Quarks - Orizzonte Scuola

La classificazione
delle particelle
elementari
The zoo of the elementary particles
Spezia Stefano
Catania 21 Agosto 2013
Elementary particles
Matter
Quarks
?
Force Carriers
Leptons
Quark-Lepton
complementarity
Gravitons
W & Z Bosons
Photons
Gluons
Strong
Hadrons
Baryons
Mesons
Nuclei
Gravity
Weak
Electromagnetism
Quantum
Quantum
Quantum
Chromodynamics Electrodynamics Gravity
Electroweak Theory
Atoms
Molecules
Grand Unified Theory
Theory of everything
Raccomandazione (2006/962/CE)
Tra le 8 competenze chiave per l’apprendimento
permanente:
 Comunicazione nelle lingue straniere
 Competenza matematica e competenze di base in
scienza e tecnologia
 Competenza digitale
… con il CLIL?
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Titolo del modulo: The zoo of the elementary particles
Classe: V Liceo Scientifico
Raccordi interdisciplinari: Chimica, Inglese
Competenze linguistiche: Inglese
Risorse e strumenti: Lavagna Interattiva Multimediale
(LIM)
Periodo scolastico: ultime 3 settimane di Maggio
Prerequisiti: Meccanica (Forze ed interazioni, Teoremi
di conservazione); Meccanica relativistica (Equivalenza
massa-energia, dilatazione del tempo); Elementi di
Quanti, Materia e Radiazione.
Numero di ore: 8,5
Compresenza: Insegnante di Inglese (3,5 ore)
Obiettivi: Competenze per i giovani
 Conoscenze
 Saper descrivere le principali famiglie di particelle
elementari;
 Saper descrivere le principali interazioni e le loro
fondamentali proprietà;
 Abilità ed Attitudini essenziali (connessioni con la
realtà)
 Essere in grado di leggere e capire un articolo
divulgativo su particelle elementari e le loro interazioni.
LESSON PLAN: Lesson 1
 Introduction to … (tempo 10 minuti):
 Attivita’ di brainstorming (tempo 20 minuti): La
classe viene sollecitata a riflettere sul alcune domande
fondamentali; ogni alunno dà il suo contributo alla
discussione
 Lezione interattiva con stimolo di interventi alla LIM
da parte degli studenti, per proporre le proprie risposte
alle questioni scientifiche presentate.
The world around us
1. What is the world made of?
2. What are the building blocks that could not be further
divided?
3. What is the smallest particle you know?
Look at the following links and find information about the
building blocks of our world:
http://www.infn.it/multimedia/particle/paitaliano/summary_sm.html
http://www.infn.it/multimedia/particle/paitaliano/exp_start.html
http://www.infn.it/multimedia/particle/paitaliano/beyond_start.html
What is the world made of?
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In the ancient time: 4 elements
17-19th century – molecules and atoms
20th century – electrons, protons and neutrons
Today – quarks and leptons
The atom in the 20th century...
 Atoms reacts through chemical reactions
 More than 100 atoms known (H, He, Fe …)
 The internal structure is not well known
The
Atomic
modern
Model
atom
 A cloud of electrons
moving constantly around
the nucleus
 Protons and neutrons
moving in the nucleus
 Quarks moving in
protons and neutrons
Sub-atomic dimensions
Nucleus
 The nucleus is small
dense. For a while it
thought to be point-like.
 However, there were
many different nuclei
many atoms
 Simplification: all nuclei
made of neutrons
protons!
and
was
so
as
are
and
Sub-atomic dimensions
Nucleus are made
neutrons and protons!
of
Neutrons and protons
are made of quarks!
Quarks and electrons are
elementary particles!
Particle physics
…small, smaller…extremely small!…
> 30 soccer fields
Point-like
< 1 hair
A small stone
Point like
New particles
 Collisions of electrons and nuclei in the cosmic rays
and in the particle accelerators brought to the
discovery of many other particles.
 At the beginning it was thought that all these particles
were fundamentals.
How can we observe these particles?
1897 - Joseph John Thomson discovers a
particle, later called Electron
Laboratorio con materiale povero:
camera a nebbia FAI DA TE (2 ore)
Cosa possiamo osservare con essa?
Cosa possiamo osservare con essa?
Teoria
Lezione frontale (2.5 ore)
Standard model
A theory has been developed that seems to explain
quite well what we do observe in nature. This model
includes 6 quarks, 6 leptons and 13 particles which
carry the force in between quarks and leptons.
Example of the standard model
Proton: u + u + d quark
Neutron: u + d + d quark
Carbon: 18 u, 18 d, 6 e-
2/3
Quarks
-1/3
0
Leptons
-1
Pauli principle
Bosons all fall into the lowest energy state,
forming a Bose Einstein condensate.
Fermions, must obey the Pauli exclusion
principle, which prohibits two identical particles
from occupying the same state.
Fermions
Leptons and
quarks
Bosons
Spin = 1/2
Baryons Spin = 1/2, 3/2, 5/2 …
Spin = 1
Force carrier
particles
Spin = 0, 1, 2 ….
Hadrons
Mesons
Fermions: the fundamental
components
1st generation
2nd generation
Massa (MeV)
3rd generation
Charge (e)
2/3
2/3
-1/3
-1/3
0
0
-1
-1
Quarks
Leptons
Matter and Anti-matter
 For every particles there is a corresponding particle of
anti-matter, or anti-particle
 These particles appear to be as their sisters of matter, but
with opposite charge
 Particles are created or destroyed with their antiparticles.
Forces in Nature
There are 4 fundamental interactions!
