BSM Journal Club
The particle theory graduate student journal club meets once a week to discuss topics of interest in beyond the Standard Model phenomenology and model building. Topics roughly alternate between review articles and new papers. For spring 2011 our theme is geometry and particle physics. See also the 2011 Winter camp.
Mondays, 1:30pm -- 3:15pm
Physical Sciences Building, Room 470
Contact:
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Spring 2010 Schedule
Topics marked (R) are review talks where some previous reading is recommended but not necessary. Topics marked (G) follow our geometry theme. Otherwise topics are "current papers" and everyone is expected to have read the main paper in advance.
DATES |
SPEAKER |
TOPIC |
REFERENCES |
24 Jan 11 |
Flip Tanedo |
Fiber bundles for pheno bumblers (R,G) |
notes
|
31 Jan 11 |
Bibhushan Shakya |
Pushforward, pullback, and all that stuff
|
Nakahara, Ch. 5 |
7 Feb 11 |
Mario Martone |
A connection between bundles and physics (R,G) |
notes |
14 Feb 11 |
Josh Berger |
Anomaly Wars: Return of the Quanta |
Phys.Rev.D36:581 (87)
Phys.Rev.D37:1020 (88)
Uses of Instantons
Phys.Rev.D30:2212 (84)
notes
|
21 Feb 11 |
David Curtin (R,G) |
Ecce (co)Homo(logy)* *--title modified by Flip |
Nash & Sen Ch 3-6 Nakahara Ch 4,6 notes |
28 Feb 11 |
Mike Saelim |
Non-relativistic EFT of DM direct detection |
1008.1591 |
7 Mar 11 |
Dean Robinson |
A prelude to index theorems (R,G) |
notes |
14 Mar 11 |
Mario Martone |
Forward, backward, and tops |
1101.0034 |
21 Mar 11 |
Itay Nachshon |
(Spring Break) |
Refs |
28 Mar 11 |
Yang Zhang |
Holomorphic bundles, characteristic classes (R,G) |
Notes |
4 April 11 |
Yang Zhang |
Applications of Characteristic classes
|
Notes |
11 April 11 |
Flip Tanedo |
Anomaly Geometry (R,G) |
Notes |
18 April 11 |
David Curtin |
Constraints on SUSY breaking |
Nucl.Phys. B202 253
notes |
25 April 11 |
Josh Berger |
SUSY Breaking in Gauge Theories |
Nucl.Phys. B202 253
notes |
2 May 11 |
Mario Martone |
A geometry crescendo (R,G) |
Nucl.Phys. B243 449
Annals of Phys. 161 423 |
9 May 11 |
n/a |
Pheno 2011 |
n/a |
Images by
R. Dijkgraaf, from
here.
Suggested/requested theme topics
This semester our journal club will have a theme, "geometry and particle physics." Speakers are free to follow this theme or not according to their own inclinations. The following is a list of proposed topics for themed talks:
- Fiber bundle construction of gauge theory
- Topological solitons
- Characteristic classes
- Anomalies
- Index theotems
- Chern-Simons Theory
Spring 2010 Abstracts
- Fiber bundles for pheno bumblers, Flip Tanedo (24 Jan).
We shall kick off this semester's geometry-themed journal club with a discussion of gauge theory in the language of fiber bundles. We will aim to sketch a broad picture of the applications of fiber bundles to physics. There will be time for a discussion for our plans for future geometry journal club talks. Reference: the usual suspects.
- Pushforward, pullback, and all that stuff
("Push it forward"), Bibhushan Shakya (31 Jan).
This will be a quick (~20 min) intro to stuff that will (hopefully) be useful for our geometry-themed journal club talks this semester (in particular Mario's talk next week). The talk will be based on Chapter 5 of Nakahara, but you don't need to have read anything. I didn't think it was a good idea to talk about two completely unrelated things, so I will not be talking about dark matter. (apologies for forgetting to send this announcement out earlier, and thanks to Mike for a post on my facebook wall that triggered this email :) Reference: Nakahara, ch. 5.
- A connection between bundles and physics, Mario Martone (7 Feb).
In about 90 minutes we will try the impossible task (not for Super-Mario, though!) to cover everything you might want to know about connections on fiber bundles. Most of the talk will be dedicated to principal bundles: we will introduce the idea of connection one-form (gauge fields), its curvature two-form (field strengths), the notion of parallel transport and holonomy group, with the purpose of enlightening the meaning of gauge fixing. We'll then move to the study of similar notions on Associated Bundles where matter fields "live". Reference: notes.
