BSM Journal Club Fall 2009
The particle theory graduate student journal club ("Pheno Club") meets once a week to discuss topics of interest in phenomenology. Topics roughly alternate between review articles and new papers.
Mondays, 1:00pm -- 3:00pm
Newman Lab, Room 311
Contact:
This is now an archived page that is no longer updated.
Return to the current journal club page.
Fall 2009 Schedule
Topics marked (R) are review talks where some previous reading is recommended but not necessary. Otherwise topics are "current papers" and everyone is expected to have read the main paper in advance.
Fall 2009 Abstracts
- Flavor Physics BSM, Itay Nachshon (31 August 2009)
This will be a review and continuation of Gilad Perez's lectures from TASI09. We will focus on using geometric quantities in flavor space to quantify theoretical constraints on the flavor structure of new physics. See: arXiv:0903.2118.
- Metastable SUSY Breaking, Flip Tanedo (7 Septemer 2009)
Until 2006, finding realistic supersymmetry breaking vacua in a SUSY gauge theory was understood to be a special occurrence in finely-engineered models. The Intriligator Seiberg Shih (ISS) solution demonstrated that metastable SUSY breaking vacua, on the other hand, can be simple and generic. We will discuss sections 1-5 and (briefly) 7 of the original ISS paper, hep-th/0602239. The level of the discussion will be at that of Csaba's course last semester, suitable review can be found in hep-ph/0702069.
- Dark Matter: From Theory to Indirect Observation and Back, Bibhushan Shakya (14 September 2009)
Even with a known theory of dark matter at hand (that is, knowing annihilation/decay channels, branching ratios, cross sections etc), deriving indirect observational effects from galactic and extragalactic sources that detectors like PAMELA and FERMI observe is nontrivial since it involves knowing how these products propagate and interact in the medium between source and observer. This talk will review the steps involved in going from the theory to what is actually seen by detectors, as well as in working backwards to use observations to distinguish between models. Reference paper: arXiv:0901.2925 (This paper is long and even I have not read all of it, but looking through it will give you a good idea of what the talk will be like).
- Little Higgs, Josh Berger (21 September 2009).
In this review discussion, I will present the basics necessary to understand Little Higgs models. Beginning with brief motivation based on dimensional deconstruction, I will introduce collective symmetry breaking in general. I will move on to describe the Littlest Higgs model, with discussion its issues and their solutions, as well as its collider phenomenology if there is time. Reference: hep-ph/0512128.
- D-Dbar mixing, David Curtin (28 September 2009).
Evidence for D-Dbar mixing was finally been found in 2007 by the Belle and BABAR collaborations. It is a highly suppressed process in the SM and of great interest for probing BSM physics, but difficult to calculate due to hadronic contributions to the mixing amplitude. This will be a pedagogical review, covering the basic formalism, classification of CP-violating effects, calculation in the SM and experimental results and considerations. References for further reading if desired: Phys.Lett.B592: 1,2004, hep-ph/0310076.
- An instant review of instantons, Yuhsin Tsai (5 October 2009).
The idea of instantons has been widely used in many different aspects of physics. Its unique property that relates the tunneling effect and the vacuum structure of the gauge theory gives interesting applications in model building, such as in QCD, SUSY and cosmology. In this discussion, we will review the connection between the tunneling and instantons. Talk about the n-vacuum and theta-vacuum in gauge theory and give classical examples like the U(1) problem and B/L-number violation. Finally, we want to review the derivation of the NSVZ beta-function in SUSY using this instanton knowledge.
- Slepton Flavor Physics: CP Violation at the TeV Scale, Josh Berger (19 Oct 2009).
If low-scale supersymmetry is realized in nature, then the large number of parameters allows for large new contributions to CP violation that can be studied at the LHC and at the ILC. A particularly clean and accessible venue for studying sflavor is the slepton sector. I will first discuss the formalism for studying slepton flavor. Discussion will then proceed to constraints from SM observables and signatures of slepton CP violation at future colliders. While this topic is not strictly "cutting-edge," it is not a standard topic and my discussion will not be strictly pedagogical, so it will be helpful to have read the references. hep-ph/0111154 (primary reference),
hep-ph/9603431,
hep-ph/9704205.
- Kinky Kinematics? MT2 is just for you, Flip Tanedo (26 Oct 2009).
I will provide an introduction to collider kinematics focusing on the MT2-type variables that extend the notion of transverse mass. For this pre-Halloween will discuss kinks and cusps and other signatures of invisible particles that go bump in the night. We will focus on the presentation by Cheng and Han, arXiv:0810.5178 and the concrete application by Cho, Choi, Kim, and Park, arXiv:0709.0288. Additional reading can be found in the references of the first work. This will be a review talk, so attendees are encouraged but not required to have read the papers beforehand.
- Gauge Invariance of the Fayet-Iliopoulos Term, David Curtin (2 Nov 2009).
