# Research with the ATLAS Detector at the Large Hadron Collider

1.  **Introduction**

> The Large Hadron Collider (LHC) is currently under construction in the
> 26.6 km circumference tunnel formerly used by the LEP collider at
> CERN, in Geneva, Switzerland. Upon its completion early in 2006, it
> will be the world's highest energy particle accelerator, colliding
> beams of protons at a center-of-mass energy of 14 TeV, and will be the
> forefront facility for particle physics well into the next decade. The
> US is a key participant in the construction of the LHC, and is making
> major contributions to both the LHC machine and its associated
> detectors.
>
> The ATLAS detector is one of two large, general purpose *pp* collider
> detectors being constructed for the LHC. US groups are making very
> significant contributions to the ATLAS detector: these groups involve
> about 250 physicists and engineers from 33 US institutions.
> Contributions to ATLAS include front-end electronics and Readout
> Drivers for pixels and silicon strips; mechanics and modules for the
> pixel system; silicon strip modules; the barrel Transition Radiation
> Tracker (TRT); readout electronics for the TRT; the Barrel Cryostat;
> feedthroughs and readout for the liquid argon calorimeter; the EM
> section of the forward calorimeters; one extended barrel scintillator
> tile calorimeter and readout electronics; Monitored Drift Tubes and
> Cathode Strip Chambers for the endcap muon system plus the readout
> electronics and alignment; and contributions to the Level 2 triggers.
>
> The US is also making substantial contributions to ATLAS offline
> computing. It is anticipated that there will be a Tier-1 and several
> Tier-2 computing centers in the US, where both simulation and physics
> data analysis will be performed. There are also major contributions to
> the ATLAS software from US collaborators, including substantial
> responsibilities for the overall software architecture, database, and
> reconstruction and analysis packages.
>
> The physics potential of the LHC is enormous. The internal consistency
> of the Standard Model requires that at least part of the explanation
> of masses, the origin of electroweak symmetry breaking, must be found
> at the TeV scale. The LHC is unique among accelerators currently
> existing or under construction in that it has sufficient energy and
> luminosity to study this mass scale in detail. Specifically, detailed
> simulations confirm that:

-   If the minimal Standard Model is correct and the Higgs boson is not
    discovered previously, it will be found at the LHC.

-   If supersymmetry is relevant to the breaking of electroweak
    symmetry, it will be discovered at the LHC and many details of the
    particular supersymmetric model will be disentangled.

-   If the Higgs sector is that of the minimal supersymmetric model, at
    least one Higgs decay channel will be seen, no matter what the
    parameters turn out to be. In many cases, several Higgs bosons or
    decay channels will be seen.

-   If the electroweak symmetry breaking proceeds via some new strong
    interactions, many resonances and new exotic particles will almost
    certainly be observed.

-   New gauge bosons with masses less than several TeV will be
    discovered or ruled out.

-   Signals for extra dimensions will be revealed if the relevant scale
    is in the TeV range.

> With the prospect of these breakthroughs in our understanding of
> matter at its most fundamental level, the LHC represents a great
> opportunity not only for US physicists but for the field of particle
> physics as a whole. The NSF has made major contributions to the
> construction of the ATLAS detector, and is also providing crucial
> support for the initial phase of the US ATLAS Physics and Computing
> project as it gears up towards ATLAS operation and data taking in
> 2006. In order for US physicists to profit fully from these
> investments, and to be at the forefront of the physics discoveries
> that we expect will be made at the LHC, it is vital that the US
> continue to be a key participant in the Research phase of ATLAS.
>
> This proposal describes the major components of the Research program
> foreseen for the five-year period beginning in 2002. A brief summary
> of the expected physics highlights at the LHC is given, followed by
> sections devoted to US ATLAS Computing, Maintenance and Operations,
> and Upgrades. Plans for continuing and expanding our successful
> Education and Outreach efforts are also described. Finally, our
> proposal to use the existing NSF-ATLAS Project Office at Columbia as a
> basis for managing the NSF-funded contributions to the ATLAS Research
> program is outlined.

