Workshop Proposal for the Aspen Center for Physics, Summer 2008 LHC: Beyond the Standard Model Signals in a QCD Environment Patrick Fox, Roni Harnik and Tilman Plehn

By the summer of 2008 the first LHC data will be taken, starting a new era of high energy physics: the LHC experiments will finally open the win- dow to the TeV scale and explain electroweak symmetry breaking. We ex- pect them to conclusively probe new physics solving the hierarchy problem. Moreover, if dark matter is indeed made of weakly interacting particles we will study it at a collider and unify collider physics with cosmology. Many exciting theoretical models, such as supersymmetry, extra dimensions, or new strong dynamics, naturally connect these seemingly separate aspects of high energy physics. As a hadron collider, the LHC is a challenging environment for discov- eries of any kind. For many new–physics signatures the Standard Model backgrounds are not (yet) implemented and understood with adequate ac- curacy. Separating very large backgrounds from complex signals relies on dedicated searches and innovative analysis techniques. All of them require state-of-the-art simulations in advance of the data being analyzed. In par- ticular, QCD effects for both signals and backgrounds must be properly described. It is easily conceivable that already in the early phase of running the LHC will confront us with signals for physics beyond the Standard Model. For example dark–matter related signatures might be extracted from back- grounds largely independent of model assumptions. However, to interpret the new physics signals we need cutting–edge Monte Carlo techniques which demand close communication between model building and modern hadron collider simulations. Such studies have only been started in a limited set of beyond the Standard Model models, mainly within the framework of su- persymmetry. Given the imminent arrival of LHC data it is important to extend this set to include a wider range of new physics models which have not been studied as intensely. As well as extending analyses to less studied models it is also important to search for new models with qualitatively new signatures. We propose a workshop devoted to the discovery of new physics at the LHC; to explore the possibilities for this new physics, how to disentangle it

1 from backgrounds, and to interpret it in a QCD environment. We will bring together experts in model building, QCD background simulation and hadron collider phenomenology. Collaboration between these largely geographically separate groups would be highly beneficial to the field at this exciting time. It is particularly important to foster communication among the large number of young and enthusiastic experts expected to carry high energy physics through the LHC era. The unique informal and intense environment at the Aspen Center for Physics encourages such discussion.

Dates of the Workshop

We propose a four week workshop, to encourage as much overlap between the various participants as possible. The preferred dates for the workshop are any 4 week period between June 29th and August 20th, during this time all the organizers are available. This is because there is a workshop at the KITP with large overlap that many potential participants will be attending that finishes June 6th, the large international conference on supersymmetry SUSY08 will take place in Korea from 16th to 21st June, and there is also a workshop in the KITPC in Beijing, China, starting on September 1st. A final restriction is that semesters are beginning in mid-to-late August.

Participants

We have carried out a preliminary survey among some of the potential par- ticipants and were encouraged by the response from a large and diverse (both geographically and physics-wise) list of people. The following people expressed interest in attending the workshop: Ben Allanach (Cambridge), Charalampos Anastasiou (CERN), Jon Bag- ger (Johns Hopkins), Christain Bauer (LBNL), Genevieve Belanger (LAPP), Thomas Binoth (Edinburgh), Fawzi Boudjema (LAPP), John Campbell (Glasgow), Marcela Carena (FNAL), Zacharia Chacko (Arizona), Hsin-Chia Cheng (UC, Davis), Andy Cohen (BU), Csaba Csaki (Cornell), Athana- sios Dedes (Durham), Stefan Dittmaier (MPP, Munich), Bogdan Dobrescu (FNAL), Manuel Drees (Bonn), Herbi Dreiner (Bonn), Gia Dvali (NYU), Jonathan Feng (UC, Irvine), Gregory Gabadadze (NYU), Thomas Gehrmann (Zurich), Tony Gherghetta (Minnesota), Gian Giudice (CERN), Nigel Glover (IPPP), Christophe Grojean (CERN), Yuval Grossman (Technion), Jean Guillet (LAPP), Howard Haber (UC, Santa Cruz), Kaoru Hagiwara (KEK), Lawrence Hall (Berkeley), Tao Han (Wisconsin), Sven Heinemeyer (CERN),

2 Gudrun Heinrich (Edinburgh), Gudrun Hiller (Dortmund), JoAnne Hewett (SLAC), D R T Jones (Liverpool), Wolfgang Kilian (DESY), Steve King (Southampton), Ryuichiro Kitano (SLAC), Graham Kribs (Oregon), Markus Luty (UC, Davis), Joe Lykken (FNAL), Fabio Maltoni (Louvain), Thomas Mannel (Siegen), Konstantin Matchev (Florida), David Miller (Glasgow), Steve Mrenna (FNAL), Per Osland (Bergen), Gilad Perez (Stonybrook), Frank Petriello (Wisconsin), Riccardo Rattazzi (CERN), Juergen Reuter (Freiberg), Peter Richardson (IPPP), Thomas Rizzo (SLAC), Martin Schmaltz (BU), Yael Shadmi (Technion), Torbjorn Sjostrand (Lund), Peter Skands (FNAL), Michael Spira (PSI), Dominik Stockinger (Edinburgh), Shufang Su (Arizona), Tim Tait (ANL), John Terning (UC, Davis), Scott Thomas (Rutgers), Carlos Wagner (ANL), Lian-Tao Wang (Princeton), James Wells (Michigan), Scott Willenbrock (UIUC), Dieter Zeppenfeld (Karlsruhe), Pe- ter Zerwas (DESY).

Organizers

Patrick Fox ∗ Theoretical Physics Lawrence Berkeley National Laboratory 1 Cyclotron Rd. 50A-5104, Berkeley, CA 94720-8162, USA Phone: (510) 486 4476 Email: [email protected]

Roni Harnik ∗∗ Theoretical Physics Group Mail Stop 81 Stanford Linear Accelerator Center 2575 Sand Hill Road Menlo Park, CA 94025, USA Phone: (415) 350 3668 Email: [email protected]

Tilman Plehn School of Physics James Clerk Maxwell Building

3 Edinburgh, EH9 3JZ, UK Phone: +44 (131) 651 7047 Email: tilman.plehn@cern.ch

∗ Organizer in charge of working to ensure diversity. ∗∗ Contact person for consultation.

Each organizer has read and approved this proposal.

4