The idea behind particle accelerators (atom smashers): ________ particles + high __________: old energy _______ particles because ________ new E = mc2 The more the ________________ given to the old particles, the more _________________ of the new ones by E = ______. energy the mass mc2

Ex: Early particle accelerators used _______________ generators: van derGraff high _______________ work done on a charge q: W = high _______________ work done on a charge q: W= voltage V qV Ex: How much KE will a proton gain when it is accelerated through a potential difference of 300,000 V? W = qV = DKE v ~ 7.6 x 106 m/s crosses the Earth in 1.7 s, but still only 2.5% of c W = (1 e)(300,000 V) W = 300,000 eV

Ex: An example of a modern particle accelerator is the_____________________ . cyclotron. v v v The _______________ field accelerates the particle. The ______________ field is ____________________ to v, so it only causes the particle to ___________________________ . electric magnetic perpendicular turn in a circle

the very first cyclotron world’s biggest cyclotron a 1939 cyclotron

The particle accelerator at Cornell University accelerator storage ring for positrons

SLAC – The Stanford Linear Accelerator Center

Fermilab in Chicago – another accelerator built in the shape of a circle.

Find the ladder for scale. …inside Fermilab

One of the largest – at CERN - Angels and Demons

A detector at CERN led to the discovery of the W and Z particles – carriers of the weak force

As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered. energy masses There seemed to be no _____________ to the________________ of newly discovered particles. pattern hundreds _____________________ tracks of subatomic particles Finally, the _________________________ was worked out in the _______________ . It explained how all of the particles are made of ________________ fundamental particles and their _________________________ .

bubble chamber tracks

As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered. energy masses There seemed to be no _____________ to the________________ of newly discovered particles. pattern hundreds _____________________ tracks of subatomic particles Finally, the _________________________ was worked out in the _______________ . It explained how all of the particles are made of ________________ fundamental particles and their _________________________ . Standard Model 1960s twelve antiparticles

The Standard Model: All matter (or antimatter) is made up of ___________or combinations of____________. leptons quarks _______ quarks leptons Let’s look at leptons first. __________________ read the fine print

increasing____________________ mass/energy only found at high energies (high temps.) everyday low-energy leptons Neutrinos have _______ _____ mass. almost no Lepton means________________________ Leptons all have charge _______or__________________ Their antiparticles are charged __________________ They occur____________________—they do not ___________________________________________. “light weight.” -1e 0 (neutral). +1e or 0. by themselves combine to form bigger particles

increasing __________________ everyday, low-energy quarks mass/energy only found at high energies (high temps.) Quarks all have charge _________or ___________ Their antiparticles are charged _________ or_________ They ___________________by themselves because you cannot have a particle with a_________________________. They occur in groups of _____________________ (+2/3)e (-1/3)e. (+1/3)e (-2/3)e never occur non-integer charge 2’s or 3’s.

particles made from ___________ quarks “mes-” means _________ masses “bary-” means _______ masses middle heavy qqq q Must be all __________ or all_____________ or matter antimatter q

Ex. A certain particle is made up of 3 quarks: 2 ________ quarks and 1 _____________ quark. u d up u down What is the total charge of the particle? u: Add up the charges: (+2/3) e u: (+2/3) e [(+2/3) + (+2/3) + (-1/3)] e d: (-1/3) e = 1 e Is this a baryon, a meson or a lepton? 3 quarks  a baryon This particle is also known as a________________ proton.

Ex. A certain particle is made up of 2 quarks: 1 ____ quark and 1 __________ quark. d u up antidown What is the total charge of the particle? Add up the charges: u: (+2/3) e [(+2/3) + (+1/3)] e : d (+1/3) e = 1 e Is this a baryon, a meson or a lepton? 2 quarks  a meson p+ (positive pion). This particle is also known as a ______________________

Ex. A certain particle is made up of 3 quarks: 1 _____ quark and 2 ________ quarks. d up down d u What is the total charge of the particle? u: (+2/3) e Add up the charges: d: (-1/3) e [(+2/3) + (-1/3) + (-1/3)] e d: (-1/3) e = 0 e Is this a baryon, a meson or a lepton? 3 quarks  a baryon This particle is also known as a_____________________ neutron.

Ex. A certain particle is made up of 3 quarks: 2 ________________ quarks and 1 _________________ quark. u d antiup u u antidown d What is the total charge of the particle? u : (-2/3) e Add up the charges: [(-2/3) + (-2/3) + (+1/3)] e (-2/3) e u : = -1 e d : (+1/3) e u d u d u u u u Compare this one: to: d d The left-hand particle is an _______________________ . It is an example of ___________________ . It has the __________ mass as the proton, but the _________________ charge. antiproton same antimatter opposite

quark content total charge type name s -1e meson K- d baryon S- b U L Determine the charge and type of each particle. quark content total charge type name s -1e meson K- d baryon S- b U L n u +1e K+ u b u d s d d u s The total charge must be ____________________________ a whole number of e's

What is matter made up of? neutron or a proton

planets, solar systems, etc Forces The Fundamental __________________ of Nature: force range relative strength what it controls strong nuclear very short 1 holds nucleus together electro- magnetic infinite (1/r2) 10-2 electricity and magnetism weak very short 10-13 radioactive decay gravita- tional 10-38 planets, solar systems, etc

Ex: How can gravity hold Earth to the Sun if it is the weakest force? Earth and Sun have a lot of ______________ Earth and Sun are _________________ , so the __________________________ force is not important. 3. Earth and Sun are_______________ , so the ________________________ forces are not important. mass. neutral electromagnetic far apart two nuclear Ex: The total amount of mass-energy in the universe is: ordinary matter: ______% (baryons and leptons) dark matter: ______% (unknown) dark energy: ______% (unknown) 5 23 72

Conservation Laws: Total before =________________ Total after Charge q 1. _____________________ is always conserved. q1 + q2 + … = q1’ + q2’ + … In the absence of_______________ , ________________ is always conserved. momentum (p) friction = p1’ + p2’ + … p1 + p2 + … 3. In the absence of________________, ________________ is always conserved. friction energy (E) Classical physics: Modern physics: ET ET’ = mass-E mass’-E’ = KE + PE KE’ + PE’ using E = mc2