- Anomaly Wars: Return of the Quanta, Josh Berger (14 Feb).
We give a review of anomalous B+L violation in the Standard Model. We discuss both thermal and quantum processes that violate B+L. Such transitions are inherently non-perturbative: they involve extended field configurations with non-trivial global topology. We give an overview the two main tools we have for studying these transitions, sphalerons and instatons, and present results obtained using these methods in both a simplified toy model and in an SU(2) gauge theory. We will also discuss the implications of these results for the Standard Model.Reference: Phys.Rev.D36:581 (87),
Phys.Rev.D37:1020 (88),
Uses of Instantons,
Phys.Rev.D30:2212 (84).
- Ecce (co)Homo(logy), David Curtin (21 Feb).
I will present a pedagogical introduction to the concepts of Homology and Cohomology, following mostly Nash & Sen Chapters 3-6 (seems more readable than Nakahara). This will form the basis for many of the future talks and has wide applications, including the Singing Ayatollah Theorem and Seiberg-Witten Theory. I plan to have notes online by Monday morning. Reference: Nash & Sen Ch 3-6, Nakahara Ch 4, 6.
- Non-relativistic EFT of DM direct detection, Mike Saelim (28 Feb).
We will study a non-relativistic effective theory of dark matter-nucleus elastic scattering that can be constrained by observations from direct detection experiments. This static effective potential parameterizes our ignorance and provides a formalism on which different experimental results can be compared. Bounds on the effective theory parameters then constrain parameters in possible UV completions. Constraints from current experimental results will also be discussed.Reference: 1008.1591.
- A prelude to index theorems, Dean Robinson (7 Mar).
This talk will introduce the machinery necessary to understand the 'index' part of the index theorems. To this end, we'll explore: associated fibre bundles and spin bundles; elliptic and Fredholm operators; elliptic complexes; and (twisted) spin complexes. Armed with these concepts, we'll be able to introduce the index of an elliptic (or spin) complex. As a specific example, we'll construct a spin complex and index involving the Dirac operator in an even-dimensional Euclidean base manifold. Reference: Nakahara.
- Forward, backward, and tops, Mario Martone (14 Mar).
In my debut in a truly phenomenological talk, I will discuss the recent result by the CDF collaboration which shows a 3 sigma deviation from the SM prediction for the top Forward/Backward asymmetry. I will start with a brief explanation of the Forward/Backward asymmetry in general and how this can arise from a Parity-preserving theory like QCD. I will then explain to the extent I understand (which is pretty limited given there is no differential geometry involved) some details of the CDF result. I will then end my talk by outlining what kind of new physics could accommodate the surprisingly large Forward/Backward top asymmetry measured. Reference: 1101.0034.
- Talk 9, Itay Nachshon (21 Mar).
Abstract. Reference: Refs.
- Holomorphic bundles and an introduction to Characteristic classes, Yang Zhang (28 Mar).
For BSM Journal Club. It is a part of the geometry theme for this semester. I will briefly review the concept of the connection and the curvature form. Then I would introduce the holomophic bundles. As an example, Hermitian geometry would be covered quickly. You would find that it is similar to our old friend, Riemann geometry, but the calculation is much simpler. Finally, I will give the beginning introduction to Chern classes, in terms of the curvature form. Reference: Notes.
- Talk 11, Yang Zhang (4 Apr).
I hope that we will finally achieve the following goals of this semester's BSM geometric theme, Curvature of a fibre bundle -> Characteristic classes -> Measure the non-triviality of a fibre bundle quantitatively -> Understand the soliton-like objects and curvature coupling in physics. Tomorrow's schedule would be,
- 1. Chern Classes (review), in informal language
- 2. Monopole, in terms of first Chern classes
- 3. Instanton, in terms of second Chern classes
- 4. D-Brane with the Chern-Simons-like coupling, in terms of Chern characters
- 5. Gravity Anomaly in higher dimensions, (if time)
- 6. Pontryagin classes and Euler classes, (if time)
I am keeping updating the note and you can read the latest version on line. Reference: Notes
- Anomaly Geometry, Flip Tanedo (11 Apr).
