An introduction to Nuclear and Particle Physics, Fall 2017, SJTU

Course InformationClass times: 12:55 – 15:40 in room East-Middle-4-506 Monday

Instructor: Name: Lie-Wen Chen (陈列文) Email: lwchen@sjtu.edu.cn

Office: 409B/INPAC(包图东副楼四楼粒子所) Telephone: 54744026

Homepage: inpac.physics.sjtu.edu.cn://lwchen.physics.sjtu.edu.cn

Assistant: Name: Jie Pu (普洁) Email: pujiephy@sjtu.edu.cn

Office: Student Office/INPAC(包图东副楼四楼粒子所) Cell: 187-2183-0340

Consultation Times: 每周星期二中午12:30-13:30

Textbook:Nuclear Physics at low, intermediate and high energies, by Tansheng Cheng and Yushu

Zhong (Peking) (In Chinese) (《低能及中高能原子核物理学》，程檀生 钟毓澍 编著，北京大学出版社， 1997)

Supplementary texts:

1. Das and T. Ferbel, Introduction to Nuclear and Particle Physics (2nd Edition), (World

Scientific, New Jersey, 2003)

2. Particle Physics, by Nai-Sen Zhang (Science Press, 1986) (《粒子物理学》，章乃森 著，科学出版社， 1986)

Assessment:

Homework + Quiz (+ Reading Report) (40%) + Final Examination (60%)

Nuclear Physics

~270

~3000

>4000

Particle Physics

reference: Fermilab

Aims and Objectives

AimsTo provide introductory coverage of modern nuclear and particle physics.

In particular, the basic concepts are emphasized.

Objectives•Understand basic properties of nuclei

•Know basic knowledge about nuclear structures and decays

•Know basic knowledge about nuclear reactions

•Know some hot topics of the present nuclear physics under extreme conditions

•Understand basic properties of hadrons

•Know basic concepts about the quantum chromodynamics (QCD)

•Understand hadron structures in phenomenological models based on QCD

•Know basic concepts about the standard model (SM)

•Know some hot topics of the present high energy collider physics

Spatial Scales

100 1018

Spatial Scales of some objects

冥王星

SI Prefixes List美学生请愿命名"10的27次方" 赫拉成新词头?

2010年03月05日 08:34:33 来源：新华网美国加利福尼亚大学一名学生在互联网上发表请愿书，希望增加国际单位制现有词头，将１０的２７次方命名为

“赫拉”（hella）。 这一请愿已得到两万多人签名支持。那么，赫拉有无机会成为新词头？网络请愿这个学生名叫奥斯汀·森德克，在加州大学攻读物理专业。他认为，现阶段科学发展要求拓宽度量范围，增加国际单

位制现有词头是大势所趋。“对很多物理现象的分析发现超过２７个数量级的自然数量，而这一数字眼下为国际单位制所忽略，”森德克在社

交网站“脸谱”上发表请愿书写道。他说：“给１０的２７次方指定一个词头对各领域的科学家都至关重要。这个数字在很多关键测量中具有重要意义，

譬如太阳能量、星系之间距离和较大样本的原子数量等。”他举例说，太阳释放的能量如果表述为０．３赫拉瓦特比３００尧它（yotta）瓦特更优美。国际度量委员会１９９１年通过尧它和泽它（zetta）为新词头，分别表示１０的２４次方和１０的２１次方。尧它

由此成为国际单位制现有最大词头。多方支持森德克的提名得到越来越多人的支持，已有超过２万名学生、科学家和公众人物在请愿书后签名。他说，赫拉是北加州俚语，意为“非常”、“许多”。如果赫拉被采用，那将载入加州科学研究史册。森德克还与单位咨询委员会负责人、英国雷丁大学化学家伊恩·米尔斯取得联系，希望获得他的支持。单位咨询委员

会是国际度量委员会的建议机构。米尔斯在给森德克的回信中承诺，向单位咨询委员会今年９月召开的大会提交森德克的请愿，并希望赫拉能获接受。

英国《每日电讯报》２日援引他的话报道：“我将在我们下次会上提出这一意见，我敢肯定，它会收到微笑。”机会渺茫不过，米尔斯认为，赫拉眼下几乎没有可能获准成为新词头。他说，随着科学发展，我们需要词头表示更大的数量级，但即便如此，赫拉的机会也很渺茫。在国际单位制中，大

部分现有词头取自拉丁语或希腊语数字，国际度量委员会更愿意延续这一传统。此外，国际度量委员会倾向于词头简单化，譬如，赫拉可以表述为千尧它。他说：“我们２０年前推介的词头仍然未被广泛使用。如果改变不受人关注，那就没有意义，只会让事情变得更加

