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Ettore Majorana: Genius and Mystery
«ETTORE MAJORANA» FOUNDATION AND CENTRE FOR SCIENTIFIC CULTURE TO PAY A PERMANENT TRIBUTE TO GALILEO GALILEI, FOUNDER OF MODERN SCIENCE AND TO ENRICO FERMI, THE "ITALIAN NAVIGATOR", FATHER OF THE WEAK FORCES ETTORE MAJORANA CENTENARY ETTORE MAJORANA: GENIUS AND MYSTERY Antonino Zichichi ETTORE MAJORANA: GENIUS AND MYSTERY Antonino Zichichi ABSTRACT The geniality of Ettore Majorana is discussed in the framework of the crucial problems being investigated at the time of his activity. These problems are projected to our present days, where the number of space-time dimensions is no longer four and where the unification of the fundamental forces needs the Majorana particle: neutral, with spin ½ and identical to its antiparticle. The mystery of the way Majorana disappeared is restricted to few testimonies, while his geniality is open to all eminent physicists of the XXth century, who had the privilege of knowing him, directly or indirectly. 3 44444444444444444444444444444444444 ETTORE MAJORANA: GENIUS AND MYSTERY Antonino Zichichi CONTENTS 1 LEONARDO SCIASCIA’S IDEA 5 2 ENRICO FERMI: FEW OTHERS IN THE WORLD COULD MATCH MAJORANA’S DEEP UNDERSTANDING OF THE PHYSICS OF THE TIME 7 3 RECOLLECTIONS BY ROBERT OPPENHEIMER 19 4 THE DISCOVERY OF THE NEUTRON – RECOLLECTIONS BY EMILIO SEGRÉ AND GIANCARLO WICK 21 5 THE MAJORANA ‘NEUTRINOS’ – RECOLLECTIONS BY BRUNO PONTECORVO – THE MAJORANA DISCOVERY ON THE DIRAC γ- MATRICES 23 6 THE FIRST COURSE OF THE SUBNUCLEAR PHYSICS SCHOOL (1963): JOHN BELL ON THE DIRAC AND MAJORANA NEUTRINOS 45 7 THE FIRST STEP TO RELATIVISTICALLY DESCRIBE PARTICLES WITH ARBITRARY SPIN 47 8 THE CENTENNIAL OF THE BIRTH OF A GENIUS – A HOMAGE BY THE INTERNATIONAL SCIENTIFIC COMMUNITY 53 REFERENCES 61 4 44444444444444444444444444444444444 Ettore Majorana’s photograph taken from his university card dated 3rd November 1923. -
The Charm of Theoretical Physics (1958– 1993)?
Eur. Phys. J. H 42, 611{661 (2017) DOI: 10.1140/epjh/e2017-80040-9 THE EUROPEAN PHYSICAL JOURNAL H Oral history interview The Charm of Theoretical Physics (1958{ 1993)? Luciano Maiani1 and Luisa Bonolis2,a 1 Dipartimento di Fisica and INFN, Piazzale A. Moro 5, 00185 Rome, Italy 2 Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany Received 10 July 2017 / Received in final form 7 August 2017 Published online 4 December 2017 c The Author(s) 2017. This article is published with open access at Springerlink.com Abstract. Personal recollections on theoretical particle physics in the years when the Standard Theory was formed. In the background, the remarkable development of Italian theoretical physics in the second part of the last century, with great personalities like Bruno Touschek, Raoul Gatto, Nicola Cabibbo and their schools. 1 Apprenticeship L. B. How did your interest in physics arise? You enrolled in the late 1950s, when the period of post-war reconstruction of physics in Europe was coming to an end, and Italy was entering into a phase of great expansion. Those were very exciting years. It was the beginning of the space era. L. M. The beginning of the space era certainly had a strong influence on many people, absolutely. The landing on the moon in 1969 was for sure unforgettable, but at that time I was already working in Physics and about to get married. My interest in physics started well before. The real beginning was around 1955. Most important for me was astronomy. It is not surprising that astronomy marked for many people the beginning of their interest in science. -
Majorana Returns Frank Wilczek in His Short Career, Ettore Majorana Made Several Profound Contributions