2.  **Physics at the Large Hadron Collider**

> The LHC machine will collide beams of protons at a center-of-mass
> energy of 14 TeV, with a design luminosity of 10^34^ cm^-2^ s^-1^. An
> initial "low-luminosity" (10^33^ cm^-2^ s^-1^) phase of operation is
> foreseen as the accelerator is commissioned, during which several
> important "discovery" searches will be possible, as well as an
> extensive program of Standard Model measurements, such as detailed
> studies of the top quark. CERN Management has recently initiated a
> study of possible upgrades to the baseline LHC, to explore the
> implications of a doubling of the center-of-mass energy and/or an
> order-of-magnitude increase in the machine luminosity (to 10^35^
> cm^-2^ s^-1^). Either of these options would have a significant impact
> on the LHC detectors.

The ATLAS detector is shown in Fig. 1. It uses a tracking system
employing silicon pixels, silicon strip detectors, and a transition
radiation trackers, all contained within a 2 Tesla superconducting
solenoid. The charged track resolution is ∆*p~T~/p~T~* = 20% at *p~T~* =
500 GeV. The tracker is surrounded by an electromagnetic calorimeter
using a lead-liquid argon accordion design; the EM calorimeter covers
η\< 3 and has a resolution of ∆*E/E* = 10%/√*E* ⊕ 0.7%. The hadronic
calorimeter uses scintillator tiles in the barrel and liquid argon in
the endcaps (η \> 1.5); its resolution is ∆*E/E* = 50%/√*E* ⊕ 3%.
Forward calorimeters cover the region 3 \< η\< 5 with a resolution
better than ∆*E/E* = 100%/√*E* ⊕ 10%. Surrounding the calorimeters is
the muon system. Muon trajectories are measured using three stations of
precision chambers in a spectrometer with bending provided by large
air-core toroid magnets. The resulting muon momentum resolution is
∆*p~T~/p~T~* = 8% at *p~T~* = 1 TeV and ∆*p~T~/p~T~* = 2% at *p~T~* =
100 GeV. A complete description of the detector is available
elsewhere^1^.

![](media/image1.wmf){width="2.88125in" height="2.2256944444444446in"}

Fig. 1: The ATLAS detector.

The current schedule for the LHC envisions commissioning the machine
starting in January 2006, with first collisions foreseen in an April
2006 pilot run. The limited availability of resources as well as
technical and schedule constraints have led the ATLAS Collaboration to
revise its construction plans for the initial detector. The current plan
foresees that the completion of some detector components will be
deferred by one to two years during the initial lower luminosity running
of the LHC. The choice of the detectors to be staged has been guided by
a thorough evaluation of the physics potential and will still allow
ATLAS to investigate the major physics topics for the initial physics
run at the LHC.

A synopsis of the major physics topics ATLAS will address is given
below.

**The Standard Model**

The Standard Model (SM) is a very successful description of the
interactions of the components of matter at the smallest scales (≤ 10-18
m) and highest energies (∼ 200 GeV) accessible to current experiments.
It is a quantum field theory that describes the interaction of spin-½,
point-like fermions, whose interactions are mediated by spin-1 gauge
bosons. The fundamental fermions are leptons and quarks, grouped in
three generations, with each generation identical except for mass. The
origin of this structure, and the breaking of the generational (flavor)
symmetry remain a mystery.

In the SM the *SU(2) × U(1)* symmetry group describes the electroweak
interactions. This symmetry is spontaneously broken by the existence of
a (postulated) Higgs field with a non-zero expectation value, leading to
massive vector bosons -- the *W^±^* and *Z* -- which mediate the weak
interaction; the photon of electromagnetism remains massless. One
physical degree of freedom remains in the Higgs sector, a neutral scalar
boson *H^0^*, which is presently unobserved. With the recent direct
observation of the ν~τ~^1^, only one observed particle from the Standard
Model has yet to be observed, the Higgs boson. The Higgs is critically
important because it holds the key to the generation of *W*, *Z*, quark
and lepton masses.

The minimal SM can only accommodate massless neutrinos and hence no
neutrino oscillations. There is now good evidence for such oscillations
from measurements of neutrinos produced in the sun and by cosmic ray
interactions in the atmosphere^2^. While it is easy to extend the SM to
include neutrino masses, understanding their small values seems to
require qualitatively new physics.

