Subatomic Particles – particles smaller than an atom

(See reference table)

Ex)

Neutrino – no charge and less mass than electron!! (Travel close to speed of light!!!!)

Did you know ...

Sun produces so many neutrinos

that 70 billion neutrinos pass through every cm² (0.15 in²) of the surface of Earth
every second.

Meson – mass somewhere between an electron and proton

made of a quark and an anti-quark

An electron is a lepton

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Baryons - relatively larger subatomic particles

ex) Protons, neutrons and hyperons (mass greater than neutron)

Baryons are made of smaller particles called quarks (see ref.)

3 quarks make up
every baryon

Ex 1)

A lithium atom consists of 3 protons, 4 neutrons, and 3 electrons. This atom contains a total of

a) 9 quarks and 7 leptons

b) 12 quarks and 6 leptons

c) 14 quarks and 3 leptons

d) 21 quarks and 3 leptons

d)21 quarks and 3 leptons

Each subatomic particle
has an "antiparticle"

(same mass, opposite charge)

The “antiparticle” of an electron
is called a positron

Ex 2)

During beta decay, a neutron decays into a proton, an electron, and an electron antineutrino. During this process there is a conversion of a

n --> p + e + neutrino

(1) u quark to a d quark

(2) d quark to a meson

(3) baryon to another baryon

(4) lepton to another lepton

Answer:

(3) baryon (neutron) to another baryon (proton)

Ex 3) Which combination of quarks could produce a neutral baryon?

(1) cdt (2) cts
(3) cdb (4) cdu

Answer:

(3) cdb

charm +2/3

down -1/3

bottom -1/3

Sum = 0

Ex 4) Which combination of quarks would produce a neutral baryon?

(1) uud (2) udd (3) -u-ud (4) -udd

Answer:

(2) udd

up: +2/3

down -1/3

down -1/3

(Sum = 0)

What does this symbol mean?

Anti up Quark

Same size as an up,
opposite sign (-2/3)