PHYSICS 362L - Rory Coker
Prof. Rory Coker
Office: PMA 8.312
Phone: (512) 471-5194 (not recommended)
Fax: (512) 471-9637 (not recommended)
Email: rory coker's civilian mail, coker's physics department mail

Office Hours:  Usual, Thur, 2 - 3 PM in PMA 8.312; also Tue, 3 to 4 PM, on days when there is a Pizza Seminar.

[C2]  [KC] [T] [T2]

The Fall 2025 unique number is 61915; the class meets from 12 to 1 PM, MWF in PMA 6.112 The TA is Ainesh Sanyal, e-mail as236935@my.utexas.edu. Office hours, Thursdays 10 am to 11 am in PMA 9.316.

Text: SUBATOMIC PHYSICS, 3rd Edition, by Henley and Garcia (World Scientific, 2007, 2010). Errata for Ch. 6, and errata for Ch. 11.  [A free pdf version of the text can be found by searching "pdf version of subatomic physics by henley and garcia".]  And here is an introduction to the theory of scattering. An even briefer introduction. Highly recommended as a supplementary text: PARTICLES AND NUCLEI, 7th edition, by Povh, Rith, Scholz, Zetsche and Rodejohann (Springer, 2015). The only reason I don't use this as the primary text is that it has no homework problems. A nice introduction to relativistic quantum field theory, which is NOT used in this course, is Quantum Field Theory as Simply as Possible, by A. Zee (Princeton University Press, 2023).

  A short syllabus is posted on the Canvas page for this course; the TA may at his discretion select Canvas to handle homework submission and grading. Check here directly for a version of the syllabus.

Basis of course letter grade: Homework 85%, daily pop quizzes 15%.

From Richard Feynman's Nobel lecture: "I ask your indulgence in another manner. I shall include details of anecdotes which are of no value either scientifically, nor for understanding the development of ideas. They are included only to make the lecture more entertaining."
Other books on course topics:
  •  Particle Physics in the LHC Era, by G. Barr, R. Devenish, R. Walczak and T. Weidberg, Oxford, 2016.
  • Modern Particle Physics, by M. Thomson, Cambridge, 2013.
  •  Particle Physics, by D. Carlsmith, Pearson, 2013.
  •  Nuclear Physics in a Nutshell, by C. A. Bertulani, Princeton, 2007.
  • Basic Ideas and Concepts in Nuclear Physics, by K. Heyde, 3rd Ed., IOP London, 2004.
  •  An Introduction to Nuclear Physics, by W. N. Cottingham and D. A. Greenwood, 2nd Ed., Cambridge, 2001.
  •  Introductory Nuclear Physics, by P. E. Hodgson, E. Gadioli and E. Gadioli Erba, Oxford, 1997.
  • A Prelude to Quantum Field Theory, by J. Donoghue and L. Sorbo, Princeton, 2022).
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    People doing Subatomic research here at UT Austin!
    First assignment: Read the text chapters on accelerators and detectors. Class lectures will begin with Ch. 5. RUNNING TABLE OF HOMEWORK DUE DATES AND TIMES: HW 1, Highest grade: 100% Lowest: 68.3% Average: 91.8%. HW 2, Highest: 100%, Lowest: 53.3 %, Average: 86.5%. HW 3, due Oct. 27.
    [The in-class quizzes are attendance checks, but if you miss the question take that as a self-diagnosis of not keeping up in the course!]
    Answers to in-class quizzes:  (1) Only 5 students in the class answered this question correctly, a really, really bad sign! The general equation for a free particle is E2 = (pc)2 + (mc2)2. Also E = K + mc2 where K is the kinetic energy. The correct answer, of course, is that the infamous equation E = mc2 applies to a free particle at rest. The corresponding result for a photon is K = pc. All the other answer choices are total and absolute nonsense.  (2) The decay involves the weak interaction, with the only boson present being the W- weak boson. The strange valence quark in the Σ+ changes to an up quark by emitting the weak boson, which then creates a pair consisting of a down and an anti-up quark.  (3) The range of the Coulomb force is infinite, so the total cross section for Coulomb scattering (Rutherford scattering) is infinite.  In fact, the equation for dσ/dΩ for Coulomb scattering is singular at θ = 0. (4) If an isospin multiplet has 7 members, there are 7 values of T3 so 2T + 1 = 7 and T = 3.  (5) E is a polar vector (proportional to the unit vector in the direction of r) and B is an axial vector (as seen from the Biot-Savart law), so the cross product of E and B, namely S,  is a polar vector, and changes sign under the application of the parity operator.  (6) Photons emitted by a fundamental pointlike particle (leptons or quarks) have to be virtual.  (7) The decay of a meson D+s to a positron, neutrino, and φ or f0 meson is semi-leptonic. That is, the decay involves hadrons (mesons in this case) but leptons are emitted during the decay process.  (8) The bosons of the strong force consist of eight gluons carrying colors and anticolors.  (9) The fact that the half-radius of all nuclei can be expressed as a constant times the cube root of the number of nucleons means that the volume is directly proportional to the nucleon number, and therefore that all nuclei have the same density.  (10) Probability is not conserved in nuclear reactions because elastic scattering is only one of many different possible outcomes of the process; the potential thus needs an imaginary term (absorption). (11) A reaction such as 90Zr(d,p)91Zr proceeds as a direct "stripping reaction," like almost all nuclear reactions, with the loosely bound neutron ripped away and captured in a nuclear bound state.  (12) ALL nonstationary states in quantum physics have transition probabilities per unit time that are time independent.  If a nucleus with a half life of 1 day has not decayed yet in any amount of time, no matter how long, the probability it will decay in the next day is 50 percent.

