To the point particle physics

Institute of Physics
University of Sindh Jamshoro
PARTICLE PHYSICS
By : Shahzada Khan
Roll NO: 2k16/mphy/38

• Hello friends, I write this book to
explaining the true meaning of particle
physics. For this reason, I try my best to
describe comprehensively every topic
of particle physics. But there are so
much other related topic which are not
here. So, please read this book and give
me feedback in my email address.
• Email: shahzadakhan14@gmail.com
About the Books
1 By :Shahzada Khan
Roll NO: 2k16/mphy/38

• Introduction(Page:01)
• Historical Background
• Elementary means
• Standard Model
• History of Particle Physics
• Classification of Particles
• Natural Particle Production (Cosmic Rays)
• Gravitational Force
• Electromagnetic Force
Index
2

• Strong Nuclear Force
• Weak Nuclear Force
• Interactions of Fundamental Forces
• Elementary particles and explanation
• Differences Between Quarks and Leptons
• Lepton
• Quarks
• Hideki Yukawa and Meson
• Feynman Diagrams
• Pions or π mesons
• Particles and Lifetimes
• Properties of Quarks
Index
3

• The Families of Matter
• Positron
• Neutrino
• Strangeness:
• Lepton Number And Law of Conservation of Lepton Number
• Baryon Number And Law of Conservation of Baryon Number
• law of Conservation Strangeness
• Particles and their transmutation process
• The Eightfold Way
• Particle Accelerator
• Collider
Index
4

• Differences Between Accelerator and Colliders
• Synchrotron (Lighting the path to innovation)
• Cyclotron
• Differences Between Synchrotron and Cyclotron
• Detectors
• String Theory
• Dark Matter
• Dark Energy
• Higgs Boson
• Big Bang Theory
• (9 STEP OF ORIGIN WITH BIG BANG)
• Quantum Electrodynamics (QED) VS Quantum Chromodynamics (QCD)
• Tables
Index
5

Introduction
Particle Physics is also known as High
Energy Physics that deals with the
nature of particles and their
interactions. In most books, Particle
physics understand that it is study of
standard model or elementary particles
of standard model which is also correct.
But in modern time, its definition is
written as, it is study of fundamental
objects of universe that constitute the
matter and radiation.
The study of Particle Physics have
following basics parameters.
•Fundamental forces of
universe
•Elementary Particles
•Interactions of
elementary particle with
forces and other
particles
The LHC tunnel
Shahzada Khan (2k16/mphy/38)
6

The W and Z bosons were discovered experimentally in 1981, and their masses were found to be as the Standard Model predicted.
After the neutral weak currents caused by Z boson exchange were discovered at CERN in 1973, the electroweak theory became widely
accepted and Glashow, Salam, and Weinberg shared the 1979 Nobel Prize in Physics for discovering it.
The Higgs mechanism is believed to give rise to the masses of all the elementary particles in the Standard Model. This includes the
masses of the W and Z bosons, and the masses of the fermions, i.e. the quarks and leptons.
In 1967 Steven Weinberg and Abdus Salam incorporated the Higgs mechanism into Glashow’s electroweak theory, giving it a modern
form.
The first step towards the Standard Model was Sheldon Glashow’s discovery in 1961 of a way to combine the electromagnetic and weak
interactions.
Historical Background

Elementary means
The word
“elementary”
is used in the
sense that
such particles
have no
known
structure,
they are
“pointlike. ”
“elementary”
depends on
the spatial
resolution of
the probe
used to
investigate
possible
structure.
8

Standard Model
Standard model is a table in which elementary particles are
arranged in a pattern of fermions and gauge particle (force
carriers).
Fermions in standard model have two categories called Quarks
and Leptons. And each Quarks and Leptons have six groups.
Standard model uses the English as well as Greek letters to
shows the elements, their masses, charges and spin.
Three Generations of Matter
I II III
Fermions
Quarks
•Fractional Charge
•Color charge
•Compose protons and neutrons
Leptons
•Families/Flavors
•Integer charge
•Solitary
9

Fermions-left half-3
generations
Quarks- fractional charges
(2/3, -1/3) and
combinations of these
make up protons and
neutrons.
Quarks carry color charge,
a different type of charge
that is not related to actual
color
Leptons each gen=a family
the electron, e-, the muon,
μ-, and the tau, τ-
In each family there is a
charged particle that gives
each family its name, and a
neutrino, ν, corresponding
to the charged particle
Ex: The electron family
consists of the
electron e- and the
electron neutrino νe
Tau and muon are like
massive electrons, all -1
charge,
Neutrinos-tiny mass and no
charge
10

Quantum Field Theories included in Standard Model
12
11

12

History of Particle Physics
1935 Hideki Yukawa published his theory of mesons, which explained the interaction between
protons and neutrons, and was a major influence on research into elementary particles.
Yukawa’s theory predicted that there was a particle – the Pion – that mediated the strong nuclear
force that bound neutrons and protons together in the nucleus
Hideki Yukawa (1907 – 1981)
1932 Carl Anderson working with high
altitude cloud chamber discovers the positron
(The anti-particle of the electron) as predicted
by Dirac’s theory
1936 Anderson also discovers the Muon –
(then known as the Mu-Meson) The Muon
was originally thought to be the Yukawa
particle (Pion) because it had a mass in the
right range ~ 200 me. However the Muon did
not interact with neutrons or protons. We now
know the Pion is the parent of the Muon.
Carl Anderson (1905 – 1991)
Pions decay into two particles, a muon and a muon neutrino or antineutrino
13

1947 Cecil Powell and collaborators at Bristol University UK finally discovered
the Pion in short tracks in nuclear emulsions.
Cecil Powell (1903 – 1969)
First Proton Synchrotron 2.3GeV (Brookhaven)
1953 First production of Strange particles
1955 Anti-proton produced
1956 Parity violation discovered (C.S. Wu)
1964 Quark model proposed (Gell-Mann, Zweig)
1967 Electroweak model proposed (Weinberg, Salam)
1974 Charm quark discovered (Richter, Ting)
1977 Bottom quark discovered (Lederman)
1983 W and Z particles discovered (CERN)
1996 Top quark discovered (Fermi Lab)
14