**Beyond the Standard Model**

The success of the Standard Model of strong, weak and electromagnetic
interactions has drawn increased attention to its limitations. In its
simplest version, the model has 19 parameters^3^, 17 of which are
currently determined with varying errors. One of the two remaining
parameters is the coefficient *θ* of a possible *CP*-violating
interaction among gluons in QCD; limits on *CP* violation in strong
interactions imply that it must be very small. The other parameter is
associated with the mechanism responsible for the electroweak symmetry
breaking. This can be taken to be the mass of the as yet undiscovered
Higgs boson, whose couplings are determined once its mass is known.
Additional parameters are needed to accommodate neutrino masses and
mixings.

The gauge theory part of the SM has been well tested, but there is
little direct evidence either for or against the simple Higgs mechanism
for electroweak symmetry breaking. The current experimental lower bound
on the Higgs mass is 113.5 GeV^4^. If the SM Higgs sector is correct,
then precision measurements at the *Z* and elsewhere can be used to
constrain the Higgs mass via its contribution to the measured quantities
from higher order quantum corrections to be less than 212 GeV at 95%
confidence^5^. As the Higgs mass increases, its self couplings and its
couplings to the *W* and *Z* bosons grow. This feature has a very
important consequence: either the Higgs boson must have a mass less than
about 800 GeV, or the dynamics of *WW* and *ZZ* interactions with center
of mass energies of order 1 TeV will reveal new structure. It is this
argument that sets the energy scale that must be probed to guarantee
that an experiment will be able to provide answers to the nature of
electroweak symmetry breaking.

The presence of a single elementary scalar boson is distasteful to many
physicists. Is the theory is part of some more fundamental theory, which
has some other larger mass scale, there is a serious "fine tuning" or
naturalness problem. Radiative corrections to the Higgs mass result in a
value that is driven to the larger scale unless some delicate
cancellation is engineered. There are two ways out of this problem which
involve new physics at a scale of order 1 TeV. New strong dynamics could
enter that provides the scale of *M~W~*, or new particles could appear
so that the larger scale is still possible, but the divergences are
canceled on a much smaller scale. It is also possible that there is no
higher scale as, for example in models with extra dimensions. In any of
the options, Standard Model, new dynamics or cancellations, the energy
scale is the same: something must be discovered on the TeV scale.

Supersymmetry is an appealing concept for which there is currently no
experimental evidence^6^. It offers the only presently known mechanism
for incorporating gravity into the quantum theory of particle
interactions, and provides an elegant cancellation mechanism for the
divergences provided that at the electroweak scale the theory is
supersymmetric. Some supersymmetric models allow for the unification of
gauge couplings at a high scale and a consequent reduction of the number
of arbitrary parameters. Supersymmetric models postulate the existence
of superpartners for all the presently observed particles: squarks,
sleptons, gluinos and gauginos. There are also multiple Higgs bosons.
There is thus a large spectrum of currently unobserved particles, whose
exact masses, couplings and decays are calculable in the theory given
certain parameters. Unfortunately these parameters are unknown.
Nonetheless, if supersymmetry has anything to do with electroweak
symmetry breaking, the masses of the superpartners should be in the
region of 100 GeV -- 1 TeV.

An example of the strong coupling scenario is "Technicolor" or models
based on dynamical symmetry breaking. Again, if the mechanism is at all
related to electroweak symmetry breaking, we would expect new states in
the region 100 GeV -- 1 TeV; most models predict a large spectrum. All
models predict structure in the *WW* scattering amplitude at around 1
TeV center of mass energy.

There are other possibilities for new physics that are not necessarily
related to the scale of electroweak symmetry breaking. There could be
new neutral or charged gauge bosons with masses larger than the *W* and
*Z*; there could be new quarks, charged leptons or massive neutrinos; or
quarks and leptons could turn out not to be elementary objects. It is
also possible that there are extra space-time dimensions^7,8^ that have
observable consequences in the TeV energy range. While we have no
definitive expectations for the masses of these objects, the LHC and
ATLAS must be able to search for them in the available energy range.

