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.

Image from Lepton Photon 2013
via Mihoko Nojiri

See also the 2014 Winter camp to be given this coming January.

Mondays, 1:30pm -- 3:00pm
Physical Sciences Building, Room 470
Contact:

Archives of past semesters (from the Flip Tanedo era):

BSM Club Fall 2009
BSM Club Spring 2010
BSM Club Fall 2010
BSM Club Spring 2011 (geometry)
BSM Club Fall 2011 (colliders)
BSM Club Spring 2012
BSM Club Fall 2012
BSM Club Spring 2013

Schedule for the current semester (modern era):

BSM Club Spring 2014

Fall 2013 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 2013 Abstracts

• The Models of Mini-Split SUSY, Nic Rey-Le Lorier (2 Sept 13).
  If, perhaps inspired by the example of the cosmological constant, we are willing to live with a fine-tuned weak scale, then we can let other principles like grand unification and dark matter guide our model building. In this talk I will present Split SuperSymmetry, a realization of the MSSM that aims to achieve these goals, and then attempt to wade into the more constraining waters of Mini-Split model building.
  Reference: arXiv:1210.0555 [hep-ph].
• talk 2, Gong Show (9 Sept 13).
  
• Learning to Live in an Unnatural World, Jack Collins (16 Sept 13).
  We take problems of naturalness seriously because we anticipate that in doing so, we will learn something new and interesting about the universe which we inhabit. But the LHC has not been answering our calls; perhaps it is time to move on? I will discuss why we should take the electroweak hierarchy problem seriously, and why we should not.
  Topics to be discussed may include: structure formation (from atoms to galaxies), Weinberg's anthropic argument for the cosmological constant, and split SUSY.
  References: Rev. Mod. Phys., 61,1 (1989), arXiv:hep-ph/0409232, arXiv:astro-ph/0401424.
• Asymmetric Dark Matter, Mathieu Cliche (23 Sept 13).
  We review the motivation and main idea of asymmetric dark matter (ADM). We start with a review of electroweak baryogenesis to show what kind of mechanism can generate an asymmetry in the particle-anti particle number. We then present various models of ADM in which the baryon asymmetry is transferred to the dark sector. We end with a discussion of the current experimental constraints on ADM.
  Reference: arXiv:1308.0338 [hep-ph]
• Dimensional Reduction of 4D Dualities, Mario Martone (30 Sept 13).
  THIS TALK HAS BEEN CANCELLED DUE TO CONFLICT WITH THE A.D. WHITE PROFESSOR AT LARGE LECTURE SERIES.
  Reference:
• Turning No-Go into Yes-Go, John Stout (7 Oct 13).
  No-go theorems are interesting in that while they doom potential avenues of research as being hopeless, skirting them often leads the way to much more interesting physics. The most famous of these is the Coleman-Mandula theorem and the subsequent development of supersymmetry. I'd to talk about a couple of the more famous ones, what their implicit assumptions are, and possible ways of turning no-go into yes-go. Reference: Review Topic
• Flavour Mediation for Natural and Split SUSY, Nic Rey-Le Lorier (21 Oct 13).
  Gauge mediation, a popular and elegant way of generating the soft SUSY-breaking terms of the MSSM, can be generalized by adding and higgsing so-called "auxiliary" gauge groups, such as flavour, to the SM. We will present the general results of such "Higgsed Gauge Mediation", and see how they can be applied to obtain both natural and split SUSY spectra.
  Reference: arXiv:1203:1622 [hep-ph], arXiv:1308:3490 [hep-ph]
• Superspace Feynman Rules, Mathieu Cliche (28 Oct 13).
  We review Feynman rules on superspace using the path integral formalism. We then show how to derive the non-renormalization theorem of the superpotential using supergraphs.
  Reference: arXiv:hep-th/0108200, Wess and Bagger
• Dimensional Reduction of 4D Dualities, Mario Martone (4 Nov 13).
  In this talk I am going to describe the general procedure to dimensionally reduce 4D dualities to 3D dualities. We will meet various subtleties along the way, showing why naive dimensional reduction of Seiberg dualities does not give rise to dualities in lower dimensions.
  We will then discuss a way to use this procedure to derive a whole new set of dualities which were previously unknown. This is accomplished "real mass deformation". We will explain in details what it entails and if time allows work out an explicit example.
