УСКОРИТЕЛИ ЗАРЯЖЕННЫХ ЧАСТИЦ В ФИЗИКЕ ВЫСОКИХ ЭНЕРГИЙ...

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УСКОРИТЕЛИ ЗАРЯЖЕННЫХ

ЧАСТИЦ В ФИЗИКЕ

ВЫСОКИХ ЭНЕРГИЙИ.Н.Мешков

VI-я Зимняя школа по Теоретической Физике

"Введение в Теорию Фундаментальных Взаимодействий"

Дубна, 26 января – 5 февраля 2008 г.

Лекция I

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Лекция I Содержание1. Введение: … из истории физики

"субядерных" частиц…ускорители – главное оружие экспериментальной ядерной физики…

2. "Битва Гигантов" 3. Эра встречных пучков4. Битва гигантов продолжается5. e+e- коллайдеры – шаг вперёд

26 January – 5 February 2008 I.Meshkov Particle Acelerators in HEP

The VIth Winter School of Theoretical Physics, JINR, Dubna



Введение: …из истории физики "субядерных"

частиц… 1995

1895

"субядерных"



The Beginning of Accelerator Physics of Microworld 1895, Konrad Röntgen:

Discovery of X-rays photon!

1897, Josef John Thomson: Discovery of electron!

Введение: …из истории физики "субядерных" частиц…



Introduction: …from History of Subnuclear Particle Physics… (Contnd)

1931, R.Van-der-Graaf: electrostatic accelerator

1932, James Chadwick: Discovery of neutron!

p + 7Li +

1932, J.D.Cockroft & E.T.S.Walton: electrostatic

accelerator ("cascade voltage multiplier")



Universe as an Accelerator("Нерукотворный ускоритель")

1912, Victor Hess: he has found in experiment with 3

electrometers carried out in a free balloon flight up to an altitude of 5300 meters that the ionization rate increased approximately fourfold over the rate at ground level. He concluded :"The results of my observation are best explained by the assumption that a radiation of very great penetrating power enters our atmosphere from above" .

It was

Discovery of what came to be called "cosmic

rays".




Universe as an Accelerator (Contnd)

1932, Carl D. Anderson: Discovery of positron

(by passing cosmic rays through a "Wilson chamber" with lead plate surrounded by a magnet to distinguish the particles charge)

Beginning of "the competition" of accelerators with cosmic rays!

Dm.Vl.Skobeltsyn missed his chance…




Advance in Accelerators

1929-1932, Ernest O. Lawrence: Invention of the resonance acceleration

method

Construction of first cyclotron

andfirst resonance linear

accelerator




Cosmic Rays do step forward !

Yukawa particle?(Hideki Yukawa, 1935)

1936, Carl D. Anderson again:

Discovery of "mesotron"

No! -meson muon




Break-through in Accelerators1944 Vladimir I.Veksler (USSR)

1945 Edwin McMillan (USA) Invention of the Phase stability principle – - the basic principle of resonance

acceleration !

Important for advancing to high energy accelerators

and high energy physics on accelerators

V. I. Veksler

V. I. Veksler & E. McMillan

JINR, June 1958

Construction of first electron synchrotron

(V.I.Veksler)and

first synchrocyclotron (E.McMillan)


E.McMillan

But (!)… they missed Nobel

prize!



Cosmic rays are progressing ! 1947, C.Powell, C.Lattes and G.Occhialini:

Discovery of pion

Pic du Midi, 2877 mPic Chacaltaya, 5421 m

with photographic emulsion exposedat 2877 m

(Pic du Midi de Bigorre, Pyrenees)and at 5421

(Pic Chacaltaya in Bolivian Andes)1947, G.D.Rochester and G.Butler:

Discovery of 0 hyperon (1115,63 2350

MeV)Discovery of K-mesons, or Kaons:

m(K+) = m(K-) = 493.67 MeV,

m(KS0) m(KL

0) = 497.67 MeV




The Doubts and The Hopes

The Doubts: Uncertainties in cosmic rays experimental studies !

The Hopes: Advance in accelerator technique

1st step - synchrocyclotrons

(sad known story of "Varitrons" –

- see Uspekhi Phys. Nauk v.61 №2 (1950))




1947, E.O.Lawrence, E.McMillan: Berkeley Synchrocyclotron 184 inches (4.7 m), d 200 MeV, 400 MeV (100

MeV/amu)

1949 Dubna Synchrocyclotron




Synchrocyclotron “Phasotron”The First Accelerator in Dubna

1949 d 280 MeV p 480 MeV

1984 p 680 MeV 201?

