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CERN Courier March 2015 Inside Story New Journal of Physics IMPACT FACTOR The open access journal at the forefront of physics 3.673 as listed in the 2013 ISI Journal Citation Report® www.njp.org Circles of light: a physicist’s tale We are pleased to announce our participation in the Sponsoring Consortium for Open Thinker or artisan? performing calculations using the theoretical tools of particle physics. In this respect, my Access Publishing in Particle Physics Lalit Sehgal on the link occupation combined the traits of a thinker with those of an artisan. (SCOAP3). between his career in physics Did the work bring me fame and fortune? A modicum of recognition, perhaps, but and a tailor he saw long ago certainly no great wealth. The main reward SCOAP3 can get your high-energy physics article published in was the joy of working with scientists, and in Lahore. sharing in the exhilaration of search and this prestigious open access journal at no cost to you. discovery. Was the work I did held in esteem? Here I have to be guarded in my reply. The For more details visit iopscience.org/NJP/articlecharge. When I was four years old, fi eld of elementary-particle physics tends to my grandfather, who was a divide itself into groups with varying ideas respected citizen of Lahore, about the important issues, priorities and came to our home in his ultimate goals. To put it crassly, some people horse-drawn carriage to take Lalit Sehgal. (Image credit: Anand Sehgal.) believe that their task is to try to read the me along on a drive through mind of God, who is a thinker. This group the city. He was known to thimble. The fl ashes appeared to merge into is convinced that the truth will be found in be a person of temper, so I decided not to a circle of light, suspended in air against the mathematical equations. Others believe that say or do anything that might risk his ire. dark background. It was a beautiful sight. God is an artisan, whose blueprint will be The drive proceeded in complete silence, When I next visited my grandfather’s discovered in the careful observation of the but I was aware that he was observing me house, I hastened to tell everyone that I had phenomena of nature. The two groups regard intently. At the end, when we returned to his decided on my future occupation: I would each other with polite tolerance, at best, and spacious house, he announced to the whole be a tailor. To my surprise the statement studied indifference, at worst. To the best family: “This young man is going to be a evoked as much hilarity as on the previous of my judgement, the people I care for did ELECTRON GUN SYSTEMS philosopher.” occasion. Somebody remarked that a tailor’s appreciate my work. Ultra-fast ps to fs Photo Emission Guns There were peals of laughter from all sides. job was that of a “Karigar” (a craftsman or Finally, I return to the “circle of light” that Not knowing what the word “philosopher” artisan), who worked with his hands and did captivated me at the tailor’s shop. Years later, High Brightness LaB6, meant, I hung my head in shame. A relative, not have much education, and that I should I had a similar sense of awe when, looking seeing me crestfallen, took me aside and be aspiring to something higher. I protested down into a valley after a shower of rain, explained: “A philosopher is someone who that I had seen a tailor doing embroidery and I saw a magnifi cent set of rainbows, both Flood Beams, EGG-3101 (10 keV) thinks a lot. Your grandfather probably found his work interesting. In reply, someone primary and secondary, against a clear blue Small Spots, noticed that you were absorbed in your own cautioned me that a tailor did not earn much sky. At that time I had learned enough physics thoughts.” “But why did they laugh?” I asked. money. It began to appear that regardless of to know that a rainbow was caused by the She said: “People assume that a person who whether I chose to be a thinker or an artisan, refraction and refl ection of light in raindrops. Energies: spends too much time thinking, instead of my future would be one of penury. A similar phenomenon that impressed me, doing something practical, will never earn Fortunately, my parents gave me freedom one winter night, was a ring around the Moon, 1 eV to enough to support himself.” I had received to fi nd my own way in life. I studied physics which, I learned later, was caused by ice my fi rst lesson of life. Too much thinking is and entered a career of research and teaching. crystals in the upper atmosphere. And fi nally, 100 keV not good, and is likely to leave you poor. Today, in the tranquillity of retirement, I fi nd once I was immersed in the fast-moving EMG-4210 (30 keV) Some days later, I accompanied my myself recalling that childhood encounter world of particle physics, an image that never parents to Anarkali, a popular shopping area in my grandfather’s house 70 years ago. My failed to enthral me was of the rings of light and meeting point for Lahore residents, after grandfather had prophesied that I would be a created by charged particles in a Cherenkov sundown. I happened to be standing next to philosopher. He was not far off the mark. My detector, such as in the Super-Kamiokande a tailor’s shop. A man seated in the doorway PhD certifi cate says “...Doctor of Philosophy experiment. was working assiduously with needle and in the fi eld of Physics...”. As Richard Feynman once remarked, the coloured thread, doing embroidery, and My relatives had expressed apprehension fact that a mysterious phenomenon can be between stitches his hand executed a circular that by choosing to be a thinker or artisan, explained in physical terms does not take EGA-1012 (1 keV) arc. The thimble that he wore fl ashed during I would end up in a job that was low in away from its beauty and allure. Even today, EGH-8123 (100 keV) each circular movement, refl ecting the esteem as well as in income. It turned out the sight of a rainbow brings to my mind an light of a lamp in the porch. As dusk turned that the fi eld I chose was elementary-particle imaginary weaver, weaving a pattern with to darkness, the tailor’s face and body phenomenology. It allowed me to combine coloured threads, while the rays of the sun ELG-2U (2 keV) receded into the shadows. The only sign of my propensity for thinking with the dance off the thimble on his moving hand. more prosaic task of analysing data and ● Lalit M Sehgal, Aachen. EMG-4193 (30 keV) his presence was the periodic fl ash of his

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