Standard Model (s)

Organizing our data helps us see deeper relationships and ultimately the underlying laws of nature.

Standard Models

Parts and how they go together 1) Atoms – Periodic Table 2) Nuclei – Chart of the nuclides 3) Particle Physics – Quark Ensembles

Mesons and Hadrons 4) “Bulk” Quark Matter – Quark-Gluon

Plasma

The parts of the Atomic Model and the roles they play Electrons Nuclei Negative Charge, e Positive Charge, Ze Small Mass (2000 A) Large Mass Fill the atom ((10^4)^3) Tiny at center 5x10^-11 m (2 to 6) 10^-15 m Volley ball (20 cm) vs. VU Campus (2 km)

Magic numbers or shells: 2, 2+6=8, 2+6+8+10 with 10 held back, and holding back gets more complicated beyond this

Most stable (noble) end period Note that these are ground states Excited states have one or more electrons of an

atom in a higher orbit. Excited atoms decay, usually in nanoseconds, to

ground states. Hydrogen atom decay picture on next slide.

Looks Familiar, but now antiproton at center and positron (antielectron) circles it

The numbers of neutrons and protons in the nucleus change. Why can we ignore that change in making our periodic chart?

These charts are for chemistry-type energy changes, a few kiloJoules/mole or eV/atom. Nuclear changes typically require 10^5 times as much energy.

Physicists think about single atoms while chemists think about moles of atoms, physicists prefer to think about 1 eV of energy rather than 6e-19 J – even though it is the same thing! You could give the mass of a piece of jewelry in tons, but why would you want to?

Size of atom – does not increase much with more electrons, not as cube root of number of electrons.

What do the electrons care about in a nucleus? The charge, Ze, of the nucleus and that it is

much heavier than an electron are the most (by far) important properties of the nucleus. Nuclear physics is a thousand to a million times more violent than chemistry and in this more violent world pieces can be knocked off the nucleus.

What can nature build out of protons and neutrons? Does nature respect rules or magic numbers when neutrons and protons are merged?

Let’s make a chart of Nuclei to see if there are regularities like we found with atoms Vertical – Number of protons Horizontal – Number of neutrons There must be a new, short range, force

much stronger than the electrostatic force or protons could not be held so close together.

Magic Numbers (either neutrons or protons) 2, 8, 20, 28, 50, 82, 126 Strong force can’t tell proton from neutron

Magic numbers of n, p – separately:2, 8, 20, 28, 50, 82, 126, …

Bang two elements together, to get a new element. 117 is latest. 126 coming??? * Actinides o 93 neptunium Np o 94 plutonium Pu o 95 americium Am o 96 curium Cm o 97 berkelium Bk o 98 californium Cf o 99 einsteinium Es o 100 fermium Fm o 101 mendelevium Md o 102 nobelium No o 103 lawrencium Lr

* Transactinide elements o 104 rutherfordium Rf o 105 dubnium Db o 106 seaborgium Sg o 107 bohrium Bh o 108 hassium Hs o 109 meitnerium Mt o 110 darmstadtium Ds o 111 roentgenium Rg o 112 copernicium Cn o 113 ununtrium Uut* o 114 ununquadium Uuq* o 115 ununpentium Uup* o 116 ununhexium Uuh* o 117 ununseptium Uus* o 118 ununoctium Uuo*

A cyclotron in Dubna accelerates a beam of Ca48 to hit a 22 mg Bk249 target

The Building blocks of the next level standard model 27 particle physicists have

won Nobel prizes for making the experimental discoveries and theoretical breakthroughs that led to our present understanding.

The Higgs boson?

Interesting to remember that 35 years ago only knew up, down, strange, e, muon, 2 neutrinos, and the photon.

Particle – anti particle reminder. All thosequarks and and leptons have antis too

And there are antiquarks corresponding to each quark. Charge quark flavor +2/3 up, charm, top -1/3 down, strange, bottom Anti on each -2/3 u, c, t +1/3 d, s, b Quark Chemistry Baryons: 3 quarks, Antibaryons: 3 antiquarks

p = 2 up + down; n = 2 down + up Mesons: a quark and an antiquark

pi = up + anti down

When we only knew about 3 quarks (up to 1975), we could summarize it (spin ½)

Or for spin 3/2 combinations

Spin 0 Mesons

And for Spin 1 Mesons

LHC AcceleratorProtons are accelerated by powerful electric fields to very close to the speed of light.

And are guided around their circular orbits by powerful superconducting dipole magnets.

The dipole magnets operate at 8.3 Tesla (200’000 x Earth’s magnetic field) & 1.9 K (-271°C) in superfluid helium.

Protons travel in a tube which is under a better vacuum and at a lower temperature than that in inter-planetary space.

wrt Tevatron (USA)Energy (7-14 TeV) x 3.5-7 No. of interactions/second x 30