Gravity is very weak
and is important at
macroscopic distances
In adding to the
electrical charge,
Quarks have
another kind of
charge called “color
charge”
The force carrier is
the photon (γ) massless and move
at the speed of light
Weak interactions
are responsible for
the decays of
heavy quarks and
leptons
The interactions are also responsible of the nucleus decays.
Forces in Nature
Force
Intensity
Carriers
Happens in
Strong Nuclear
~1
Gluons
(massless)
Atomic nuclea
Elettromagnetic
10-3
Photons
(massless)
Atomic levels
Beta radioactive
decay
Heavy bodies
~
Weak Nuclear
~10-5
W+,W-,Z0
(heavy)
Gravitation
~10-38
Gravitons
(not observed)
Interactions happen by exchange of one or more
particles (carriers or bosons)
Forces and distances
R > 106 m
(gravitational)
R ~ 10-11 - 10-10 m (electroweak)
R ~ 10-15 m (strong nuclear)
The gluon
A heavy nucleus contains many protons, all with positive
charges. These protons repulse each others. Why the nucleus
does not explode?
The strong force keeps the quark together, to form the
hadrons. The force carriers are the gluons: there are 8 different
gluons.
Coloured quarks and gluons
There are 3 colour charges and 3 anti-colour charges
Every quark has one of the three colour
charges and every anti-quark has one of
the three anti-colour charges
Baryons R + G + B = white
Mesons color + anti-color = white
Baryons and Mesons as
coloured quarks
All baryons, such as the proton and neutron shown here, are
composed of three quarks. All mesons, such as the pions
shown here, are composed of a quark-antiquark pair.
What can we say about mass?
 The SM cannot explain
why a given particle is
characterized by its mass.
 Physicists “invented” a new
particle,
called
Higgs
boson, which interacts
with all the other particles
to give their masses.
 Its discover has been
announced on 4 July 2012
and confirmed in March
2013.
Fase applicativa (1,5 ore):
Utilizzo di Flash Learning Objects
Applicazione guidata e controllata, con esercizi interattivi
da parte degli studenti e supervisione costante
dell'insegnante (approccio collaborativo).
 Gruppi omogenei di alunni;
 Gruppi eterogenei di alunni.
THE FIREWORKS OF THE ELEMENTARY
PARTICLE PHYSICS
By
Elena Symeonidou
Tra gli esercizi per casa…
Applicazioni per dispositivi Android (giochi, simulatori,
wallpaper, strumenti di misura virtuali, calcolatori,
tascabili (pockets),…)
Physics: The Standard Model
Verifica sommativa e valutazione
 La verifica è fornita in inglese e propone quattro
tipologie di esercizi:
 Gli esercizi possono essere risolti, senza che sia
richiesto agli studenti la totale padronanza nella
composizione in lingua inglese. Hanno invece
sicuramente bisogno della comprensione durante la
lettura per capire la consegna.
Esempio di prova di verifica (1.5 ore)
Try to make each initial answer correct. Don't just guess - research and
show me that you have learned the correct answers. Be careful!
Single answer
1. What is the charge of an UP quark (in unit of the elementary
charge e)?
a. -1;
b. -1/3;
c. 2/3;
d. +1.
2.
a.
b.
c.
d.
What is the charge of a DOWN quark?
-1;
-1/3;
2/3;
+1.
Esempio di prova di verifica
Single answer
3. What is the quark composition of a proton?
3. ddd;
4. ddu;
5. duu;
6. uuu.
4. What is the quark composition of a neutron?
a. ddd;
b. ddu;
c. duu;
d. uuu.
Esempio di prova di verifica
Single answer
5. Which of the four fundamental forces is not included in the
Standard Model?
a. Electromagnetic;
b. Gravitational;
c. Strong Nuclear;
d. Weak Nuclear.
6. Which of the fundamental forces has a range of only a few
angstroms (0.1 nm)?
a. Electromagnetic;
b. Gravitational;
c. Strong Nuclear;
d. Weak Nuclear.
Esempio di prova di verifica
True or False
1.Single quarks have been observed experimentally; False
2.3rd generation quarks (TOP and BOTTOM) are constituents
of everyday matter; False
3.The W-, W+, and Z0 bosons are carriers for the weak nuclear
force which is responsible for radioactive decay; True
4.MeV/c2 and GeV/c2 are units which are dimensionally
equivalent to grams according to Einstein's equation, E =
mc2. False
Esempio di prova di verifica
Multiple answer
1. Which of the fundamental force(s) have an
infinite range?
a.
b.
c.
d.
Electromagnetic;
Gravitational;
Strong Nuclear;
Weak Nuclear.
Esempio di prova di verifica
Complete the phrases
Higgs boson gives particles their
Interactions with the ______
unique masses;
______ and neutrinos are classified as leptons;
Electrons
Gluons are the bosons, or force carriers, for the strong
_____
force which holds nuclear particles and the nucleus
together;
Esempio di prova di verifica
Open questions
What is the difference between hadrons and leptons?
What is the difference between fermions and bosons?
What is the difference between baryons and mesons?
"Young man, if I could remember
the names of these particles,
I would have been a botanist!“
E. Fermi to his student
L. Lederman (both Nobel
laureates)
The Particle Physicist’s Bible:
Particle Data Book
https://pdg.lbl.gov
Most particles are not stable and can decay to lighter particles..
Bibliografia
 Paul Davies, Superforza, Arnoldo Mondadori
Editore S. p. A. 1986
 Ugo Amaldi, La fisica di Amaldi, Zanichelli editore,
2007
 George Gamow, The Great Physicists from Galileo
to Einstein, Dover publications 1986
 Jonathan Allday, Quarks, Leptons and The Big
Bang, IOP Publishing 2002
 M. G. Veltman, Martinus Veltman, Facts and
Mysteries in Elementary Particle Physics, World
Scientific Publishing- Singapore, Ed. 2003