ClassificationofParticles
In standard model, particles
are arranged in following
pattern.
Fermions
Quarks
leptons
Gauge
Higgs boson
Elementary Particles are
also arranged in term of
Quarks Composition
In term of interaction of
particles with anti-particles
and quarks composition
Quarks Hadrons
Meson
Pions
Keons
Baryons
Proton
Neuton
Leptons
Electron
Muon
Tau
15

Natural Particle Production (Cosmic Rays)
The first new particles to be detected were muons (1937), pi
ons (1947) and kaons (1947).
These new particles can be detected at ground level by cloud
chambers and other detectors.
The protons strike gas atoms in the upper atmosphere and p
roduce new short lived particles and antiparticles.
Cosmic rays consist of high energy protons and nuclei emitte
d from stars including the Sun.
16

The gravitational force is the force of mutual attraction
between any two objects by virtue of their masses. It is
a universal force. Every object experiences this force due
to every other object in the universe.
All objects on the earth experience the force of gravity
due to the earth. Gravity governs the motion of the
moon and artificial satellites around the earth, motion
of the earth and planets around the sun.
Gravitational Force
17

Electromagnetic force is the force between charged particles.
When charges are at rest, the force is given by Coulomb’s law :
attractive for unlike charges and repulsive for like charges.
Charges in motion produce magnetic effects and a magnetic field
gives rise to a force on a moving charge. Electromagnetic force acts
over large distances and does not need any intervening medium.
Electromagnetic force can be attractive or repulsive.
Electromagnetic Force
18

The strong nuclear force binds protons and
neutrons in a nucleus. The strong nuclear
force is the strongest of all fundamental
forces, about 100 times the
electromagnetic force in strength.
It is charge-independent and acts equally
between a proton and a proton, a neutron
and a neutron, and a proton and a
neutron. Its range is, extremely small, of
about nuclear dimensions (10-15m). It is
responsible for the stability of nuclei.
Strong Nuclear Force:
19

The weak nuclear force appears only in certain nuclear processes such
as the β-decay of a nucleus. In β-decay, the nucleus emits an electron
and an uncharged particle called neutrino.
The weak nuclear force is not as weak as the gravitational force, but
much weaker than the strong nuclear and electromagnetic forces. The
range of weak nuclear force is exceedingly small, of the order of 10-16
m.
Weak Nuclear Force :
20

Interactions of Fundamental Forces
Interaction of fundamental forces
occurs due to gauge particles.
Which are following
Photons
Gluon
Z or w
boson
Graviton.
Electromagnetic interaction or electromagnetic force: It
causes attraction and repulsion between electrically charged
particles and carrier particle of this phenomena is the
photon γ. Photons is a massless particle that travel at speed
of light and responsible for the electromagnetic spectrum.
Except this, this is responsible for : chemistry, biology,
magnetism, many other forces we encounter everyday.
21

It is defined as those particles
whose internal structure is
unknown and responsible for
constituents of matter are
called Elementary Particles.
Which are following.
• Fermions
• Quarks
• leptons
Force carrier
QUARKS: Such smaller
particles that combine to
forms the Hadrons and carry
the fraction charges is known
as Quarks. There are six types
of quarks consequently six
types of anti-quarks. Quarks
combine with its types to form
a Hadrons. And that hadrons
have divided further into two
groups of Baryons and
Mesons. Quarks have following
types.
• UP QUARK: Up quark is included in first generation of quark that is represented by “u”.
That possesses the charge value +2/3. and have the spin ½.
• DOWN QUARK: Down quark is also included in second generation of quark which is
expressed by “d”. That have charge value -1/2 and have the spin ½.
• CHARM QUARK: Charm quark is included in second generation of quark and denoted by
the letter “c”. Charm quark have charge value +2/3 and spin number ½.
• STRANGE QUARK: Strange quark is also included in second generation of quark and
denoted by the symbol “s”. It have charge value -1/3 and spin number ½.
• TOP QUARK: Bottom quark is included in third generation of quark and represented by
the letter “t”. It have charge value +2/3 and spin number ½.
• BOTTOM QUARK: Bottom quark is also included in third generation of quark and
represented by the letter “b”. It have charge value +2/3 and spin number ½.
Elementary particles and explanation
22

Differences Between Quarks and Leptons
S. No Quarks Leptons
1 Interaction in quarks are due to strong force Interaction in leptons are because of electromagnetic and weak force.
2 Colors properties are found in quarks. Leptons do not have suck colors properties
3 Six types of quarks have electric charge Three neutrinos of leptons do not have electric charge.
4 Quarks are heavier particles. Leptons are lighter particles
5 Quarks are not stable particles Leptons can be found in stable form.
6 Quarks are elementary particles of matter. Leptons are elementary as well as fundamental particles.
Colors Charges
Colors charge is a property of force that occurs between the Quarks and Gluon. This property of colors
charge responses as a strong force. And appears in a three basic colors of Red, Blue and Green. Three
anti-quarks also possess this colors property. And colors of anti-quarks are yellow, magneta and cyan.
23

