Sandip was a magnet. People naturally gather around him. On top of his scientific genius, he had a warm personality and an approachable affinity to people at all levels. From 1977 to 1987, we had our weekly “boys night out” dinner, instigated by San Fu Tuan and joined by Walter Simmons, sometimes also Peter Dobson or frequent visitors such as Hirotaka Sugawara, Vernon Barger, and Francis Halzen. Those were happy memories. In 1996, Sandip was visiting Vanderbilt, and Tom Weiler hosted the Festschrift for his 60th birthday. We had a great time. Also there was Sandip’s advisor Peter Rosen (who passed away in 2006) whose advisor was Blin-Stoyle, and through him, Sandip’s scientific lineage goes all the way back to Newton. In 2014, Eileen and I treated Heide and Sandip to a delightful dinner in Santa Barbara at a nice Italian restaurant. It was the last wonderful moment we shared. I benefited a great deal in life and career from having known Sandip. His legacy lives on, as others surely will also attest.

I had the pleasure of having Sandip in my PhD committee back in 1998 to 2000. He was a great teacher and mentor. His presence at the weekly colloquium will be surely missed.

Though not knowing professor Sandip the biography you have shared shows he was a great person and a scientist to the core. Most of the Indians who settle in the USA choose either East or west coasts but he made Honolulu, Hawai his home, a beautiful place to live. RiP🙏🙏🙏

Sandip and I first met in 1964, when I was a Cornell grad student and he was a Syracuse postdoc. We came to collaborate on a number
of projects over the years, and our final face-to-face meeting was to share an outdoor meal with our wives Heide and Joan under a full
Hawaiian moon. Sandip’s mix of scientific and human qualities was unlike anything I had ever experienced, before or since. And his
interest in fundamental physics persisted (even in the months before his demise, he and I were corresponding about the direct experimental observation of T-violation).

From Sandip, I learned much about physics, but even more about how to live life. How lucky we all were to know him!

Sandip joined Syracuse University as George Sudarshan’s postdoc, the very same year I entered graduate school. Starting in Tokyo and Kyoto (1981), at neutrino conferences, at dinner or at any other social event, we found many common interests and became friends.

Sandip was an insightful physicist and a pioneering neutrinophile. He also was a human being of culture and perspective.
We enjoyed each other’s company talking neutrinos, consuming eels in Osaka, or sharing a gourmet dinner with our spouses at Stockholm’s Grand Hotel. An anecdote illustrates Sandip’s gentle and thoughtful way:

After Sandip told me of Maki, Nakagawa and Sakata who were the first to suggest flavor neutrino oscillations, I started calling the lepton mixing matrix the MNS matrix at a conference in Trieste. Unaware of the MNS contribution, friends and students of Bruno Pontecorvo chastised me because of my omission (Pontecorvo had much earlier suggested neutrino-antineutrino oscillations, but the data suggested MNS flavor oscillations). Nambu who was listening in silence simply extended his hand and said “thank you”.

Thank you Sandip! you are already missed

I first met Sandip in 1966 at Syracuse.He had joined us as a post doc in 1965. I had returned from

a one year leave to Syracuse then. The physics department was in the process of

being built up and we did not have a building or proper offices. Sandip and other post docs were

housed in a rented house in Irving Avenue .I used to go there in the afternoons for

discussions . Among his colleagues at that time, I remember Imre Gyuck, who came with him from

Purdue. Imre became the Energy Storage Program Manager in the U.S. Department of Energy . The

house naturally got named as the Irving Institute of Physics. We entered our present building in

1967, the year that Sandip left to join Hawaii. San Fu Tuan who was trying to build a theory group in

physics in Hawaii had recruited him with a faculty position.

The physics exchanges between Sandip and I were limited and superficial .He was then working

on weak interactions and nonleptonic decays , topics which I knew little of. But we did interact

socially : our cultural backgrounds as Indians united us.

Our meetings became sporadic after he left Syracuse. I do recall one more of our meetings in the

US.That was in Seattle, perhaps in the summer of ’67 when there was a summer school there. Besides

Sandip, R.Ramachandran (‘ R.R.’ ) was also there and we used to move around together quite a lot.

I knew R.R. as a student in Chicago. He joined the Indian Institute of Technology, Kanpur after a post doc

period and eventually became the Director of the Institute of Mathematical Sciences ( IMSc) in Chennai He

held this post till his retirement.

