researchers, also directing the Doctoral School in Physics, Astrophysics and Applied Physics from 2003 to 2008.

He was a member of the Council of the European Physical Society from 1980 to 1983, of the European Committee for Future Accelerators from 1983 to 1986. He was also a consultant for the Steering Committee for Research Evaluation (CIVR), a member of the Istituto Lombardo Accademia di Scienze e Lettere, and an honorary member of the Italian Physical Society.

Source: INFN press release

Dear friends,

I am very sad to inform you that Gianpaolo, our great, historic spokesperson who brought Borexino to the worldwide success in neutrino physics, passed away this evening. We will never forget the passion, the dedication, the commitment, the effort that for more than 30 years he devoted to Borexino, the greatest scientific achievement of his
lifetime. We will never forget also the profound human touch and kindness, since the beginning of Borexino, towards all the members of the Collaboration, who for Gianpaolo were first friends and then collaborators. Under his guidance, Borexino became more than a working group, but a real scientific family of people connected by an enduring link, persisting also now that the  experiment is closed .

The legacy that Gianpaolo leaves us is enormous, but I am sure that following his lifetime lesson of dedication to science we all will try to do our best to keep it alive. This will be also the best way to honor his memory.

As soon as I will know how the events will be planned over the next days to give Gianpaolo the last salute, I will keep you informed.

Gioacchino

A terrible news. Gianpaolo has led the collaboration to its successes for 30 years.
I am speechless now… but this is truly the end of an era.

Marco

Dear Gioacchino, dear friends,

What terrible news.

Gianpaolo has been such a defining presence in Borexino for so many years that it is hard to grasp that he is no longer with us. It truly feels like the end of an era.

There is something particularly poignant in the fact that Gianpaolo, who devoted such a large part of his life to studying solar neutrinos, passed away on the day of a solar eclipse, when so much of the world turned its attention to our star.

I still remember knocking on Gianpaolo’s door in 2005, when I was looking for a postdoctoral position in Milano. I was amazed to discover that there was an experiment dedicated to solar neutrinos — a subject that had fascinated me since, as a child, I had read about the Homestake experiment. I could not have known then how much that encounter would shape my life.

Thanks to Gianpaolo and Borexino, I started my path in neutrino physics and built my experience in solar-neutrino and antineutrino analysis. What I learned during those years became the foundation for much of the work I have done since and for where I am professionally today.

I also remember Gianpaolo on a very human level — for example, how worried he was about me when I decided to go on a trek deep into the Algerian Sahara. He was genuinely concerned that I might be kidnapped. That mixture of scientific passion and personal concern for the people around him is something I remember very well.

In more recent times, Gianpaolo called me several times, and I am particularly grateful now that we had those conversations and the opportunity to reconnect. Looking back, they give me a peaceful sense of closure to a very long and important chapter of my life.

Unfortunately, I will not be able to attend the funeral tomorrow. Gioacchino, could you please let me know an address to which I could send a letter of condolences to Gianpaolo’s family?

I will remember Gianpaolo with gratitude for the decisive role he played at the beginning of my scientific path, for the extraordinary experiment and scientific community that he shaped and led for decades, and for a scientific legacy that will remain part of neutrino physics for generations.

Livia

dear all,

this is a terrible news for all of us.

I was expecting it, since the last time I have talked to him two months ago in occasion of his birthday, I found him very tired and almost resigned to give up, which was very unusual for him. On the other
hand, I found him as lucid as ever… until the end he has kept clear mind and very sharp reasoning.

Buon viaggio Gianpaolo.

Barbara

Dear Gioacchino, dear all,

I and all my colleagues from Kurchatov institute, are very saddened to hear of the passing of Gianpaolo.

I had the privilege of knowing Gianpaolo since 1998 after my visit to Milano in order to discuss Kurchatov’s group’s participation in the Borexino experiment.

Over the years, it has always been a pleasure to communicate with him on scientific and non-scientific topics. He told me how he conducted research in Russia at the accelerator and retained the best memories and love for our country.

We will remember him as a great scientist who made significant contributions to the development of neutrino physics.

Unfortunately, I will not be able to attend the funeral, so let me ask to convey my sincere condolences to his family.

Misha

Dear friends,

It is hard to accept the fragility of our existence, but Professor Bellini’s passing at a time when the whole world was looking at the eclipse of the Sun brings me a strange sense of peace.