    Course notes: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10.  Notes for the last few weeks of the course are entirely on the web pages projected during the class lectures.

    CLASS SLIDES FOR 362L: Accelerators &relativity, Diagrams, cross sections, Running coupling constants, Particles, Observing, Symmetry, Isospin, PCT, EM radiation, Weak 1, Gauge Symmetry, Electroweak1, Strong1, Supersymmetry? Quarkonium, Valence Quarks, Fermi Gas, IMP, Optical Model, Heavy ions, Direct Reactions, Mass Formula, Nuclear Vibrations, Nuclear Rotations, The Little Bang, Unstable Nuclei, Radiation, Power, Fusion, Stars, Evolution, Late Stages, Neutron Stars, Nucleosynthesis, Pioneers, Cosmology, The Big Flash! Dark Matter, More, Matter Origins, Dark Energy, Inflation, When Chiral Symmetry Breaks, Strings, Black Hole History, Black Hole Primer, Unruh radiation, Quantum Gravity? Loop Quantum Gravity, CDT-CS, Nuclear Chemistry, Frontiers? [The remaining two links were not used in this class.] Unused 1, Unused 2

    This class sometimes is allowed to use the  Lectures Online recording system, although the current class is not in a room where it is available. This system records the audio and video material presented in class for you to review after class. Links for the recordings will appear in the Lectures Online tab on the Canvas page for this class. You will find this tab along the left side navigation in Canvas. To review a recording, simply click on the Lectures Online navigation tab and follow the instructions presented to you on the page. Where no recent class has a full recording, this happens when the battery-powered classroom microphone has not been put back on charge by previous (mindless) users, and is completely dead.  The recorded lectures are not videos of the lecture. They have only the audio track, and  views of the specific document camera and computer images projected on screen during class. You can learn more about how to use the Lectures Online system at this link. You can find additional information about Lectures Online at this link.


    Here is a way to get extra credit!

    CLASS SLIDES FOR 302L:  Relativity 1, Relativity 2, Twins! Length Contraction! Binding Energy, Einstein's Theory of Gravity, Quantum 1, Quantum 2, Atoms, Spin and Pauli Principle, Molecules and Solids, X rays and Lasers, Nuclear1, Nuclear2, Radiation, Fission and Fusion, The Sun, Particles! The Proton, Early Universe, THE DARK!


    Einstein

    No fairer destiny could be allotted to any physical theory, than that it should of itself point out the way to the introduction of a more comprehensive theory, in which it lives on as a limiting case. [From his 1920 book summarizing the Special and General Theories of Relativity]

    In Fall 2025, watch for the Pizza Seminar! ♣



    Coker's Homepage     ♥


    Bose

    Fermi

    Before I came to the conference, I was confused about this subject. Having listened to your lecture, I am still confused. But on a higher level.  [Fermi to a conference speaker.]

    Dirac

    The steady progress of physics requires for its theoretical formulation a mathematics which get continually more advanced. This is only natural and to be expected. What however was not expected by the scientific workers of the last century was the particular form that the line of advancement of mathematics would take, namely it was expected that mathematics would get more and more complicated, but would rest on a permanent basis of axioms and definitions, while actually the modern physical developments have required a mathematics that continually shifts its foundation and gets more abstract. Non-euclidean geometry and noncommutative algebra, which were at one time were considered to be purely fictions of the mind and pastimes of logical thinkers, have now been found to be very necessary for the description of general facts of the physical world. It seems likely that this process of increasing abstraction will continue in the future and that advance in physics is to be associated with continual modification and generalisation of the axioms at the base of mathematics rather than with a logical development of any one mathematical scheme on a fixed foundation. [Paper on Magnetic Monopoles (1931)]

    Feynman

    Trying to understand the way nature works involves a most terrible test of human reasoning ability. It involves subtle trickery, beautiful tightropes of logic on which one has to walk in order not to make a mistake in predicting what will happen. The quantum mechanical and relativity ideas are examples of this.

    Gell-Mann

    In our work, we are always between Scylla and Charybdis; we may fail to abstract enough, and miss important physics, or we may abstract too much and end up with fictitious objects in our models turning into real monsters that devour us.

    Weinberg

    I do not think it is possible really to understand the successes of science without understanding how hard it is [to do science]— how easy it is to be led astray, how difficult it is to know at any time what is the next thing to be done.
    Salam

    From time immemorial, man has desired to comprehend the complexity of nature in terms of as few elementary concepts as possible.

    Witten

    In Newton's day the problem was to write something which was correct --- he never had the problem of writing nonsense, but by the twentieth century we have a rich conceptual framework with relativity and quantum mechanics and so on. In this framework it's difficult to do things which are even internally coherent, much less correct. Actually, that's fortunate in the sense that it's one of the main tools we have in trying to make progress in physics. Physics has progressed to a domain where experiment is a little difficult... Nevertheless, the fact that we have a rich logical structure which constrains us a lot in terms of what is consistent, is one of the main reasons we are still able to make theoretical advances.




    Two Pb nuclei collide at 160 GeV per nucleon.
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