**ATLAS Physics Goals**

The fundamental goal of ATLAS and the LHC is to uncover and explore the
physics behind electroweak symmetry breaking. Specifically, the
following goals are expected to be successfully realized:

-   Discover or exclude the Standard Model Higgs and/or the multiple
    Higgs bosons of supersymmetry.

-   Discover or exclude supersymmetry over the entire theoretically
    allowed mass range up to a few TeV.

-   Discover or exclude new dynamics at the electroweak scale.

The energy range opened up by the LHC also gives us the opportunity to
search for other objects:

-   Discover or exclude any new electroweak gauge bosons with masses
    below several TeV.

-   Discover or exclude any new quarks or leptons that are kinematically
    accessible.

-   Discover or exclude extra-dimensions for which the appropriate mass
    scale is below several TeV.

Finally, we have the possibility of exploiting the enormous production
rates for certain SM particles to conduct the following studies:

-   Study the properties of the top quark and set limits on exotic top
    decays.

-   Study of *b*-physics, particularly that of *b*-baryons and *B~s~*
    mesons.

> The extensive studies and simulations performed to arrive at these
> conclusions are documented in detail elsewhere^1^. Fig. 2 highlights
> the results of one particularly important analysis, showing not only
> that the Higgs can be discovered over all of the allowed mass range,
> but that its mass should be measured with better than 1% accuracy over
> all of that mass range.

![](media/image2.wmf){width="2.4090277777777778in"
height="2.3680555555555554in"}

Fig. 2: Expected errors on the Higgs mass in ATLAS.

On the basis of these studies, we believe that the physics potential of
the LHC is enormous. Among currently approved projects in high energy
physics, it uniquely has sufficient energy and luminosity to probe in
detail the TeV energy scale relevant to electroweak symmetry breaking.

3.  **Computing**

> ATLAS will start producing data in 2006 and will reach Petabyte scale
> data size by 2007. The computing effort for ATLAS far exceeds that of
> previous high energy physics experiments in the scale of data volume,
> CPU requirements, data distribution across a global network,
> complexity of the software environment, and a widespread geographic
> distribution of developers and users of software.
>
> The ATLAS computing model is based on a hierarchical network of sites,
> starting with CERN as the primary (Tier 0) site. The assumption is
> that all of the raw data from ATLAS will be stored at this Tier 0
> site. A US Regional Center, or Tier 1 site, located at Brookhaven
> National Laboratory, will cache a subset of these data and perform
> computing tasks as required by both the ATLAS Collaboration and US
> ATLAS in support of US responsibilities and analysis activities.
> Beyond the Tier 1 site will be five or six Tier 2 centers, located at
> universities across the US. Each of these individual centers will have
> a fraction of the capabilities of the Tier 1 site, but will have a
> combined CPU power roughly equal to that of the Tier 1 center. The
> various sites will be linked together by a computational grid,
> allowing transparent access to users and automatic scheduling of
> resources, providing US physicists with the optimal environment for
> efficient analysis of experimental data. The ATLAS analysis software,
> data storage and database management frameworks must be able to handle
> this widely distributed large data system. A substantial amount of R&D
> must be devoted at the outset to establish this grid computing model
> as a viable operation. The NSF is supporting advanced IT development
> to address some of these issues in US ATLAS, most notably through the
> GriPhyN and iVDGL grid initiatives.
>
> The ATLAS software can be broadly divided into two main categories:
> general purpose (or core) software that is not specific to any one
> detector subsystem, and detector specific simulation and
> reconstruction software. Requirements on the software are developed by
> the international Collaboration, and deliverables negotiated as part
> of software Memoranda of Understanding. Such agreements serve to
> formalize national and institutional commitments and ensure that the
> work is fully integrated into the official ATLAS software. Because of
> the large scale and long time span of ATLAS, the experiment has
> committed to developing all software in object-oriented technology,
> currently using C++ as the programming language. This choice, and
> experience from recent experiments that have chosen this technology,
> require that we rely on professional software engineers to design and
> implement much of the core of the ATLAS software.
>
> In the run up to 2006, significant effort will be needed to produce
> and analyze simulated data, as well as to implement Mock Data
> Challenges that will test the full ATLAS computing and software
> framework. A full schedule of ATLAS computing milestones is available
> at http://atlassw1.phy.bnl.gov/Planning/usPlanning.html.
>
> For the US ATLAS Physics and Computing project there are two primary
> goals. The first is to provide the software, computing and support
> resources to enable US physicists to fully participate in, and make
> significant contributions to the physics program of ATLAS. The second
> is to contribute to the overall ATLAS Computing efforts to a degree
> that is both commensurate with the proportionate scale of the US
> contributions to the detector construction and well matched to the
> expertise of the US physicists specializing in computing. These
> contributions are being formalized in the form of software
> "deliverables" to ATLAS.
>
> There are three components of the US ATLAS Physics and Computing
> project:

