IB+DP+Atomic+and+Nuclear+physics

 Niels Bohr //An expert is a person who has made all the mistakes that can be made in a very narrow field. // //If anybody says he can think about quantum theory without getting giddy it merely shows that he hasn’t understood the first thing about it! //

Richard Feynman // It is safe to say that nobody understands quantum mechanics. // media type="youtube" key="LDaZZnQCJw4" width="560" height="315"
 * [|Physics - Radioactivity: The Discovery of Radioactivity][|EducationCommonsRW] Published on 16 Aug 2010 ||
 * [|How Small Is An Atom] ? Spoiler: Very Small [|Kurzgesagt – In a Nutshell] Published on 20 Jan 2015 ||

7.1 Discrete energy and radioactivity

Essential idea: In the microscopic world energy is discrete. Nature of science: Accidental discovery: Radioactivity was discovered by accident when Becquerel developed photographic film that had accidentally been exposed to radiation from radioactive rocks. The marks on the photographic film seen by Becquerel probably would not lead to anything further for most people. What Becquerel did was to correlate the presence of the marks with the presence of the radioactive rocks and investigate the situation further. (1.4)

Understandings • Discrete energy and discrete energy levels • Transitions between energy levels • Radioactive decay • Fundamental forces and their properties • Alpha particles, beta particles and gamma rays • Half-life • Absorption characteristics of decay particles • Isotopes • Background radiation

International-mindedness: • The geopolitics of the past 60+ years have been greatly influenced by the existence of nuclear weapons

Theory of knowledge: • The role of luck/serendipity in successful scientific discovery is almost inevitably accompanied by a scientifically curious mind that will pursue the outcome of the “lucky” event. To what extent might scientific discoveries that have been described as being the result of luck actually be better described as being the result of reason or intuition?

Applications and skills: • Describing the emission and absorption spectrum of common gases • Solving problems involving atomic spectra, including calculating the wavelength of photons emitted during atomic transitions • Completing decay equations for alpha and beta decay • Determining the half-life of a nuclide from a decay curve • Investigating half-life experimentally (or by simulation)

Guidance: • Students will be required to solve problems on radioactive decay involving only integral numbers of half-lives • Students will be expected to include the neutrino and antineutrino in beta decay equations

Data booklet reference: • E = hf • l = hc/E

Utilization: • Knowledge of radioactivity, radioactive substances and the radioactive decay law are crucial in modern nuclear medicine • How to deal with the radioactive output of nuclear decay is important in the debate over nuclear power stations (see Physics sub-topic 8.1) • Carbon dating is used in providing evidence for evolution (see Biology subtopic 5.1) • Exponential functions (see Mathematical studies SL sub-topic 6.4; Mathematics HL sub-topic 2.4)

Aims: • Aim 8: the use of radioactive materials poses environmental dangers that must be addressed at all stages of research • Aim 9: the use of radioactive materials requires the development of safe experimental practices and methods for handling radioactive materials Nucleus are 100,000 times smaller than the size of the atoms. The negatively charged electrons in atoms can exist at only well defined discrete energy levels (quantized steps) and they cannot exist in between the levels(Bohr). When I heat Hydrogen gas, the electron in an hydrogen atom can jump from low energy states to high energy states. When electrons do so, they can leave empty energy states but later on they fall back to occupy the energy states again. When electrons fall from higher energy states to low energy states, light energy releases and we can see the discrete emission spectrum (discrete frequencies/wavelenths). Emission spectra image from K.A.Tsokos IB DP Physics text p270
 * [|What Does An Atom REALLY Look Like]? =[|The Science Asylum] Published on 12 Jul 2017= || [|A Brief History Of Quantum Mechanics] [|Best 0f Science] Published on 24 Dec 2009 ||

Atomic spectra Emission spectrum: When an electron changes from a high energy level to a low one, a photon of light is emitted. The electron can only exist in discrete energy levels. Absorption spectrum: Absorption and emission spectra image from K.A.Tsokos IB DP Physics text p273
 * atomic electrons can only exist in certain **discrete** energy levels.
 * light is made up of **photons**.
 * when electrons lose energy they give out **discrete** frenquencies of light.
 * when light is absorbed by an atom it gives energy to the electrons.