I will present the recent result by Seiberg and Komargodski regarding why there are no supersymmetric models whose low-energy limit can be understood in terms of D-term breaking. The proof is based on the gauge invariance of the D-term. We shall focus on the non-supergravity case. Please read the paper ahead of time to get the most out of this discussion. arXiv:0904.1159
- Composite MSSM particles from Dynamical SUSY Breaking without Messengers, Yuhsin Tsai (9 Nov 2009).
An appealing approach to gauge mediation is to have the strong dynamics that breaks SUSY also produce composite MSSM particles. In this kind of single sector DSB model, SUSY is broken from baryon runaways around the confinement scale. This generates composite degrees of freedom with interesting phenomenological applications, such as small Yukawa couplings and suppression of flavor-changing neutral currents. In this talk, we will discuss the pros and cons of the model and what can be done with it. The main material for the talk is the paper hep-ph/9712389.
- Sphericity Kills Sommerfeld (Bounds on Sommerfeld Enhancement of Dark Matter Signals), Bibhushan Shakya (16 Nov 2009).
Sommerfeld enhancement is currently the most likely mechanism to bridge the 3 orders of magnitude separating dark matter annihilation cross sections predicted by WIMP models and that required to explain PAMELA and FERMI observations. We will discuss the constraints on Sommerfeld enhancement from halo shape and relic density considerations, based on 0911.0422.
- Interaction from NP in the neutrino sector, Itay Nachshon (23 Nov 2009).
We will study the effect that NP (at a the weak scale) has on the neutrino sector. In particular how NP interaction in the production or detection processes and neutrino oscillations combine to give a measurable effect in experiments. The paper to read is hep-ph/0105159.
- A new symmetry to protect the Zbb coupling, Yong Hui Qi (30 Nov 2009).
We discuss Zbb physics in this lecture. To set up a new model beyond the SM, after the Electroweak Precision Test(EWPT), and that the flavor changing currents appear only at charged sector at tree level(FCNC), the remaining problem is there is a tension between keeping the ZBB couplings within the tolerable fluctuation around the well measured experimental constrain on bottom quark gauge currents and getting a sufficient larger heavy top quark mass. In other words, how to get a enough heavy top quark mass without giving larger correction to the ZBB vertex. Thus the Zbb vertex has some dependence on the top quark physics, which is important due to "Top priority". One of the approaches to solving the problem is by introducing a new custodial symmetry, which is a combination of custodial symmetry and a Z2 parity symmetry to protects the Zbb couplings. This new custodial symmetry can also be imbedded into the adjoint representation of SO(5) or fundamental representation of G2 as in Pseudo-Goldstone models, in order to explore the dynamics of fundamental theory. A proof will be given, that the introducing of this new custodial symmetry is equivalent to make choices of one of two constraints on the gauge representation of fermions, by imposing one of which, the Zbb couplings will be protected after spontaneously symmetry breaking (SSB). As an illustrated example, I will give a concrete discussion based on left-right symmetric Higgsless model on warped AdS5 gravitational background. A natural result of applying the constraint to the bulk gauge group of the model, is that a unconfined fundamental particle with fractional charge appears simultaneously. This will be a distinguished prediction that can be tested at a near future Larger Hadron Collider(the LHC). Reference: arXiv:hep-ph/0607146.
- Out of This World Supersymmetry Breaking, Stefan Sjors (7 Dec 2009; Special room: Newman 305).
I will discuss the following paper by Randall and Sundrum: hep-th/9810155. I will explain how sequestering solves the supersymmetric flavor problem and, if time allows, also how the gaugino mass problem, the supersymmetric CP problem, and the mu-problem are solved.
2010 Winter 'Pheno Camp': 4D CFTs
This is a week-long, in-depth student workshop focusing on 4D conformal field theories in phenomenology. Meetings will be roughly 10 - 5pm every day with all participants in the same room. The dates have been fixed for 18 January - 22 January 2010, please schedule your winter break plans accordingly. We will study the 4D (super)conformal group and consider applications in supersymmetry, technicolor, AdS/CFT, renormalization group, compositeness, and as a solution to the hierarchy problem.
Primary and preparatory reading
- Homework, read this before: Di Francesco, Mathieu, Senechal, Conformal Field Theory (book), Chapter 4. This is a fifteen page introduction to the conformal group and QFT with conformal symmetry. The rest of this large book focuses on 2D CFTs which we will completely ignore.
- Our primary resource will be the Francesco Sannino's lectures at the 49th Cracow School, arXiv:0911.0931. These cover a broad range of topics related to conformal field theory in contemporary model building including recent results on the phase diagrams of chiral gauge theories. There's a lot of material here, so we can choose our path as we go along and brach off into other references as needed.
Background Reading
This is a list of 'light reading' for those interested in preparing over the holidays. Participants are encouraged to familiarize themselves with the conformal algebra as a common starting point for our camp. It is strongly suggested that everyone reads chapter 4 of Di Francesco (above).
- Di Francesco, Mathieu, Senechal, Conformal Field Theory (book), Chapter 4. This is a fifteen page introduction to the conformal group and QFT with conformal symmetry. The rest of this large book focuses on 2D CFTs which we will completely ignore.
