PoS(EMC2006)016 http://pos.sissa.it/ ∗ [email protected] r Speaker. This article reports part of the invited talkon delivered Majorana by Legacy" the held author at at the the Department “International5 of Conference and Physics, 6 University Octorber, of 2006: Catania, Catania, Conferenceof Italy, organized on the for Italian celebrating theoretical the physicist 100th Ettorethe anniversary Majorana; XX of probably century the the (Enrico birth brightest Fermi Italian regardedmany theoretician him people of as Majorana the is brightest still in knownwas mainly the 31. for world his of misterious his disappearance, In time), inlife: this even 1938, if the writing when biographical to we he data outline being based theby on significance the letters, of author documents, some during testimonies almost discovered publications or 30Epistolario, of collected years, Testimonianze, his, Documenti" and as (initially contained published well in by the aspublished, Mondadori, book his Milan, in by and 2002, Recami, presently by "Il Di Caso Renzoadded Majorana: with Editore, regard Rome). to the manuscripts At left last, unpublished some by information Majorana. and comments are ∗ Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. c

International Conference — Ettore Majorana’s legacyOctober and 5-6 the 2006 Physics of the XXIUniversity century of — Catania, Italy Erasmo Recami Ettore Majorana: His Scientific andPersonality Human Università statale di Bergamo, Bergamo, Italy;E-mail: and INFN-Sezione di Milano, Milan, Italy PoS(EMC2006)016 , which com- Erasmo Recami ].) 12 Volumetti ], he wrote from CERN (July 18, 1965): 3 2 “mesons" (at that time called mesotrons or yukons), which are µ notes written in Rome between 1927, when he abandoned his studies in engineering study Majorana was such a pioneer, that even his manuscripts known as the “It was actually while I was staying with Fermi in the small laboratory on the second floor, “It was then that Fermi, trying to make me understand the significance of this loss, expressed And, with first-hand knowledge, Bruno Pontecorvo, adds: “Some time after his entry into Ettore Majorana disappeared rather mysteriously on March 26, 1938, and was never seen again “In January 1938, after having just graduated, I was invited, essentially by you, to come to Ettore Majorana’s fame solidly rests on testimonies like the following, from the evocative pen ]. The myth of his “disappearance" has contributed to nothing more than the notoriety he was 4 to take up physics, and 1931, arewith a an paragon index, not only but of also order,books based could of on be conciseness, argument regarded and as essentiality even an supplied andyears, excellent originality: modern and text a of So “gold-mine" theoretical much of physics, so even seminal after that new about theoretical, those eighty physical, note- and mathematical ideas and hints, entitled to, for being a true genius and a genius well aheadprise of his his time. absorbed in our work, with Fermireveal working mesons with at a the end piece of of their Wilson’sof range) chamber on the (which a chamber, would lathe using help and the me to flash constructinga produced a battery, by jalopey that for the Ettore the explosion Majorana illumination of came an infew aluminum search ribbon words. of shortcircuited Fermi. on A I was dark introducedwhile face. to I him And and was we that still exchanged was withNaples it. Fermi had not in An arrived. that easily I same forgettable remembersome workshop, experience that days, if, news Fermi he of busied after had himself the Ettore a with impression Majorana’s few telephoning that disappearance weeks around Ettore in would until, never after be found. himself in quite a peculiarat way; this he point, who I would was‘Because, like so you to objectively see, repeat harsh in his when the words, world judgingtertiary just there people. standing, as are who I various And do can categories so, of their stillwho scientists: hear best come them people but to of ringing do a discoveries in not secondary my of gohere or memory: great very I had far. importance, the fundamental There impression are for thatGalileo he also the and placed those development himself Newton. of of in high Well, science’ that Ettore standing, category).had (and was ‘But [...]’" one then there of are them. geniuses like Majorana had what no oneFermi’s group, else Majorana in already the possessed world suchcomprehension an of erudition physics and had that reached he suchproblems. was a able Fermi high himself to level held speak of him on toastounded the be [...]