SLIDE 1
aconway@fnal.gov 1
aconway@fnal.gov 2
Higgs Cross Section vs Beam Width
- Peak value of SM
125GeV Higgs Breit- Wigner convoluted with Gaussian beam.
- Does not include initial
state radiation effects
– These reduce the total
Higgs Factory Studies etc. Work in progress aconway@fnal.gov 1 - - PowerPoint PPT Presentation
Higgs Factory Studies etc. Work in progress aconway@fnal.gov 1 - - PowerPoint PPT Presentation
Higgs Factory Studies etc. Work in progress aconway@fnal.gov 1 Higgs Cross Section vs Beam Width Peak value of SM 125GeV Higgs Breit- Wigner convoluted with Gaussian beam. Does not include initial state radiation effects These
SLIDE 2
SLIDE 3
3
Machine Parameters
- 0.003% spread→ 2.65MeV at 125GeV
- Higgs x-section = 37.4pb with this spread
- 1x10^32/cm^2/s = 1x10^-5 pb^-1/s
– = 1.7x10^2 pb^-1 / Snowmass year – → 6.4x10^3 Higgs/yr (on-peak)
SLIDE 4
4
Higgs Signal vs Background
- No initial state
radiation effects included.
– Expected to increase
background and decrease signal
– Background here not
used.
- R=0.003% (2.65MeV)
beam smearing
SLIDE 5
5
Higgs Signal vs Background
- Pythia-simulated backgrounds
– Includes some form of initial state
radiation, using default settings, unclear how accurate.
- Using these backgrounds for
- now. Good enough?
- Same backgrounds as spring
report
– Higgs cross sections slightly
larger.
SLIDE 6
6
Higgs Measurements
- Process:
– Choose total luminosity, bin
spacing, energy range
- Bin spacing = beam gaussian width
- Energy range = Higgs c.o.m. +/-
25MeV
– Simulate data
- Poisson-distributed random
numbers with <N> = (s + b)*L.
– Fit to Breit-Wigner convoluted
with Gaussian
- Free parameters:
– Higgs mass, width, branching fractions
- Known values:
– Beam width, integraged luminosity,
background cross section
SLIDE 7
7
Higgs Measurements
- Perfect b-tag and selective
energy cuts
– 52% signal, 15% of
background
– S/b = 1.3
- Fit errors reflect accuracy to
a decent degree
– Could improve estimation with
estimation of luminosity error.
SLIDE 8
8
Higgs Measurements
- WW*:
– Four-lepton decay; ~16%
- f h0 → WW* signal, 1.3pb
– 0.015pb background – S/b ~= 85
- Not as good for width
measurement
- What figures to quote for
uncertainty?
SLIDE 9
9
Software and Computing Status
- Attempting to create/document working simulation and
reconstruction environment.
– https://confluence.slac.stanford.edu/display/MCPDS/Simulation+and+Reconstruction
- Using:
– Pythia (or other stdhep event generator) and MadGraph5 – SLIC detector simulation – ILCSoft reconstruction tools: PandoraPFA algorithms – Org.lcsim, JAS3 and NetBeans
- Port Steve Magill's dual-readout analysis tools for SiD to MCDRCal
- Set up environment on mcdrd machine for use
- Set up environment for submitting simulation jobs to GRID
SLIDE 10
10
Software and Computing Status
- Pythia/MadGraph5
– Working fine – Instructions for generating accurate muon collider events would be good.
- SLIC
– Getting warnings during simulations with new mcdrcal01, talking to Jeremy. – Simulated dataset had read error after one event.
- ILCSoft – ilcinstall scripts
– slicPandora (package for PandoraPFA) doesn't build currently. – Generally somewhat tricky to get set up in a given environment. – Have identified some bugs and gotten them resolved.
- Org.lcsim, JAS3 et al.
– Winter tutorial instructions still apply – Have not worked on Steve Magill's dual readout code yet. Will bring it to the mcd.analysis project on
CVS
- GRID
– Have not looked into it yet, but will probably take some work. GRID experts? – Will be necessary for full event simulaitons