Transcript Revisão Histórica de Física de Partículas e Nucleos

Revisão Histórica de
Desenvolvimento em
Física de Partículas e Nucleos
Os primeiros passos
• 1986 - Descoberta de radioatividade de
Urânio por Henri Becquerel (1852-1908)
Descoberta de elétron
Joseph John Thomson (1856-1940)
Nobel Lectures Joseph John Thomson (1856-1940)
Carriers of negative electricity
Nobel Lecture in Physics, December 11, 1906. [from Introductory
In this lecture I wish to give an account of some investigations which have led to the conclusion
that the carriers of negative electricity are bodies, which I have called corpuscles, having a mass
very much smaller than that of the atom of any known element, and are of the same character from
whatever source the negative electricity may be derived. The first place in which corpuscles were
detected was a highly exhausted tube through which an electric discharge was passing. When an
electric discharge is sent through a highly exhausted tube, the sides of the tube glow with a vivid
green phosphorescence. That this is due to something proceeding in straight lines from the cathode-the electrode where the negative electricity enters the tube--can be shown in the following way
(the experiment is one made many years ago by Sir William Crookes): A Maltese cross made of
thin mica is placed between the cathode and the walls of the tube. When the discharge is past, the
green phosphorescence no longer extends all over the end of the tube, as it did when the cross was
absent. There is now a well-defined cross in the phosphorescence at the end of the tube; the mica
cross has thrown a shadow and the shape of the shadow proves that the phosphorescence is due to
something travelling from the cathode in straight lines, which is stopped by a thin plate of mica.
The green phosphorescence is caused by cathode rays and at one time there was a keen controversy
as to the nature of these rays. Two views were prevalent: one, which was chiefly supported by
English physicists, was that the rays are negatively electrified bodies shot off from the cathode
with great velocity; the other view, which was held by the great majority of German physicists, was
that the rays are some kind of ethereal vibration or waves.
The arguments in favour of the rays being negatively charged particles are primarily that they are
deflected by a magnet in just the same way as moving, negatively electrified particles. We know
that such p
Trabalhos de Curie-CurieBecquerel
THE DREAM BECOMES A REALITY
THE DISCOVERY OF RADIUM by Marie Curie
I HAVE already said that in 1897 Pierre Curie was occupied with an investigation on the growth of crystals. I
myself had finished, by the beginning of vacation, a study of the magnetization of tempered steels which had
resulted in our getting a small subvention from the Society for the Encouragement of National Industry. Our
daughter Ir鈩e was born in September, and as soon as I was well again, I resumed my work in the laboratory with
the intention of preparing a doctor's thesis.
Our attention was caught by a curious phenomenon discovered in 1896 by Henri Becquerel. The discovery of the
X-ray by Roentgen had excited the imagination, and many physicians were trying to discover if similar rays were
not emitted by fluorescent bodies under the action of light. With this question in mind Henri Becquerel was
studying uranium salts, and, as sometimes occurs, came upon a, phenomenon different from that he was looking
for: the spontaneous emission by uranium salts of rays of a peculiar character. This was the discovery of
radioactivity.
The particular phenomenon discovered by Becquerel was as follows: uranium compound placed upon a
photographic plate covered with black paper produces on that plate an impression analogous to that which light
would make. The impression is due to uranium rays that traverse the paper. These same rays can, like X-rays,
discharge an electroscope, by making the air which surrounds it a conductor.
Henri Becquerel assured himself that these properties do not depend on a preliminary isolation, and that they
persist when the uranium compound is kept in darkness during several months. The next step was to ask whence
came this energy, of minute quantity, it is true, but constantly given off by uranium compounds under the form of
radiations.
The study of this phenomenon seemed to us very attractive and all the more so because the question was entirely
new and nothing yet had been written upon it. I decided to undertake an investigation of it. It was necessary to find
a place in which to conduct the experiments. My husband obtained from the director of the School the
authorization to use a glassed-in study on the ground floor which was then being used as a storeroom and
machine shop.
Descoberta de Partículas a e b
E. Rutherford - 1989
Earnest Rutherford 1871-1937
As primeiras idéias..
"The cause and origin of the radiation continuously emitted by uranium
and its salts still remain a mystery. All the results that have been obtained
point to the conclusion that uranium gives out types of radiation which,
as regards their effects on gases, are similar to Röntgen rays and the
secondary radiation emitted by metals when Röntgen rays fall upon them.
If there is no polarization or refraction the similarity is complete."
Destinção de a, b, g
Ainda no ano 1900, não há magnet que pode desviar o “raio alfa’’
emitido do Urânio. Rutherford em 1903, conseguiu mostrar com
magnet mais forte na epoca e também com o campo elétrico, o
desvio do raio alfa, e portanto concluindo como feixe de partícula
carregada.