复杂。”米尔斯说，无论如何，“一名学生提出这样一个问题非常令人鼓舞”。

SI Prefixes List

gr. – 希腊语lat. – 拉丁语it. – 意大利语den. – 丹麦语

SI Prefixes List《国务院关于在我国统一实行法定计量单位的命令》

颁布单位:国务院 颁布时间:1984.02.27 实施时间: 1984.02.27

表5 用于构成十进倍数和分数单位的词头

所表示的因数 | 词头名称 | 词头符号

10的18次方 |艾[可萨] | E

10的15次方 |拍[它] | P

10的12次方 |太[拉] | T

10的 9次方 |吉[咖] | G

10的 6次方 | 兆 | M

10的 3次方 | 千 | k

10的 2次方 | 百 | h

10的 1次方 | 十 | da

10的-1次方 | 分 | d

10的-2次方 | 厘 | c

10的-3次方 | 毫 | m

10的-6次方 | 微 | μ

10的-9次方 |纳[诺] | n

10的-12次方 |皮[可] | p

10的-15次方 |飞[母托] | f

10的-18次方 |阿[托] | a

一九五九年国务院发布《关于统一计量制度的命令》，确定米制为我国的基本计量制度以来，全国推广米制、改革市制、限制英制和废除旧杂制的工作，取得了显著成绩。为贯彻对外实行开放政策，对内搞活经济的方针，适应我国国民经济、文化教育事业的发展，以及推进科学技术进步和扩大国际经济、文化交流的需要，国务院决定在采用先进的国际单位制的基础上，进一步统一我国的计量单位。经一九八四年一月二十日国务院第二十一次常务会议讨论，通过了国家计量局《关于在我国统一实行法定计量单位的请示报告》、《全面推行我国法定计量单位的意见》和《中华人民共和国法定计量单位》。现发布命令如下：

Time Scales

The First Three Minutes, Steven Weinberg

Time Scales

Can we unify all the forces with one equation or one theory ?

Celestial

Gravity

terrestrial

Gravity

Electricity

Magnetism

Weak Force

Strong Force

Q.E.D.

Newton Einstein

Superstrings ?

Standard

Model1970's

1870'sMaxwell

Q.C.D.

Fundamental Interactions in Nature

1. Strong interaction (QCD) scale: 1

- responsible for nuclear binding- alpha decay, nuclear fission and fusion processes

2. Electromagnetic interaction scale: 0.01

- correction to binding energies, N>Z for heavy nuclei - gamma decay of excited states

3. Weak interaction scale: 0.0000001

- nuclear beta decay- mirror symmetry violation

4. Gravitational interaction scale: 10-36

- forget it!

Fundamental interactions in nuclei (2 protons, 1 fm apart)

History 1870’s-19191873 Maxwell's theory of E&M describes the propagation of light waves in a vacuum.

1874 George Stoney develops a theory of the electron and estimates its mass.

1895 Röntgen discovers x rays.

1898 Marie and Pierre Curie separate radioactive elements.

Thompson measures the electron, and puts forth his "plum pudding" model of the atom -

- the atom is a slightly positive sphere with small, raisin-like negative electrons inside.

1900 Planck suggests that radiation is quantized.

1905 Einstein proposes a quantum of light (the photon) which behaves like a particle.

Einstein's other theories explained the equivalence of mass and energy, the particle-wave

duality of photons, the equivalence principle, and special relativity.

1909 Geiger and Marsden, under the supervision of Rutherford, scatter alpha particles off a

gold foil and observe large angles of scattering, suggesting that atoms have a small,

dense, positively charged nucleus.

1911 Rutherford infers the nucleus as the result of the alpha-scattering experiment performed

by Geiger and Marsden.

1913 Bohr constructs a theory of atomic structure based on quantum ideas.

1919 Rutherford finds the first evidence for a proton.

History reference: http://particleadventure.org/particleadventure/other/history/index.html

Nobel Prize

winners in red

History 1920’s

1921 Chadwick and Bieler conclude that some strong force holds the nucleus together.

1923 Compton discovers the quantum (particle) nature of x rays, thus confirming photons as

particles.

1924 de Broglie proposes that matter has wave properties.

1925 Pauli formulates the exclusion principle for electrons in an atom. Bothe and Geiger

demonstrate that energy and mass are conserved in atomic processes.

1926 Schroedinger develops wave mechanics, which describes the behavior of quantum

systems for bosons. Born gives a probability interpretation of quantum mechanics.G.N.

Lewis proposes the name "photon" for a light quantum.

1927 Certain materials had been observed to emit electrons (beta decay). Since both the

atom and the nucleus have discrete energy levels, it is hard to see how electrons produced in

transition could have a continuous spectrum (see 1930 for an answer).

1927 Heisenberg formulates the uncertainty principle.

1928 Dirac combines quantum mechanics and special relativity to describe the electron.

History 1930’s1930 There are just three fundamental particles: protons, electrons, and photons. Born, after

learning of the Dirac equation, said, "Physics as we know it will be over in six months."

