VU lecture – Introduction to Particle Physics Thomas ...web.vu.lt/ff/t.gajdosik/files/2014/04/WoP_Historical_Particles.pdf · VU lecture – Introduction to Particle Physics Thomas

VU lecture – Introduction to Particle Physics Thomas Gajdosik, FI & VU

Introduction to Particle Physics

Thomas GajdosikFizikos Institutas

Vilnius Universitetas, Teorinės Fizikos Katedra

The Particle Zoo Symmetries The Standard Model


The Particle Zoo


1897

the electrone-

ThomsonThomson


1897

the photon

1900-1924

γ

PlanckPlanck EinsteinEinstein

ComptonCompton

e-


1897

the proton

e-

1900-1924

γ

1914

RutherfordRutherford

p


1897

the neutron

e-

1900-1924

γ

1914

n

p

1932

ChadwickChadwick


1897

the muon

e-

1900-1924

γ

1914

µ

p

1932

n

1937

Whoorderedthat one?

• Hess• Anderson,

Neddermeyer

• Street, Stevenson

spark chamber


1897

the pion

e-

1900-1924

γ

1914

π

p

1932

n

1937

µ

1947

PowellPowellYukawaYukawa

prediction discovery


1897

the positron (anti-matter)

e-

1900-1924

γ

1914

e+

p

1932

n

1937

µ

1947

π

AndersonAnderson

DiracDirac

prediction

discovery


1897

the neutrino

e-

1900-1924

γ

1914

ν

p

1932

n

1937

µ

1947

π

e+

FermiFermiPauliPauli


1897

strange particlese-

1900-1924

γ

1914

KK

p

1932

n

1937

µ

1947

π

e+

Rochester,Butler,...

1947-...

ν

ΣΣ

ΛΛ


1897

„I have heard it said that the finderof a new elementary particle usedto be rewarded by a Nobel Prize,but such a discovery now ought tobe punished by a $10,000 fine.“

e-

1900-1924

γ

1914K

p

1932

n

1937

µ

1947

π

e+

1947-...

ν

Σ

Λ

Willis Lamb, in his Nobel prize acceptancespeech 1955, expressed the mood of thetime:

LambLamb


mean life time (s)

n

µ

πc

KL

D

Kc

KS

π0

η

τ

B

φ

J/ψϒ1s ϒ2s

ϒ3s

ϒ4sω

ρ

D*

Σc

Σ0

Ω−

mass (GeV/c2)

1s

1 ms

1 µs

10-15s

10-20s

10-25s

100000 e- p

1 ns

The Particle Zoo

W±

Zo


• electron accelerators: very short-waved particleprobes, shot directly at the „target“ probe; most widely-known example: electron microscopes

• at even higher energies of the probes, new particlescan be produced – short-lived particles, which existedshortly after big bang, can be „revived“: a „mini bigbang“ in the lab!

• to get even closer to big bang:build colliders, whereaccelerated particles collidehead-on

Particle accelerators


• in the early times: electro-static accelerators(cascade generator, Van-de-Graff generator)

• in parallel, high-frequency linear accelerators havebeen developed:



• the betatron, a „free-flighttransformator“: a magnet field (whichholds particles in an orbit) is increasedwith time, thus producing a circularelectric induction field whichaccelerates the particles


• the cyclotron, peak of development of accelerator physics in the 1920ies: a charged particle circulates in a magnetic field, and is accelerated byswitched electro-static fields. At non-relativistic energies, the rotationalfrequency is independent of the momentum (or energy) of the particle, onlythe orbit radius increases with time spiral path


Particle acceleratorsthe synchrotron is the advancement of thecyclotron to relativistic energies. It consistsof several modules which take over different tasks:

• bending magnets force particles on theircircular path• high-frequency cavities take care of theacceleration• focussing magnets keep the particle beamstogether

The world‘s largest electron-positron collideris the LEP, built in the 1980ies and used until2000 at CERN, Geneva reaching ~200 GeVof energy. It is now replaced by the LHC, which collides protons at energies of 14 TeV SPS tunnel


J/Ψ196645 GeVe+ e-SLAC

gluon19782 x 20 GeVe+ e-PETRA

antiproton19546 GeVpBevatron

discoverystartedEbeamparticlesaccelerator

J/Ψ1959/1960

29 / 33 GeVp, p, e±PS/AGS

first artificial mesons

19533,3 GeVpCosmotron



15199226 + 820 GeVp e±HERA

>10 00020092 x 7000 GeVp pLHC

5000199910,5 GeVe+ e-PEP II

luminosity[ 10-30 cm-2 s-1]startedEbeamparticlesaccelerator

13 000199910,5 GeVe+ e-KEK B

2519872 x 900 GeVp pTEVATRON



1897

antiproton

e-

1900-1924

γ

1914

p

1932

n

1937

µ

1947

π

e+

cosmic rays,Bevatron,PS (CERN)

ν

p_

1955

also antiprotons!


1897

antineutrino

e-

1900-1924

γ

1914

p

1932

n

1937

µ

1956

π

e+

reactors:Clyde Cowan, Frederick Reines

ν

_

1955

1947

ν


partons / parton model

e-

γp

nµ

π

e+

ν

Richard Feynman1969

1900-1924

1897 1914 19471932

1937 1955

1947

1969


charm quark: J/Ψ

e-

γp

nµ

π

e+

Burt Richter (SLAC), Samuel Ting (BNL)1974

ν

c

1900-1924

1897 1914 19471932

1937 1955

1947

1969

1974


tau lepton: τ

e-

γp

nµ

π

e+

Martin Perl (SLAC-LBL)1975

ν

τ

19751900-1924

1897 1914 19471932

1937 1955

1947

1969

1974


bottom quark

e-

γp

nµ

π

e+

E288 (Fermilab)1977

ν

b

19751900-1924

1897 1914 19471932

1937 1955

1947

1969

1974 1977


Gluon

e-

γp

nµ

π

e+PETRA (DESY)1979

ν

g

19751900-1924

1897 1914 19471932

1937 1955

1947

1969

1974 1977

1979


W- and Z-boson

e-

γp

nµ

π

e+

discovery: UA1, UA2 (CERN)1983

ν

W,Z evidence: 1973 Gargamelle bubblechamber (CERN)

1900-1924

1897 1914 19471932

1937 1955

1947

19831969 `73


top quark

e-

γp

nµ

π

e+

ν

tCDF, D0 (Fermilab)1995

19751900-1924

1897 1914 19471932

1937 1955

19951947

19831969

1974 1977

1979


tau neutrino: ντ

e-

γp

nµ

π

e+

DONUT (Fermilab)2000

ν

ντ

19751900-1924

1897 1914 19471932

1937 1955

19951947

19831969

1974 1977

20001979


19751900-1924

1897 1914 19471932

1937 1955

?1947

19831969

1974 1977

2000`73 1979

Higgs particleH

ATLAS, CMS (CERN)

201x

CDF, D0 (Fermilab)

2009 ? ?

?1995

?

?

VU lecture – Introduction to Particle Physics Thomas ...web.vu.lt/ff/t.gajdosik/files/2014/04/WoP_Historical_Particles.pdf · VU lecture – Introduction to Particle Physics Thomas

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