Capitulo 1: Introducción al Modelo estándar

Presentación del tema: "Capitulo 1: Introducción al Modelo estándar"— Transcripción de la presentación:

1 Capitulo 1: Introducción al Modelo estándar
Partículas fundamentales Fuerzas fundamentales

2 ¿De donde viene todo …? What is the matter? 13 March 1998
Since time immemorial people have pondered on the world around them, as exemplified in this splendid cartoon by Sidney Harris. What is it made of? How does it work? Little by little we have developed a scientific view of matter and I will first briefly describe the current view of the smallest particles of matter and how we achieved that view. However if you are looking for complete answers you will be disappointed. Unfortunately at the end of the lecture we will still be pondering the question where the hell did it all come from, although I hope to have given you some insight into a physicist’s view of the Universe. M G Green

3 ¿Que es materia? What is the matter? 13 March 1998
As we look around us we find that matter comes in many forms natural man-made small scale large scale simple complex inanimate animate So many forms in fact that it is natural to look for some simplifying way of classifying matter. M G Green

4 Que pasaría si pudieramos cortar y cortar hasta el infinito?..

5 Que tienen que estar hechas de algo,
UN INDIVISIBLE.

6 El concepto de elemento
What is the matter? 13 March 1998 El concepto de elemento En la filosofía de Aristoteles Había cuatro elementos The first attempt seems to have come from ancient Greece where the four elements of earth, water, air and fire were recognized. This scheme is quite attractive at a trivial level and if you get bored during the rest of the talk you could amuse yourselves constructing some of the objects around us from these four elements. However during the last few hundred years a more useful idea of elements developed. Substances such as gold, sulphur, lead, nitrogen were recognized as elemental in the sense that they were contained in different substances in different mixtures but could not themselves be broken down further. By the beginning of the last century Dalton had identified twenty elements and listed them together with their relative weights. Dalton (1808) listó, con pesos, muchos de los elementos reconocidos hoy M G Green

7 La tabla periódica Mendeleev (1869) introdujo la tabla periódica
What is the matter? 13 March 1998 La tabla periódica However the definitive word was given by Mendeleev in 1869 when he arranged the known elements in a beautiful pattern. Moreover his pattern was predictive in that some elements were missing with properties that could be predicted. All were later discovered. Thus by the end of the last century the concept of elements was well developed. The smallest piece of an element was known as an atom with atoms imagined as small spheres. However 100 years ago the electron was discovered and it became clear that it not only played an important role in electricity but was also contained inside atoms, i.e. atoms have sub-structure. Mendeleev (1869) introdujo la tabla periódica M G Green

8 What is the matter? 13 March 1998 El modelo del pudding J J Thomson creía que los electrones estaban metidos en una matriz de carga positiva, como una tarta One of the first models to incorporate this feature, due to J J Thomson, was known as the ‘plum pudding model’ since he imagined that the electrons, with their negative charge, were scattered throughout some blob of positive matter. M G Green

9 Estructura de los átomos
What is the matter? 13 March 1998 Estructura de los átomos Rutherford (1912) Mostró que los átomos tienen estructura Chadwick (1932) Descubrió el neutrón dentro del núcleo However it was in 1912 that the New Zealander Ernest Rutherford gave us our modern view of the atom when he showed that atoms have a positive nucleus surrounded at a relatively large distance by the electrons, a picture that everyone today recognizes as the symbol for the atom. The photograph shows Rutherford in his lab. The sign says ‘Talk softly please’ supposedly put there because the detectors were sensitive to noise. However the more likely explanation is that it was aimed at Rutherford by his colleagues, since he was renowned for his booming voice. Now it became clear what differentiates the elements - the number of electrons and the charge on the nucleus - for example hydrogen has one electron, helium has two, carbon six, lead eighty-two etc. However the story doesn’t stop there. Electrones orbitan alrededor del núcleo con energías bien definidas y posiciones muy mal 10-10 m M G Green