A lepton is an elementary, half-integer spin (spin 1⁄2) particle that does not undergo strong interactions. Particles that do participate in strong interactions are
called hadrons.
There are six leptons in the present structure, the electron, muon, andtau particles and their associated neutrinos. Leptons are said to be elementary particles; that is, they
do not appear to be made up of smaller units of matter. They behave as point-like particles. All leptons are fermions, i.e. leptons are spin- 1⁄2 particles and thus that they are
subject to the Pauli exclusion principle. This fact has key implications for the building up of the periodic table of elements.
Two main classes of leptons exist.
•Electron. The electron is a negatively charged particle with a mass that is approximately 1/1836 that of the proton. Electrons are located
in an electron cloud, which is the area surrounding the nucleus of the atom. The electron is only one member of a class of elementary
particles, which forms an atom.
•Muon. The muon is an elementary particle similar to the electron, with an electric charge of −1 e and a spin of ½. Muons are heavier,
having more than 200 times as much mass as electrons. The muon is an unstable subatomic particle with a mean lifetime of 2.2 µs.
•Tau. The tau (τ), also called the tau lepton, tau particle, or tauon, is an elementary particle similar to the electron, with an electric
charge of −1 e and a spin of ½. Taus are approximately 3,700 times more massive than electrons. Tau leptons have a lifetime of
2.9×10−13 s.
Charged leptons.
Charged leptons can combine with other particles to
form various composite particles such
as atoms and positronium.
•Electron neutrino. The electron neutrino is a subatomic lepton elementary particle which has the symbol νe. It has no net electric charge
and a spin of ½. Together with the electron it forms the first generation of leptons, hence the name electron neutrino.
•Muon neutrino. The muon neutrino is a subatomic lepton elementary particle which has the symbol νμ. It has no net electric charge
and a spin of ½. Together with the muon it forms the second generation of leptons, hence the name muon neutrino.
•Tau neutrino. The tau neutrino is a subatomic lepton elementary particle which has the symbol ντ. It has no net electric charge and a
spin of ½. Together with the tauon it forms the third generation of leptons, hence the name tau neutrino
Neutral leptons
Neutral leptons (better known as neutrinos) are
electrically neutral particles that rarely interact with
anything, and are consequently rarely observed. A
neutrino is an elementary subatomic particle
with infinitesimal mass (less than 0.3 eV..?) and with no
electric charge. Neutrinos are weakly
interacting subatomic particles with ½ unit of spin.
Lepton Shahzada Khan (2k16/mphy/38)
24

HADRONS: Hadrons are those particle whose composition is made from Quarks and Anti-Quarks. These particles interact through strong
interaction.
Hadrons are classified into two groups
•Baryons
•Mesons
BARYONS: Baryons are those particles in which three quarks take part for its combination. And these quarks held together by strong force.
Example of baryons are Protons and Neutrons,
Baryons are also called ‘fermions’.
MESONS: Mesons are those particles whose combination made from a quarks with anti-quarks. In simple words, a quark and anti-quark held
together to form the Mesons.
Mesons are classified into two groups.
•Pions
•Kaons
Quarks
25

Hideki Yukawa and Meson
Hideki Yukawa was the Japanese physicist who developed the idea of a quantum field theory
(theory of exchange forces).
Statement: “He said that all the force is occurred due to the exchange of particles.”
Consider the example of two protons in space. Yukawa said that the protons exchange
photons and repel each other because of this exchange.
This photon exchange is the electromagnetic force.
Yukawa explained that the electromagnetic force was long range (in fact infinite in range) because photons "live
forever" until they are absorbed.
Yukawa explained that the strong force was short range (in fact only in the nuclear range) because the strong
force exchange particle (the gluon) has a very short life.
LONG RANGE EXCHANGE PARTICLE (photon)
SHORT RANGE EXCHANGE (VIRTUAL) PARTICLE (gluon)
Hideki Yukawa (1907 – 1981)
26

Feynman Diagrams
Introduction: It is graphical representation of the interaction between two particles. It was developed by Richard
Feynman. A Feynman diagram is a qualitative graph of time and space that shows time on the vertical axis and space on
the horizontal axis.
Note: Actual values of time and space are not important as well as the actual paths of the particles are not shown.
Explanation
Feynman Diagrams And Two Electrons: Let us take a example of two electron which are interacted
together. when two electrons each other, according to the quantum theory of fields, they exchange a
series of photons called virtual photons, because they cannot be directly observed.
The photon is the field particle that mediates the interaction. The photon transfers energy and
momentum from one electron to the other.
The Virtual Photon: The existence of the virtual photon seems to violate the law of conservation of
energy. But due to the uncertainty principle and its very short lifetime, the photon’s excess energy is
less than the uncertainty in its energy.
Figure: Feynman space time diagram. El
ectrons interact through mediation of a
photon. The axes are normally omitted.
27

Space
Time
-
e e-
e- e-
28

Space
Time
n
p
e-
e
w -
eepn  
w -
29

Space
Time
p
n
w+
eenp  
e
+
νe
w+
30

Space
Time
p
w+
enep  
w+
e-
n ve
31

Space
Time
n
w+

 epn e
w+
ve
p
e-
32

Space
Time
p
w+

 enp e
w+
n e+
e
33

Space
Time
p
w-
enep  
w-
n ve
e-
34

Pions or π mesons
Pions belongs to the family of mesons whose combination occurs due to a quark and a anti-quark. Pions can be found in three types.
• Positively charged (π+)
• negatively charged (π - )
• uncharged (π0).
Pions are the lightest mesons and play an important role in explaining low-energy properties of the strong nuclear force.
They are all very unstable and decay by the weak interaction.
π+ decays into an antimuon and a neutrino
π - decays into an muon and an antineutrino
π0 decays into two high energy photons
Pion decay via weak interactionKaons or K mesons
Kaons or K mesons also
belongs to the family of
mesons whose combination
made from a quark and a
anti-quark. They can be found
in three types.
Positively charged (K+), Negatively charged (K- ) Uncharged (K0).
They have rest masses
greater than pions but less
than a proton (about 1000 x
the electron).
They are all unstable and
decay by the weak
interaction far more slowly
than pions.
This relatively slow rate of
decay (about 10 - 10 s) was
unexpected and led to these
particles being called
‘strange’ particles.
Kaons decay into pions,
muons and neutrinos.
35

