Российский Квантовый Центр Russian Quantum Center

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Open RQC colloquium. Lecture 13

The thirteenth lecture "2S-4P SPECTROSCOPY IN HYDROGEN ATOM: THE NEW VALUE FOR THE RYDBERG CONSTANT AND THE PROTON CHARGE RADIUS" in "Open RQC colloquium" will be held in National University of Science and Technology MISIS (Moscow, Leninskiy prospekt 4), lecture hall № Б-536 (5th floor) on 2nd of December at 10:00 a.m by prof. Kolachevsky Nikolay, PhD, Candidate to members of RAS, Director of P.N. Lebedev Physical Instititue.


"The “proton radius puzzle” has been baffling physicists for more than six years now. The core of this matter is the dissatisfying discrepancy of four standard deviations between the proton root mean square charge radii (rp) determined from regular hydrogen (H), the simplest natural atomic system, and its exotic brother, the muonic hydrogen atom (μp). We have measured the 2S-4P transition frequency in regular hydrogen, utilizing a cryogenic beam of H atoms and directly demonstrate that quantum interference of neighboring atomic resonances can lead to apparent line shifts much larger than the proton radius discrepancy. We motivate an asymmetric fit function that eliminates these shifts to leading order and obtain rp = 0.8293(91) fm and the Rydberg constant R∞ = 10 973 731.568 037 (91) m-1. The accuracy of our measurement matches the one from the aggregate of the previous H world data. Our value is 3.8 combined standard deviations smaller than the latter result, but in good agreement with the value from μp."


Kolachevsky Nikolay graduated from the department of general and applied physics of MIPT in 1994. He got his PhD degree in physics and mathematics in 1997 with the title "Spectroscopic studies of the components of multilayer x-ray optics with laser plasma radiation source". He received the doctoral degree "Coherent laser spectroscopy of hydrogen atoms and rubidium" in 2006. Since 1997 he works in P.N. Lebedev Physical Institute. In 2014, he was appointed as a Deputy Director for scientific work. In 2015, he became Director of the Institute. Since 2014 he is Professor of the department №78 of National Nuclear Research University MEPhI. In 2011 he was elected as a Fellow of Russian Academy of Sciences in the section of physics.

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