Mikhail Gr. Mescheryakov

Igor V. Kurchatovand Venedict P. Dzhelepov

Pion & muon physics

Muon-catalysis

Cancer therapy

Nuclear physics

Phasotron upgrade:

renewed transfer line

(2002)




Beginning of the 50th, pion physics at

Dubna Synchrocyclotron

1948, Lattes and E. Gardner:

first artificial production of pions at

Berkeley Synchrocyclotron:

+ 12C ++ X




Since that time accelerators became

The Main Tool of High Energy Physics

Majority of experimental results of

fundamental character has been obtained

both in particle, and nuclear physics at

accelerators.


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"The Third Way" (nuclear reactor)

1930, W.Pauli Theoretic prediction:

1956, C.Cowan, F.Reines et al.

Experimental proof:

registration of direct interaction of

electron antineutrinos from nuclear

reactor with nucleons of a target

in reaction

e + p n + e+ ~~



And what about

neutrinos?


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2. The Battle of Giants 1953 (1948) 1968 The Cosmotron – proton

synchrotron at Brookhaven Nat. Lab., USA), 3.3 GeV; the first accelerator with extraction of the particle beam meson physics 1955 1993 The Bevatron - proton synchrotron at

Lawrence Berkeley Nat. Lab.(USA), 6.3 GeV ("Billions of eV")

E.McMillan & E.Lofgren on

the shielding of the Bevatron

the first

dedicated accelerator:

Discovery of antiproton

(E.Segre & O.Chamberlain,

1955)



1957 2001 The Synchrophasotron proton synchrotron at JINR, USSR, 10 GeV; C =

251 m Various problems in particle physics,

1960 V.I.Veksler et al.:

Discovery of -

1970th A.M.Baldin:

Relativistic nuclear

physics The Synchrophasotron was the last

weak focusing synchrotron: magnet of 36 000 tons

2. The Battle of Giants (contnd)



’Grand mother

(babushka),

why is a synchrotron

so large…?’

'Just because pc =

eB’


For instance, Synchrophasotron:

pc E = 10 GeV, B = 1.6 T (iron!) = 21 m

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'And why is it so

heavy?’

'Because nobody believed yet in strong focusing principle!…'… proposed

already!


*) The project of Synchrophasotron was started ~ in 1950

("Die erste kolonne marschiert…", L.Tolstoi) 26 January – 5 February 2008 I.Meshkov Particle Acelerators in HEP


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N.Kristofilos (1950, not published)

E.Courant, M.Livingston & H.Snyder (1952)

The Next Break-Through

in Accelerator Technique -

-The Strong Focusing Principle





1959 PS ("Proton Synchrotron"), CERN 26 GeV 1960 AGS ("Alternating Gradient Synchrotron"),

Brookhaven Lab., USA 28 GeV

First Strong Focusing Proton Synchrotrons

AGS

PS




July 1973 PS CERN: Direct evidence of the weak neutral current

Neutrinos are generated with p-beam from PS and bombardthe liquid in the bubble chamber Gargamelle. Such events are called neutral current, because neutral Z0 boson

transfers interaction.

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AGS Brookhaven National Laboratory:

1962, Discovery of the muon-neutrino,

L.Lederman, M.Schwartz and J.Steinberger




The Quark Model

1964 M.Gell-Mann & G.Zweig

Hypothesis of quark structure of adrons

u and d quarks nucleons

s-quark K-mesons (Kaons) discovered even

in 1947

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1967 U-70 (Proton Synchrotron), IHEP, Protvino, USSR 76 GeV U-70

1971 Discovery of "The Serpukhov Effect":

Growth of total cross section of strong interaction with energy in the energy range of 25 – 65 GeV

(K-mesons x nucleons).

Yu.D.Prokoshkin, S.P.Denisov et al.

Yuri Dm.Prokoshki

n

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2008 U-70 Today

U-70

Booster U-1.5 U-70 today:

Energy 70 (76) GeV

Intensity 1.51013 / 10 s

Proton Synchrotron U-1.5

Energy 1.5 GeV

Intensity 81011 p/s

Repetition rate 20 (16.7) Hz

Development

plans:

p

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1972 "Main Ring" (Proton Synchrotron)

Fermilab, USA

200 500 GeV (1976)

CRing = 6.28 km



"High Rise" – Symbol of Fermilab


1976 SPS ("SuperProton Synchrotron")

CERN

400 GeV

SPS

John Adams in PS control room




Three "Elephants" in HEP SPS, Main Ring, U-70



3. Era of Colliding Beams

"… A word was first…"

1956, D.W.Kerst et al., – The First Idea

Fixed target experiment

Colliding beams



3. Era of Colliding Beams (Contnd)

And what is a profit?

1,EE2Es total2

total1

totalCMS

And what is a problem?

Luminosity!