Properties of Quarks
Quarks and anit-quarks have some
properties that you might not have
encountered before.
• Relative Charge: all quarks and anti-quarks carry a charge which is a
fraction of the charge of the electron. In all interactions charged must be
conserved.
• Baryon number: all quarks and anti-quarks have a baryon number. The
baryon number is +1/3 for quarks and -1/3 for all anti-quarks. In all
interaction baryon number must be conserved.
• Strangeness: All quarks and anti-quarks have strangeness = 0 apart from
the strange quark ( strangeness= -1) and the anti-strange quark
(strangeness = +1). In all interactions involving the strong force strangeness
must be conserved, but in weak interactions strangeness can be conserved.
Particles and Lifetimes
The lifetimes of particles are also
indications of their force
interactions.
Particles that decay through the
strong interaction are usually the
shortest-lived, normally decaying
in less than 10−20 s.
The decays caused by the
electromagnetic interaction
generally have lifetimes on the
order of 10−16 s, and
The weak interaction decays are
even slower, longer than 10−10 s.
37

symbol relative
mass
charge
proton = 1
baryon
number
strangeness
up u 1 + ⅔ + ⅓ 0
down d 2 - ⅓ + ⅓ 0
strange s 40 - ⅓ + ⅓ -1
charm c 600 + ⅔ + ⅓ 0
top t 90 000 + ⅔ + ⅓ 0
bottom b 2000 - ⅓ + ⅓ 0
1
2
40
+ ⅔
- ⅓ + ⅓
+ ⅓
+ ⅓
- ⅓
0
0
- 1
up u
down d
strange s
charm c 600 + ⅔ + ⅓ 0
bottom b 2000 - ⅓ + ⅓ 0
top t 90 000 + ⅔ + ⅓ 0
Properties of Quarks Shahzada Khan (2k16/mphy/38)
38

The
Families
of Matter
Most of the mass in the universe is made from
the components in the first generation (electrons
and u and d quarks).
The second generation consists of the muon, its
neutrino, and the charmed and strange quarks.
The members of this generation are found in
certain astrophysical objects of high energy and
in cosmic rays, and are produced in high-energy
accelerators.
The third generation consists of the tau and its
neutrino and two more quarks, the bottom (or
beauty) and top (or truth). The members of this
third generation existed in the early moments of
the creation of the universe and can be created
with very high energy accelerators.
39

•Positron is also known as a positive electron which produce from following ways
•The transformation of proton into neutron.
•when a up quark transform into down quark then a positron appears.
•When a photon strikes the nucleus.
Positron
• The ultimate fate of positrons (antielectrons) is annihilation with electrons.
• After a positron slows down by passing through matter, it is attracted by the
Coulomb force to an electron, where it annihilates through the reaction
Positron-Electron
Interaction
40

Resonance particles: Resonance are those particles which have short-
lived. Time of their life exist around 100 atto second. In laboratory, time is
calculated as 10 femto second. They can not be detected directly. Their
properties can be inferred from data on their decay products.
Neutrino: these are energy particles which occurs in the beta decay of the
neutron. And we are already familiar with the electron neutrino and have
the following properties.
• Neutrinos have zero charge.
• Their masses are known to be very small. The precise mass of neutrinos may have a bearing on
current cosmological theories of the universe because of the gravitational attraction of mass.
• All leptons have spin 1/2, and all three neutrinos have been identified experimentally.
• Neutrinos are particularly difficult to detect because they have no charge and little mass, and
they interact very weakly.
Picture of the sun, taken not with
light, but with neutrinos, made at
the Japanese neutrino observatory
Super-Kamiokande.
41

• Collision of a particle with other particle or a target is known as interaction. That’s why
following conservation laws are occurs in interaction to study the particles.
• All interactions must conserve:
• ENERGY
• ELECTRIC CHARG
• Conservation of a Lepton Number
• Conservation of a Baryon Number
• and with strong interactions only: STRANGENESS
Interaction
conservation
rules:
Strangeness:
Strangeness was introduced by
Murray Gell-Mann and Kazuhiko
Nishijima to explain the fact. It is
states that “whenever a reaction or
decay occurs via the strong force,
the sum of strangeness before the
process must be equal to the sum
of the strangeness number after
the process”.
For example kaons were created
easily in particle collisions, yet
decayed much more slowly than
expected for their large masses.
In strangeness, strong and
electromagnetic interaction obey
the law of conservation of
strangeness, but weak interaction
does not.
The reactions below happen 10-8s
and lose their strange quark.
Meaning that they cannot occur by
strong or EM interaction
42

Lepton Number
•In particle physics, the lepton number is used to denote which particles are
leptons and which particles are not. Each lepton has a lepton number of 1 and
each antilepton has a lepton number of -1. Other non-leptonic particles have a
lepton number of 0. The lepton number is a conserved quantum numberin all
particle reactions. A slight asymmetry in the laws of physics allowed leptons to be
created in the Big Bang.
•The conservation of lepton number means that whenever a lepton of a certain
generation is created or destroyed in a reaction, a corresponding antilepton from
the same generation must be created or destroyed. It must be added, there is a
separate requirement for each of the three generations of leptons, the electron,
muon and tau and their associated neutrinos.
Law of
Conservation of
Lepton Number
•Conservation of Lepton Number – (Electron Capture): Consider the electron capture mode. The
reaction involves only first generation leptons: electrons and neutrinos.
•The antineutrino cannot be emitted, because in this case the conservation law would not be
fulfilled. The particle emitted with the neutron must be a neutrino.
43

Conservation of
Lepton Number –
(Neutron Decay):
•Consider the decay of the neutron. The reaction involves only first generation leptons:
electrons and neutrinos.
•Since the lepton number must be equal to zero on both sides and it was found that the
reaction is a three-particle decay (the electrons emitted in beta decay have a continuous rather
than a discrete spectrum), the third particle must be an electron antineutrino.
Conservation of
Lepton Number –
Muon Decay
• The observation of the following decay reaction leads to the conclusion that
there is a separate lepton number for muons which must also be conserved.
• This is in fact the most common decay mode of the -.
44