10 Estructura de los núcleos
What is the matter? 13 March 1998 Estructura de los núcleos The nucleus itself has structure and contains positively charged protons and neutral neutrons, the latter discovered by Chadwick in 1932. Can we go further down the levels of sub-structure? The answer is yes. Núcleo contiene protones con carga +, e y neutrones son carga 10-14 m M G Green

11 Estructura de los núcleo
What is the matter? 13 March 1998 Estructura de los núcleo In the 1960s it became apparent that protons and neutrons have structure and contain objects called quarks, tiny in comparison with the neutrons and protons, but moving at very high speed and bound together by a force known as the strong nuclear force. The quarks will be the major players in my story this evening, but before we turn to look at them in detail there are two other issues I would like to consider. The first is the obvious one. Are there more layers? Los protones y neutrones contienen quarks 10-15 m M G Green

12 ¿Estructura en los quarks?
What is the matter? 13 March 1998 ¿Estructura en los quarks? ? Currently the answer is that we don’t know of any deeper levels. Attempts have been made to find further sub-structure, some of which have been made within the particle physics group here at Royal Holloway, led recently by my colleague Terry Medcalf, but if such objects do exist they are smaller than m. No hay evidencia de estructura <10-18 m M G Green

13 Nuestro entendimiento de la materia 目前我們對於物質世界的組成的了解

14 Evidencia de subestructura
What is the matter? 13 March 1998 Evidencia de subestructura Átomos absorben energía La energía del electrón aumenta Secondly let me very briefly explain how we know about sub-structure. The first type of evidence is the existence of what are called ‘excited states’ of systems. If we shine light on atoms we can excite them - meaning that one of the electrons goes into a higher energy orbit. Later it will de-excite. We find the same effects in nuclei and thus know that they have substructure, and also in protons and neutrons. Solo ciertos estados de energía están permitido, ciertas órbitas Más tarde se des excitan M G Green

15 Evidencia de subestructura
What is the matter? 13 March 1998 Evidencia de subestructura Medida del tamaño de los objetos (Rutherford 1912) The second piece of evidence arises if we fire projectiles at material. Of course the projectiles must be tiny themselves. Rutherford and his co-workers used the nuclei of helium atoms, known as alpha particles. Because the nuclei are so tiny, almost all projectiles go nowhere near a nucleus and are therefore undeflected. A few, heading straight for the nucleus, are turned around by the electrostatic force between the alpha particle and the nucleus. A few others, passing close to the nucleus are deflected. Rutherford’s big step forward was to realize that detailed measurements on a large number of such collisions allowed him to determine the size of the nucleus. In a similar way around 1970, by firing electrons accelerated to close to the speed of light at protons and neutrons, it was clearly demonstrated that they have substructure. Moreover properties of that substructure could be determined. 1970 – subestructura de los protones y neutrones fueron descubiertas usando electrones como proyectiles M G Green

16 Constituyentes de la materia
What is the matter? 13 March 1998 Constituyentes de la materia quarks electrón 2 3 e + 1 - -e carga u d Thus we now have a very simple picture of the matter around us. It comprises a large number of different types of atoms, but they contain just protons, neutrons and electrons. Moreover the protons and neutrons contain just two types of quark. Note particularly the charges on each quark. It’s particularly interesting to point out that in this picture the difference between a proton and a neutron - one contains two up and one down quark, the other contains two down and one up quark. Moreover the charge on a proton appears to be exactly opposite that of the electron. If this were not so then theUniverse could not exist, but we still have no idea why this is the case. However the story of matter is not quite so simple as this. In reaching this picture in the 1960s several complications were discovered along the way. Protones contienen uud - carga = +e Neutrones contienen udd - carga = 0 M G Green

17 Acelerador de energía 加速器能量
Point-out the higher accelerator energy. Again ask the audience what they think will happen. Most guess correctly. Point out that the resulting fragments are the “basic building blocks” Acelerador de energía 加速器能量

18 Bloques universales de la materia
Química! Quarks Lepton Up (u) Electron Down (d) uud = proton udd = neutron 3 grupos de quarks  Nucleones