. same the greatest level I theoretical with remember physicist Fermi exactly ofproposed, about our these no scientific time. words one He that in often Fermi the was spoke: world can ‘If resolve a it problem better has than already Majorana.’[ " been (See also [ produced by cosmic rays [...] the Institute of Physics atI the University was in there Rome I for sixchair would months at have as Camerino the a a good teaching few assistant,the fortune months products and of earlier) of once joining and disintegration of Fermi, Ageno (he, Bernardini too, (who a had new been graduate), given in a the research of of Giuseppe Cocconi. At the request of Edoardo Amaldi[ E.Majorana: Scientist and Man 1. Historical Prelude. PoS(EMC2006)016 Erasmo Recami ]; and republished in 2006 in the original 6 3 ]. But Majorana’s most interesting notebooks or papers –those that constituted 7 Let us recall that Majorana, after having switched to physics at the beginning of 1928, grad- With respect to the last point, let us recall that in 1937 there were numerous Italian competitors Italian language[ E.Majorana: Scientist and Man quite stimulating and useful forbeen modern published research. for the Such first scientific time manuscripts, (in incidentally, 2003) have by Kluwer[ his “research notes" will not seeinterpreting the and...electronically light typing in them! the Each nearone notebook future: year, was starting it written from being the during too years a hard —asing period the we his of said task studies above— about of during at selecting, which the Ettore Universitytopics Majorana of was covered Rome. complet- in Thus academic the contents coursesin of to the these topics level notebooks at of range the sophistication, from frontiers the typical an style of example, in research. we which refer Despite any here particular to thisit topic Majorana’s unevenness study is is of treated placed the is shift in never in obvious. athe the As “cricket melting magnetic simile." point field Also of remarkable or, a is substance more hisand when interestingly, treatment lucid of his contemporary manner, examination physics such of topicsDirac in as heat an equation Fermi’s propagation original with explanation using its of applications,preferred and the by the electromagnetic him. Lorentz mass group, As of revealing farilluminating in the as examples: some frontier electron, the cases research study the the arguments of literature are quasi-stationaryyears, concerned, states, and Fermi’s let anticipating theory Fano’s us of theory atoms, here by reporting recallappropriate about analytic only boundary solutions 20 conditions of two the in Thomas-Fermi terms equation of with lacking. simple quadratures, which to our knowledge were still uated with Fermi on JulyEnrico 6, Fermi 1929, and and Franco wentsubdivision Rasetti on of (at which to the was collaborate formed start with mainlyMajorana, with (in the the Gian O.M.Corbino’s famous order important Carlo group of help); Wick, their created entrance GiulioPiero a by into Caldirola. Racah, theoretical the The Institute) Giovanni members by Gentile of Ettore the Jr.,Bruno experimental Ugo Pontecorvo, subgroup were: Eugenio Fano, Fubini, Emilio Bruno Segré, Mario Ferretti, Edoardo Ageno,car Amaldi, and Giuseppe D’Agostino. Cocconi, along with(“Libera the Afterwards, Docenza") chemist on Majorana Os- November qualified 12, 1932; forduring spent 1933; university about and six teaching then, months for in of some Leipzig theoretical unknowngroup. with reasons, W. physics Heisenberg stopped He participating in even the ceased activitiesmetrica