May 1, 2002
TO: American Linear Collider Working Group Leaders
FROM: Jim Brau and Mark Oreglia
SUBJECT: The Santa Cruz meeting
We would like to propose some coordination and direction for your working
group diliberations at Santa Cruz, in addition to your general agenda
of reports on progress and new results. Much understanding has developed
from the past few years of effort on the linear collider physics case,
and we think it is now time to focus a significant fraction of the attention
in all of the groups, including the physics groups, on the decisions that
we will soon face regarding the accelerator and the detector. Therefore,
we are asking each of the groups to devote time at Santa Cruz addressing
these issues, and to report back on the third day in the summary reports
a first response on this. As we go forward, we expect the responses to
mature and provide critical guidance. Please, as working group leaders,
prepare an initial response to this, which can then serve as discussion
leads during your sessions (see the plan for the sessions below).
If you could send your comments/drafts/whatever on this plan to us
by the second week of June, it would be very helpful for us to understand how
this is working out.
As detailed below, we would ask each working group to include the following
in their parallel session:
1.) organize an evaluation of key issues relating to the choice of
detector and accelerator technology
2.) coordinate the on-going and proposed R&D efforts;
please encourage all planned participates to give brief reports
on their intentions during the parallel sessions at Santa Cruz
-----------------
PHYSICS WORKING GROUPS
What are the value, priority, and importance to the physics program
of the LC performance options. At Santa Cruz you will only have time
to begin this evaluation. Please consider issues such as:
initial and eventual energy reach
integrated luminosity
positron polarization
how much is needed/useful
gamma-gamma collisions
electron-gamma collisions
electron-electron collisions
More detailed issues that we would like to understand as we go forward
will include:
energy spectrum
beam bunch structure
other collider parameters
DETECTOR WORKING GROUPS
What are the impact of the accelerator parameters on detector performance?
Investigate
luminosity
backgrounds
beam bunch structure
other relevant collider parameters
Specify your priorities for R&D. Set these priorities separately
for software and hardware issues. For example, your list might look
like
- software
o priority 1
o priority 2
- hardware
o priority 1
etc.
Also break the work down within subareas, such as
Central Calorimetry
Forward Calorimetry
Central Tracking
Forward Tracking
Intermediate Tracker
Make a software and hardware list in each subarea. You may indicate
overall priority across subarea.
Please divide the software work into: "service work" (general
characterization and simulation, for example) and "physics impact studies."
Indicate what "service work" is required for the "physics impact studies."
Below you will find a list of R&D issues that we have compiled. You may
find this list a useful way to start. You may also find it useful to
refer to the international R&D report, soon to be posted at:
http://blueox.uoregon.edu/~jimbrau/LC/LCrandd.ps
--------------------
Now for the plan for the Santa Cruz meeting. Since we only have one day
for the parallel sessions, it was decided to have overlapping sessions.
Session I 8:30 - 10:00 Physics
Higgs SUSY Alternative/Strong Gauge Top/QCD Precision/Loops
Session II 10:30 - 12:00 Physics Accel Sim
Higgs SUSY Alternative/Strong Gauge Top/QCD Precision/Loops
Accel R&D & Instr. IR Gamma/gamma and e-/e- Simulation
Session III 1:30 - 3:00 Detectors Accel Sim
Accel R&D & Instr. IR Gamma/gamma and e-/e- Simulation
VTX Tracking Calorimetry Muon/PID
Session IV 3:30 - 5:00 Detectors
VTX Tracking Calorimetry Muon/PID
Mini-Plenary
5:00 - 5:30 Report from consortia
5:30 - 5:45 Perspectives from Jim
(5:45 - 6:00) Persepctives from head of Accel steering subgroup
6:00 - 7:00 Free-for-all
Some of the nuance:
*) Jim's talk will focus specifically on issues regarding the
incorporation of the consortia into the overall structure
*) The simulation parallel session, in order to minimize overlap,
and to the extent permitted by sanity, should focus on
detector-related issues in the morning and physics-related
issues in the afternoon
*) The parallel sessions should include some or all of the
following elements:
o) Brief presentations from everyone expecting to submit
a proposal to some funding agency or another
o) Somewhat longer talks on the progress of ongoing
studies
o) Invited `sub-plenary' talks on major issues
o) Summary and perspectives from the WG leaders
o) Time for group discussion if appropriate
*) To the extent possible, talks of interest to the larger
body should be put in the non-overlapping sessions (1 and
4), while talks of specificity and detail should be put
in the overlapping sessions (2 and 3).