Baryon Number
In particle physics, the baryon number is used to denote which particles are baryons and which particles are not. Each baryon has a baryon number of 1 and each
antibaryon has a baryon number of -1. Other non-baryonic particles have a baryon number of 0. Since there are exotic hadrons like pentaquarks and tetraquarks, there is a
general definition of baryon number.
where nq is the number of quarks, and nq is the number of antiquarks.
The baryon number is a conserved quantum number in all particle reactions. The term conserved means that the sum of the baryon number of all incoming particles is the
same as the sum of the baryon numbers of all particles resulting from the reaction. A slight asymmetry in the laws of physics allowed baryons to be created in the Big Bang.
Law of
Conservation of
Baryon Number
•In analyzing nuclear reactions, we apply the many conservation laws. Nuclear reactions are subject to classical conservation laws
for, momentum, angular momentum, and energy (including rest energies). Additional conservation laws, not anticipated by classical physics,
are electric charge, lepton number and baryon number. Certain of these laws are obeyed under all circumstances, others are not.
•Baryon number is a generalization of nucleon number, which is conserved in nonrelativistic nuclear reactions and decays. The law of conservation
of baryon number states that:
•The sum of the baryon number of all incoming particles is the same as the sum of the baryon numbers of all particles resulting from the reaction.
45

For example, the following reaction has never been observed:
• Even if the incoming proton has
sufficient energy and charge, energy,
and so on, are conserved. This reaction
does not conserve baryon number since
the left side has B =+2, and the right has
B =+1.
• On the other hand, the following
reaction (proton-antiproton pair
production) does conserve B and does
occur if the incoming proton has
sufficient energy (the threshold energy
= 5.6 GeV):
• As indicated, B = +2 on both sides of this
equation.
• From these and other reactions, the
conservation of baryon number has
been established as a basic principle of
physics.
• From these and other reactions, the
conservation of baryon number has
been established as a basic principle of
physics.
• This principle provides basis for
the stability of the proton. Since the
proton is the lightest particle among all
baryons, the hypothetical products of its
decay would have to be non-baryons.
Thus, the decay would violate the
conservation of baryon number. It must
be added some theories have suggested
that protons are in fact unstable with
very long half-life (~1030 years) and that
they decay into leptons. There is
currently no experimental evidence that
proton decay occurs.
46

•Strange particles are those particles that have the unusual properties of their production and decay into
other. These particles were discovered in 1950. Except this, strange particles appears in pair production
through strong interaction but process of decay is slow.
Strange Particles
•Strangeness is a properties of strange particles in term of quantum number or the number which shows
the slow decay of some particles is known as strangeness.
•It is introduced by Murry Gell-Mann, Abraham and Kazuhiko Nishijimo. It states that whenever a reaction
or decay occurs via strong force, the sum of strangeness number before the process must equal the sum
of the strangeness number after the process. Strong and electromagnetic interaction obey the law of
conservation of strangeness but weak does not.
law of Conservation Strangeness
•Consider: p- + n  K+ + S-
•Before: S=0+0=0 (no strange particles)
•After: K+ has S=+1, S- has S = -1 thus the net strangeness S = +1-1 = 0
•So reaction does not violate law of conservation of strangeness, the reaction is allowed
Example 01
48

𝛽−
𝐷𝑒𝑐𝑦
•𝐼𝑛 𝑏𝑒𝑡𝑎 𝑑𝑒𝑐𝑎𝑦 𝑎 𝑛𝑒𝑢𝑡𝑟𝑜𝑛 𝑖𝑛 𝑡ℎ𝑒 𝑛𝑢𝑐𝑙𝑒𝑢𝑠 𝑑𝑒𝑐𝑎𝑦𝑠 𝑡𝑢𝑟𝑛𝑠 𝑖𝑛𝑡𝑜 𝑎 𝑝𝑟𝑜𝑡𝑜𝑛, 𝑎 𝑓𝑎𝑠𝑡 𝑚𝑜𝑣𝑖𝑛𝑔 𝑒𝑙𝑒𝑐𝑡𝑟𝑜𝑛 𝛽 −
Particles and their transmutation process 49

• The model that express the connection of properties of particles such
as strangeness and electric charge is known as Eightfold Way.
The Eightfold Way
50

Particle Accelerator
• Any device that accelerates charged particles to very high speeds using electric field as
well as magnetic field.
• Basic Principle: All accelerators are based on the same principle. A charged particle
accelerates between a gap between two electrodes when there is a potential difference
Accelerator as super-
microscope
• Tiny particles (smaller than a micron) can be examined by using electrons, provided their
energy large enough. This is the principle of the electron microscope (SEM, TEM,
HRTEM…)
• The electron microscope is actually a small accelerator. It conveys energy to charged
particles (electrons) to make wavelength small enough to view such details.
• The smaller the details you want to see, the larger the accelerator you will have to build.
Accelerator as energy transformer
In accelerators, charged particles are
accelerated to high energy (high speed) by
electric fields.
In particle collisions, more or all the
available energy can be transformed into
other particles or into X-rays:
The more powerful accelerators and higher
energies, the more massive and sometimes
new particles can be discovered
51

Collider
A collider is a type of particular accelerator involving directed beams of particle. Colliders may either
be ring accelerator or linear accelerators and may collider a single beam of particle against a
stationary target or two beams head on.
The first serious proposed for a collider originated with a group at the Mid western Universities
Research Association (MURA). This group proposed building two tangiest radial sector. FFAG
accelerator rings. The first electron-positron collider was build in late 1950. and 1960 in Italy. In 1966,
work began on the interesting storage rings at CERN and in 1971, this collider was operational. The
ISR was a pair of storage rings that accumulated particles injected by the CERN Proton-Synchrotron.
A collider is used as a research tool in particle physics by accelerating particles to very high kinetic
energy and letting them impact other particles. Analysis of the by products of these oscillations gives
scientist good evidence of the structure of the subatomic world and the laws of nature govern it.
These may become apparent only at high energies and for tiny periods of time and therefor may be
hard or impossible to study in other ways.
Colliders
52

Differences Between Accelerator and Colliders
S.No Accelerator Collider
1 A accelerator used in many application such as
radio-theraphy, research.
A collider is used as a research in particle physicse
2 One beam is used in accelerate for specific task. More than one beams are used in colliders.
3 Particles in accelerator are used to hit the target. Particles in colliders are used to hit the target as well
as to collider with each other.
4 Accelerates have many types or shapes. Colliders are found in particular type of accelerator.
53