Sandip used to visit IMSc every two years or so where I am a regular visitor and where I used to meet him.

Our last meeting was in 2017 or 2018. I will miss him in Chennai.

I was shocked to hear of Sandip’s demise. A great friend and colleague is no more. I first met Sandip at the Tata Institute in 1972 (I think) when he was visiting TIFR and I had just joined the latter. We hit it off right away and became buddies. He visited TIFR many times after that since he would come to India almost every other year. We used to walk to the nearest tea shop and have chai together. he would inevitably have a paan after that and his lips would be red. He was a great paan lover and in fact took some paan leaves back to Hawaii, but unfortunately could not grow them there. I introduced him to a famous shark dish at the Trishna restaurant in Mumbai which he appreciated greatly. During my two long visits to Hawaii, he introduced me to the Thank God, It’s Friday group and we drank beer there every Friday evening. I am also grateful to Sandip for inducing me to visit Baroda, the location of his Alma Mater, which I found to be a delightful city.

Sandip’s physics was characterized by original ideas rather than heavy calculations. He loved neutrinos and flavor physics in general. His crucial role in bringing the Kobayashi-Maskawa work to the attention of the world has already been highlighted by others. I shall always cherish my collaborations and discussions with him. He played a crucial role in germinating the idea of a seesaw mechanism for a Dirac neutrino mass in my mind, a project which was worked out later in collaboration with O. Shanker. But, much to our disappointment, Sandip refused to have his name included in the paper since he had not done any of its calculations. Of course, Sandip was an undoubted world authority on neutrinos. It was unfortunate that he got into a controversy with Pontecorvo regarding the genesis of neutrino oscillations. But Sandip’s point that Pontecorvo had not proposed oscillations between neutrino flavors but between neutrinos and antineutrinos was correct.
The other thing worth mentioning about Sandip was the rapport that he enjoyed with experimentalists. He was involved in some way or other with every international big neutrino experiment and of course wrote many papers with experimental colleagues. He was the inspiration behind the INO project and a successful commissioning of the INO experiment would be a fitting memorial to him.

Sandip is gone, but I will cherish his memory as long as I am alive.

I met Sandip first at a conference in Laguna Beach where U.S. theorists used to meet every fall. It was a long time ago, and the only thing he and I remember, not surprisingly, is having dinner one evening at a French restaurant near John Wayne Airport.

I had the pleasure to share more time with Sandip when he spent a sabbatical in Madison in 1978. As a theorist, he was a purist and did not venture far from weak interactions, but we convinced him to tackle the problem on how to find the top quark at a hadron collider. Sandip always was an inspiring collaborator, and this paper has his approach to physics written all over it (Phys. ReV. D, 20, 2862, 1979). It also came a decade before its time because, by the time UA1,2 took data, its ideas were in a category where one had long forgotten that they had had to be invented.

Sandip and friends invited me to spend a memorable semester in Hawaii in 1980: I taught an informal seminar, which became Halzen and Martin three years later, and I suspect that my many lunches with John Learned and his DUMAND crew may have somehow influenced my life although I must admit that I had no clue what they were doing at the time. Most importantly, I was adopted into the circle of Sandip and Heide’s friends that, from then on, I joined at meetings across the globe for physics and, mostly, good restaurants—from Venice to Paris to Honolulu, where we discovered Roy’s Hawaii Kai before it became an empire.

I loved Sandip and I loved every minute I spent with him, including a long evening at a sushi bar last January made possible by a trip to the AAS meeting in Honolulu.

Sandip was an inspiration for young beginning physicists of my generation. Seeing an Indian name on first-rate papers, such as the famous 1980 paper on matter resonance and the paper on high-energy neutrino flavor ratio, gave a lot of confidence to me personally when I was beginning my research career. Later when I met him at workshops and conferences, I came face-to-face with the sharp mind behind those papers. He was always warm and friendly, and approached life with a light and masterful touch. I feel a deep loss that he is no more. Of course, the Sandip-style of neutrino physics lives on in the work of all who he inspired!

I was a postdoc at UH Manoa from 2015 to 2018 and, like so many of us, remember Sandip both for sparkling conversation— physics and otherwise— and for his warmth and humanity.

I particularly remember a conversation about where to play bar trivia in Honolulu and a chat where he took the the time to make sure that I had really thought out my post-physics plans. I’m really going to miss him.