of publishing dell’elettrone Fermi’s the e del results positrone," ofcolleagues which his to (ready remove research, from since except a 1933) drawer for Majoranafor and three his was publish full-professorships. persuaded paper just by prior “Teoria to his sim- the 1937 Italian national competition for these posts, and many ofRacah, them Gian were Carlo of Wick, and exceptional Giovanni caliber;same Gentile above name, Jr. all: and (the Ettore the son Majorana, of inventorwas Giulio the of chaired by famous “parastatistics" E. philosopher in Fermi bearing and quantum the On had mechanics). as the members recommendation The E. of Persico, judging G. the committee stalled Polvani, judging A. Majorana committee, Carrelli, as and professor the O. of Italian Lazzarino. theoretical Ministerwell-deserved physics fame," of at independently National Naples of University Education the because in- competition ofto itself; apply his the actually, “great normal “the and university Commission competition hesitated proceduresactivities to of him." Ettore The Majorana, attached report sent on to the the scientific minister by the committee, stated: PoS(EMC2006)016 ]: “The first Erasmo Recami 14 ] that he actually followed 11 4 ]. 2 ]): and arose the admired comments of many (especially British) scholars. The remaining Majorana delivered his lectures only during the beginning of 1938, starting on Jan.13 and “Without listing his works, all of which are highly notable both for their“In modern originality nuclear theories, of the the contribution made by this researcher to the introduction of the “In atomic physics, the merit of having resolved some of“Lastly, the he most devised a intricate brilliant questions method on that permits the us to treat the positive and negative electron One of the most important works of Ettore Majorana, the one that introduces his “infinite- The details of Majorana and Fermi’s first meeting were narrated by E. Segré [ 1 six lecture-notes, which had goneAntonino lost, Drago, have and been just rediscovered appeared in in 2005 print[ by Salvatore Esposito and important work written by Fermi instatistical Rome [‘Su properties alcune of proprietà the statistiche atom)] dell’atomo’found (On is certain that today known he as needed theboundary the Thomas-Fermi conditions solution method. . in to . . order a tocalculated When non-linear proceed, Fermi the differential in solution equation with a characterized a weeka by little of short unusual hand assiduous time calculator. work earlier with Majorana,probably and his who was had usual who wrong entered energy, was and he the that alwaysFermi’s Institute it original very just equation would skeptical, into have a decided been Riccatiutilizing that better equation, his to and Fermi’s extraordinary resolved verify numeric aptitude it it. for solution withoutskeptically numeric the He compared calculation. aid went of the When home, any little he calculator, transformed piece returnedbook, of to paper and the on found Institute which that and he theirindulged had results in written coincided the his exactly, foregoing results he anecdote to could sinceequation Fermi’s not the have note- hide in pages his the on end amazement." which been Majorana found, solved We and have Fermi’s it differential has been shown recently [ ending with his disappearance (March 26). Butextremely his high. activity was For intense, the and benefit his interest ofhe for his prepared teaching beloved careful students, notes and for perhapsref.