•Synchrotron is a particular type of cyclic particle accelerator that produces very bright light.
Synchrotron light (also known as synchrotron radiation) is a electromagnetic radiation that is
emitted when charged particle are moved at close to the speed of light by forcing to changed
direction with the help of magnetic field. It produces not only visible light, but also infrared
light, ultraviolet light and x-rays. The light produced by synchrotron are 100 million times
brighter than x-rays.
•Edwin McMillan constructed the first electron synchrotron in 1945 and in 1952, sir marcus
designed the first proton synchrotron.
•A synchrotron has four components. First is a Electron-Gun that uses 220,000VDC power to
heat up a tungsten oxide “button” which emits a small stream of electrons into a vacuum tube
. These electrons are speed up in the linear acceleration to nearly the speed of light.
•Booster ring is a second component of synchrotron inn which electrons comes from
accelerator. Booster ring boosts the power of electrons stream.
•Storage ring is a third component of synchrotron in which electrons come from booster ring
and walks in a circular path. After the circulating around the storage ring, these electrons are
passed through wiggler and undulators to release the electromagnetic waves.
•End station is a fourth and last part of synchrotron where synchrotron light is filtered to select
the appropriate wavelength to answer specific questions
Synchrotron (Lighting the path to innovation)
•It provides the molecular level image.
•It gives the information about extensive chemical.
•It allows advanced technology microscopic.
Synchrotron produces extremely brilliant light for following purposes.
54

• The cyclotron was one of the earlier types of particle
accelerators, and still used as the first stage of some large multi-
stage particle accelerators. One of the most interesting
applications of motion of charge particle in electric field and
magnetic is cyclotron. It produces very high energy charge
particles.
• E.O lawerance and M.S Livingston were the first person who
invented cyclotron in 1934.
• Cyclotron makes use of the magnetic force on a moving charge
to bend moving charges into a semicircular path between
accelerator by an applied electric field. The applied electric filed
accelerates charged particles between the “Dees” of the
magnetic field region.
• The cyclotron consists of two flat semicircular metallic boxes
called Dees and have the shape D. The two dees are separated
by a narrow parallel gap. A high frequency of oscillator which
provides an alternating current is connected between two Dees.
Cyclotron
55

Differences Between Synchrotron and Cyclotron
S.No Synchrotron Cyclotron
1 Synchrotron uses the high voltage DC power
source to accelerate the particle.
Cyclotron uses the AC power source to accelerate the
charge particles.
2 Synchrotron helps the heat to flow the charged
particles.
Cyclotron uses the frequency by oscillator to flow the
particles.
3 Synchrotron accelerate the every kinds of
charged particles
Cyclotron can not accelerate the electron or neutron.
4 Particles in synchrotron can accelerate at high
values of energy.
Positive ions can not accelerate the at certain limits.
56

Detectors
Detectors are such instruments
that are used to detect or
identify the particle and its
characteristics. And its effect
the interaction of particles
with matter.
So, a detector have the following
roll in particle physics.
• To identify the particle
• measure the position, time and
energy
• To know the properties of
particle.
57

String Theory
•Statement: “Such theory that shows the particles of particle physics in the design of string. And express
a framework of point like particles in a dimension.”
•String theory describes the propagation of string of particles in a space and interaction with other
particle. String theory expresses the particle in a larger distance as a ordinary particle with its mass,
charge and other properties. And these properties can be determined by the state of the string.
•Vibrational state of string theory is responsible for graviton and quantum mechanic particle that’s why
this theory is also known as theory of quantum gravity.
String Theory have following
benefits.
•It expresses the apparent wave nature of reality very well.
•It shows the particle wave duality because particle being composed of string.
The Theory of (Almost) Everything
• A theory that describes three of the four
fundamental forces of nature and the various
particles that make up matter in the
Universe. This theory is consistent with
Relativity and Quantum Mechanics.
58

• Technicolor theories try to modify the Standard Model in a minimal way by introducing a new
QCD-like interaction. This means one adds a new theory of s0-called techniquarks, interaction via
so called Techigluons. The main idea is that the Higgs-Boson is not a elementary particle but a
bound state of these objects.Technicolor
Theory
• According to preon theory there are one or more orders of particles more fundamental than
those (or most of those) found in the Standard Model. The most fundamental of these are
normally called preon, whi h is derived from “pre-quarks’. In essence, preon theory tries to do
for the Standard model what the Standard Model did for the particle zoo that came before it.
Most models assume that almost everything in the Standard Model can be explained in terms of
three to half a dozen more fundamental particles and the rules that govern their interactions.
Interest in preons has waned since the simplest models were experimentally rued out in the
1980s.
Preon
Theory
59

•It is an invisible phenomenon that acts on the visible matter (a pencil, a table..) allowing us to notice its existence. Its
presence is indicated by unexplained gravitational effects on stars and galaxies.
Dark Matter
•It is not formed by atoms.
•It does not allow light to absorb or to emit.
•It has same gravitational properties as a ordinary matter.
•It binds the universe together.
Characteristics of Dark Matter
Detection of Dark
Matter
•In 1933, a Swiss astronomer called Fritz Zwicky discovered some kind of
“invisible matter” meanwhile examming the Coma galaxy. And in the
1970’s, an astronomer called Vera Rubin was sure about the existence of
dark matter and she started to understand the universe in a proper way.
•Although neither of them were mistaken, they were disregarded.
•Astronomers know dark matter is there by its gravitational effect on the
matter that we see, and there are ideas about the kinds of particles it
must be made of.
•Dark matter does not reveal its presence by emitting any type of
electromagnetic radiation. It emits no infrared radiation, nor does it give
off radio waves, ultraviolet radiation, X-rays or gamma rays.
•The best estimates of the total mass of everything that we can see with
out telescopes is roughy 0.01 M. The other 99% of the stuff inn the
universe is dark matter.
Fritz Zwicky
Vera Rubin
60