19 Multiplicados por billones y billones
Construímos átomos electrons Helium Atom 氦原子 At this point can ask the audience what they see – older ones will understand that they see the constituents of helium. Again this shows how we use the basic “Lego” bricks to build bigger things. protons neutrons Multiplicados por billones y billones

20 And you get…the Universe!
Et voila!

21 Pero esto no es el final de la Historia

22 Las colisiones de energía fueron creadas para producir partículas que ya no existen en la naturaleza de forma natural, aunque existieron Now it gets really interesting! Ask again what they think will happen with even higher collision energy/speed. Most will say “even smaller pieces” but some may be more cautious. But they never expect the dinosaurs! Emphasize that this is just an illustration – we don’t really make dinosaurs (sounds obvious but year olds can take things literally!). Can ask if they recognise the equation and ask them what it means – even a lot of the year olds do know! Another reason why dinosaurs are appropriate: CERN is at the foot of the Jura mountains – the origin of the “Jurassic” period due to the number of dinosaur bones found in the mountains. And what CERN is doing goes WAY back further in time than the dinosaurs. Accelerator Energy

23 Así que los experimentos son maquinas del tiempo
Hace 13,700,000,000 el universo contenía otras cosas que ahora podemos crear en el laboratorio Así que los experimentos son maquinas del tiempo

24 Una partícula es fundamental cuando no tiene estructura interna.
INDIVISIBLES = PARTÍCULAS FUNDAMENTALES? CORRECTO ✔ Una partícula es fundamental cuando no tiene estructura interna.

25 PERO,¿Que pequeño es PEQUEÑO?

26

27

28 Mosca de la fruta: 3 mm (0.003 m)

29 Mosca de la fruta: 3 mm (0.003 m)

30 Ácaros: 500 µm ( m)

31 Ácaros: 500 µm ( m)

32 Bacteria: 0.5 µm ( m)

33 Bacteria: 0.5 µm ( m)

34 Virus: 100 nm ( m)

35 Virus: 100 nm ( m)

36 Molécula de proteina: 10 nm (0.00000001 m)

37 Molécula de proteina: 10 nm (0.00000001 m)

38 Cadena de átomos: 2 nm (0.000000002 m)

39 Cadena de átomos: 2 nm (0.000000002 m)

40 Átomo( OJO, No está a escala!!): 100 pm (0.0000000001 m)

41 Átomo (OJO, no está a!!): 100 pm (0.0000000001 m)
proton 1 fm ( m)

42 Átomo(OJO no está a escala!!): 100 pm (0.0000000001 m)
proton 1 fm ( m) neutron 1 fm ( m)

43 Átomo(OJO, no está a escala!!): 100 pm (0.0000000001 m)
electron < 1 am ( m) proton 1 fm ( m) neutron 1 fm ( m)

44 Up Quark & Down Quark: < 1 am (< 0.000000000000000001 m)

45 Toda la materia visible del universo esta hecha de las siguientes partículas:

46 Toda la materia visible del universo esta hecha de las siguientes partículas:
El electron (e-)

47 Toda la materia visible del universo esta hecha de las siguientes partículas:
El electron (e-) El quark up (u)

48 Toda la materia visible del universo esta hecha de las siguientes partículas:
El electron (e-) El quark up (u) El quark down (d)

49 Toda la materia visible del universo está hecha de las siguientes partículas:
El electron (e-) El quark up (u) El quark down (d) MÁS una…

50 …el escurridizo: neutrino

51 …el escurridizo: neutrino
≈ 1 ym ( m) * * Neutrino size is energy-dependent. Stated size is for a 1 MeV particle

52 LAS PARTÍCULAS SON:

53 (Es decir, NO tienen estructura )
LAS PARTÍCULAS SON: FUNDAMENTAL (Es decir, NO tienen estructura )

54 (Es decir, NO tienen estructura)
LAS PARTÍCULAS SON: FUNDAMENTAL (Es decir, NO tienen estructura) O COMPUESTAS (Es decir, están formadas por alguna combinación de partículas fundamentales )