Deeply moved,

Marcin

Gianpaolo was a great example of strength, determination, and passion for all of us. That is the beautiful memory of him that will truly stay with us, as a source of inspiration for everyone.

Ciao, Gianpaolo. We will miss you.

Nicola

Dear Gioacchino, all,

I am very sorry to hear this sad news.

It is difficult to grasp. Gianpaolo was such a constant presence in our scientific lives — always there, and uncompromisingly dedicated to Borexino.

Please convey my deepest condolences to his family, also on behalf of all my colleagues in Munich.

Yours sincerely,
Stefan

Dear friends and colleagues,

The sad news of the passing of Gianpaolo is, as others have said, a closing of an era that has defined the career of many of us and one that led solar neutrinos into the realm of precision physics.

I met Gianpaolo in 1994 when, with Cristian Galbiati and Elisa Resconi, I took the advanced lab course that he ran. That experience changed our paths and led all three to pursue a career in neutrino/astroparticle physics. Since joining Borexino in 1998, I remember Gianpaolo’s role in getting Borexino through the toughest times and in recognizing the junior collaborators who took a risk with the experiment at uncertain times.

I am grateful to have been able to attend the nice event for Gianpaolo’s 90th birthday last year that saw his contributions to science acknowledged by his longtime collaborators, and for the interactions I had with him until then during the writing of the Borexino review paper and the book that he also recently published.

As will not be able to attend the funeral tomorrow, I ask Gioacchino and others who can be there to convey my sympathy to his family.
I will remember Gianpaolo fondly as a key figure of my becoming a physicist and will greatly miss him.

Andrea

Dear Gioacchino, all,

This is very sad news.
Gianpaolo’s scientific legacy and his dedication to Borexino will be remembered with great respect by
the scientific community.
Please convey my sincere condolences to his family on behalf of myself and all colleagues in Krakow.

Grzegorz

In the sadness of this moment I want just to say: Grazie Gianpaolo. His scientific and human legacy is part of us and it lives on in us.

Sandra

Dear friends and colleagues,

This is very sad news for all of us. I first met Gianpaolo in 1992, when I came to Italy for the very first time.  The Dubna group had already joined the experiment in 1991, and this was my first encounter with Italian colleagues and the backbone of the Borexino collaboration.
Gianpaolo had earlier taken part in the joint Russian–Italian experiment at the Protvino accelerator, so inviting the Dubna group was not a random decision — he was the one who shaped the collaboration.

On a personal level, working with Gianpaolo gave me the opportunity to remain in physics during a very hard period for my country. We cooperated for more than thirty years — essentially all of my best years in physics. During these decades, a remarkable collaboration grew into what I would call the Borexino family, and Gianpaolo always treated us as part of that large family. Now I have the feeling that our family has become orphaned.

I will always be thankful that my path led me to the experiment under Gianpaolo’s leadership.

To Gianpaolo’s family and all who held him dear, please accept our deepest sympathy from all of us in Dubna.

Oleg

Dear Gioacchino and Borexino friends and colleagues,

Gianpaolo surely lived a rich and fulfilling life, and we are all better for it.  His legacy lives on in the many, many people he helped launch into life, myself included.

Thank you Gianpaolo, and Blessings to all and his family in particular,

Bruce

Dear all,

For many of us, Borexino and working alongside Gianpaolo were a major part of our scientific lives. Together with him, we believed in the project even when it seemed almost too difficult to accomplish. He deserves great credit for guiding it towards its technical and scientific success. This is part of Gianpaolo’s legacy, and it will remain within the scientific community, well beyond Borexino.

Over all these years of working together, we have accumulated so many personal memories of him. I will mention just one. I remember that, many years ago, he gave me a large forsythia plant as a gift. I planted it in my garden, and it is still there. Every spring it blooms again.

Farewell, Gianpaolo. Now those yellow flowers that return every spring have a special meaning.

Gemma

Stimata famiglia Bellini,
Caro Gioacchino,
cari colleghi di Borexino,

Ho appreso con grande costernazione della morte di Gianpaolo, e nonostante tutto vi ringrazio molto per avermi avvisato.

Per tutti noi Gianpaolo è stato una personalità straordinaria e un punto di riferimento nella pianificazione, realizzazione e direzione scientifica durante i molti anni di lavoro comune su Borexino. Senza di lui, questo progetto unico certamente non avrebbe raggiunto un tale successo straordinario. La sua forza di leadership e determinazione era senza pari.