•Dark energy is a hypothetical form of energy that
permeates all of space and produces a negative
pressure, resulting in a repulsive gravitational force.
Dark energy may account for accelerated expansion
of the universe, as well as most of its mass.
Dark Energy
Dark energy produces an effect opposite to the force of gravity, thus opposing the approach and subsequent collision of all the elements that make it. It is responsible for the
continued expansion of the universe accelerating and causing separation the above elements and the percentage of the visible universe.
Function of Dark Energy
The first static and the second dynamic. To distinguish between the two very precise measurements of the expansion of the universe is needed to see if the expansion rate changes
over time. These measurements are a topic of current research.
Types of Dark Energy
Cosmological constant Quintessence
61

Higgs Boson
•The particles which gives MASS to other particles.
•It is one of the 17 particles of the standard model which makes the SM complete.
•If HIGG’s particles does not exist, according to the SM everything in the universe would be mass less.
•In the Standard Model, the Higgs particle is a boson with no spin, electric charge, or color charge.
•It is also very unstable, decaying into other particles almost immediately.
•It is a quantum excitation of one of the four components of the Higgs field.
Higgs Boson name history
The Higgs Boson is named for Peter Higgs who, along with two other teams, proposed the mechanism that suggested such
a particle in 1964 and was only one to identify some of its theoretical properties.
In mainstream media, it is often referred to as “The Good Particle”, after the title of Leon Lederman’s book on the topic
(1993).
62

Properties Of Higgs Boson
Mass 125.09 (syst.) GeV/𝒄 𝟐
(CMS+ATLAS)
Mean lifetime 1.56 × 10−22
𝑠 (predicated)
Decays into • bottom - ant bottom pair (predicated)
• Two W boson (observed)
• Two gluons (predicted)
• Tau-anti tau pair (predicated)
• Two Z-bosons (observed)
• Two photons (obserbed)
• Various other decays (predicated)
Electric charge 0
Colour charge 0
Spin 0
63

Reason Behind Higgs Boson as a god Particle
The reason behind the Higgs Boson as a called god particle is that it gives the information about formation of the universe. How universe got the
current shape after big bang? And how dark matter and dark energy posses in this universe. These questions have been solved by Higgs Boson.
64

Big Bang Theory
A theory in
astronomy: the
universe originated
billions of years ago in
an explosion from a
single point of nearly
infinite energy
density.
The Big Bang theory is
an effort to explain
what happened at the
very beginning of our
universe. Discoveries
in astronomy and
physics have shown
beyond a reasonable
doubt that our
universe did in fact
have a beginning.
Prior to that moment
there was nothing;
during and after that
moment there was
something: our
universe. The big
bang theory is an
effort to explain what
happened during and
after that moment.
In the 1920s, astronomer Edwin Hubble
discovered the universe was not static.
Rather, it was expanding, a find that
revealed the universe was apparently
born in a Big Bang. After that, it was long
thought the gravity of matter in the
universe was certain to slow the
expansion of the universe. Then, in 1998,
the Hubble Space Telescope's
observations of very distant supernovae
revealed that a long time ago, the
universe was expanding more slowly
than it is today. In other words, the
expansion of the universe was not
slowing due to gravity, but instead
inexplicably was accelerating. The name
for the unknown force driving this
accelerating expansion is dark energy,
and it remains one of the greatest
mysteries in science.
65

66

Step 1: How It All Started
The Big Bang was not an explosion in space, as the theory's name might suggest. Instead, it was the appearance
of space everywhere in the universe, researchers have said. According to the Big Bang theory, the universe was
born as a very hot, very dense, single point in space.
Cosmologists are unsure what happened before this moment, but with sophisticated space missions, ground-
based telescopes and complicated calculations, scientists have been working to paint a clearer picture of the
early universe and its formation. [Full Story]
A key part of this comes from observations of the cosmic microwave background, which contains the afterglow
of light and radiation left over from the Big Bang. This relic of the Big Bang pervades the universe and is visible
to microwave detectors, which allows scientists to piece together clues of the early universe.
(9 STEP OF ORIGIN WITH BIG BANG)
67

Step 2: The Universe's First Growth Spurt
When the universe was very young — something like a hundredth of a billionth of a trillionth of a
trillionth of a second (whew!) — it underwent an incredible growth spurt. During this burst of expansion,
which is known as inflation, the universe grew exponentially and doubled in size at least 90 times.
"The universe was expanding, and as it expanded, it got cooler and less dense," David Spergel, a
theoretical astrophysicist at Princeton University in Princeton, N.J., told SPACE.com. [Full Story]
After inflation, the universe continued to grow, but at a slower rate. As space expanded, the universe
cooled and matter formed.
68

Step 3: Too Hot to Shine
Light chemical elements were created within the first three minutes of the universe's formation.
As the universe expanded, temperatures cooled and protons and neutrons collided to make
deuterium, which is an isotope of hydrogen. Much of this deuterium combined to make helium.
For the first 380,000 years after the Big Bang, however, the intense heat from the universe's
creation made it essentially too hot for light to shine.
Atoms crashed together with enough force to break up into a dense, opaque plasma of protons,
neutrons and electrons that scattered light like fog.
69

Step 4: Let There Be Light
About 380,000 years after the Big Bang, matter cooled enough for electrons to
combine with nuclei to form neutral atoms. This phase is known as "recombination,"
and the absorption of free electrons caused the universe to become transparent. The
light that was unleashed at this time is detectable today in the form of radiation from
the cosmic microwave background.
Yet, the era of recombination was followed by a period of darkness before stars and
other bright objects were formed.
70

Step 5: Emerging from the Cosmic Dark Ages
Roughly 400 million years after the Big Bang, the universe began to come out of its dark ages. This period in the
universe's evolution is called the age of re-ionization.
This dynamic phase was thought to have lasted more than a half-billion years, but based on new observations,
scientists think re-ionization may have occurred more rapidly than previously thought.
During this time, clumps of gas collapsed enough to form the very first stars and galaxies. The emitted ultraviolet
light from these energetic events cleared out and destroyed most of the surrounding neutral hydrogen gas. The
process of re- ionization, plus the clearing of foggy hydrogen gas, caused the universe to become transparent to
ultraviolet light for the first time.
71

