New Physics:

The Standard Model (SM) has shown consistent agreement with experiment, yet the cause of Electroweak Symmetry Breaking (EWSB), necessary to give mass to the W and Z bosons, remains experimentally unconfirmed. While the Higgs mechanism tends to be the most popular theoretical explanation for EWSB, the mass of the Higgs suffers from quadratic divergences of its radiative corrections. In light of this, other models outside of the Standard Model framework have been developed. The Standard Model also contains 21 arbitrary parameters and is unable to explain the number of quark/lepton families, dark matter, the matter-antimatter asymmetry of the Universe, or gravity, suggesting that there may be some other more fundamental processes in nature which we have yet to understand. Many theories beyond the Standard Model (BSM) attempt to account for these deficiencies.

Dilepton Final States - Exotics Group

Beyond the Standard Model processes might exist at an energy scale higher than we are able to probe at the LHC. Without directly knowing the intermediate process, one can write an effective Lagrangian describing the new interaction:

The interaction appears experimentally as a deviation from the SM dilepton mass spectrum, which originates from Drell-Yan (DY) production. An increase of dilepton events in the long tail of the DY mass spectrum may indicate new physics such as quark/lepton compositeness or Large Extra Dimensions.

TeV Scale Gravity

One way to approach the hierarchy problem (the enormous gap between the fundamental scales of gravity (M_planck) and the other fundamental interactions (~1 TeV) is postulate that, in fact, there is but one fundamental scale: the electroweak scale around 100 - 1000 GeV. This would imply that gravitational interactions become strong at this same scale. In other words, M_planck is really only about 1 TeV. Such a scenario can be accomplished by assuming: (1) There are "large", compact submillimeter dimensions beyond the three with which we are familiar; (2) Only the graviton propagates in the extra dimensions (the "bulk") -- the Standard Model fields are localized on a 3-d "brane." In effect, at length scales larger than the extra dimensions gravity is "weak" (effective M_planck large) because of its "dilution" in the bulk.

Muon Reconstruction

Event Data Model

Muon Combined Performance

Muon Spectrometer Isolation:

Fake Rates:

Muon Software Commissioning/Validation

Software Validation: We are currently developing Run Time Testing (RTT) jobs, specifically to test how the various software releases perform while processing cosmic muon data. The code will be able to compare the output histograms of the RTT to a standard histogram and flag differences, so that potential problems with the reconstruction can be more easily identified.

Detector Region Failure Simulation Studies: If a portion of the Muon spectrometer fails during data taking, it will be important to know whether the detector has the redundancy to still reconstruct events, and what effect this will have on the efficiency and resolution of the detector. We are conducting simulation studies to address this question.

Offline Combined Muon Data Quality

Tag/Probe Method: Using the tag/probe method, we are able to find the track-finding efficiencies of the Muon Spectrometer from Z->mumu data. Currently, we are developing this method within the offline DQA framework to determine the efficiency and resolution for combined muons (MS + Inner Detector tracks) as a function of eta, phi, pT and various other cuts, such as isolation. This method will be ready to be used on data taken in the first years to understand the insitu Muon Specrometer performance.