perspective Majorana returns Frank Wilczek In his short career, Ettore Majorana made several profound contributions. One of them, his concept of ‘Majorana fermions’ — particles that are their own antiparticle — is finding ever wider relevance in modern physics. nrico Fermi had to cajole his friend Indeed, when, in 1928, Paul Dirac number of electrons minus the number of Ettore Majorana into publishing discovered1 the theoretical framework antielectrons, plus the number of electron Ehis big idea: a modification of the for describing spin-½ particles, it seemed neutrinos minus the number of antielectron Dirac equation that would have profound that complex numbers were unavoidable neutrinos is a constant (call it Le). These ramifications for particle physics. Shortly (Box 2). Dirac’s original equation contained laws lead to many successful selection afterwards, in 1938, Majorana mysteriously both real and imaginary numbers, and rules. For example, the particles (muon disappeared, and for 70 years his modified therefore it can only pertain to complex neutrinos, νμ) emitted in positive pion (π) + + equation remained a rather obscure fields. For Dirac, who was concerned decay, π → μ + νμ, will induce neutron- − footnote in theoretical physics (Box 1). with describing electrons, this feature to-proton conversion νμ + n → μ + p, Now suddenly, it seems, Majorana’s posed no problem, and even came to but not proton-to-neutron conversion + concept is ubiquitous, and his equation seem an advantage because it ‘explained’ νμ + p → μ + n; the particles (muon is central to recent work not only in why positrons, the antiparticles of antineutrinos, ν¯ μ) emitted in the negative − − neutrino physics, supersymmetry and dark electrons, exist. -
Double-Beta Decay and the Search for (Elementary) Majorana Particles
Double-beta decay and the search for (elementary) Majorana particles Giorgio Gratta Physics Dept. Stanford University Summer Undergraduate Program, Aug Neutrinos - Gratta 1 2020 Summer Undergraduate Program, Aug Neutrinos - Gratta 2 2020 For the first ~50 years since the neutrino was invented by Pauli, its properties could be fairly well described by quoting just 2 papers: Neutrinos really exist! Summer Undergraduate Program, Aug Neutrinos - Gratta 3 2020 Neutrinos are left handed particles Summer Undergraduate Program, Aug Neutrinos - Gratta 4 2020 Helicity is the property that correlates the spin of a particle to its momentum Because of special relativity the helicity of a particle is related to its mass The observer above sees a neutrino passing-by and reports its helicity (the scalar product between spin vector and momentum vector) as negative (left-handed) Summer Undergraduate Program, Aug Neutrinos - Gratta 5 2020 Helicity is the property that correlates the spin of a particle to its momentum Because of special relativity the helicity of a particle is related to its mass Now the observer is cruising in the same direction of the neutrinos, at higher speed. While overtaking the neutrino he will claim that its helicity is positive! Summer Undergraduate Program, Aug Neutrinos - Gratta 6 2020 Helicity is the property that correlates the spin of a particle to its momentum Because of special relativity the helicity of a particle is related to its mass But if the neutrino has zero mass nothing can overtake it Neutrinos with fixed helicity -
The Conceptual Origin of Majorana Fermion Salon of Science
Salon of Science The Conceptual Origin of Majorana Fermion Cao Zexian 2014.11.01 Outline ¾QM and Relativistic QM for Electron ¾Antiparticle & Antimatter ¾Complex Field vs. Real Field ¾Majorana Fermion ¾Searching MF, in Solids? QM begins with the understanding of gas dynamics (Boltzmann 1877) and black-body radiation (Planck 1900) nexp(p)p ∝ −β n 0 + n1 + n 2 + ... + n p = n 2 0 ⋅ n + 1⋅ n + ... + p ⋅ n = E ∂ Skν 0 1 p 2 =− ∂+UU(hU)ν ννν Energy in unit To distribute the energy UN (P portions) among N Dies diskrettisierung ist oscillators (for the calculation of entropy with fȕr die Argumentation classical concept of billiard balls) with frequency υ. unentbehrlich! Suppose UN is indefinitely large, divisible, and the total number P of equal part P = U /ε = U / hν (P + N −1)! W = Planck called it P!(N −1)! ‘Energieelement’ 1 ∂S S = Nk[(1+ U )ln(1+ U ) − U ln U ] = N ε ε ε ε T ∂U ε 4hνν2 U = e = exp(ε / kT) −1 v cexp(h/kT)12 ν − M. Planck, Annalen der Physik, 4, 553(1901). The concept of Energy Quanta was taken by Einstein in 1905 to the interpretation of photoelectron effect Energie- quantum In 1908 Johannes Stark applied it to ionization of gases and to photochemical reactions. And QM proceeded with the understanding of spectral features of radiation of ELECTRON H Spectral lines arise from the ‘jump’ of ELECTRON between different stationary states. Then came the question: what is ELECTRON, of which the existence was conceived from observation of chemical reactions. -
