University of Maryland Department of Physics, College Park, MD Physics 441,Topics in Particle and Nuclear Physics, Fall 2017

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1 University f Maryland Department f Physics, Cllege Park, MD Physics 441,Tpics in Particle and Nuclear Physics, Fall 2017 Instructr: Prf. Thmas Chen (I prefer t be addressed as Tm) Office: 3158 Physical Science Cmplex Phne: chen@physics.umd.edu Curse Infrmatin and Assignments Prblem sets and exam dates will be made available n the curses Canvas page. Time and Place: T-Th 2:00-3: Atlantic Building

2 Office Hurs Official Office hurs are frm 3:15 Tuesday. Hwever, I am als generally available in my ffice and happy t see students; just drp by--r, better yet, send me a and then drp by. Curse Descriptin The curse is intended as an intrductin t varius aspects f particle and nuclear physics with an emphasis n the rle f symmetry. There are many ways such a curse culd be taught ranging frm purely qualitative descriptins f phenmena discussed in a histrical manner t frmal treatments in terms f quantum field thery. Alternatively, ne can emphasize experimental methds and results. Similarly, a curse can be a survey cvering a wide swath f material superficially r ne that fcuses deeply n a few tpics. The basic philsphy underlying the class as currently planned is t intrduce many f the fundamental ideas in nuclear and particle physics using relatively sphisticated mathematical tls---but t d s in as a simplified a cntext t explain the underlying ideas. Thus, fr example the Higgs mechanism culd be discussed in terms f an Abelian Higgs mdel. The emphasis will be largely, but nt entirely theretical in rientatin. Hwever, the precise apprach will be kept smewhat flexible and will depend in large part n students backgrunds and interest. The gal is fr students t develp an understanding f many the underlying issues in a relatively sphisticated way. Tentative Curse utline: Intrductin t nuclear physics a smewhat histrical treatment The discvery f radiactivity α, β and γ radiatin/distinctin f strng, weak and electrmagnetic interactins Expnential decay; half-life Rutherfrd and the nucleus The predictin f the neutrin by Pauli Cnstituents f the nucleus/the discvery f the neutrn Basic ideas f nuclear level and reactins The semi-empirical mass frmula; shrt range nature f nuclear frces Yukawa s idea f the mesn Electrn scattering, frm factrs and nuclear sizes. Mdeling the nucleus Current prblems in nuclear physics Mathematical Tls Relativity and fur vectrs The Klein-Grdn and Dirac Equatins; antiparticles Quantum Field thery and Feynman Diagrams QED The Yukawa ptential Fermi Thery f weak interactins Renrmalizatin and renrmalizability Gauge theries; nnabelian gauge theries Symmetry & Symmetry Breaking Symmetry in Quantum Mechanics and field thery

3 Cntinuus and Discrete Symmetries; Parity, time reversal Discvery f parity vilatin θ τ puzzle Lee-Yang suggestin Wu experiment Discvery f time reversal vilatin Isspin Selectin Rules; the Wigner-Eckert therem (baby versin); applicatins t hadrnic and nuclear physics Spntaneus symmetry breaking, Gldstne s therem Chiral symmetry, its breaking; pins Twards the standard mdel f particle physics Gauge Symmetry The quark mdel Need fr clr Assympttic freedm and cnfinement The Higgs Mechanism and Electr-weak unificatin Beynd the Standard Mdel/pen prblems Reading There is n textbk fr the curse. Lecture ntes will be made available n Canvas/Elms. Last year s mstly hand written ntes will be psted at the beginning f the year and will be updated and imprved as the semester ges n. In additin, mre prfessinal typed sets f ntes may be psted as the class ges n. Hwever, the fllwing bks may be useful t students as references: Intrductin t Nuclear and Particle Physics, A. Das and T. Ferbel, ISBN-13: (This bk is a survey written at the undergrad level and emphasizes experimental as well as theretical physics and cvers bth nuclear and particle physics) Intrductin t Elementary Particles, D. Griffiths, ISBN-13: (This bk is very well written, it is at the undergrad level and cvers particle physics.) Fundatins f Nuclear and Particle Physics, T. W. Dnnelly, J. A. Frmaggi, B. R. Hlstein,. R. G. Milner and B. Surrw ISBN-13: (This bk is at a smewhat mre advanced level. It emphasizes nuclear physics.) These bks are all available n Amazn.cm ; they will als be place n reserve in the engineering library.

4 Assignments and Grading Plicies Prblem sets: It is nt pssible t learn the material withut wrking thrugh prblems. Prblem sets will be assigned typically every ther week but ccasinally they may be every week. As the assignments will usually be bi-weekly, they may be lnger than a typical prblems set. Yu are permitted and strngly encuraged t wrk with classmates n prblem sets. Hwever, simply cpying a classmate s assignment is nt permitted. Only a subset f the prblems will be graded; slutins will be prvided n the curse web site. Exams. It is currently planned that there will be ne midterm take-hme exam and a take-hme final. Because the exams are take-hme, it is imperative that all f yu live up t the highest standards f intellectual integrity. In this regard, it is wrth nting that science depends n the intellectual integrity f thse engaged in it. Science depends n trusting that ther scientists are nt cking the data. By giving take-hme exams, I am depending n yu t live up t the ethical nrms f the field. Paper. Students will be required t write a paper abut sme aspect f nuclear r particle physics. The paper shuld be pages in length and deal with either a tpic cvered in the class by explring it in mre detail r a tpic in cntemprary nuclear r particle physics that was nt cvered in the class. The paper shuld be written with an apprpriate level f sphisticatin. The paper will be due the last day f class Grading plicies Grades will NOT in general be given accrding t the scheme in which numerical scres greater than 90 crrespnds t an A, between 80 and 90 a B etc. The reasn fr this is that assignments are f varying difficulty. Mrever, it is smetimes nt clear even t the writer f an exam just hw hard it is. Similarly the class will nt be graded accrding t a rigid curve in which a predetermined fractin f students are given A s, B s etc. Rigid curves can lead t inequitable grade assignments. Instead, every attempt will be made t assign grades in a fair manner taking int accunt the actual difficulty f the exams. The apprximate weight f the varius assignments is tentatively: hw 15%, paper 20%,

5 midterm 30%, final 35%.