D E = // hf // D E : Change in energy // h // : Plank constant // f // : Photon frequency

EXAMPLE 1: In an atom with electrons in two energy levels, calculate the wavelength that gives the rise to a photon when the change in energy is from the -4 eV to the - 10 eV. SOLUTION: D E = 6 eV = 6 x 1.6 x 10 -19 = 9.6 x 10 -19 // f = //D E // /h // = ( 9.6 x 10 -19 ) / ( 6.63 x 10 -34 ) = 1.45 x 10 -15 Hz

c = f <span style="background-color: #ffffff; font-family: Symbol,sans-serif;">l <span style="background-color: #ffffff; font-family: Symbol,sans-serif;">l = ( 3 x 10 8 ) / ( 1.45 x 10 -15 ) = 207 nm [UV light] Image from K.A.Tsokos IB DP Physics text p274
 * **Four fundamental forces**
 * 1) Gravitational force
 * 2) Electromagnetic force
 * 3) Strong Nuclear Force
 * 4) Weak Nuclear Force || [[image:particles.PNG width="273" height="215"]] ||

A [|nuclide] is a type of atom whose nuclei have specific numbers of protons and neutrons. Both protons and neutrons are called nucleons. The proton and neutron are called **nucleons**. A set of nuclei for a single element having different numbers of neutrons are called isotopes. A particular isotope of an element is called a species or a **nuclide**.

It is a process in which atoms with unstable nuclei spontaneously decay emitting subatomic particles and energy as they reconfigure into more stable forms.
 * Radioactivity ** : The emission of ** radiation  ** by unstable atomic nuclei undergoing **  radioactive decay  **.

**Radioactive decay**: The spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles. The rate of decay of radioactive substances such as carbon 14 or uranium is measured in terms of their ** half-life  **. [|Radioactive decay] (image to the left) from University of Cambridge A graph showing neutron number vs atomic number Properties of alpha, beta and gamma radiations (table 7.2) from K.A.Tsokos IB DP Physics text p275, p277
 * Decay:
 * 1. a spontaneous transformation of an elementary particle into two or more different particles
 * 2. of an excited atom or molecule, losing energy by the spontaneous emission of photons
 * media type="custom" key="29417895" || media type="custom" key="29417897" ||
 * [|Alpha decay] from phet.colorado.edu || [|Beta decay] from phet colorade.edu ||

PRACTICE 1 ) Find equation of each radioactive decay listed below. 1. Alpha decay: a nucleus emits an alpha particle. The atomic mass number decreases by 4 and the atomic number decreases by 2  a) uranium decaying into thorium b) Radium decaying into radon c) Polonium decaying into lead

2-1. beta minus decay: a neutron turns into a proton, an electron and an anti-neutrino a) thorium decaying into a nucleus of protactinium b) lead decaying into bismuth c) potassium decaying into calcium 2-2. beta plus decay: a proton turns into a neutron, a positron and a neutrino  a) sodium decaying into neon b) nitrogen decaying into carbon

3. gamma decay: a nucleus emits a gamma ray(a photon of high frequency electromagnetic radiation) a) uranium emits gamma ray b) magnesium emits gamma ray

Decay series: The set of decays that takes place until a given nucleus ends up as a stable nucleus. Worked example 7.2) question taken from Physics for the IB Diploma K. A. Tsokos A nucleus X with the atomic number of Z and atomic mass of A, decays by alpha decay followed by two successive beta minus dacays. Find the atomic and mass numbers of the resulting nucleus.

[|GCSE Physics - Radioactivity - Half-Life and Carbon Dating] [|Capra Physics] Published on 1 Feb 2012

The law of radioactive decay: The rate of decay is proportional to the number of nuclei that have not yet decayed.

<span style="font-family: Symbol,sans-serif;">D N/<span style="font-family: Symbol,sans-serif;">D t = - <span style="font-family: Symbol,sans-serif;">l N

where<span style="font-family: Symbol,sans-serif;"> l = decay constant (ln 2 / t 1/2 ) N is the number of nuclei present.


 * Half-life: ** The HALF-LIFE of an atom is the __ interval of ime __ for HALF of the radioisotopes in a sample to decay. The decay of radioisotopes can be used to measure the material’s age.

