Physics Projects

Ground Rules for this Page

Projects listed here should always include the following:

• Brief description
• Starting date
• Primary person responsible plus nominal supervisor in case of students
• Link to "clean" copy of accomplishments and status
• Link to "dirty" copy of status, i.e. the electronic logbook for collaborative development

Projects involving students

Projects involving Undergraduates

Intro to Comphep

Brief Description: Install Comphep on uaf and hepuser, document how to use it, and use it to calculate some standard model cross sections as described in detail at IntroComphep? .

Starting Date: June 2006 BruceThayre? supervised by HaifengPi? IntroComphep? IntroComphepElog

Generator Study of Higgs Decay to ZZ(*)

Brief Description
Study Higgs decays to ZZ(*) at generator level.

Starting Date: June 2006
RamiVanguri? supervised by JamesLetts?
HtoZZatGenLevel?
HtoZZatGenLevelElog

Search for bosophilic (fermiophobic) Higgs-like particles

Brief Description:
As an extension of the CDF observation of WZ in the tri-lepton final state, we want to search for WWW final states with all 3 W's decaying into lnu. An outline of this analysis might look as follows.

• use Comphep or some other appropriate tool to understand the Xsection * BR as a function of mH.
• use Pythia WH production to generate signal MC with full simulation.
• Use the DBNTuple package to determine acceptance, and define an optimal signal region.
• Analyze the data, write a paper.

Starting Date: November 2006
Ending Date: November 2006
RamiVanguri? supervised by FkW? .

Background Reading is available at BosophilicReadingList .
After initial reading, as documented on the BosophilicReadingList it seems that this isn't worth persuing.

Comparison of NLO and LO pt of the Z spectra in WZ production

Brief Description:
We presently intend to determine anomolous triple gauge couplings from the pt distribution of the Z in WZ in the trilepton plus MET final state. Unfortunately, we expect that the Standard Model prediction for the pt spectrum has significant uncertainties as it is not calculated in all orders of perturbation theory. To estimate these uncertainties, we compare leading order (LO) with next to leading order (NLO) predicted spectrum using mcfm.

Results are documented at NLOversusLOinWZ

December 2006
FkW? using scripts from RamiVanguri? .

Comparison of NLO vs LO for transverse Mass and pt of the Z spectra in WZ production

Brief Description:
Following up on NLOversusLOinWZ we investigate to what extend transverse mass is less affected by higher order QCD effects than the pt of the Z. We first show that transverse mass (MT) and pt of the Z have very similar sensitivity to anomolous triple gauge couplings, and then compare NLO with LO spectra for standard model in MT using mcfm.

Results are documented at TransversMassInWZ

January 2007
FkW? using scripts from RamiVanguri? .

Projects involving Ph.D. Graduate students

Introduction to the CMS Detector

Brief Description: Use cmssw to generate, simulate, digitize, and reconstruct electrons, muons, and pions in the CMS detector. These are all single particle gun simulations. Use the event display to get an initial understanding of the CMS detector, and then determine efficiency, and resolution curves, reproducing those in the physics TDR volume 1.

Search for H decaying into WW into lnu lnu

Brief Description: Develop a Matrix Element Fitter to fit the di-lepton plus MET sample in CDF for a Higgs to WW to lnu lnu signature at fixed Higgs mass. Then scan across the Higgs mass region from about 100GeV to 170GeV or so. Determine a 95% CL upper limit for the product of Xsection times branching fraction for H to WW. Interpret this in terms of standard model, fermiophobic model, and possibly derive a limit on the Wilson Coefficients for the kind of model suggested by ManoharWise in their recent paper, where they predict Xsection enhancements up to a factor 2-3, independent of higgs mass.

Shih-Chih Hsu Thesis supervised by Lipeles/msn/fkw.

Anomolous Triple Gauge ZZZ Coupling

Brief Description: In di-lepton plus di-jet sample, search for anomolous ZZZ coupling via the pt distribution for Z->ll. It turns out that the high pt region beyond the range of Z+jets receives significant contributions from ZZZ couplings as limited by LEP. A very crude estimate of CDF sensitivity indicates that we might improve upon the lep limits by a factor 3 using 1fb-1 of data.

Matt Norman "back-up" Thesis supervised by fkw/msn/lipeles.

Study of fakes and selection criteria

Brief Description: Look at lepton selection criteria and fake rates using CMSSW ntuples. LeptonFakes

Warren Andrews (and Reza Farsian), supervised by FKW, began April 2008

Projects Involving Staff

Searching for new physics with 1pb-1, 10pb-1, 100pb-1, 1fb-1 of CMS data

Brief Description: The purpose of this exercise is to understand what signatures are interesting to look for as CMS starts data taking, and to what extend these signatures are constrained by searches at the Tevatron, especially CDF.

• Basic Arguments involving PartonLuminosity
• 1pb-1
  As argued in PartonLuminosity in reasonably general terms, there's really nothing that the LHC can do at 1pb-1 that hasn't already been ruled out by CDF and D0 if they care to do the analysis with their full data samples.
• 10pb-1
  As argued in PartonLuminosity in reasonably general terms, this is likely to be the regime of " AmbulanceChasing? ". Signatures that CMS has a 5sigma discovery potential with 10pb-1 are likely to be seen as a hint in CDF or D0 with 4fb-1 of data before the end of 2008. Some of the "accidents" to be chased are listed on the AmbulanceChasing? page. Let's see if I can keep this updated for the next year.
• 100pb-1
  As argued in PartonLuminosity in reasonably general terms, this is likely to be the minimal amount of data required at CMS to clearly exceed the discovery potential of the Tevatron in at least some signatures. It's thus worthwhile to take a closer look at the most likely signatures and compared the supposed physics reach as stated in the CMS Physics TDR vol2. This is done on the CMSDiscoveryPotential? page.

Starting Date: December 31st 2006.
FkW? .

-- FkW - 30 Dec 2006