1930 Pauli suggests the neutrino to explain the continuous electron spectrum for b-decay.

1931 Dirac realizes that the positively-charged particles required by his equation are new

objects (he calls them "positrons"). This is the first example of antiparticles.

1931 Chadwick discovers the neutron. Nuclear binding and decay become primary problems.

1933 Anderson discovers the positron.

1933-34 Fermi puts forth a theory of beta decay that introduces the weak interaction. This is the

first theory to explicitly use neutrinos and particle flavor changes.

1933-34 Yukawa combines relativity and quantum theory to describe nuclear interactions by an

exchange of new particles (mesons called "pions") between protons and neutrons. From the size

of the nucleus, Yukawa concludes that the mass of the conjectured particles (mesons) is about

200 electron masses. Beginning of the meson theory of nuclear forces.

1937 A particle of 200 electron masses is discovered in cosmic rays. While at first physicists

thought it was Yukawa's pion, it was later discovered to be the muon.

1938 Stuckelberg observes that protons and neutrons do not decay into electrons, neutrinos,

muons, or their antiparticles. The stability of the proton cannot be explained in terms of energy

or charge conservation; he proposes that heavy particles are independently conserved.

History 1940’s

1941 Moller and Pais introduce the term "nucleon" as a generic term for protons and neutrons.

1946-47 Physicists realize that the cosmic ray particle thought to be Yukawa's meson is instead

a "muon," the first particle of the second generation of matter particles to be found. This

discovery was completely unexpected -- Rabi comments "who ordered that?" The term

"lepton" is introduced to describe objects that do not interact too strongly (electrons and muons

are both leptons).

1947 A meson that interact strongly is found in cosmic rays, and is determined to be the pion.

1947 Physicists develop procedures to calculate electromagnetic properties of electrons,

positrons, and photons. Introduction of Feynman diagrams.

1948 The Berkeley synchro-cyclotron produces the first artificial pions.

1949 Fermi and Yang suggest that a pion is a composite structure of a nucleon and an anti-

nucleon. This idea of composite particles is quite radical.

1949 Discovery of K+ via its decay.

Era of “Strange” Particles

History 1950’s1950 The neutral pion (p0)is discovered.

1951 “V”-particles are discovered in cosmic rays. The particles were named the L0 and the K0.

1952 Discovery of particle called delta: there were four similar particles (D++, D+, D0, and D-).

1952 Glaser invents the bubble chamber (looking at beer). The Brookhaven Cosmotron, a 1.3

GeV accelerator, starts operation.

1953 The beginning of a "particle explosion" -- a proliferation of particles.

1953 -57 Scattering of electrons off nuclei reveals a charge density distribution inside protons,

and even neutrons. Description of this electromagnetic structure of protons and neutron

suggests some kind of internal structure to these objects, though they are still regarded as

fundamental particles.

1954 Yang and Mills develop a new class of theories called "gauge theories."Although not

realized at the time, this type of theory now forms the basis of the Standard Model.

1955 Chamberlain and Segre discover the antiproton

1956 Lee and Yang find parity violation (experimental test, Wu et al., 1957)

1957 Schwinger writes a paper proposing unification of weak and electromagnetic interactions.

1957-59 Schwinger, Bludman, and Glashow, in separate papers,suggest that all weak interactions

are mediated by charged heavy bosons, later called W+ and W-. Note: Yukawa first discussed

boson exchange 20 years earlier, but he proposed the pion as the mediator of the weak force.

History 1960’s1961 As the number of known particles keep increasing, a mathematical classification

scheme to organize the particles (the group SU(3)) helps physicists recognize patterns of

particle types.

1962 Experiments verify that there are 2 distinct types of neutrinos (e and m neutrinos).

Also inferred from theoretical considerations (Lederman, Schwartz, Steinberger).

1964 Gell-Mann and Zweig tentatively put forth the idea of quarks.

Glashow and Bjorken coin the term "charm" for the fourth (c) quark.

Observation of CP violation in Kaon decay by Cronin and Fitch

1965 Greenberg, Han, and Nambu introduce the quark property of color charge.

1967 Weinberg and Salam separately propose a theory that unifies electromagnetic and

weak interactions into the electroweak interaction. Their theory requires the existence of a

neutral, weakly interacting boson Z0).

1968-9 Bjorken and Feynman analyze electron scattering data in terms of a model of

constituent particles inside the proton. They use the word “parton” not quark.

By mid-1960’s > 50 “elementary” particles! Periodic table

3 quarks introduced to “explain” the periodic table.

BUT quarks were not considered to be “real” particles.

History 1970’s

1970 Glashow, Iliopoulos, and Maiani (GIM)brecognize the critical importance of a fourth

type of quark in the context of the Standard Model.