**Activity:** The decay rate. The number of decays per second. The unit of activity is the becquerel (Bq) Image taken from [|tap.iop.org/atoms/radioactivity] <span style="background-color: #ffffff; color: #cc0000; font-family: Helvetica,Arial,Verdana,sans-serif; font-size: 12px;">[|Episode 515-2: Half-life and time constant (Word, 35 KB)] The half-life of radioisotopes varies from seconds to billions of years from <span style="background-image: url(">[|ndt-ed.org] Further reading: [|Radioactive Half Life] from hyperphysics.phy-astr.gsu.edu and [|Decay constant] from britannica.com

<span style="background-color: #ffffff; font-family: &#39;Times New Roman&#39;; font-size: 14.6667px;">Task: Simulate decay by rolling dice and to estimate the decay constant and half-life from the decay curve.

<span style="background-color: #ffffff; font-family: &#39;Times New Roman,Bold&#39;; font-size: 14.6667px;">Reference:
 * Giancoli, 6th Edition Physics
 * Physics for the IB Diploma sixth edition K.A.Tsokos

<span style="background-color: #ffffff; font-family: &#39;Times New Roman,Bold&#39;; font-size: 14.6667px;">Assessment Criteria:
 * Time: 1.0 hrs.

<span style="background-color: #ffffff; font-family: &#39;Times New Roman,Bold&#39;; font-size: 14.6667px;">Due Dates: <span style="background-color: #ffffff; font-family: &#39;Times New Roman&#39;; font-size: 14.6667px;">13th December 2013

Background radiation: Radiation coming from other sources including cosmic rays from the Sun, radioactive material in rocks and the ground, radiation from nuclear weapons testing grounds, etc.

7.2 Nuclear reactions

Essential idea: Energy can be released in nuclear decays and reactions as a result of the relationship between mass and energy.Nature of science: Patterns, trends and discrepancies: Graphs of binding energy per nucleon and of neutron number versus proton number reveal unmistakable patterns. This allows scientists to make predictions of isotope characteristics based on these graphs. (3.1)

Understandings: • The unified atomic mass unit • Mass defect and nuclear binding energy • Nuclear fission and nuclear fusion

Applications and skills: • Solving problems involving mass defect and binding energy • Solving problems involving the energy released in radioactive decay, nuclear fission and nuclear fusion • Sketching and interpreting the general shape of the curve of average binding energy per nucleon against nucleon number

Theory of knowledge: • The acceptance that mass and energy are equivalent was a major paradigm shift in physics. How have other paradigm shifts changed the direction of science? Have there been similar paradigm shifts in other areas of knowledge?

Utilization: • Our understanding of the energetics of the nucleus has led to ways to produce electricity from nuclei but also to the development of very destructive weapons • The chemistry of nuclear reactions (see Chemistry option sub-topics C.3 and C.7)

Guidance: • Students must be able to calculate changes in terms of mass or binding energy • Binding energy may be defined in terms of energy required to completely separate the nucleons or the energy released when a nucleus is formed from its nucleons

Data booklet reference: • <span style="color: #ad13da; font-family: Symbol,sans-serif;">D E = <span style="color: #ad13da; font-family: Symbol,sans-serif;">D mc 2

Aims: • Aim 5: some of the issues raised by the use of nuclear power transcend national boundaries and require the collaboration of scientists from many different nations • Aim 8: the development of nuclear power and nuclear weapons raises very serious moral and ethical questions: who should be allowed to possess nuclear power and nuclear weapons and who should make these decisions? There also serious environmental issues associated with the nuclear waste of nuclear power plants.
 * Elementary charge: e = 1.60 x 10 -19 C || 1 eV = 1.60 x 10 -19 (C) x 1 (J/C) ||
 * V = W/Q= E/Q || **1 eV = 1.60 x 10 -19 J** ||

Mass defect: The mass of the protons plus the mass of the neutrons is larger than the mass of the nucleus. The difference is known as the mass defect <span style="font-family: Symbol,sans-serif;">d <span style="font-family: Symbol,sans-serif;">d = total mass of nucleons - mass of nucleus

<span style="font-family: &#39;Times New Roman&#39;; font-size: medium;"><span style="font-family: arial,helvetica,sans-serif; font-size: 13px;">Binding energy ( <span style="font-family: Symbol,sans-serif; font-size: 13px;">d <span style="font-family: arial,helvetica,sans-serif; font-size: 13px;">c <span style="font-family: arial,helvetica,sans-serif; font-size: 9.1px; vertical-align: super;">2 <span style="font-family: arial,helvetica,sans-serif; font-size: 13px;"> ): The mass equivalent to the mass defect. The binding energy of a nucleus is the work (energy) required to completely separate the nucleons of that nucleus.