Inoltre, era anche un amico e un partner; sotto la sua guida la collaborazione si è trasformata in un gruppo di amici, praticamente in una famiglia, che sicuramente continuerà a esistere.

Tutti noi lo sentiremo molto, ma cercheremo anche di preservare e trasmettere la sua eredità scientifica e personale. Per me è particolarmente sconvolgente quanto sia già ridotto il gruppo degli iniziatori di Borexino.

Franz v. Feilitzsch

—

Hoch verehrte Familie Bellini
Lieber Gioachino
liebe Borexino- Kollegen

Mit großer Bestürzung habe ich vom Tot des Gianpaolo erfahren, trotz allem vielen Dank dass Du mich benachrichtigt hast.

Gianpaolo war für uns alle eine herausragende Persönlichkeit und Stütze bei der Planung, Durchführung und und wissenschaftlichen Leitung während der vielen Jahre gemeinsamer Arbeit an Borexino. Ohne ihn wäre dieses einzigartige Projekt sicherlich nicht zu dem außerordentlichen Erfolg gelangt. Seine Führungsstärke und Durchsetzungskraft war einzigartig.

Darüber hinaus war er aber auch Freund und Partner, unter seiner Führung konnte sich Kollaboration zu einer Freundesgruppe, eigentlich einer Familie, entwickel, die sicherlich auch weiterhin bestehen wird.

Wir alle werden ihn sehr vermissen aber auch versuchen sein wissenschaftliches und persönliches Erbe zu erhalten und weiter zu geben. Für mich ist es besonders erschütternd wie sehr sich bereits die Gruppe der Initiatoren von Borexino reduziert hat

Franz v. Feilitzsch

I am deeply saddened to hear about the passing of Gianpaolo. I had the pleasure to meet him the first time in November 1992 at my first Borexino collaboration meeting at lake Garda. I think it was the meeting where the – at that time very small – collaboration decided to build a test facility at Gran Sasso, the famous CTF.

Gianpaolo was leading the collaboration through many storms. Sometimes it seemed to me to be to hard to get it accomplished, but especially during my years at Gran Sasso, first as Marie-Curie fellow then as project manager, I learned directly how strong Gianpaolo was pushing and fighting for it. This was enormeously encouraging for me and I believe it was Gianpaolo’s strong leadership which made Borexino flying and finally so successful.

I extend my deepest condolences to Gianpaolo’s family.

Lothar

Borexino will continue to stand as a lasting legacy to Gianpaolo. He will be greatly missed.

Wick Haxton

Please pass on my sympathy to your Borexino colleagues and to his family. Gianpaolo has been a leader in the neutrino physics community and the Borexino experiment provided legacy results with his leadership.

Sincerely,
Art McDonald

Thank you for providing the sad news about Gianpaolo. He provided the administrative oversight that was essential to make Borexino successful.

Gianpaolo and I battled on many occasions, but we both came to respect each other and he helped me make contributions that were unique to Borexino. I will always be thankful for the opportunities Gianpaolo and Frank provided me.

Jay Benziger

Very sad news indeed. I will not be able to travel to Bergamo tomorrow, but would be grateful if you could bring my deepest condolences to Gianpaolo’s family.

I totally subscribe to the words of Gioacchino. I came to Milano as a student 30 years ago. The lively scientific environment of the Borexino collaboration, which, due in a major way to his leadership, always welcomed deep, detailed discussions in a friendly and truly collaborative way while at the same time providing a high example of dedication and persistence in the face of difficulties, strongly impacted my development as a scientist.

On a more personal note, the warm and sustained welcome I received from him in Milano, and his 3 visits to Portugal at that time, have helped me tremendously to, a few years later, bring neutrino physics to Portugal.  I will always be deeply grateful for that crucial help in my early steps. On such a sad day, I choose to remember him how I saw him 2 years ago at the Neutrino conference in Milano: joyful, full of energy, passion and pride for the great scientific achievement he led in Borexino.

José Maneira

So sorry to hear the sad news about Gianpaolo. He was a giant scientist, amazing leader, and a remarkable human being. He was a close colleague and friend of John, and I will always cherish wonderful and fun times with them in Italy and elsewhere. Gianpaolo will be sorely missed, but his legacy will shine forever.

Sadly,
Neta Bahcall