[ his also lectures. for writing And down ten a of book, such lectures appeared in print in 1987 (see two independent (and quite original) pathsan to Abel, the rather same than mathematical a result, Riccati, one equation. of them leading to methods utilized as well asfollowing: for the importance of the achieved results, weforces limit called ourselves “Majorana to forces" is the universally recognizedthat as permits the us one, to theoretically among comprehend the the mosttoday reasons fundamental, serves for as nuclear a stability. basis The for work the of most Majorana important research in thisstructure field. of spectra through simple and elegant considerations of symmetry is duein to Majorana. a symmetrical way, finallysatisfactory eliminating hypothesis the of an necessity infinitely to large relybeen electrical tackled on charge in diffused the vain in extremely by space, artificial many a other and question scholars." that un- had components equation" was not mentioned, sincenote, it however, had that not the yet proper been light(today understood. was climaxing shed It on in is his interesting its theory to applicationeliminate of to electron the neutrinos and hypothesis and anti-electron known symmetry anti-neutrinos) asartificial and and the on unsatisfactory," his “Dirac despite the resulting sea," fact ability a that to hypothesis in general that it was had defined been uncritically as accepted. “extremely E.Majorana: Scientist and Man PoS(EMC2006)016 (1932) is intro- 9 works are (1931) 58- 13 Erasmo Recami published (1937) 171-184. Rendiconti Accademia Nuovo Cimento (1931) 22-28. 14 (1932) 43-50. 8 9 Majorana-Brossel effect (1931) 78-83. 8 (1931) 107-113. (1933) 137-145; and “Sulla teoria dei 8 Nuovo Cimento 82 Nuovo Cimento Nuovo Cimento Rendiconti Accademia Lincei 5 Nuovo Cimento Nuovo Cimento (1942) 55-56]. We already know that Majorana switched (1) (1933) 559-565. 36 [ 4 Zeitschrift für Physik Scientia incompleti," ], an in-depth examination of these works leaves one struck by their 3 P’ (1928) 229-233. La Ricerca Scientifica 8 nuclei," 335-344. 61. sità delle righe del Cesio," in collaboration with Giovanni Gentile Jr., Lincei The first papers, written between 1928 and 1931, concern atomic and molecular physics: Majorana published few scientific articles: nine, actually, besides his sociology paper entitled (9) “Teoria simmetrica dell’elettrone e del positrone," (8) “Über die Kerntheorie," (7) “Teoria relativistica di particelle con momento intrinseco arbitrario," (6) “Atomi orientati in campo magnetico variabile," (5) “Teoria dei tripletti (4) “Reazione pseudopolare fra atomi di Idrogeno," (3) “I presunti termini anomali dell’Elio," (1) “Sullo sdoppiamento dei termini Roentgen ottici a causa dell’elettrone rotante e sulla inten- (2) “Sulla formazione dello ione molecolare di He," mainly questions of atomic spectroscopy or chemical bondsAs (within E. quantum mechanics, Amaldi of course). has written [ duced. In it, Majorana predictsoscillating and magnetic calculates field. the modification This of work thespin-flip. has spectral also Its line remained shape results a due —once classic to in generalized, an the as treatment suggested of by non-adiabatic Majorana himself, by Rabi in 1937 and superb quality: They reveal bothdetail, a and deep an knowledge uncommon of ease, the without experimentalthe equal quantum data, at states even that in in time, order the to in minutest qualitativelyfor the simplify their use problems quantitative of and resolution. the choose Among symmetry the the properties mostabile" first suitable of papers, (Atoms method “Atomi oriented orientati in in campo a magneticofamous variable vari- among magnetic atomic physicists, field) that deserves the special effect now mention. known as It the is in this article, a mine of ideas andus techniques list of his theoretical nine published physics articles: that still remains partially unexplored. Let from engineering to physicscollaboration in with 1928 his (the friend Gentile) year andonly in then for which went a on he very to few published years, publish his practically his only works first until in article, 1933. theoretical written physics in Nevertheless, even his “Il valore delle leggi statistichein nella physics fisica and e the nelle socialmously) scienze by sciences), G. sociali" which Gentile (The was Jr., in value however of published statistical not laws by Majorana but (posthu- E.Majorana: Scientist and Man 2. Ettore Majorana’s Published Papers. PoS(EMC2006)016 Erasmo Recami ]. 