-   Physics: Support of event generators, physics simulation,
    specification of physics aspects of facilities support.

-   Software: Development and maintenance of software deliverables to
    the international ATLAS project, as specified in software agreements
    and Memoranda of Understanding between CERN, the international ATLAS
    Collaboration and the US ATLAS Physics and Computing project.

-   Facilities: Hardware, networking and software support of US
    collaborators in data analysis and in computing contributions to
    ATLAS.

> The funding for the Physics and Computing project is derived from a
> combination of: NSF and DOE R&D funds directed at collaborations of US
> ATLAS physicists with computer scientists; direct DOE funds; and
> direct NSF funding (this proposal). In this proposal, we are
> requesting funds in each of these three categories, to complete the
> funding needs of the project.
>
> For the Physics subproject, we are requesting funding for directed
> effort to support mock data challenges in the US and the support of
> simulation interfaces.
>
> The Software subproject is divided into several categories: "core"
> software, that is not specific to a given detector subsystem; detector
> specific simulation and reconstruction; training; and collaborative
> tools. In terms of core software, the US has taken on major
> responsibilities in two major areas: the overall architecture/control
> framework and the database software. This is as a result of existing
> expertise among US collaborators as well as the overall need in ATLAS
> for this crucial component of the software. The US is of course active
> in many other areas of ATLAS computing. Traditionally, detector
> specific simulation and reconstruction activities have been carried
> out by physicists and in the past have not involved the use of Project
> funds for their support. With modern software methodology, and the
> increased complexity associated with the scale of the ATLAS Computing
> project, it is necessary to have a more systematic approach to this,
> including the use of some software professionals to support the
> activities of physicists and assist in the maintenance of
> reconstruction and simulation packages. We are requesting NSF funding
> to support the software deliverables to ATLAS.
>
> For the Facilities subproject, we are requesting NSF support for
> activities mostly related to the Tier 2 centers, and the associated
> computing grid development. (Funding for the BNL Tier 1 center,
> associated support functions, and contributions to some of the US core
> computing responsibilities will be sought from the DOE.) It is
> anticipated that there will be approximately five ATLAS Tier 2 centers
> in the US, providing hardware and software support functions for US
> ATLAS institutions in their neighboring regions. Two prototype Tier 2
> centers have already been established, with NSF support, at Boston
> University and Indiana University, and are now beginning the R&D work
> necessary to validate both the grid computing concept and the ATLAS
> tiered computing model. Selection of the locations for the final Tier
> 2 sites is expected to occur in 2003, with funding for these centers
> beginning in FY04. The specific funding requests are for: completion
> of funding to deploy grid-related software that has not been fully
> covered by other proposals (GriPhyN, iVDGL, PPDG), this is mainly
> targeted at infrastructure at the prototype Tier 2 sites; and a ramp
> up of Tier 2 centers, with both personnel and hardware, starting in
> 2004, as part of the preparation for data taking at the LHC.
>
> It is likely that the physics output of US ATLAS collaborators will be
> computing limited during the Research phase of the experiment, and it
> is vital that adequate priority be given to computing to ensure that
> US physicists are on the forefront of research and discovery at the
> LHC.

