Every particle has an anti-particle - Electron and positron - Proton and antiproton - Neutrino and antineutrino - Quarks and anti-quarks - They both have mass - They have opposite sign - If they meet, they self-annihilate and release energy MODERN PHYSICS: II n p+ e- p+ n e-

How much energy is released if a proton meets an antiproton? How much energy is released if a positron meets an electron? n p+ e- p+ n e-

The energy is released as gamma radiation – a gamma ray! Gamma rays are another name for high intensity electromagnetic radiation (see ref table). They are transverse waves, propagate through a vacuum at v = c, and interact with matter better than neutrinos but worse than electrons, protons, and neutrons. n p+ e- p+ n e-

Note that charge is unitary (+1, 0, -1) outside the nucleon and fractional (+/- 1/3 or +/- 2/3) inside it. Charge is quantized.

Light (not heavy) These don’t live long Heavy Here there be nucleons

Note that charge is unitary (+1, 0, -1) outside the nucleon and fractional (+/- 1/3 or +/- 2/3) inside it. Charge is quantized. Light (not heavy) These don’t live long Heavy Here there be nucleons

What is the world made of?" and "What holds it together?“ 1. All matter is comprised of Leptons and Quarks. There are 6 leptons and 6 quarks 2. There are 4 fundamental forces – Strong, Weak, Electromagnetic, Gravity.

Leptons They are elementary particles Have no measurable size or structure Known leptons: – Electron&electron neutrino – Muon&muon neutrino – Tau&tau neutrino The neutrinos do not have electric charge And each of the six has an anti-particle

Electron, Muon, Tau All three have a charge of -1 The electron is found in everyday matter The muon and the tau have a lot more mass than the electron The muon and the tau are not part of everyday matter because they have very short lifetimes

Neutrinos Neutrinos are three of the six leptons They have no electrical or strong charge Neutrinos are very stable and are all around Most neutrinos never interact with any matter on Earth – Around 60,000,000,000,000 neutrinos pass through you every second. (6x10^14/sec)

Quarks Elementary particles Used to create other particles Six quarks: – Up – Down – Strange – Charm – Bottom – Top

Quarks Each quark has an anti-particle Quarks have a physical property called color, it could be blue, green or red Each color also has an anti-color They are not really different colors, it is a property, like charge Quarks cannot exist individually because the color force increases as they are pulled apart.

Hadrons Consist of particles that interact through the strong force. Hadrons are set apart from leptons because they are composed of other, smaller particles Separated into two categories Baryons&Mesons These are distinguished by their internal structure Most of the mass we observe in a hadron comes from its kinetic and potential energy.

Baryons Baryons are composed of three quarks All but two baryons are very unstable, they are: – The proton and neutron!! Most baryons are excited states of protons and neutrons Other Baryons

Protons & Neutrons Protons are made of three quarks, two up quarks and a down quark – This is written as uud Neutrons are also made up of three quarks, one up quark and two down quarks – This is written as udd

Mesons Composed of a quark and anti-quark All are very unstable They are not part of everyday matter Have a mass between that of the electron and the proton All decay into electrons, positrons, neutrinos and photons.

Generations of Matter Mass increases from 1 generation to the next Going down in each generation, the charges are: 2/3, -1/3, 0, -1 These are all in multiples of the elementary charge

Fundamental Forces

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

The Strong Force The strongest of the 4 forces Is only effective at distances less than meters (about the size of the nucleus) Holds quarks together This force is carried by gluons

Residual Strong Force We know that protons and neutrons are bound together in the nucleus of an atom This is due to the residual strong force that is binding the quarks together in each of the baryons

The Weak Force A very short-ranged nuclear interaction that is involved in beta decay This is ten thousand billion times weaker than the strong force ( ) Effective only at distances 1000 times smaller than the strong force This force is carried by the W +, W -, and the Z o particles.