The binding energy is the amount of energy that is released when a nucleus is assembled from its component nucleons. It comes from a decrease in mass. The binding energy would therefore also be the energy that needs to be added in order to separate a nucleus into its components nucleons. So the mass defect is a measure of the binding energy.

EXAMPLE 2) Calculate how much energy corresponds to a mass of 1 u. <span style="color: #ad13da; font-family: Symbol,sans-serif;">D E = <span style="color: #ad13da; font-family: Symbol,sans-serif;">D mc 2 1 u x c 2 = 1.6605402 x 10 -27 x (2.9929 x 10 8 ) 2 J = 1.4923946316 x 10 -10 J 1 eV = 1.602177 x 10 -19 J, and thus 1.4923946316 x 10 -10 J / 1.602177 x 10 -19 J eV -1 = 931.5 M eV Therefore, **1 u = 931.5 M eV c -2 **

Worked examples 7.8: Determine the energy equivalent to the mass of the proton, the neutron and the electron. Worked examples 7.9: Determine the binding energy per nucleon of the nuclues of carbon-12. Worked examples 7.10: Calculate the ratio of the kinetic energies of the alpha particle to that of the radon nucleus in the decay of radidum ( 226 Ra 88 ) to radon ( 222 Rn 86 ). Assume that the radium nucleus decays at rest. Determine how uch energy the alpha particle carries. Worked examples solutions taken from Physics for the IB Diploma sixth edition K.A.Tsokos

**Nuclear fission** Highly unstable nucleus splits into two lighter nuclei, it releases energy while shooting out two or three neutrons. The splitting of the nucleus is called fission. {Natural uranium is a dense radioactive metal. It is mostly made up of two isotopes: uranium-238(over 99%) and uranium-235(less than 1%).} nuclear fission from cyberphysics.co.uk Image from [|www.nuclear-power.net] [|Facts about fission products] from Hyperphysics [|Nuclear fission] from phet.colorado.edu <span style="background-image: url(">[|Why is Uranium-235 ideal for nuclear power?] from science.howstuffworks.com

Worked examples 7.11: One fission reaction of uranium -235 releases 173 MeV for each decay. Estimate the energy released by 1 kg of uranium-235. ( P.291 Physics for the IB Diploma sixth edition K.A.Tsokos )

**Nuclear Fusion** <span style="background-color: #ffffff; color: #333333; font-family: verdana,helvetica,arial,sans-serif; font-size: 12.6464px;">Two atomic nuclei joining to make a large nucleus. Energy is released during the process of Nuclear fusion so it can also be used as a source of energy. [|Where Does The Sun Get Its Energy?] [|Veritasium] Published on 6 May 2012

Deuterium is a Hydrogen-2 atom and Tritium is a Hydrogen-3 atom. This is the most common fusion reaction in the Sun Image from [|nuclear-energy.net] || media type="custom" key="29417885" Finding Neutrinos - Sixty Symbols [|Sixty Symbols]Published on 26 Sep 2014 Fusion in the Sun from [|Neutrinos] - [|Sixty Symbols] Published on 15 Jun 2010 || || Published on 10 Nov 2016 || Task: Complete the diagram showing [|fusion process in the Sun] || Fusion: [|How to Put the Sun in a Magnetic Bottle - with Ian Chapman] [|The Royal Institution] Published on 8 Jun 2016
 * [[image:sciencelanguagegallery/nuclear fusion.PNG width="584" height="336"]]
 * **<span style="background-color: #ffffff; background-image: url(">[|What is nuclear fusion] ** from www.iter.org
 * <span style="background-color: #ffffff; background-image: url(">[|How close are we to nuclear fusion] **** from forbes.com ** || <span style="background-image: url(">[|Fusion Power Explained – Future or Failure] [|Kurzgesagt – In a Nutshell]