Neutrinoless Double Beta Decay: 2015 Review
Neutrinoless double beta decay: 2015 review Stefano Dell'Oro,1, ∗ Simone Marcocci,1, y Matteo Viel,2, 3, z and Francesco Vissani4, 1, x 1INFN, Gran Sasso Science Institute, Viale F. Crispi 7, 67100 L'Aquila, Italy 2INAF, Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34131 Trieste, Italy 3INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy 4INFN, Laboratori Nazionali del Gran Sasso, Via G. Acitelli 22, 67100 Assergi (AQ), Italy (Dated: April 20, 2016) The discovery of neutrino masses through the observation of oscillations boosted the importance of neutrinoless double beta decay (0νββ). In this paper, we review the main features of this process, underlining its key role both from the experimental and theoretical point of view. In particular, we contextualize the 0νββ in the panorama of lepton-number violating processes, also assessing some possible particle physics mechanisms mediating the process. Since the 0νββ existence is correlated with neutrino masses, we also review the state-of-art of the theoretical understanding of neutrino masses. In the final part, the status of current 0νββ experiments is presented and the prospects for the future hunt for 0νββ are discussed. Also, experimental data coming from cosmological surveys are considered and their impact on 0νββ expectations is examined. PACS numbers: 14.60.Pq,23.40.-s DOI: 10.1155/2016/2162659 u u I. INTRODUCTION d d d u W- In 1937, almost ten years after Paul Dirac's \The quan- - tum theory of electron" [1,2], Ettore Majorana proposed e ν a new way to represent fermions in a relativistic quan- M e- tum field theory [3], and remarked that this could be - especially useful for neutral particles. -
Bruno Touschek in Germany After the War: 1945-46
LABORATORI NAZIONALI DI FRASCATI INFN–19-17/LNF October 10, 2019 MIT-CTP/5150 Bruno Touschek in Germany after the War: 1945-46 Luisa Bonolis1, Giulia Pancheri2;† 1)Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany 2)INFN, Laboratori Nazionali di Frascati, P.O. Box 13, I-00044 Frascati, Italy Abstract Bruno Touschek was an Austrian born theoretical physicist, who proposed and built the first electron-positron collider in 1960 in the Frascati National Laboratories in Italy. In this note we reconstruct a crucial period of Bruno Touschek’s life so far scarcely explored, which runs from Summer 1945 to the end of 1946. We shall describe his university studies in Gottingen,¨ placing them in the context of the reconstruction of German science after 1945. The influence of Werner Heisenberg and other prominent German physicists will be highlighted. In parallel, we shall show how the decisions of the Allied powers, towards restructuring science and technology in the UK after the war effort, determined Touschek’s move to the University of Glasgow in 1947. Make it a story of distances and starlight Robert Penn Warren, 1905-1989, c 1985 Robert Penn Warren arXiv:1910.09075v1 [physics.hist-ph] 20 Oct 2019 e-mail: [email protected], [email protected]. Authors’ ordering in this and related works alternates to reflect that this work is part of a joint collaboration project with no principal author. †) Also at Center for Theoretical Physics, Massachusetts Institute of Technology, USA. Contents 1 Introduction2 2 Hamburg 1945: from death rays to post-war science4 3 German science and the mission of the T-force6 3.1 Operation Epsilon . -
Bruno Touschek, from Betatrons to Electron-Positron Colliders
