Computing decay rates for new physics theories with FeynRules and MadGraph 5_aMC@NLO
Not Available
Alwall, Johan↗
Engineering topics
Alwall, Johan
Publications and source records attributed to Alwall, Johan.
QCD Radiation in the Production of Heavy Colored Particles at the LHC
Abstract Not Provided
Phenomenology-HEP,HEPPH↗
Measuring Sparticles with the Matrix Element
We apply the Matrix Element Method (MEM) to mass determination of squark pair production with direct decay to quarks and LSP at the LHC, showing that simultaneous mass determination of squarks and LSP is possible. We furthermore propose methods for inclusion of QCD radiation effects in the MEM. The goal of the LHC at CERN, scheduled to start this year, is to discover new physics through deviations from the Standard Model (SM) predictions. After discovery of deviations from the SM, the next step will be classification of the new physics. An important first goal in this process will be establishing a mass spectrum of the new particles. One of the most challenging scenarios is pair-production of new particles which decay to invisible massive particles, giving missing energy signals. Many methods have been proposed for mass determination in such scenarios (for a recent list of references, see e.g. [1]). In this proceeding, we report the first steps in applying the Matrix Element Method (MEM) in the context of supersymmetric scenarios giving missing energy signals. After a quick review of the MEM, we will focus on squark pair production, a process where other mass determination techniques have difficulties to simultaneously determine the LSP and squark masses. Finally, we will introduce methods to extend the range of validity of the MEM, by taking into account initial state radiation (ISR) in the method.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Searching for $Z'$ bosons decaying to gluons
The production and decay of a new heavy vector boson, a chromophilic Z{prime} vector boson, is described. The chromophilic Z{prime} couples only to two gluons, but its two-body decays are absent, leading to a dominant decay mode of Z{prime} {yields} q{bar q}g. The unusual nature of the interaction predicts a cross-section which grows with m{sub Z{prime}} for a fixed coupling and an accompanying gluon with a coupling that rises with its energy. We study the t{bar t}g decay mode, proposing distinct reconstruction techniques for the observation of an excess and for the measurement of m{sub Z{prime}}. We estimate the sensitivity of current experimental datasets.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Matched predictions for Higgs production via heavy-quark loops in the standard model and beyond
Not Available
Alwall, Johan↗
New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 - New Physics Working Group
We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high p{sub T} leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 11-29 June, 2007).
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Novel Reconstruction Technique for New Physics Processes With Initial State Radiation
Abstract Not Provided
Phenomenology-HEP,HEPPH↗
Searching for Gluinos at the Tevatron and Beyond
This paper describes how to perform model-independent searches for new pair-produced color octet particles that each subsequently decay into two jets plus missing energy. The details of this analysis are focussed on the Tevatron, however, all of the lessons can be carried over to the LHC. Current searches are not sensitive to all regions of parameter space because they employ CMSSM-motivated cuts. Optimizing the H{sub T} and E{sub T} cuts expands the sensitivity of searches for all kinematically allowed decays.
43 PARTICLE ACCELERATORS↗
New Developments in MadGraph/MadEvent
We here present some recent developments of MadGraph/MadEvent since the latest published version, 4.0. These developments include: Jet matching with Pythia parton showers for both Standard Model and Beyond the Standard Model processes, decay chain functionality, decay width calculation and decay simulation, process generation for the Grid, a package for calculation of quarkonium amplitudes, calculation of Matrix Element weights for experimental events, automatic dipole subtraction for next-to-leading order calculations, and an interface to FeynRules, a package for automatic calculation of Feynman rules and model files from the Lagrangian of any New Physics model.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