Introduction of Nuclear Physics

How can we probe the structure in the smaller scale? Discovery of nuclear structure Development of nuclear physics –Nuclear structure –Exotic nuclei –Heavy ion collisions –Relativistic heavy ion collisions –Virtual photon from deep inelastic scattering with electron beam –Laser-electron photon, Bremsstrulumg photon –Laser Nuclear Physics

1897 – ELECTRON discoveryJ.J. Thomson 1909 – PROTONdiscovery E. Rutherford 1932 – NEUTRONdiscoveryJ. Chadwick 1935 – EXCHANGEtheoryYukawa 1948 – QEDtheoryFeynman,… W & ZtheoryGlashow 1964 – QUARKtheoryGell-Man, Zweig 1964 – HIGGStheoryHiggs, Englert,… 1967 – ELECTROWEAK theoryWeinberg, Salam,… 100 Years of Particle Physics

1971 – NON-ABELIANt’Hooft, GAUGEtheoryVeltman 1972 – QCDtheoryGell-Man, Frizsch 1973 – ASYMPTOTICGross, FREEDOMtheoryWilzcek, Politzer 100 Years of Particle Physics

1974 – CHARMdiscoveryTing, Richter 1977 – BOTTOMdiscoveryLederman JADE 1979 – GLUONdiscoveryTASSO, JADE, MARK-J, PLUTO 1983 – W & ZdiscoveryRubbia/UA1 UA2 DØ 1995 – TOPdiscovery DØ & CDF 100 Years of Particle Physics

Geiger-Marsden experiment The Geiger-Marsden experiment (also called the Gold foil experiment or the Rutherford experiment) was an experiment done by Hans Geiger and Ernest Marsden in 1909, under the direction of Ernest Rutherford at the Physical Laboratories of the University of Manchester which led to the downfall of the plum pudding model of the atom. They measured the deflection of alpha particles (helium ions with a positive charge) directed normally onto a sheet of very thin gold foil. Under the prevailing plum pudding model, the alpha particles should all have been deflected by, at most, a few degrees. However they observed that a very small percentage of particles were deflected through angles much larger than 90 degrees; some were even scattered back toward the source. From this observation Rutherford concluded that the atom contained a very physically-small (as compared with the size of the atom) positive charge, which could repel the alpha particles if they came close enough, subsequently developed into the Bohr model.

Low-Energy electron scattering from Carbon

High-Energy electron scattering from Carbon

Parton Structure of Proton - Quark

Elementary Particles discovered: 1898  Donald Glaser invented the bubble chamber. The Brookhaven Cosmotron, a 1.3 GeV accelerator, started operation.

Back to Year 1964 A hundred or so types of particles were identified: –Baryons (fermion): n, p, , , , …. –Mesons (boson) : , , ….. quarksMurray Gell-Mann (Mendeleev of elementary particle physics) proposed “ the eightfold way ” to put these particles in order, suggesting more elementary constituents: quarks. –Three types of quarks, u, d and s. –Baryons composed of 3 quarks. –Mesons composed of 2 quarks: a quark and an antiquark.

Baryon Octet (s=1/2)

Meson Octet (s=0)

Baryon Decuplet (s=3/2) (1232) (1384) (1533) (1672)

Deep Inelastic Scattering with Electrons beam

A November revolution: the birth of a new particle J/  BNL: p+A  e+e- X SLAC: e+e-  X

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 Upsilon

Three-jet Events: Proof of “radiated” Gluon

1995 European Physical Society High-Energy and Particle Physics Prize

Observation of “Neutral Currents” in 1973

Discovery of W and Z in On 25 January 1983, CERN called a press conference to announce the discovery of the W particles.

W and Z Production Isolated, high p T leptons Missing transverse momentum in W's Z events provide excellent control sample Typically small hadronic (jet) activity Number of candidates in ~200pb -1 : ~64000 W  e ~51000 W   ~2900 Z  ee ~4900 Z  

W Mass Measurement W mass information contained in location of transverse Jacobian edge Insensitive to p T (W) to first order. Reconstruction of p T  sensitive to hadronic response and multiple interactions Provides cross-check of production model. Needs theoretical model of p T (W) Provides cross-check of hadronic modelling

Detector Calibration: Lepton Energy Scale Energy scale measurements drive the W mass measurement Calibrate lepton track momentum with mass measurements of J/  and  decays to  Calibrate calorimeter energy using track momentum of e from W decays Cross­check with Z mass measurement, then add Z's as a calibration point Z   Z  ee

Signature of Top Quark Production

e+e-  X around Z bosons : Proof of “three-generation” of neutrios

A hadron event - a neutrino interacting with a nucleon and emerging as a neutrino : first observation of "neutral currents" in the Gargamelle heavy liquid bubble chamber.