[|Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte] [|MIT Club of Northern California] Published on 25 Feb 2016 Worked examples 7.12: This fusion reaction takes place in the interior of stars. Write the fusion equation: Four hydrogen nuclei fuse into a heliu nucleus plus two positrons, two electron neutrinos and a photon. Calculate the energy released in this reaction. Use M He = 4.002600 u. ( P.292 Physics for the IB Diploma sixth edition K.A.Tsokos )

Whenever a nuclear reaction releases energy, the products of the reaction are in a lower energy state than the reactants. Mass lost must be the source of this energy. To compare energy states of different nuclei, physicists calculated the **binding energy per nucleon = total binding energy/number of nucleons** A reaction is energetically feasible if the products of the reaction have a greater binding energy per nucleon when compared with the reactants. The binding measure per nucleon is a measure of how stable the nucleus is, which means __**the highe**__r the binding energy per nucleon, the __** more **__ stable the nucleus. The above plot is taken from [|Nuclear Binding Energy]. [|Graph] source from science.uwaterloo.ca [|Binding energy] from schoolphysics.co.uk
 * Binding Energy per Nucleon**


 * __Task:__** To extract data from an online database and produce a plot of nuclear binding energy per nucleon as a function of mass number for several of the known isotopes.
 * __Reference:__**
 * This practical aims to address syllabus topic 7.2
 * Tsokos, Physics for the IB Diploma 6th Ed., Cambridge
 * Giancoli, 6th Edition Physics
 * Pearson, Baccalaureate HL Physics


 * __Assessment Criteria:__**
 * Time: 1.5 hrs.
 * ICT: Database


 * __Due Date:__ 21st November 2017**
 * Final draft: Upload it into MB and submit the print out including Collections of Data, Process of each data set and Conclusion (You may need to compare your graph with Figure 7.12 on page 288 of your text before submission ).

[|Atomic physics revision] from schoolphysics.co.uk

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">7.3- The structure of matter

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Nature of science: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Predictions: Our present understanding of matter is called the Standard Model, consisting of six quarks and six leptons. Quarks were postulated on a completely mathematical basis in order to explain patterns in properties of particles. (1.9) <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Collaboration: It was much later that large-scale collaborative experimentation led to the discovery of the predicted fundamental particles. (4.3)

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Understandings: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Quarks, leptons and their antiparticles <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Hadrons, baryons and mesons <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• The conservation laws of charge, baryon number, lepton number and strangeness <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• The nature and range of the strong nuclear force, weak nuclear force and electromagnetic force <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Exchange particles <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Feynman diagrams <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Confinement <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• The Higgs boson

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Applications and skills: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Describing the Rutherford-Geiger-Marsden experiment that led to the discovery of the nucleus <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Applying conservation laws in particle reactions <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Describing protons and neutrons in terms of quarks <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Comparing the interaction strengths of the fundamental forces, including gravity <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Describing the mediation of the fundamental forces through exchange particles <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Sketching and interpreting simple Feynman diagrams <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Describing why free quarks are not observed

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Guidance: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• A qualitative description of the standard model is required International-mindedness: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Research into particle physics requires ever-increasing funding, leading to debates in governments and international research organizations on the fair allocation of precious financial resources

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Theory of knowledge: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Does the belief in the existence of fundamental particles mean that it is justifiable to see physics as being more important than other areas of knowledge?

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Utilization: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• An understanding of particle physics is needed to determine the final fate of the universe (see Physics option sub-topics D.3 and D.4)

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Aims: <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Aim 1: the research that deals with the fundamental structure of matter is international in nature and is a challenging and stimulating adventure for those who take part <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Aim 4: particle physics involves the analysis and evaluation of very large amounts of data <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Aim 6: students could investigate the scattering angle of alpha particles as a function of the aiming error, or the minimum distance of approach as a function of the initial kinetic energy of the alpha particle <span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">• Aim 8: scientific and government organizations are asked if the funding for particle physics research could be spent on other research or social needs

<span style="color: #ad13da; font-family: Arial,Helvetica,sans-serif; font-size: medium;">Data booklet reference:
 * **Charge** |||||| **Quarks** || **Baryon number** ||
 * (2/3)//e// || u || c || t || 1/3 ||
 * -(1/3)//e// || d || s || b || 1/3 ||
 * //All quarks have a strangeness number of 0 except the strange quark that has a strangeness number of -1// ||