Preprint of an invited article submitted for publication in Reviews of Accelerator Science and Technology, Vol. 8. http://www.worldscientific.com/worldscinet/rast c 2015 by World Scientific Publishing Company Bruno Touschek, from Betatrons to Electron-positron Colliders Carlo Bernardini∗ Physics Department, University of Rome Sapienza Rome, 00185, Italy Giulia Pancheriy INFN Frascati National Laboratory, Via E. Fermi 40 Frascati, I00044, Italy Claudio Pellegriniz Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095 SLAC National Accelerator Laboratory, Menlo Park, California, 94025 Bruno Touschek's life as a physicist spanned the period from World War II to the 1970s. He was a key figure in the developments of electron-positron colliders, storage rings, and gave important contributions to theoretical high energy physics. Storage rings, initially developed for high energy physics, are being widely used in many countries as synchrotron radiation sources and are a tool for research in physics, chemistry, biology environmental sciences and cultural heritage studies. We describe Touschek's life in Austria, where he was born, Germany, where he participated to the construction of a betatron during WWII, and Italy, where he proposed and led to completion the first electron-positron storage ring in 1960, in Frascati. We highlight how his central European culture influenced his life style and work, and his main contributions to physics, such as the discovery of the Touschek effect and beam instabilities in the larger storage ring ADONE. Keywords: Storage rings, colliders, electron-positron colliders, radiative corrections, electron beam instabili- ties arXiv:1510.00933v1 [physics.hist-ph] 4 Oct 2015 ∗ [email protected] y [email protected] z [email protected] 2 I. -
Via Panisperna Boys”: the Role of Ettore Majorana
JCOM 1 (3), September 2002 Science Communication and the “via Panisperna boys”: the Role of Ettore Majorana Angelo Mastroianni Università degli Studi “La Sapienza” di Roma Enrico Fermi’s work gave birth to a real cultural revolution in the Italian scientific scenario. His scientific studies concerned almost every field in physics and had far-reaching effects of which virtually everybody, above all in Italy, is still taking advantage. Two important “by-products” of Fermi’s ideas and initiatives will be here taken into consideration: the new way of carrying out research and communicating science invented by Fermi and his group and his publications for the general public, which often stood for high examples of scientific popularisation. Then the focus will shift on Ettore Majorana’s role to try to understand why his work in the field of communication within the School of Physics of Rome was basically non-existent despite the excellent communicative skills he demonstrated both during his university lectures – also published in this magazine – and in his article “Il valore delle leggi statistiche nella fisica e nelle scienze sociali” [20], the only one which does not deal with pure physics issues and which will be also taken into account in this paper Fermi’s Cultural Revolution In the first thirty years of the 1900s, two important innovations were introduced in the field of modern physics: the theory of relativity and quantum mechanics. The promoters of both these changes were born or worked in Central Europe, except Gregorio Ricci Curbastro and Tullio Levi Civita (Italy), Satyendra Nath Bose (India), Arthur Holly Compton and Alfred Landè (USA, but the latter 1 was of German origin). -
The Relevance of Double Beta Decay
The relevance of double beta decay I. Is the neutrino its own antiparticle? II. Double beta decay? While the electron e - and the positron e + are clearly Back in 1935, Maria Goeppert-Meyer was investigating an different particles, having opposite values of electric unusual form of the beta-decay, in which two neutron charge, such a distinction is not obvious in the case of the change to two protons almost simultaneously. The resulting Neutrinos and neutrino, which is an electrically neutral particle. nuclei are lighter than the initial ones, and four particles are emitted in the decay, two electrons and two anti-neutrinos: Cosmology + 2+ 2 In the hot early Universe, neutrinos The question was first raised by Ettore Majorana in 1937. were created and annihilated in While Dirac’s theory leads to 4 possible states of a nucleus A nucleus B electrons anti-neutrinos equilibrium with other particles, in neutrino - particle and antiparticle, each right-handed or particular with photons: left-handed - Majorana’s theory leads only to two states: Since it involves the weak force twice, the process is very the right-handed ( νRH ) and left-handed ( νLH ) versions of a rare, albeit observable. With a half-life on the order of 10 single particle: billion times the age of the Universe (which is 14 billion years old), it has been seen in a number of even-even As the Universe expanded, it cooled momentum momentum nuclei: 48 Ca, 76 Ge, 82 Se, 96 Zr, 100 Mo, 116 Cd, 128 Te, 130 Te, down and around 1 s after the Big 150 Nd, 238 U. -
