1. Shri Agrasen Kanya Autonomous P.G. College,
Varanasi
A Project on: Elementary particles
Subject:- Physics
Session: 2015-16
Bachelor of Science
In
Physics
Internal Supervisor External Supervisor Submitted by
Dr. Shubha R. Saxena (HOD) Shweta Shukla
Dr. Sunil Mishra Anjali Singh
Dep. of Physics B. Sc. (Final Year)
Shri A. K. A. P. G. College
Varanasi

2. Sri Agrasen Kanya Autonomous P.G. College
Varanasi – 221001
CERTIFICATE
This is to certify that the Project Work entitled Elementary
Particles in Atom.
A Project report has been undertaken in much supervision
and guidance, the result presented in the project report is based on
her own independent effort that had been checked and verify by
me. I am fully satisfied with the work which is being presented by
Shweta Shukla & Anjali Singh.
Forwarded by Supervised by
Dr. Kumkum Malviya Dr. Shubha R. Saxena (HOD)
Principal Dr. Sunil Mishra
Sri A.K.A.P.G. College Department Of Physics
Bulanala, Varanasi Sri A.K.A.P.G. College
Bulanala, Varanasi

3. ACKNOWLEDGEMENT
I am thankful to our Principal Dr. Kumkum
Malviya, I am deeply indebted by our Mam Dr. Shubha
R Saxena Head, of Department of Physics, Shri A. K.
A. P.G. College, Varanasi for inspiring and providing
important book S. N. Ghosal, S.Chand & Griffit for this
work.
I am thankful to respected teacher Dr. Sunil
Mishra Department of Physics, Shri A. K. A. P.G. P.G.
College, and Varanasi for helping me lots by; giving
suggestion and guidance.
I am heartily thankful to all our teachers of the
department whose great blessing and love made it
possible for me to go and succeeded in my work.
Shweta Shukla & Anjali Singh
B.Sc. (Physics)
Final year

4. CONTENTS
 INTRODUCTION
 CLASSIFICATION
 PRODUCTION
 MEMBERS OF ZOO
 CONSTITUENTS OF MATTER
 FUNDAMENTAL FORCES
 SUMMARY

5. INTRODUCTION
The elementary Particles are separated in to two
general groups called Bosons and Fermions. These
two groups have different type of spin and their
behaviors in controlled by a different kin d of
statistic. (I.e. the Bose statistic and the Fermi
Statistic)
Bosons are particles with intrinsic angular momentum
equal to an integral of one. Fermions are all those
particles with in which the spin is half integral.

6. ClassificationElementaryParticles

7. Production of ElementaryParticles
BOSONS
Bosons are a term which not only includes material particles
but also includes those quanta and photon.
PHOTON
Photon was discovered in 1905 by Einstein.
Photon has no mass and no charge particles.
GRAVITION
A mass-less bosons is called a Graviton with probable spin of two units.
Free Graviton is emitted only by large masses (i.e. stars) subject so very
large.
MESONS
The rest mass of these particles varies between about 250 me and 1000 me .
The mesons particles are lighter than a proton and heavier than an electron
and position i.e. intermediate between the electrons and proton.
When boson created by the field interaction are essentially of one two
distinct kinds. First there are those which are known as pion.
The second groups of Boson are much heavier than of pion and known
kaon.

8. FERMION
Leptons
Small or light weight particles
Are points like particles- no internal
structure (yet?)
6 leptons
Electrons e, muon µ tau τ
And their associated neutrinos:
Also, their antiparticles
Neutrinos have tiny mass, ̴̴̴̴̴̴̴̴̴3eV/C2

9. Hadrons
(strong force interaction, composed of quarks)
We already met the mesons (middle weights)
 Decay into electrons, neutrinos and photons
Baryons, i.e. the proton and neutron (the
heavy particles)
Still other more exotic baryons:
• ƩɅΩΣΛΞ≡ all are heavier than the proton
• Decay into end products that include a proton

11. Characteristic properties of elementary particles:-
Mass- an elementary particles has always the same rest mass. The
magnitude of the rest mass serves as the principal label to identify the
particle uniquely.
Charge- all elementary particles have charge +e, -e or zero. This charge
or conserved in any collision process. It may be seen from the following
neutron-proton(n-p) collision:
n + p -> p + p + π¯
Life time- all elementary particles, except photon, electron, proton and
neutrinos, are unstable and decay into other elementary particles of
smaller mass.
Spin- the particles of half integral, i.e., spins ,, etc. obeying Fermi-Dirac
statistics, are called Fermions. The particles of spins are electrons,
positrons, protons, neutrons, neutrinos, antineutrinos, µ-mesons and many
hyperons. Particles having zero or integral spins, i.e., 0,1,2 etc. are
bosons because they obey Bose-Einstein statistic.

13. What do youthink?
What is all the matter in the Universe made of?
And
What holds it together?
 All matter is comprised of Leptons and Quarks.
 Force carrier particles hold all matter together.
(There are 4 fundamental forces- Strong, Weak,
Electromagnetic, and Gravity).

14. The Four Fundamental Forces
These forces include interactions that are attractive
or repulsive, decay and annihilation.

15. The Strong Forces
The strongest of the 4 forces.
Is only effective at distances less
than 10-15 meters (about the size of
the nucleolus).
Holds quarks together.
The forces are carried by gluons.

17. Residual Strong Forces
We know that protons andneutrons are bound
together in the nucleus ofan atom
This is due to the residualstrong forces that is
binding the quarks together in eachof the baryons

19. The Weak Forces
A very short-ranged nuclear
interaction that is involved in beta
decay
This is ten thousand billion times
weaker than the strong forces (10-13)
Effective only at distances 1000
times smaller than the strong forces
This force is carried by the W+, W-,
and the Z0 boson particles

21. The Electromagnetic Force
Causes opposite charges to attract
and like charges to repel
Carried by a particles called a
photon
Its effects decrease with the
inverse square of the separation (as
we learned earlier)

22. Gravity
Has a negligible effect on elementary
particles
A long-rang forces (as we learned
earlier)
Carried by the graviton
This is by far the weakest of the 4
fundamental forces.

23. Fundamental Force

24. Summary