16 ] for higher spin values (one, three- 10 ] and others[ (1966) 314] what Majorana many years 15 34 I am writing some articles in German. The 6 Am. J. Phys. (to represent complex spinors by a set of three, or two, points on the Majorana sphere Majorana’s last three articles are all of such importanceThe that article “Teoria none relativistica of di them particelle can con be momento set intrinseco arbitrario" aside (Relativistic As soon as the news of the Joliot-Curie experiments reached Rome at the beginning of 1932, without comment. theory of particles withtime arbitrary that spin) it is became a understoodcommonly typical and thought evaluated example that in of one depth could a only write many workwith relativistic years zero that quantum or later. equations is half Around only spin. so in 1932 Convinced the farbegan it of case constructing was ahead the of suitable contrary, of particles Majorana quantum-relativistic —as its equations we [ know from his manuscripts— Majorana understood that they had discovered the “neutraleven proton" before without having the realized it. official Thus, announcementChadwick, of Majorana the was discovery able of toof explain the the protons neutron, structure and made and neutrons, soon stability antedating afterwards ofSegré in and atomic by this Amaldi nuclei have way with recounted. also the Majorana’s the colleaguesconcluded help remember that pioneering that protons work even and before of neutrons Easter (indistinguishable D. he withbound Ivanenko, had respect by to as the the both “exchange nuclear interaction) forces" were originatingnot from also the exchange of of their their spins, spatialthe as positions Heisenberg deuteron) alone would (and saturated propose), with so respect ashis to to own produce the article the binding on alpha energy. particlecolleague the (and Only in same not Leipzig; after problem and Heisenberg was finally hadin Heisenberg Fermi published the was able able paper to to “Über convince die persuaderecognized Majorana Kerntheorie." Majorana by to Majorana’s the to paper publish scientific his on community meet –a results the his raretimely stability event, famous “propaganda" as of made we nuclei know, by from was Heisenberg his immediately himself. writings–brief thanks passages to We from that seize Majorana’s the letters present from(the opportunity Leipzig. italics to are quote On ours): two February “The 14,with environment 1933, Heisenberg, of he with the writes Hund, physics his institute and mother is with very everyone nice. else. I have good relations E.Majorana: Scientist and Man by Bloch and Rabi in 1945—reverse established the the spin theoretical also basis for of thefor neutrons experimental example, by in method a all used polarized-neutron radio-frequency to spectrometers. field,the This a so-called Majorana method paper that does moreover is introduce stillsurface practiced of today, a sphere), as noted not long ago by R.Penrose[ halves, etc.); and he evenstill devised a he method published for nothing, writing untilinfinite the he series equation of discovered for cases, that a that generic one is,time spin-value. could the an known But write entire particles infinite a could be family single counted ofthese on equation particles one “infinite to of hand). components" arbitrary cover In equations, order spin an to (even Majorana implementgroup if his invented several at programme years a that with before technique Eugene for Wignerdimensional did. the unitary And, representation what representations of is of a more, the Majoranahis Lorentz obtained 1939 and the group 1948 infinite- that works. will The entire beGelfand theory and re-discovered was collaborators) re-invented by by in Soviet a Wigner mathematicians series in (in of particular years articles from later. 1948 Sadly, to 1958 Majorana’s and initial finallyFradkin, article applied informed by remained by physicists in E. Amaldi, the released shadows [ earlier for had a accomplished. good 34 years until D. PoS(EMC2006)016 ]. 