-----------------------------------
Linear Collider Detector R&D Topics
Calorimetry
energy flow
need detailed simulation
followed by prototype beam test demonstration
further develop physics cases for excellent energy flow
eg. Higgs self-coupling, WW/ZZ at high energy, recon of top and W
for anomalous couplings?, others (SUSY, BR(H>160))
integrate E-flow with flavor tagging
study readout differences for Tesla/NLC
importance of K0/Lambda in energy flow calorimeter
parametrize E-flow for fast simulation
forward tagger requirements
study effect of muons from collimators/beamline
further development of simulation
clustering
tracking in calorimeter
digital calorimeter
study parameter trade-offs (R seg, layers, coil location, transverse seg.)
in terms of general performance parameters
in terms of physics outcome
refine fast-sim parameters from detailed simluation
integrate electronics with silicon detectors in Si/W
reduce silicon detector costs
engineer reduced gaps
mechanical/assembly issues
B = 5 Tesla?
can scintillating tile Ecal compete with Si/W in granularity, etc.?
crystal EM (value/advantages/disadvantages)
barrel/endcap transition (impact and fixes)
Tracking
refine the understanding of backgrounds
tolerance of trackers to backgrounds
will large background be a problem for the TPC (field distortions, etc)
are ionic space charge effects understood?
study pattern recognition for silicon tracker (include vxd)
study alignment and stability of silicon tracker
what momentum resolution is required for physics,
eg. Higgs recoil, slepton mass endpoint, low and high energy
understand tracker material budget on physics
physics motivation for dE/dx (what is it?)
detailed simulation of track reconstruction, especially for a silicon option,
complete with backgrounds and realistic inefficiencies
include CCDs (presumably) in track reconstruction
timing resolution
readout differences between Tesla/NLC time structure
role of intermediate layer
tracking errors in energy flow (study with calorimeter)
forward tracking role with TPC
alignment (esp. with regard to luminosity spectrum measurement)
develop thorough understanding of trade-offs in TPC, silicon options
large volume drift chamber (being developed at KEK)
development of large volume TPC (large European/US collaboration at work)
development of silicon microstrip and silicon drift systems
(being developed in US & Japan)
study optimal geometry of barrel and forward system
two track resolution requirements (esp. at high energy)
this impacts calorimetry - how much?
study K0 and Lambda efficiency
impacts calorimetry?
2D vs. 3D silicon tracker
Vertex Detector
resolve discrepancy in Higgs BR studies
understand degradation of flavor tagging with real physics events
compared to monojets (as seen in past studies)
understand requirements for inner radius, and other parameters
what impact on physics
develop hardened CCDs
develop CCD readout, with increased bandwidth
develop very thin CCD layers (eg. stretched)
segmentation requirements (two track resolution)
500 GeV u,d,s jets
pixel size
Muons
requirements for purity/efficiency vs. momentum on physics channels
understand role in energy flow (work with calorimetry)
detailed simulation
prototype beam tests
mechanical design of muon system
development of detector options, including scintillator and RPCs
Beamline and other areas
luminosity spectrum measurement
beam energy measurement
polarization measurement
positron polarization
systematics of the Blondel scheme
veto gamma-gamma very forward system
General issue
is calibration running at Z0 peak essential/useful/useless?
In general it would be good if more work was done exercising the
simulation code that has been put together under the leadership
of Norman Graf. Much work has been devoted toward developing a
detailed full simulation.