An example:

Fixed target E1 = 100 GeV/u

An equivalent:Colliding beams (E1)kin = (Ekin)2 = 8.8 MeV/u

u/MeV46.19s

,u/MeV938.0E,u/MeV938.0100E total2

total1




What is "Luminosity"?

dt

dNln

fS

NN

L

etargt0

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Fixed target

Colliding beams

N1, N2 – particle number in colliding beams, S –

beam crosssection (cm2), f – particle revolution frequency (s-1),

n0 - target density (cm-3), l – target thickness (cm),

dN/dt - particle flux bombarding the target (s-1).

The experiment (accelerator) characteristics: parameter equal to number of events per sec when interaction cross sectiron is 1 cm2.




Integral luminosity:

L·dt

1 b = 10-24 cm2 1 b-1 = 1024 cm-2

1 pb-1 = 1·1036 cm-2, 1 fb-1 = 1·1039 cm-2.

Typical luminosity range 1025 1034 cm-

2s-1



One day in the beginning

of the 60th…

(Novosibirsk)

…but two ones are much better!

G.Budker and A.Skrinsky

…One head is good…





Pioneers of colliding beams

From the left to the right:G.Kulipanov, S.Popov,A.Skrinsky, G.Tumaykin

electron beam "image"

in synchrotron

radiation (betatron

resonance)

Storage

rings

Synchrotron B2-

S

First e-e- collider VEP-1 (INP, Novosibirsk)

2 x 160 MeV, L = 31027 cm-2s-1



3. Era of Colliding Beams (contnd)

Meanwhile in California…

The only remaining piece of the Princeton-Stanford Electron-Electron Collider is a stainless steel bowl - the vacuum chamber in the machine's collision region.

1st ring

2nd ring

Wolfgang ("Pief")

PanofskyPrinceton-

Stanford

group:

G. K. O'Neill, B.Richter et al.

2 x 500 MeV




1965 Simultaneous Triumph:

HEP Conference in Frascati (Italy)

Both groups reported of results of first experiments

performed at first e-e- colliders.

Test of QED at small distances:

xp ħ

VEP-1: p 2E/c = 2160 MeV/c

x ~ (6.5810-16/2160106)31010 ~ 510-14 cm

A propos, today: LEP2 2E = 2110 GeV, x ~ 110-16 cm




VEPP-2 at INP, Novosibirsk

The First e+e- Collider 2 x 700 MeV, L = 21028 cm-

2s-1 The Beginning of Physics at e+e- colliders

600 700 800 900 1000

2E [MeV]

F2

“ - peak”

40

30

20

10

0

22222

4

2

m)mE4(

mkF

m = 764 0.15

MeV

k = 0.59 0.15

= 93 15 MeV




1974 Discovery of

J-meson(S.Ting et al.)

AGS Brookhaven NationalLaboratory:

Samuel Ting

SPEARSLAC

1974 Discovery of

-meson(B.Richter et al.)

J/, or The Story of One Discovery




J/, or The Story of One Discovery (Contnd)

Stanford Positron-Electron Asymmetric Ring, e+e-, 2 x 3

GeVm(J/) 3.097 GeV




J/, or The Story of One Discovery (Contnd)

And what about The

USSR?

AGS

U-70

SPEAR

VEPP-3If one would

propose!

If one would

know!




The Next Success at SPEAR

e+

e- -

e-

e~

+~

+1975 M.Perl Discovery of -

lepton

Martin Perl Receives The Nobel Prize




The Next Success at SPEAR (Contnd)

e+

e- -

e-

e~

+~

+

From the discovery of -lepton immediately follows an evident conclusion of an associated neutrino existence.

First evidence for this third neutrino type came from the observation of missing energy and momentum in tau decays (analogous to the beta decay leading to the discovery of the e-neutrino).




1974 – 1975

Quark model's progress

?



4. The Battle of Giants continues

1977 Discovery of b-quark

Leon Lederman

1977 Discovery of and ' mesons

Robert Wilson1981 "Run for Lederman"

Success at "Main Ring" - the next achivement

of fixed target experiments




Discovery of b-quark was the next achivement of fixed target

experiments

?




Robert Wilson's

sculpture



5. e+e- Colliders - The Step Forward1979 e+e- collider PETRA s = 14 46 GeV

The first experimental evidence for gluons

_

And how did you manage

it?



5. e+e- Colliders - The Step Forward (Contnd)

1979 e+e- collider PETRA s = 14 46 GeV

3 jet events - the first experimental evidence for gluons

_

e+

e-

hTwo h-jets event

hh

h

e+

e-

h

Three h-jets event

h

h

gh

h

?

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The End of The Lecture I

Thank you for Today!



УСКОРИТЕЛИ ЗАРЯЖЕННЫХ ЧАСТИЦ В ФИЗИКЕ ВЫСОКИХ ЭНЕРГИЙ...

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