9 Erasmo Recami ] that the present 8 the Dirac function[ δ is a constant and ε in German. Again, in a letter dated February 18, 7 , where ." Actually, Majorana published nothing more, either ) t ( ε δ the only paper = I will publish in German, after having extended it, also my latest q 2 ω + q ...." The work that is already ready is, naturally, the cited one on nuclear ] and kept at the “Domus Galilaeana" of Pisa, Italy. Our analysis of these manuscripts 10 Majorana also left us several unpublished scientific manuscripts, all of which have been cata- As we said, from the existing manuscripts it appears that Majorana was also formulating the logued [ According to Touschek, the properties ofconnection the Majorana with oscillator its are energy very spectrum: interesting,much But especially more no in recently, literature C.Becchi seems pointed to out existmulation how, yet of in on the the it. first quantum pages actionSchwinger’s Another of principle and example: the appears, Symanzik’s present works, the paper, for a samequantum example, clear principle field for- has that theory. brought in about later quite years, important through advances in 3. Ettore Majorana’s Unpublished Papers. has allowed us to ascertain thatthe all rough the existing copy material of seemsmentioned— to his seems have last to been written have article, by beenwas 1933; which ready confirmed. even Majorana by Indeed, 1933, proceeded we the are toexcept year unaware for publish of in a what in which series he the 1937 of did discovery1937, 34 in —as in of letters the reply already the written following to by years positron his from Majorana unclethe 1934 between Quirino Italian to March —a Physical 1938, renowned 17, Society— experimental 1931, who physicist and and hadown November at experiments. been 16, a pressing By time Majorana contrast, president for his of theoretical sisterhad Maria explanations reduced recalled of his that, his visits even to in Fermi’sturn Institute, those from starting years, Leipzig)— from Majorana continued the —who to beginning study of andDid 1934 work he (that at continue is, home to many after dedicate hours his himself during re- the to day physics? and at From night. a letter of his to Quirino, dated January 16, article implicitly contains also whatby he the called simple the equation theory of the “Majorana oscillator", described essential lines of his symmetric theoryeven of though electrons and he anti-electrons published duringcompetition the this for years theory 1932-1933, a only professorship, years under(Symmetrical the later, theory title when of “Teoria participating simmetrica the dell’elettrone inexclusively electron for e the and having del forementioned positron), introduced positrone" the aA Majorana publication representation consequence that of of the was this Dirac initiallyand theory matrices noted Majorana in is almost suggested real that that form. a neutrinoswritings, neutral could this fermion be article particles has also of tonowadays started this expressions be to type. like identical Majorana gain spinors, As with prominence Majorana with itsable. mass, only Majorana’s and anti-particle, As decades other Majorana already later, neutrinos mentioned, are Majorana’s beginning fashion- publicationsgold-mine in (still for 1957; little physics. known, and despite Many it years all) ago, is for a potential example, Bruno Touschek noticed[ E.Majorana: Scientist and Man first one is already ready forces, which, however, remained he tells his father (we italicize):article “ which appeared inin Nuovo Germany Cimento or after hisspeak. return It is to therefore Italy, of except importanceparticular, for to he know the was that expanding article Majorana his was (in article engaged 1937) about in the of writing infinite-components other which equations. papers: we in are about to PoS(EMC2006)016 Zeitschrift für Erasmo Recami , edited by B.Preziosi (Bibliopolis pub.; Neaples, 8 ...." In the second one (dated March 3, 1933) he even declares, (1934) 709], I remained absolutely convinced that what Majorana had 7 Nuovo Cimento Helv. Phys. Acta archives? Our own search ended in failure]. One must moreover not forget that the above- Ettore Majorana – Lezioni all’Università di Napoli 1987). Do any other unpublished scientific manuscripts of Majorana