We will highlight interesting geometric observations about the consistent non-Abelian anomaly in relation to several of the ideas we've developed this semester. We will use the Wess-Zumino consistency condition as a launching point to discuss BRST cohomology, the curious fermionic character of Fadeev-Popov ghosts, and the Stora-Zumino descent equations. The first part of the talk will be accessible to those with only a QFT background, and the rest of the talk will be mostly words and impassioned gesticulation. Reference: Refs.
- Constraints on SUSY breaking, David Curtin (18 Apr).
I will try and review Witten's classic paper where he derives the Witten Index, demonstrating that dynamical supersymmetry breaking does not occur in certain interesting classes of theories. I just realized today that the paper is 60 pages long (!!), so I'll try to get through as much as I can. I might concentrate on a particular sub-result for our interest. Reference: Nucl.Phys. B202 253.
- SUSY Breaking in Gauge Theories, Josh Berger (25 Apr).
With the Witten index constraint on SUSY breaking having been introduced in last week's Journal club, we proceed to explicitly determine the constraints on the Witten index in several important classes of gauge theories. We begin by going over the calculations necessary to understand Abelian gauge theory case in more depth, as this will be our template for the other calculations that we will do. In particular, we will generalize the method applied to Abelian gauge theories to discuss a large class of non-Abelian theories, briefly touching on some subtleties that can arise with non-standard gauge groups. Finally, we will discuss possible inclusions of matter (chiral) superfields and their effects on the analysis to the extent that they are understood. The discussion will be based on sections 6, 8, and 9 in Witten's paper. Reference: Nucl.\ Phys.\ {\bf B202}, 253 (1982); Weinberg, S.~``The quantum theory of fields. Vol. 3: Supersymmetry.''.
- A geometry crescendo, Mario Martone (2 May).
In the last talk of this semester extremely successful Geometry Journal Club, I will try to wrap up everything we learned since winter camp by going carefully through the topology underpinning the chiral and gauge anomalies. After a quick refresh of the crucial aspects of non-trivial bundles, index theorem and characteristic classes, I will turn into a brief explanation of Chern-Simons topological forms and a clarification on the relation between index theorem and chiral anomaly. This will provide a good warm up to make an attempt to tackle the main part of the talk which involves the topological meaning of the gauge anomaly (read clarification/formalization of what Flip told us few weeks ago). If time allows (both for me to learn it and for me to explain it) I will elaborate on gravitational anomalies as well. Reference: Nucl.Phys. B243 449,
Annals of Phys. 161 423.
2011 Winter Workshop: 17-21 January 2011
This will be a week-long, in-depth student workshop (Winter Camp) focusing on monopoles, from 17-21 January 2011. Meetings will be roughly 10 - 5pm every day with all participants in the same room. Each day will have a convener and a closing summary talk with ample time for discussion. The primary resource will be Preskill's 1984 review.
We hope that this will be an effective launching point for next semester's journal club, which will be loosely themed around extended field configurations and geometry.
Resources
Unsure about places to start looking for talk ideas? Here are a few suggestions, geared towards the pedagogical side.
- Collections of reviews and lectures: The Net Advance of Physics, Ulrich Theis' page, or The String Wiki.
- It may also be worth looking through journals that specialize in review articles: RMP, Physics Reports, Annual Reviews, Reports on Progress in Physics, Proceedings of Science, Living Reviews.
- You can also use tools like SPIRES and arXiv Structure to find papers and reviews. For example, you can search for proceedings from summer schools (TASI, Les Houches, SLAC, Cargese, Cracow)
Scanning: it is often helpful to share your notes with the journal club, especially for review talks. Hand written notes may be scanned easily using the document scanner in Clark 614 or Mann library (photocopiers with free scanning option). These have automatic document feeders and can e-mail you a pdf of your notes.
Guidelines
- Announce your topic two weeks in advance, include a link to the relevant paper(s).
- You should give one pedagogical talk and one 'new paper' talk over the course of the semester.
- All members are required to have read 'new papers' that are being presented. Pedagogical talks should be accessible without pre-reading. Review and 'new paper' talks should alternate to give students time to read the new paper.
- Use discretion when presenting a new paper; if it is based on a topic that is unfamiliar to our group, it would be better to coordinate a pedagogical talk before presenting the paper.
- Speakers should focus on leading a discussion rather than giving a 1.5 hour lecture; students are expected to participate actively. Chalkboard talks are strongly preferred.
- Because of the composition of pheno students we have, we are in a unique position to take advantage of this kind of activity. This will only work if we all make this a priority.