  Reference: 10.1007/JHEP07(2013)149
• Non-perturbative Renormalization, Michael Savastio (11 Nov 13).
  Quantum field theory contains many features which we may naively expect to be fundamental and readily apparent but which are extremely difficult or impossible to discern even after some 80 years of practice. Perhaps the major cause of this is the failure of standard perturbative methods in certain regions of parameter space. Some couplings which are perturbative at some scale may eventually run to values too large to be suitable for perturbation theory. This behavior obscures some extremely important features such as non-trivial fixed points and makes it difficult to determine whether a theory is renormalizable. As a prominent example, there is mounting evidence that gravitation is asymptotically safe and in fact renormalizable after all. Even if QFT as a fundamental theory of gravitation is not realized in nature, the possibility that it is nonetheless renormalizable may force us to re-examine the reasons why. In this talk I'll discuss all this and introduce the functional renormalization group equation. I'll also use the requirement of the asymptotic safety of gravity to correctly predict the Higgs mass assuming only the top mass, the SM gauge couplings, and a modest constraint on the gravitational part of the Higgs quartic \beta function.
  Reference: arXiv:hep-ph/0005122, arXiv:0708.1317, arXiv:0912.0208
• The Higgs as a Pseudo-Nambu-Goldstone Boson, Riccardo Pavesi (18 Nov 13).
  A review of composite Higgs models.
  Reference: arXiv:1005.4269, arXiv:hep-ph/0512128, TASI 2009: "The Higgs as a Pseudo-Goldstone boson"
• Unveiling Unparticles, Wee Hao Ng (25 Nov 13).
  The Hilbert spaces of most BSM theories is composed of states that are asymptotically described by particles. What if we introduce an unparticle sector that cannot be described by particles, such as an interacting conformal field theory? We will discuss how such a possibility might be realized, as well as the experimental signatures specific to these models.
  Reference: arXiv:hep-ph/0703260, arXiv:0704.2457, arXiv:0904.1962
• Jets Without Jets, Michael Saelim (2 Dec 13).
  We'll look at a method recently developed by Jesse Thaler and company to calculate jet-dependent event-level observables (jet multiplicity, H_T, etc.) without actually clustering jets. I know you're all going "Dude, wicked sick!" To which I would respond, "I know, right?"
  Reference: arXiv:1310.7584
• Axions!, Jack Collins (9 Dec 13).
  We will begin by briefly reviewing some key aspects of the U(1)_A problem and the strong CP problem, and how this was solved by the symmetry Peccei Quinn. We will discuss the subsequent realization of the existence of physical particles associated with this symmetry, the pseudo-goldstone bosons called axions. The second half of the talk will consist of a whirlwind review of a random collection of some interesting aspects of axion cosmology, astrophysics and detection.
  Reference: Kuster, Raffelt and Beltrain, Weinberg Vol. II, arXiv:0807.3125
• Why is the SM the Standard?, Judit Kovacs (16 Dec 13).
  It really bugs me when I read "the Standard Model does not explain the neutrino masses, so we need to go beyond the SM", when actually we could just include three right-handed neutrinos and extend the lepton sector similarly to the quark sector. So I will review just that model, called the nuMSM, where besides the additional Yukawa couplings these new 'sterile' neutrinos can have Majorana masses too, and see what it can explain.
  Reference: arXiv:0901.0011

2014 Workshop: January 2014

This will be a week-long, in-depth student workshop (Winter Camp) taking place in January of 2014. The exact subject, date and location have yet to be determined. Reference: Reference.

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 LASSP document scanner on the 5th floor of Clark 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.

History

The current BSM journal club was started in 2007 by Flip Tanedo, David Curtin, Itay Nachshon, Josh Berger, and Yuhsin Tsai. Previous manifestations include a collider journal club organized by Matt Reece and Patrick Meade. In the distant past Michael Peskin explains that the students had a "Gradshteyn" seminar since it was meant to integrate the collective knowledge of the graduate students.