1900 Descoberta de g
Paul Villard
Paul Villard 1860-1934
Identificado como radiação eletromagnética em
1914 por E. Rutherford
Abertura da nova era
Max Planck 1858 - 1947
1900 Introdução de constante h
Premio Nobel 1918
1905 - Annus Mirabilis / A. Einstein
Efeito fotoelétrico
Movimento Browniano
Relatividade Restrita
Premio Nobel 1921
1908 Experimento de espalhamento de alfa por Au
1H.
Geiger and E. Marsden, Roy. soc. Proc. vol. lxxxii. p. 495 (1909).
2E. Rutherford, Phil. Mag. vol. xxi. p. 669 (1911).
From the distribution obtained, the most probable angle of scattering
could be deduced, and it was shown that the results could be explained
on the assumption that the deflexion of a single a particle is the resultant
of a large number of very small deflexions caused by the passage of the
a particle, through the successive individual atoms of the scattering
substance.
In an earlier paper1, however, we pointed out that a particles are
sometimes turned through very large angles. This was made evident by
the fact that when a particles fall on a metal plate, a small fraction of
them, about 1/1800 in the case of platinum, appears to be diffusely
reflected. This amount of reflection, although small, is, however, too
large to be explained on the above simple theory of scattering. It is easy
to calculate from the experimental data that the probability of a
deflection through an angle of 90° is vanishingly small and different
order to the value found experimentally
1909 Robert Millikan Medida da carga de elétron
Premio Nobel 1923
Conferência Solvay Bruxela 1911
1914 Espectro Contínuo de Eletron num decaimento beta
J. Chadwick (1891-1971)
Estabelecimento de conceito sobre existência de proton e
sua identidade como nucleo de hidrogênio
1898
1913
1917
Wien
J.J. Thomson
Experimento de Rutherford
Niles Bohr (1885-1962)
1913 - On the Constitution of Atoms
and Molecules, Philosophical
Magazine, and Journal of Science
Premio Nobel em 1922
A. Sommerfeld (1868 – 1951)
1915 - 1916 Generalização do
modelo do Bohr. Surgimento da
Velha Mecânica Quântica
A. H. Compton
A Quantum Theory of the Scattering of X-rays by
Light Elements
Washington University, Saint Louis
Phys. Rev. 21, 483 (1923)
Received 13 December 1922
Premio Nobel 1927
Charls T. Wilson (1869-1959)
Invenção de Camara de Wilson
Premio Nobel 1927
Louis Victor deBroglie (1892 - 1987)
1924 Tese de Doutoramento, Recherches sur la
Théorie des Quanta, Univ. Paris
Premio Nobel 1929
W. Heisenberg (1901-1976)
1925 "My entire meagre efforts go toward killing off
and suitably replacing the concept of the orbital paths
that one cannot observe.."
1927 Princípio de incerteza
Premio Nobel em 1932
M. Born (1901-1976)
1902-1980
1925 Born-Jordan Z. fur Physik 34 (1925) 858
1928 Interpretação probabilistica
Premio Nobel em 1954
Pascual Jordan 1902-1980
Ervin Schrödinger (1887-1961)
1926 Equação de Schrödinger
1927 Princípio de incerteza
Premio Nobel em 1932
Paul Adrien Maurice Dirac (1902-1984)
1926 Tese “Quantum Mechanics”
1928 Relativistic Electron Theory
1930 Teoria de buracos, previsão de positron
1930 Principles of Quantum Mechanics
Premio Nobel em 1932
Phone call from Copenhagen to Berlin, 1926:
Niels Bohr:
Erwin, I don't get it. Here I had a nice model that explains so much about the light spectrum, black body radiation, the periodic table of elements -- all the
chemists were so excited and, besides, it just looks so cool and drawable. I can see high school teachers way in the future drawing little balls in the center with
beads of electrons zipping around. What are you doing messing in with your waves?
Erwin Schrodinger:
Niels, you gotta be kidding. Everyone knows your model violates all the traffic laws of nature. You've taken old man Planck's quantum leaps one leap too far.
Particles jumping from one orbit to another without traversing the space in between! I mean, if something can leave one place and turn up instantaneously in
another, then anything could happen! And if anything could happen, then what are we scientists for?
Niels:
Okay, so it's weird. Life is weird, Erwin. And waves don't make it any less so.
Erwin:
Oh, yeah? Waves are the classic model for all energy forms. Water waves. Sound waves. Force waves. Light waves. That's the way we've been explaining
energy for years and you crazy Danes have no right to change it!