55 (Es decir, NO tienen estructura) O COMPUESTAS
LAS PARTÍCULAS SON: FUNDAMENTAL (Es decir, NO tienen estructura) O COMPUESTAS (Es decir, están formadas por alguna combinación de partículas fundamentales ) EL ELECTRON, EL QUARK y EL NEUTRINO SON PATÍCULAS FUNDAMENTALES

56 (Es decir, NO tienen estructura) O COMPUESTAS
LAS PARTÍCULAS SON: FUNDAMENTAL (Es decir, NO tienen estructura) O COMPUESTAS (Es decir, están formadas por alguna combinación de partículas fundamentales ) EL ELECTRON, EL QUARK y EL NEUTRINO SON PATÍCULAS FUNDAMENTALES ÁTOMOS, NUCLEOS, PROTONES y NEUTRONES SON PARTíCULAS COMPUESTAS

57 EL átomo más simple conocido es el HIDROGENO.

58 EL átomo más simple conocido es el HIDROGENO.
Está compuesto de 4 partículas fundamentales:

59 EL átomo más simple conocido es el HIDROGENO.
Está compuesto de 4 partículas fundamentales: EL ELECTRON + DOS QUARKS UP UN QUARK DOWN

60 EL átomo más simple conocido es el HIDROGENO.
Está compuesto de 4 partículas fundamentales: EL ELECTRON + DOS QUARKS UP UN QUARK DOWN Los quarks esta juntos formando el PROTON

61 SI ESTAS 4 PARTÍCULAS HACEN EL UNIVERSO.
electron neutrino up quark down quark

62 ¿EXISTEN MAS PARTÍCULAS FUNDAMENTALES?

63 ¿EXISTEN MAS PARTÍCULAS FUNDAMENTALES?
SI………VARIAS MAS

64 “Fundamental” Particle
September 6, 2006 origen de la masa/UIMP “Fundamental” Particle 1st family 2nd family 3rd family QUARKS LEPTONS las particulas fundamentales, son aquellas son indivisibles. Actualmente creemos que son fundamentales los quarks, leptones. Son un conjuntos de femriones que forman todas los hadrones, atomos, ect conocidos de la nturaleza. Los quarks up y down, son aquellos que forman los nucleos de los atomos que vemos en nuetra vida diaria. Los otos quarks forman la segunda y teercera familia y son copias exactas (tienes las mispropiedades y sufren las mismas interaciones) pero mas masivas. Los quarks sufren la fuerza fuerte y esto hace que no sea posible encontrarles solo, siempre estan en grupos, son particulas muy sociables. Por otro lado tenemos los leptones, cuya primera familia esta formada por el electron que es una aprticula muy conocida y querida para nosotros puesto que ha sido esencial para el grado de desarrollo actual, al igual que los quarks existen tres familas que son mas pesadas. Estas particulas sufren solo la fuerza electrodebil, y por tanto son particulas solitarias, que aparecen rodeadas de sus “mosquitas” los neutrinos.

65 \ e e u d 1ª familia 2ª familia   c s   t b 3ª familia
(1 MeV 1.810-30 kg) m [MeV] < eV 0.511 3 6 <0.19 106 1250 120 <18.9 1777 175000 4200 1995 1974 1976 1975 1956 1897 1963 1937 1961 2000 \ © 1998 Este cuadro es el mismo que el anterior pero explicamos masa y año del descubrimiento.

66 Partículas de materia exóticas
Otras partículas subatómicas son copias mas pesads de estas que hacen la materia ordinaria (u, d, e, ve)

67 Las piezas mas pequeñas de la naturaleza
La física nuclear y de partículas estudia los bloques mas pequeños del universo y las interacciones entre ellos Focalizandose en partículas unicas o grupos de partículas, pero no en los millones de atomos o moleculas que hace una estrella o planeta particleadventure.org

68 … y sus largos efectos…

69 … todo esto nos afecta a nosotros.
Historia: alquimía, etc. Astronomia: brillo solar, “metales”, cosmología Medicina: PET, MRI, quimioterapía Casa: detectores de humo, radon Computers: World-Wide Web Archaeology & Earth Sciences: dating