 * **Charge** |||||| **Leptons** ||
 * -1//e// || e || m || t ||
 * 0 || n <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%; vertical-align: sub;">e || n m  || n t  ||
 * //All leptons have a lepton number of 1 and antileptons have a lepton number of -1// ||


 * || **Gravitational** || **Weak** || **Electromagnetic** || **Strong** ||
 * **Particles experiencing** || All || Quarks, leptons || Charged || Quarks, gluons ||
 * **Particles mediating** || Graviton || W +, W - , Z 0 || g || Gluons ||

[|Rutherford scattering] simulation from Phet.colorado.edu modified resource taken from[| TES (aer)] [|Rutherford scattering simulation.pdf] from quarknet.org media type="youtube" key="2zZ1kv6vlq0" width="560" height="315" [|Elementary Particles - A Level Physics] [|DrPhysicsA] Published on 24 Mar 2012
 * [[image:sciencelanguagegallery/Rutherford scattering trajectories of alpha particles.jpg]] || [[image:Rutherford scattering trajectories depend on the impack parameter.jpg]] ||

Hadrons are particles made up of quarks. This includes **baryons** ( composed of //__three quarks__// ) and **measons** ( comprise of __//quark and anti-quark//__ pairs ). The strong interaction acts on all hadrons while weak interaction acts on both hadrons and leptons. Bryon number for quark is 1/3 and for an antiquark is -1/3. A strange quark has a strangeness of - 1, and a strange antiquark has a strangeness of + 1. This property of strangeness is conserved when strange particles are created but it is not conserved when they subsequently decay. All leptons have a lepton number of + 1 and antileptons have a lepton number of -1. Mass-energy, momentum, charge and baryon number are all conserved during the interaction as well as lepton numbers. Images taken from Oxford 2014 IB DP Physics P.295 P.303 [|Image of leptons and quarks] from www.physi.uni-heidelberg.de/ [|Standard model of elementary particles] from www.hep.phy.cam.ac.uk || Physics for the IB Diploma sixth edition K.A.Tsokos P.302 Physics for the IB Diploma sixth edition K.A.Tsokos P.305 ||
 * [[image:sciencelanguagegallery/Hadron.PNG]] || [[image:sciencelanguagegallery/baryons.PNG width="342" height="233"]] || [[image:sciencelanguagegallery/Mesons.PNG width="346" height="233"]] || [[image:Standard model including Higgs.PNG width="308" height="239"]] ||
 * Hadrons || Baryons || Mesons || The Standard Model including the Higgs boson ||
 * [[image:LEPTONS AND QUARKS.jpg width="893" height="645"]]


 * [[image:Force exchange particles.PNG]] || [[image:Quarks and the charges.PNG]] || [[image:Leptons and charges.PNG]] ||
 * Force and the exchange particles || Quarks || Leptons ||

Images taken from Oxford 2014 IB DP Physics P.294 P.295 P.300 <span style="background-image: url(">[|Particle advanture] from www.particleadventure.org <span style="background-image: url(">[|Quarks] [|Proton and neutron structure] [|Fundamental forces] [|Fermi theory of beta decay] [|Some nuclcear units] from hyperphysics
 * <span style="background-image: url(">Further reading: **
 * Interesting subatomic particle ** [|Neutrino] from Britannica

Feynman diagrams
Feynman diagram is representation of one way of going from initial state to final state. It gives probability of that process occurring out of all the possible combinations. In **beta plus decay**, a proton turns into a neutron. The positive charge is transferred by the W+ boson, which then becomes a positron and an electron neutrino. Note how the positron arrow points towards the interaction, as the positron is an antiparticle. [|Beta decay] occurs in proton rich nuclei (link from indiana.edu/BetaDecay.pdf). Example: || Equations of examples of beta + and - decay || The electron strikes the nucleus from outside. The negative charge is transferred from the electron to the proton using the W- boson. To ensure that all quantum numbers are balanced, an electron neutrino is emitted.
 * [[image:Feynman diagram beta + decay.PNG width="289" height="179"]]

Images taken from Oxford 2014 IB DP Physics P.295 - P.303 || The electron falls from one of inner shells. It is attracted by the electromagnetic interaction, but the negative charge is transferred to the proton by the W+ boson. An electron neutrino is emitted. Electron capture is another way in which a proton can be turned into a neutron. ||

Baryons decay to **protons**, either directly ( S +  ® p + p 0 ) or indirectly ( W- ® L0 + K, then  L0 ® p  +  p- ). Meso ns decay to ** photons ** or ** leptons **.