Arxiv:1812.11847V2 [Physics.Hist-Ph] 22 Nov 2019
LNF ISTITUTO NAZIONALE DI FISICA NUCLEARE Laboratori Nazionali di Frascati INFN-18/12/LNF December 31, 2018 Bruno Touschek with AdA in Orsay: The first direct observation of electron-positron collisions Giulia Pancheri1, Luisa Bonolis2 1)INFN, Laboratori Nazionali di Frascati, P.O. Box 13, I-00044 Frascati, Italy 2)Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany Abstract We describe how the first direct observation of electron-positron collisions took place in 1963-1964 at the Laboratoire de l’Accel´ erateur´ Lineaire´ d’Orsay, in France, with the storage ring AdA, which had been proposed and constructed in the Italian National Lab- oratories of Frascati in 1960, under the guidance of Bruno Touschek. The obstacles and successes of the two and a half years during which the feasibility of electron-positron col- liders was proved will be illustrated using archival and forgotten documents, in addition to transcripts from interviews with Carlo Bernardini, Peppino Di Giugno, Mario Fascetti, Franc¸ois Lacoste, and Jacques Ha¨ıssinski. arXiv:1812.11847v2 [physics.hist-ph] 22 Nov 2019 Drawing by Bruno Touschek (Amaldi 1981). Authors’ ordering in this and related works alternates to reflect that this work is part of a joint collaboration project with no principal author. Contents 1 Introduction1 1.1 Sources and outline . .6 2 Prequel8 2.1 Electron-positron collisions from Kiev to Rome and Frascati . 10 2.2 July 1961: a visit from Orsay . 17 3 AdA’s arrival and installation in Orsay: Summer 1962 19 3.1 First experiments: weekends and long nights or sixty hours in row . -
Majorana Neutrinos and Other Majorana Particles
Majorana neutrinos and other Majorana particles: Theory and experiment Evgeny Kh. Akhmedov∗† Max-Planck-Institut f¨ur Kernphysik, Saupfercheckweg 1 D-69117 Heidelberg, Germany Abstract This is a somewhat modified version of Chapter 15 of the book “The Physics of Ettore Majorana”, by Salvatore Esposito with contributions by Evgeny Akhmedov (Ch. 15) and Frank Wilczek (Ch. 14), Cambridge University Press, 2014. arXiv:1412.3320v1 [hep-ph] 10 Dec 2014 ∗Also at the National Research Centre Kurchatov Institute, Moscow, Russia †email: [email protected] What are Majorana particles? These are massive fermions that are their own antipar- ticles. In this chapter we will concentrate on spin-1/2 Majorana particles, though fermions of higher spin can also be of Majorana nature. Obviously, Majorana particles must be genuinely neutral, i.e. they cannot possess any conserved charge-like quantum number that would allow one to discriminate between the particle and its antiparticle. In particular, they must be electrically neutral. Among the known spin-1/2 particles, only neutrinos can be of Majorana nature. Another known quasi-stable neutral fermion, the neutron, has non-zero magnetic moment which disqualifies it for being a Majorana particle: the antineutron exists, and its magnetic moment is negative of that of the neutron1. Neutrinos are exactly massless in the original version of the standard model of elec- troweak interaction, and are massive Majorana particles in most its extensions. Although massive Dirac neutrinos is also a possibility, most economical and natural models of neutrino mass lead to Majorana neutrinos. Since only massive neutrinos can oscillate, the interest to the possibility of neutrinos being Majorana particles rose significantly after the first hints of neutrino oscillations obtained in the solar and atmospheric neutrino experiments.