1972 t’ Hooft, Veltman construct the quantum theory of gauge fields

1973 First indications of weak interactions with no charge exchange (due to Z0 exchange.)

1973 A quantum field theory of strong interaction is formulated (QCD)

1973 Politzer, Gross, and Wilczek discover that the color theory of the strong interaction has

a special property, now called "asymptotic freedom."

1974 Richter and Ting, leading independent experiments, announce on the same day that

they discovered the same new particle J/Y, bound state of charm anti-charm).

1976 Goldhaber and Pierre find the D0 meson (anti-up and charm quarks).

1976 The tau lepton is discovered by Perl and collaborators at SLAC.

1977 Lederman and collaborators at Fermilab discover the b-quark.

1978 Prescott and Taylor observe Z0 mediated weak interaction in the scattering of polarized

electrons from deuterium which shows a violation of parity conservation, as predicted

by the Standard Model, confirming the theory's prediction.

1979 Evidence for a gluon radiated by the initial quark or antiquark.

History 1980’s-Now

1983 Discovery of the W± and Z0 using the CERN synchrotron using techniques developed

by Rubbia and Van der Meer to collide protons and antiprotons.

1989 Experiments carried out in SLAC and CERN strongly suggest that there are three and

only three generations of fundamental particles.

1995 Discovery of the top quark at Fermilab by the CDF and D0 experiments.

1998 Observation of Neutrino oscillations by SuperK collaboration. (neutrinos have mass!)

2000-1 Observation of CP violation using B-mesons by BABAR, BELLE experiments.

2002 Solar Neutrino problem “solved”.

2012 Discovery of the “Higgs” at LHC by the CMS and ATLAS experiments

Experiments Theory

The Physicist‘s first and second laws: (T.D. Lee)

物理学家第一定律：没有实验物理学家，理论物理学家就要漂浮不定

物理学家第二定律：没有理论物理学家，实验物理学家就要犹豫不决

Why do we need High Energy?

Recall: To see an object the wavelength of light (l) must be

comparable or smaller in size than that of the object.

To view a small object you need a small wavelength.

How SMALL a wavelength do we need ?

Recall: de Broglie relationship:

l=h/ph = Planck’s constant =6.63x10-34 J-s= 4.14x10-24 GeV-s

p = momentum of object

What momentum do we need to “see” a nucleus ?

Assume size of nucleus 1 fm = 10-15 m

p=h/l=(4.14x10-24 GeV-s)/(10-15 m) = 4.14x10-9 GeV-s/m

= 1.2 GeV/c (c=speed of light)

So, could do this with an electron with 1 GeV Energy ! (big battery)

The most convenient energy unit for HEP is electron volts not Joules

Typical nuclear binding energies are MeV (106 eV)

The most convenient mass unit for HEP is MeV/c2 not kg.

mass of electron = 0.51 MeV/c2 = 9.1x10-31 kg

mass of proton = 938 MeV/c2 = 1.67x10-27 kg

The most convenient length unit for HEP is fm not m.

1 fm = 10-15 m

The most convenient system of units for HEP are Natural Units

Planck’s constant ( =h/2p)=1; speed of light c=1; Energy in eV (or MeV)

Boltzmann Constant k=1:

k=1.38 × 10-23 JK-1 => temperature has the same dimension as energy

1 eV = 1.16×104 K, 1 K = k=1.38 × 10-23 J=8.62 ×10-5 eV

Dielectric constant

Natural Units

h

0

2

2 2

1 2 1 2

0

0

22

1/(4 ), then Coulomb Potential becomes

and the fine structure const

( )4

1.ant , 44 fm M and4

V e

Q Q e Q Q eV r

r r

cce e

e

p

p

p

h

h g

Easy to write equations:

Relativistic relationship between energy, momentum and mass:

Becomes:

Converting between systems is “easy”:

In MKS units

Examples:

The cross section (s) for the reaction e+e-m+m- is: sth=A/E2, A=constant

Put this formula back into MKS units: A cross section has units L2:

We have 3 equations: a-2=0, 2a+b-4=2, and 4-a-b=0 => a=2, b=2 and then

Cross sections are often expressed in minibarns, where 1 mb=10-3b=10-27cm2. Using

GeV units, show that

1 GeV-2=0.389 mb

1 2 1 0 1 12 2 2 4 4

2 1 2 2 2

( ) ( )

( )

a b a ba a b a bc M L T M LT

L M L TE M L T

h

2 2 2/A c Es h

2222 )()( mcpcE 222 mpE

1 2 1 0 1 1 1 2 2and and EnergyM L T c M LT M L T h

-2 2 2 2 2 2

30 2 26 2

1GeV =( c) GeV 0.197327 fm 0.0389 fm

0.0389 10 m 0.0389 10 cm 0.389 mb

h

Homework:

1.5,

1.6,