PRACTICE Q3: Show that this decay is possible for the lambda baryon. L 0 ® <span style="font-family: Times New Roman,serif;">p + p  - [|solution] || and [|hyperphysics] || [|Examples of particle decay] from antonine-education.co.uk || Feynman diagrams examples from IB STUDY GUIDES FOR THE IB DPPLOMA 2014 edition Tim Kirk OXFORD p.80
 * <span style="font-family: Symbol,sans-serif;"><span style="font-family: arial,helvetica,sans-serif;">Table of Feynman diagrams; b + decay || <span style="font-family: Symbol,sans-serif;">b - decay / [|Equations of nuclear decay] || [|Proton - Electron collision] [|SnapRevise] Published on May 2017 || [|Electron capture from antonine-education]
 * <span style="background-color: #ffffff; color: #000099; font-family: &#39;Comic Sans MS&#39;,MarkerFelt-Thin,cursive,sans-serif; font-size: small;">If an electron is released then an antineutrino is needed to blanace the leptons and if a positron is released a neutrino is needed to balance the leptons

Worked examples a) Show that, when a proton collides with a negative poin, the collision products can be a neutron and an uncharged pion. b) Deduce the quark composition of the uncharged pion.
 * EXAMPLE 1:

EXAMPLE 2: Explain whether a collision between two protons could produce two portons and a neutron. || EXAMPLE 3: Draw Feynman diagrams to show the following interaction: a) positive beta (positron) decay b) proton-electron collision c) the two types of neutron-electron neutrino collision Worked examples solutions OXFORD IB DP Physics text || <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: small;">QED: a quantum field theory that deals with the electromagnetic field and its interaction with electrically charged particles. <span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: small;">QCD: a quantum field theory in which the strong interaction is described in terms of an interaction between quarks mediated by gluons, both quarks and gluons being assigned a quantum number called “colour”.
 * Quantum Electrodynamics and Quantum Cromodynamics**
 * Particle Interactions, [|QED and QCD: An Introduction - Part 1] [|DrPhysicsA] Published on 6 Feb 2012 || [|QED and QCD: An Introduction - Part 2] [|DrPhysicsA] || [|QED and QCD: An Introduction - Part 3] [|DrPhysicsA] ||

Find solutions of the qestion above (9) and the question right (12) from [|global.oup.com]
 * [[image:Feynman diagram beta + decay questions.PNG]]

Images taken from Oxford 2014 IB DP Physics P.298 P.302 P.306 || ||


 * [|Why do you think human beings feel compelled to do basic research?] [|View discussion]

[|Why is the discovery of the Higgs boson important?] [|View discussion] || [|Your Mass is NOT From the Higgs Boson][|Veritasium] Published on 8 May 2013 || media type="youtube" key="IElHgJG5Fe4" width="560" height="315" [|The basics of the Higgs boson - Dave Barney and Steve Goldfarb] <span style="color: var(--ytd-video-primary-info-renderer-title-color,var(--yt-primary-text-color)); font-family: var(--ytd-video-primary-info-renderer-title-font-family,inherit);">Published on 3 May 2013 <span style="background-image: url(">[|Higgs Boson discussion] from TEDEd Further reading: <span style="background-image: url(">[|Paradigm Shifts Thomas Kuhn] pdf

[|Positron on Neutron capture reaction, radiative corrections and neutron EDM] <span style="background-color: #ffffff; font-family: &#39;Lucida Grande&#39;,helvetica,arial,verdana,sans-serif; font-size: medium;">[|Mikhail Khankhasayev] <span style="background-color: #ffffff; font-family: &#39;Lucida Grande&#39;,helvetica,arial,verdana,sans-serif; font-size: medium;">, <span style="background-color: #ffffff; font-family: &#39;Lucida Grande&#39;,helvetica,arial,verdana,sans-serif; font-size: medium;">[|Carol Scarlett] - Cornell University