exist? The question, raised by his Some of Majorana’s other ideas, when they did not remain concealed in his own mind, have We attach to this paper a short Bibliography. Far from being exhaustive, it provides only some [1] letters from Leipzig to hisaddressed family, to becomes of the greater National importance(dated Research when January Council one 21, of reads 1933), also Italy Majoranaof his asserts: (CNR) a letters theory during “At for the that the moment, period. description Isummary of notice am arbitrary-spin In in occupied particles with the that I the first began elaboration one in Italy and of which I gave a survived in the memories ofWriting his from colleagues. Pisa One on October suchme], 16, reminiscence 1978, we mentioned he owe by recalls: to Segré, Gianbefore “...The Carlo happened Majorana’s scientific Wick. in contact sojourn Rome [between in Ettore onrestaurant, Leipzig). and the and occasion therefore The of without conversation the arana took ‘A. blackboard...; described place Volta in but Congress’ in even words (long in Heitler’s wasidea the company a of absence at ‘relativistic field of theory quantization’ a details, of (secondarticle what charged quantization). [ particles Majo- When of much zero later spin I based saw on Pauli the and Weisskopf’s references about the topics touched upon in this paper. 4. Acknowledgments. The author is quite grateful to allF. the Catara, Organizers E. of this Migneco, Catania S. Conference: Lo A. Nigro,for Agodi, constant F. P. Porto, encouragement Castorina, or E. collaboration, Rimini, he and thanks inLicata, Franco particular Bassani, Fabio Salvatore A. Majorana, Esposito, Rapisarda. Bruno Ignazio Preziosi Moreover, and Silvano Sgrignoli. References E.Majorana: Scientist and Man 1936, we find a first answer,time, because with we quantum get electrodynamics"; to knowing learn Majorana’s that modestythis Majorana and no had love doubt been for means occupied understatements, “since that some byin 1935 the field Majorana of had quantum profoundly electrodynamics. dedicated himself to original research Physik cited letter to Quirino Majorana,work on dated theoretical January physics 16, even subsequently, 1936,electrodynamics. occupying himself revealed in that depth, his at least, nephew with continued quantum to discussed was the same thing...." referring to the same work:have the “I manuscript have of sent a anjournal new article in a theory on few on nuclear days." elementary theory Consideringtheory that particles to was the ready, Zeitschrift already article and für of described will Physik. here aa send as very I a copy it high “summary to level, of notice" one the of its can a same final imagine new how version, interesting which it went would be unpublished. to discover [Is it still, perhaps, in the PoS(EMC2006)016 Atti IX (Bologna, (Il Mulino (1982). 9 43 Erasmo Recami 110 (1975) Proceedings , 3 vols., edited by (2002) 852-856; (Milan), 19 October Physique , 2nd edition (Oscar, 70 , ]. (Bologna, 1988) p.13. , 5 (1999), pp.19-68; and Scientia (2002) 2417-2426. (Milan), 28 November 4 4 41 Giornale di Fisica , edited by A.Zichichi (1998) 231; and E.Giannetto; (Palermo), 22 and 23 July 1975; 28 Am. J. Phys. Autobiografia di un Fisico L’Ora Corriere della Sera Il Nuovo Saggiatore Int. J. Theor. Phys. Domenica del Corriere Found. Phys. , edited by S.Esposito and E.Recami (Zanichelli , edited by S.Esposito, E.Majorana Jr., A. van der 9 (Accademia dei Lincei; Roma, 1966); “Ettore Majorana: (Zanichelli pub.; Bologna, 1971). , edited by S.Esposito (Bibliopolis pub.; Neaples, 2006). (Editori Riuniti pub.; Rome, 1972); and in , edited by F.Bevilacqua (Milan, 1988) p.173. Quaderni di Storia della Fisica (S.I.F.) (1974) 568 [interesting also for a possible physical interpretation 11 (Zanichelli; Bologna (1971); and Via D’Azeglio 57 (1985) 140 e 145; “Su alcuni manoscritti inediti di E.Majorana", in Strong and Weak Interactions. Present problems (Turin), 1st June and 29 June 1975; in 44 (1984) pp.1–322; E. Amaldi: in Il caso Majorana: Epistolario, Documenti, Testimonianze Scienziati e tecnologi