Announcements for Physics 752 (Prof. Agashe)  Spring 2014
(0). For all homeworks, please read carefully the
statements of problems, especially since notes/hints have been given in many
places.
(1). Details of term paper to be written/presented by you are here.
Tentatively, we will have presentations of term paper on May 19 (Monday) and if
needed on May 20 (Tuesday) and the actual term paper will be due Wednesday,
May 21.
(2). The last two HWÕs: 9 and 10 (on Standard Model phenomenology) have
been assigned here
and are due on
Monday, May 19.
Some comments on previous HWÕs:
(i) Note that in HW 4.2,
you are to study only the case of vectorlike
coupling of electron to photon.
(ii) zetazeta scattering in exercise 13.14 from
LP (HW 3.3) means 2 zetas in both
initial and final state, just like etazeta scattering in HW 3.4 (i.e., Fig. 13.2, exercise 13.15
from LP) means zeta and eta in both states).
(iii)
Some comments have been
added to HW 5.2.1 and 5.3.3, but there is no
change in what you are actually supposed to do
here.
(iv) HW 8.5 is somewhat complicated/long, but
several hints are given along the
way.
(3). There will an extra lecture on Friday, May 2 at 11 am.
(4). Solutions to HW 1 through 4 are now posted here.
(5). Plan for lectures starting April 14: we
will use the 3 QFT topics that we studied so far to first construct the standard model and then study its phenomenology
(based on chapter 15
of LP, supplemented by other references that I will give as we go).
The
topic that we finished just before was nonabelian gauge theories:

first, we will consider global symmetries (sec. 13.2
of LP), , including their spontaneous breaking (sec. 13.4.3)

then we will gauge these symmetries and discuss the
classical theory (sec. 14.1 to 14.4 of LP)

finally, quantization of nonabelian
gauge theories will be studied (sec. 14.5 of LP)
The
even earlier topic of Higgs
mechanism is needed for describing weak (nuclear) force
within the SM: the outline here was

first, we will discuss spontaneous breaking of a global symmetry (section 13.4 of LP).

above model will be shown to have massless scalar particle (called NambuGoldstone boson): we will discuss nature of its
Interactions (section 13.5 of LP).

finally, gauge
the above global symmetry section 13.6 of LP) to find that the corresponding
gauge boson acquires mass (and NambuGoldstone boson "goes away") and theory
remains
renormalizable.
Finally,
the 1^{st} QFT topic was renormalizability of
QED, based on chapter 12 of LP,
(6).
Please try to print and fill out the feedback
survey here
and return it to me (without your
name on it) during lecture: this is just to help me improve teaching: thank you
very much in advance for doing this!
(7).
A few of notes have been posted:
(i) The argument form Weinberg's QFT book about why a superposition of the 2 minima for a
discrete symmetry model [sec. 13.4.1 and Fig. 13.1 (b) of LP] is not the ground state is here.
(ii) In the lecture on March 24, I
discussed the relation between the models with explicit gauge boson mass term
vs. spontaneous breaking, involving fermioncoupled to gauge boson in 2
ways (what I called "closing the circle"). This issue is
somewhat subtle and so (detailed) notes are posted here.
(iii) Calculation
of decay of Z boson into fermion and antifermion is here.
(iv) Electronpositron annihilation into muon and antimuon is here.