Step 6: Birth of Our Solar System
Our solar system is estimated to have been born a little after 9 billion years after
the Big Bang, making it about 4.6 billion years old. According to current
estimates, the sun is one of more than 100 billion stars in our Milky Way galaxy
alone, and orbits roughly 25,000 light-years from the galactic core.
Many scientists think the sun and the rest of our solar system was formed from a
giant, rotating cloud of gas and dust known as the solar nebula. As gravity
caused the nebula to collapse, it spun faster and flattened into a disk. During this
phase, most of the material was pulled toward the center to form the sun. [Solar
System Info graphic: From the Inside Out]
72

Step 7: The Invisible Stuff in the Universe
In the 1960s and 1970s, astronomers began thinking that there might be more mass in the universe than what is
visible. Vera Rubin, an astronomer at the Carnegie Institution of Washington, observed the speeds of stars at
various locations in galaxies.
Basic Newtonian physics implies that stars on the outskirts of a galaxy would orbit more slowly than stars at the
center, but Rubin found no difference in the velocities of stars farther out. In fact, she found that all stars in a
galaxy seem to circle the center at more or less the same speed.
This mysterious and invisible mass became known as dark matter. Dark matter is inferred because of the
gravitational pull it exerts on regular matter. One hypothesis states the mysterious stuff could be formed by
exotic particles that don't interact with light or regular matter, which is why it has been so difficult to detect.
Dark matter is thought to make up 23 percent of the universe. In comparison, only 4 percent of the universe is
composed of regular matter, which encompasses stars, planets and people.
73

Step 8: The Expanding and Accelerating Universe
In the 1920s, astronomer Edwin Hubble made a revolutionary discovery about the universe. Using a newly
constructed telescope at the Mount Wilson Observatory in Los Angeles, Hubble observed that the universe is not
static, but rather is expanding.
Decades later, in 1998, the prolific space telescope named after the famous astronomer, the Hubble Space
Telescope, studied very distant supernovas and found that, a long time ago, the universe was expanding more
slowly than it is today. This discovery was surprising because it was long thought that the gravity of matter in the
universe would slow its expansion, or even cause it to contract.
Dark energy is thought to be the strange force that is pulling the cosmos apart at ever-increasing speeds, but it
remains undetected and shrouded in mystery. The existence of this elusive energy, which is thought to make up
73 percent of the universe, is one of the most hotly debated topics in cosmology.
74

Step 9: We Still Need to Know More
While much has been discovered about the creation and evolution of the universe,
there are enduring questions that remain unanswered. Dark matter and dark energy
remain two of the biggest mysteries, but cosmologists continue to probe the
universe in hopes of better understanding how it all began.
It took quite a bit more than seven days to create the universe as we know it today..
75

Quantum
Electrodynamics (QED)
QED is abbreviation of Quantum Electrodynamics. It is
theory of Quantum Field that lead us to the concept of
electromagnetic force. Taking the example of the force
between two electrons, the classical theory of
electromagnetism would describe it as arising from
electric field produced by each electron at the position of
the other. The force can be calculated from Coulomb’s
law. Instead of this, the quantum field theory approach
visualizes the force between the electrons as an
exchange force from the exchange of virtual photons. It is
represented by a series of Feynman’s diagram. Quantum
Electrodynamics (QED) applies to all electromagnetic
phenomena associated with charged fundamental
particles such as electrons and positron and the
associated phenomena such as pair production.
Quantum
Chromodynamics (QCD)
QCD is abbreviation of Quantum Chromodynamics. It is
defined as thatthe theory that describes the action of the
strong force. QCS was constructed in analogy to quantum
electrodynamics (QED). The quantum field theory of the
electromagnetic force.
In 1973, the concept of color as the source of a “strong
field” was developed into theory of QCD by European
Physicists. In particular theory employed the general field
theory developed in the 1950 by Chen Ning Yang and
Robert Mills in which the carrier particles of the force can
themselves radiate further carrier particles.
76

Lepton Table
PARTICLE CHARGE SPIN NO STRANGNESS REST ENERGY (MeV) MEAN LIFE (s)
Electron -1 1
2
0 0.511 Stable particle
Electron
Neutrino
0 1
2
0 7.0× 10−6 Stable particle
Muon -1 1
2
0 106 2.2× 10−6
Muon
Neutrino
0 1
2
0 0.17 Stable particle
Tau -1 1
2
0 1777 2.9× 10−13
Tau Neutrino 0 1
2
0 24 Stable particle
77

Meson Table
Particle Charge Spin No Strangeness Rest Energy
(MeV)
Mean Life (s)
Pion 𝜋+ +1 0 0 140 2.2× 10−8
Pion 𝜋0 0 0 0 135 8.4× 10−17
Kaon k+ +1 0 +1 494 1.2× 10−8
Kaon k+ 0 0 +1 498 9× 10−20
Psi 0 8× 10−21
Upsilon 0 1.3× 10−20
78

Baryon Table
Particle Charge Spin No Strangeness Rest Energy
(MeV)
Mean Life (s)
Proton +1 1
2
0 938 1031
Neutron 0 1
2
0 939 885
Lambda 1
2
-1 1115.7 2.6× 10−10
Sigma∈+ 1
2
-1 1189.4 8× 10−11
sigma∈0 1
2
-1 1192.67 7.4× 10−20
Xi 1
2
-2 1314.9 2.6× 10−10
79

Field Particle
Particle Charge Spin No Strangness Rest Energy
(MeV)
Mean Life (s)
Photon 0 1 0 0 Stable
W-boson +1 1 0 80.33× 103
3× 10−25
Z-boson 0 1 0 19.19× 103
3× 10−25
Gluon 0 1 0
80

To the point particle physics

To the point particle physics

Recomendados

Más contenido relacionado

Was ist angesagt?

Was ist angesagt?(20)

Similar a To the point particle physics

Similar a To the point particle physics(20)

Último

Último(20)

To the point particle physics