- Coleman, Why dilatation generators do not generate dilatations (Ann. Phys. 67) and Aspects of Symmetry (book) Chapter 3. An excellent discussion of scale invariance and renormalization in quantum field theory. (All of Coleman's papers are classic. We could do an entire journal club semester on Coleman's papers.)
- Ginsparg, Applied CFT (hep-th/9108028).
- Ferrara, Gatto, Grillo, Conformal algebra in space-time and operator product expansion (Springer Tracts Mod. Phys. 67). This is a rather technical discussion of conformal symmetry in field theory and is not necessarily recommended as a first reading.
Conformal Technicolor
- Luty and Okui, Conformal Technicolor (hep-ph/0409274).
- Hill and Simmons, Strong Dynamics and Electroweak Symmetry Breaking (hep-ph/0203079).
- Many other references for walking technicolor. See Sannino lectures.
Superconformal Symmetry
- Buchbinder and Kuzenko, Ideas and Methods of Supersymmetry and Supergravity (book). Section 1.7 for an introduction to the algebra.
- West, Introduction to Supersymmetry and Supergravity (book). See chapter 25.
- Terning, Modern Supersymmetry: Dynamics and Duality (book) or TASI 2002: Non-perturbative SUSY (hep-th/0306119). See the relevant chapter on superconformal symmetry.
- Minwalla, Restrictions Imposed by Superconformal Invariance on Quantum Field Theories (hep-th/9712074).
- Intriligator and Wecht, The Exact Superconformal R-Symmetry Maximizes a. (hep-th/0304128) A-maximization is now an very important tool in superconformal theories. Neat applications include Csaki, Meade, and Terning's discovery of a new phase in SUSY gauge theories (hep-th/0403062) and Simmons-Duffin and Poland's construction of flavor structure from previously 'incalculable' models (arXiv:0910.4585). For a brief review, see Wecht's lectures at SISW02.
- Nieuwenhuizen, Supergravity (Phys. Repts. 68). See section 4 on conformal supergravity.
- Osborn, Superconformal QFT (hep-th/9808041).
AdS/CFT
- Rangamani, Lectures on AdS/CFT (SISW02.)
- Lectures at the ICTP Introductory School on the Gauge/Gravity Correspondence. (notes)
- Zaffaroni, Introduction to the AdS/CFT correspondence (Class. Quantum Grav. 17).
- Nastase, Introduction to AdS/CFT (arXiv:0712.0689).
- McGreevy, Holographic duality with a view toward many-body physics (arXiv:0909.0518). Lectures from the 2009 KITP workshop on "Quantum Criticality and the AdS/CFT Correspondence", i.e. AdS/CFT for condensed matter. The string theorists read this review together and suggested it as a non-technical introduction to the subject. (We will ignore all applications to condensed matter physics.)
- D'Hoker and Fredman, Supersymmetric Gauge Theories and the AdS/CFT Correspondence (hep-th/0201253). Also a very good references for superconformal symmetry independent of AdS/CFT.
Holography with Randall-Sundrum
- Rattazzi and Zaffaroni, Comments on the Holographic Picture of the Randall-Sundrum Model (hep-th/0012248).
- Luty and Sundrum, Supersymmetry Breaking and Composite Extra Dimensions (hep-th/0105137)
- Jarvinen and Sannino, Holographic Conformal Window - A Bottom Up Approach (arXiv:0911.2462)
- Agashe, Contino, Pomarol, The Minimal Composite Higgs Model (hep-ph/0412089).
Other
- Dorigoni and Rychkov, Scale Invariant + Unitarity = conformal invariance and more? (arXiv:0910.1087).
- Antipin, Tuominen, Resizing the Conformal Window: A beta function Ansatz (arxiv:0909.4879)
- Unparticles. Maybe start with Georgi and Terning's papers.
- Holthausen, Lindner, Schmidt, Conformal Left-Right Symmetry and the Hierarchy Problem. (arXiv:0911.0710)
- Hung and Xiong, Renormalization Group Fixed Point with a Fourth Generation. (arXiv:0911.3890, arXiv:0911.3892)
- Schmaltz, Sundrum. Conformal Sequestering Simplified (hep-th/0608051). And references therein.
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)
- Video lectures: Serkan Cabi's collection, Fermilab Academic Lectures, Fermilab VMS, Perimiter Institute Recorded Seminar Archive, CERN Academic Training Lectures, KITP Talks, Newton Institute Programs, IAS SNS recordings.
- Other journal clubs, reading lists: University of Michigan HET Student Journal Club, David E. Kaplan's BSM Reading list, Francesca Borzumati's Collection of Lecture Notes, University of Chicago Theory Reading List, University of Washington Particle Theory Journal Club.
- Blogs often mention recent 'hot research' topics, sometimes with generous portions of personal commentary. Some suggestions: Resonaances (A. Falkowski), A Quantum Diaries Survivor (T. Dorigo), Not Even Wrong (P. Woit).
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 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.