Niels:
Waves in water I get. Same with waves in the air. But waves in an atom are downright ludicrous! You can't have waves without something waving, Erwin!
Erwin:
A detail. So you caught me on a detail. Look, we figured everything else out. We'll figure this one out eventually as well. The main thing is we got rid of those
doggone quantum disappearing acts.
Niels:
So waves in the nothingness is okay. But disappearing acts are not. Now if that isn't arbitrary…
Erwin:
Niels, your buddy Albert already established that energy and matter are really the same stuff. So let's just do away with this whole notion of matter and tiny
beads in orbit and say the whole world is made of energy. And energy is waves.
Niels:
Now there's no such thing as matter. So exactly who's going too far here? And another thing I want to know: If there aren't any electron particles, why is it my
Geiger counter registers a click when they hit? Waves don't click, you know that Erwin. They splash or buzz, but they don't click. And how do you explain the
whole black body radiation thing?
Erwin:
You are the one going too far, Niels. Because I know just where you're going with all this. First you have them disappearing from one place and appearing
elsewhere. Then you'll tell us they could be anywhere, their position and velocity is just an array of possibilities. And if they could be anywhere, then all of
causality breaks down. I know what your pet whippersnapper student, Heisenberg is up to, Niels. No longer will we be able to say that this happened because
that happened. And if all those things are gone, then, gevald Niels! Why are we scientists?
Listen, Niels, electrons are energy. Energy is waves. Waves are the wave of the future. You got problems with it, go work it out. But don't go tearing down the
basic laws of physics with particles that act like ghosts.
Niels:
They're particles.
Erwin:
They're waves.
Niels:
Particles.
Erwin:
In the name of the Motherland, they are waves!
Niels:
Your Motherland wears army boots. Now get your tushy up here to Copenhagen and we'll have it out like men, face to face.
Erwin:
Danishes at two feet?
Niels:
Satyendra Nath Bose 1894-1974
1920 Dedução de Distribuição de Planck
Usando a estatistica de partícuas identicas
1925 Einstein publica o artigo.
Subrahmanyan Chandrasekhar (1910-1995)
1930 Limit de Chandrasekhar
Eddington – No such things....
Premio Nobel em 1983
Wolfgang Pauli (1900-1958)
1924 Proposta de Princípio de Exclusão, Grau de liberdade de spin
1926 decução de espectro de hidrogênio usando a teoria de
Heisenberg
1927 Invenção de Matrizes de Pauli
1930 Proposta de partícula neutra não observãvel no decaimento de
beta.
1940 Prova de teorema de Spin-estatistica
Premio Nobel em 1945
Enrico Fermi (1901-1954)
1926 Estatistica de Fermi
1934 Construção de Teoria de decaimento beta, Fermi interaction
Premio Nobel em 1938 Reações nucleares com neutrons
Início de Física Nuclear
1932 Descoberta de neutrons
James Chadwick (1891-1974)
1932 Trabalhos de Heisenberg sobre a estrutura nuclear
Relatividade e Mecanica Quântica
Positron
1930 P.A. M. Dirac
Carl D. Anderson (1905-1991)
Physical Review 43, 491 (1933).
Os primeiros passos de
Teoria Quantica de Campos
1937 Propsta de píons para explicar a
força nuclear
Hideki Yukawa (1907-1981)
Descobertas de partículas novas
1937 J. C. Street and E. C. Stevenson
"New Evidence for the Existence of a Particle
Intermediate Between the Proton and Electron"
Phys. Rev. 52, 1003 (1937). -> muon
Descobertas de pion
1947 G.Ochialini, C. Lattes, C. Powell,
Cesar Lattes
Início da era de acceleradores
1939 750 KeV Cockroft-Walton (Cavendish Lab)
Nucleon
Atomo
Moleculas
quarks
Núcleo
Correlações quânticas de quarks e gluons
no Vácuo Físico da QCD
Hadrons
Barions
(Protons, Neutrons..)
q
q
q
Mésons
(Píons, Kaons..)
q
q
RHIC / Brookhaven National Laboratoy - USA
LHC/ CERN - Geneve
Deteção de partículas finais
- Phenix
Explosão da materia produzida...
Universo Primodial como a panela de pressão
(estamos dentro dela…)
Imagem atual do Universo
Superstrings,
Quantum Gravituy
Histórico
Standard Model
QCD
Photon Freezeout
Formação de grande
escala
3K Blackbody radiation
Astrofísica de altas energias
Antes
Depois
SN1987-a
Supernova 1998S no NGC 3877
pulsar
Estrutura de estrela de neutrons