<< Chapter < Page Chapter >> Page >
After the Big Bang, matter and anti-matter were balanced.As Universe cooled down, at 10^-10 sec, Salem-Weinberg Transition Phase decouples W and Z massive Bosons. These massive Bosons suppress certain transformations leading to CP violation. This CP violation leads to freezing out the baryonic and leptonic number. From then onward Baryonic and Leptonic number are conserved and from that our present Universe has evolved out.

SSPD_Chapter 1_Part 13_continued_Asymmetric Universe


Before Hubble’s discovery (1929) of expanding Universe, it was sacredly held that matter is constant and conservation of matter holds good. Universe was suppose to be static and unchanging.

In 1928, P.A.M.Dirac successfully reconciled Quantum Mechanics and Special Theory of Relativity in his relativistic Wave Equation. This predicted the existence of anti-particle. It gave the correct value of the magnetic moment of electron. In May 1931, Dirac postulated an anti-particle in a following manner,” a hole, if there were one, would be entirely a new kind of particle, unknown to experimental physics, having the same mass but opposite charge of electron.” This was a bold assertion. In 1932 the anti-particle of electron was discovered by C.D.Anderson in Cosmic Rays. This was positron. This was not proton. E.Seagre, O.Chamberlain and their colleagues produced anti-proton in High Energy Labs in 1955.

After that a series of anti-particle was discovered namely anti-proton , anti-neutron and mesons. It became difficult to classify mesons- are they particle or antiparticle. Now we know that they are admixtures of particle and anti-particle depending upon the composition of a doublet as already discussed in Chapter 1_Part13_constituent particles.. Rewriting Eq.1.125 we get

Up quark Strange antiquark K + Meson
Charge (2/3) e 0 (1/3) e 0 +e 0
Equivalent mass 310MeV -505MeV -195MeV
Spin (1/2)ћ (-1/2) ћ

Through C harge conjugation, P arity inversion and T ime reversal we get the following anti-particle of positive K meson. To maintain CPT symmetry, existence of K + Meson and Anti-K + Meson or K - Meson is a physical reality.

Up anti quark Strange quark Anti-K + MesonOr K - Meson
Charge -(2/3) e 0 -(1/3) e 0 -e 0
Equivalent mass -310MeV 505MeV 195MeV
Spin (-1/2)ћ (1/2) ћ

These discoveries changed the basic law of conservation of matter. Today ant-particles and anti-atoms are being routinely created in High Energy Particle accelerators.

According to Dirac, there is a symmetry between particle and anti-particle. And this requires continuous creation and annihilation of matter and anti-matter.

e + anti e ↔ 2γ (soft gamma photons)

p + anti p ↔ 2γ (hard gamma photons)

After the Big Bang, both matter and anti-matter were created in equal amount. Somewhere down the path of evolution. Matter was favoured over anti-Matter. This led to the conservation of :

(Baryon-antiBaryon)/(no. of energy quanta) = Baryonic Number

And conservation of:

(Lepton- antiLepton)/(no. of energy quanta)=Leptonic Number.

Thus the Law of Conservation of Matter was replaced by “symmetry of matter and anti-matter” and “conservation of Baryon Number and Lepton Number”.

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Solid state physics and devices-the harbinger of third wave of civilization. OpenStax CNX. Sep 15, 2014 Download for free at http://legacy.cnx.org/content/col11170/1.89
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Solid state physics and devices-the harbinger of third wave of civilization' conversation and receive update notifications?