contemporanei: Enciclopedia Biografica 111 that appear in this article (as well as all the biographic documentation regarding Fermi e la fisica moderna Lett. Nuovo Cimento La Vita e l’Opera di E. Majorana La Stampa Enrico Fermi, Fisico documents International Conference on the History of Particle Physics, Paris, July 1982 “Majorana transformation for differential equations", pub.; Rome, 1995). of the photon wave-function]. SeeLett. also Nuovo S.Esposito: Cimento Congresso Naz.le di Storia della Fisica Majorana”, 1982 and 13 December 1983;L’opera scientifica “Ricordo edita di e Ettore inedita", Majorana in a sessant’anni dalla sua scomparsa: Man and scientist," in (Academic Press; New York, 1966); “Ricordo di Ettore Majorana", in p.577; in moreover VV.AA.: E.Macorini (Mondadori pub.; Milan, 1974);G.C.Graziosi: M.Farinella: “Le in lettere del mistero Majorana", in Lezioni di Fisica Teorica – Ettore Majorana at that time, Touschek’s comment. pub.; Bologna, 2006). 1968) p.300; E. Amaldi: “FromPhysics the Reports discovery of the neutron to the discovery of nuclear fission", in E.Majorana, directly discovered or collected bybook E.Recami by in E.Recami: almost 30 years)Mondadori can pub.; be Milano, found 1991), in pp.230; the and2002), in pp.273. particular [They in are its protected 4th sincewith edition 1986 E.Recami, (Di by and, Renzo copyright now, pub.; in with Roma, favour DiFrench, of Renzo performed Maria Publisher]. by Majorana F. together Of and those Ph. book Gueret it (unpublished). exists a good translation into 1972; S.Ponz de Leon: “Speciale(“Canale News: Cinque"); Majorana", B.Russo: TV piece “Ettore broadcast MajoranaDecember on – 1990 30 Un (“RAI September giorno Tre–Sicilia"); 1987 di F.Tomandl marzo", ebroadcast TV A.Stadler: at piece the large broadcast end radio on of piece 18 2004 on by Ettore the Majorana Ettore “Austrian Majorana Radio", - Vienna. Notes on TheoreticalMerwe, Physics and E.Recami (Kluwer Acad. Pub.; Dordrecht, BostonEttore and Majorana London, – Nov. 2003). Appunti Inediti di Fisica Teorica [2] [3] E.Amaldi, [4] The [5] See also E. Recami: “I nuovi documenti sulla scomparsa di E.Majorana", in [9] See page 70 in the IV edition (2002) of the book by Recami, quoted in ref.[ [8] B.Touschek: private communications (1976). Thanks are due to E.Pessa for having forwarded to us, [6] [7] [12] B.Pontecorvo, [13] Cf. also, e.g., G.Enriques: [14] E.Segré: [11] S.Esposito: “Majorana solution of the Thomas-Fermi equation", [10] M.Baldo, R.Mignani e E.Recami: “About a Dirac–like equation for the photon, according to Ettore E.Majorana: Scientist and Man PoS(EMC2006)016 Stud. Hist. Erasmo Recami (Rizzoli pub.; 1996), Quaderni di Storia , edited by 3 (2006), issue no.10. , ed. by R.Bonifacio (A.I.P.; (1999) 19-68. 5 300 Years of Gravitation , edited by B.Preziosi (Bibliopolis pub.; Napoli, 10 , edited by I.Licata (Di Renzo pub.; Rome, 2006), which EJTP Electr. J. Theor. Phys. (S.I.F. pub.; Bologna) Ombre della Mente (Shadows of the Mind) (1993) 697; R. Penrose: Mysteries, Puzzles, and Paradoxes in Quantum Mechanics 24 della Fisica (of the Giornale di Fisica) Ettore Majorana – Lezioni all’Università di Napoli can be found also in the electronic journal 1987), pp.175-197; and E. Recami, “Ettore Majorana: L’opera edita ed inedita," S.W.Hawking and W.Israel (University Press; Cambridge, 1987);Phil. Sci. J. Zimba and R. Penrose, pp.338–343 and 371–375; and the subsequentA.Vaglica e studies, G.Vetri: performed “ at Quantum Palermo, visibility, by phase-differencepreprint C.Leonardi, operators, (Phys.Dept., F.Lillo, and Univ. of the Palermo, Majorana Italy; Sphere", space", 1998); in “Majorana and Fano alternativesWoodbury, N.Y., to 1999), the pp.312-315; Hilbert F.Lillo: “AspettiFotoni", Fondamentali PhD nell’Interferometria thesis a (C.Leonardi Uno supervisor), e Dept. Due of Physics,Majorana University Legacy of in Palermo, Contemporary 1998. Physics E.Majorana: Scientist and Man [15] R.Penrose, “Newton, quantum theory and reality," in [17] M.Baldo, R.Mignani, e E.Recami, “Catalogo dei manoscritti scientifici inediti di E. Majorana," in [16]