The Electromagnetic Force Causes opposite charges to attract and like charges to repel Carried by a particle called a photon It’s effects decrease with the inverse square of the separation (as we learned earlier)

Photons Carry the electromagnetic force They have no mass Photons do not carry charge Photons do carry energy

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

Gravitons Have not yet been observed Although, there is indirect evidence that gravitons do exist Gravitons should have no mass or charge If gravitational energy is radiated, it would be in discrete quanta

Fundamental Forces Summary

Which Fundamental Interaction/Force is responsible for: Friction? – Electromagnetic. Nuclear Bonding? – Residual Strong Nuclear. Orbiting Planets? – Gravity. Which force carriers have not been observed? – Gravitons (Gluons have been observed indirectly)

More About Quarks

More About Leptons

Other name candidates included the: "hold-on," "duct-tape-it-on," "tie-it-on!" Just Kidding

The Muon and Tau These two heavier leptons decay into lighter leptons or quarks When they decay, three particles are produced One of the particles produced is always it’s corresponding neutrino The other particles could be a quark and it’s anti- quark or another lepton and it’s anti-neutrino Muon decay experiment on Mt. Washington in NH was explained through Einstein’s theory of relativity.

n p+ e-e- n e-e- Electrons don’t stay in pretty “orbits”, either. We like to think of electrons as particles, but they also act like waves and spend part of the time inside the nucleus!

All of the known energy in the universe comes from the conversion of mass into energy - In stars, - Fusion turns hydrogen into Helium (with several stops along the way) - Fusion turns Helium into Carbon and Nitrogen and Oxygen and … Iron - When stars run out of Helium they blow up - Spewing all the bits into space! n p+ e- p+ n e-

Covered Standards: Mon 5/7 5.3f Among other things, mass-energy and charge are conserved at all levels (from subnuclear to cosmic). 5.3g The Standard Model of Particle Physics has evolved from previous attempts to explain the nature of the atom and states that: atomic particles are composed of subnuclear particles the nucleus is a comglomeration of quarks which manifest themselves as protons and neutrons each elementary particle has a corresponding antiparticle Stress Tues 5/8: 5.3b Charge is quantized on two levels. On the atomic level, charge is restricted to multiples of the elementary charge (charge on the electron or proton). On the subnuclear level, charge appears as fractional values of the elementary charge (quarks). 5.3j The fundamental source of all energy in the universe is the conversion of mass into energy.*

NYS Regents Standards

5.3b Charge is quantized on two levels. On the atomic level, charge is restricted to multiples of the elementary charge (charge on the electron or proton). On the subnuclear level, charge appears as fractional values of the elementary charge (quarks). 5.3f Among other things, mass-energy and charge are conserved at all levels (from subnuclear to cosmic). 5.3j The fundamental source of all energy in the universe is the conversion of mass into energy.* 5.3g The Standard Model of Particle Physics has evolved from previous attempts to explain the nature of the atom and states that: atomic particles are composed of subnuclear particles the nucleus is a comglomeration of quarks which manifest themselves as protons and neutrons each elementary particle has a corresponding antiparticle

observe and explain energy conversions in real-world situations recognize and describe conversions among different forms of energy in real or hypothetical devices such as a motor, a generator, a photocell, a battery 4.1b Energy may be converted among mechanical, electromagnetic, nuclear, and thermal forms.

4.3a An oscillating system produces waves. The nature of the system determines the type of wave produced. 4.3b Waves carry energy and information without transferring mass. This energy may be carried by pulses or periodic waves. 4.3d Mechanical waves require a material medium through which to travel. 4.3g Electromagnetic radiation exhibits wave characteristics. Electromagnetic waves can propagate through a vacuum. 4.3j The absolute index of refraction is inversely proportional to the speed of a wave.* 4.3k All frequencies of electromagnetic radiation travel at the same speed in a vacuum.* 4.3l Diffraction occurs when waves pass by obstacles or through openings. The wavelength of the incident wave and the size of the obstacle or opening affect how the wave spreads out. 4.3 Explain variations in wavelength and frequency in terms of the source of the vibrations that produce them, e.g., molecules, electrons, and nuclear particles. iv. differentiate between transverse and longitudinal waves

5.3a States of matter and energy are restricted to discrete values (quantized). 5.3c On the atomic level, energy is emitted or absorbed in discrete packets called photons.* 5.3 Compare energy relationships within an atom’s nucleus to those outside the nucleus. i. interpret energy-level diagrams ii. correlate spectral lines with an energy- level diagram

5.3h Behaviors and characteristics of matter, from the microscopic to the cosmic levels, are manifestations of its atomic structure. The macroscopic characteristics of matter, such as electrical and optical properties, are the result of microscopic interactions. 5.3i The total of the fundamental interactions is responsible for the appearance and behavior of the objects in the universe.

5.3d The energy of a photon is proportional to its frequency.* 5.3e On the atomic level, energy and matter exhibit the characteristics of both waves and particles.