Last Updated
March 8, 2006

Aspen 2005 Summer Workshop

"New Approaches to Electroweak Symmetry Breaking''

June 20 - July 8, 2005


In 2005 the Aspen Center for Physics hosted a three week summer workshop focussing on new approaches to electroweak symmetry breaking.


Stephen Adler, Kaustubh Agashe, Andreas Birkedal, Gustavo Burdman, Giacomo Cacciapaglia, Spencer Chang, Mu-Chun Chen, Hsin-Chia Cheng, Sekhar Chivukula, Roberto Contino, Csaba Csaki, Keith Dienes, Bogdan Dobrescu, Joshua Erlich, Tony Gherghetta, Walter Goldberger, Christophe Grojean, Steven Gubser, Ami Katz, Chris Kolda, Graham Kribs, Ian Low, Guido Marandella, Konstantin Matchev, Hitoshi Murayama, Yasunori Nomura, Takemichi Okui, Maxim Perelstein, Gilad Perez, Eduardo Ponton, Pierre Ramond, Michele Redi, Matthew Schwartz, Marco Serone, Yael Shadmi, Marc Sher, Yuri Shirman, Elizabeth Simmons, Witold Skiba, Shufang Su, Fumihiri Takayama, John Terning, Arkady Vainshtein, Scott Willenbrock.


The aim of this workshop was to gather active young particle theorists working on topics related to various approaches to electroweak symmetry breaking as well as their phenomenological signatures at existing and future colliders. Among the topics discussed at this workshop were:

1) The Standard Model. Review of the Higgs mechanisms and its signatures at the Tevatron and the Large Hadron Collider (LHC) for Higgs discovery (talk given by Shufang Su).

2) Supersymmetry. We heard reviews of the standard SUSY search strategies at the Tevatron and LHC (talks by Chris Kolda and Scott Willenbrock) and the prospects for precision SUSY studies at the International Linear Collider (talk by Hitoshi Murayama). Graham Kribs and Spencer Chang presented extensions of the MSSM in which the Higgs boson properties and discovery signatures are modified. The model presented by Kribs raises the upper bound on the Higgs mass by making it a composite object. The models considered by Chang allow for new Higgs decay channels which weakens the existing experimental lower bounds on the Higgs mass.

3) Little Higgs. We heard a general review by Ian Low on little Higgs models with an emphasis on those which are least constrained by the precision data (models with T-parity). Maxim Perelstein discussed the collider signals of these models and methods of testing their generic predictions. Mu-Chun Chen presented her analysis of the impact of precision electroweak constraints on the parameter space of little Higgs models.

4) Extra dimensions and their role in electroweak symmetry breaking. Kaustubh Agashe presented a model based on a warped extra dimension which is a 5D dual of a composite Higgs model. In the 5D language the Higgs will be the extra dimensional component of the gauge field (A_5). Roberto Contino showed that these models can incorporate gauge coupling unification. Marco Serone presented models with a flat extra dimension where the Higgs can again be identified with A_5. Giacomo Cacciapaglia discussed how to use extra dimensions to break electroweak symmetry without a Higgs (via boundary conditions) and some of the experimental constraints on these models. Andreas Birkedal showed the experimental signatures and the discovery potential of the LHC for the Higgsless models. Bogdan Dobrescu gave a review of signatures of extra dimensions at colliders. Tony Gherghetta presented a partly supersymmetric model based on a warped extra dimensional theory. Ami Katz showed how to find a holographic (extra dimensional) description of QCD. Gilad Perez talked about the flavor physics of extra dimensional theories.

Talks were held from 9:30-12:30 every Tuesday and Thursday morning in an informal setting. All speakers were required to use the blackboard. These talks generated lively discussions.

There were several discussions regarding the LHC Theory Initiative which resulted in a draft proposal, endorsed by 25 of the workshop participants.


Csaba Csaki, Konstatin Matchev. John Terning