4.  **Maintenance and Operations**

> The US participation in the ATLAS experiment supported by the NSF was
> structured with two goals in mind: to make the contributions to the
> construction of the experiment as effective as possible within the
> resources available, and to use these resources to strengthen the
> scientific capabilities in the US universities. These goals are
> compatible because there is in the universities a large intellectual
> capital developed in past projects to construct major physics
> experiments, which can be tapped by adding resources to build up teams
> to produce new detectors for ATLAS. This enables us to make
> contributions that are extremely valuable to the international ATLAS
> Collaboration, more valuable than might be expected by looking at the
> level of the dollars alone. This has been a great opportunity for the
> universities, since the scientific infrastructure in the universities
> has not kept pace with the technological opportunities over the last
> decades. The Construction project is far enough along that we can now
> report that the universities have risen successfully to the challenge
> of some really substantial construction projects that many observers
> might have believed needed the scale of a national laboratory to
> complete.
>
> Examples, among the thirty university construction efforts, are the
> collaboration of seven universities to build hundreds of square meters
> of Monitored Drift Tube tracking detectors for muons with a
> construction and alignment accuracy of about twenty-five micrometers.
> This effort included the electronic readout and laser alignment
> systems, and included no national laboratories. Another group
> consisted of four universities with no national lab participation,
> building a system combining tracking and transition radiation
> detection, with hundreds of thousands of small "straws" for tracking,
> together with very advanced radiation-hard electronics. The net effect
> has been to make an investment on university campuses that has raised
> the level of the whole physics enterprise in a qualitative manner.
> Quantitatively, we note that twenty U.S. ATLAS universities are
> involved in very advanced electronic projects, including the most
> advanced sub-micron technologies and the most advanced radiation-hard
> processes. Twenty-one of the universities are carrying out mechanical
> construction using advanced techniques, often involving large scale
> construction typically using undergraduate students. These efforts
> have been used very successfully as an outreach tool with high school
> students and teachers.
>
> The US commitments to the ATLAS Construction project are specified in
> terms of well defined deliverables to the experiment, as described in
> the (Revised) US ATLAS Construction Project Management Plan^10^, and
> references therein. In many cases, the US obligation for these
> Construction project deliverables concludes when all components have
> been delivered to CERN, while in others a limited amount of effort is
> provided for testing at the CERN site or initial installation of the
> equipment.
>
> According to reasonable and customary practice in collaborations,
> including the international collaborations that the US has
> participated in, groups have continuing responsibilities for the
> detector components they have built as the detector is installed in
> the experimental cavern, and during the commissioning and operation
> phases. Three categories of Maintenance and Operation (M&O) activities
> are included in this proposal: pre-operations, operations and
> maintenance:

-   Pre-operations: Includes final testing (and associated material,
    electrical, gas, water supplies etc.), calibration, and integration
    with other detector components or subsystems.

-   Operations: Includes activities both during experimental run periods
    and during shutdowns, for example routine replacement of parts, or
    implementing improvements to software code, etc.

-   Maintenance: Also includes activities both during run periods and
    shutdowns, for example costs of spare parts, additional
    tooling/infrastructure required for accessing and repairing detector
    components, etc. In some instances, particularly for the various
    radiation-hard ICs needed in ATLAS, spares must be bought early as a
    "lifetime buy", since it is known that the relevant technologies may
    become obsolete.

> In addition to the M&O costs for specific US deliverables, it is
> anticipated that each detector subsystem will request that Common
> Expenses for that subsystem be shared in proportion to the respective
> contributions to the Construction project. Such Common Expenses might
> include the costs of contract labor supplied by CERN (e.g. for
> cabling, plumbing, on-site machining, etc.), consumables (gases,
> coolant fluids, etc.), and general support of surface assembly
> equipment and infrastructure.

(Further details...?)

5.  **Upgrades**

> The initial ATLAS detector for the start of LHC operation will be a
> staged version of the planned full detector. While the staging plan
> has been carefully optimized to minimize the impact on the initial
> physics program, there will inevitably be some reduced capabilities.
> For example, the discovery potential for a Higgs signal in several
> final states will be degraded such that 20% more LHC running time will
> be needed to compensate for this loss. This is acceptable for this
> high priority initial goal, but the degradation for higher mass states
> like those at the TeV scale suggested by the new theories of extra
> dimensions will be more serious. This means that upgrades to the
> detector will be highly productive investments. The upgrades will
> replace the capabilities lost by staging, but the advance of
> technology will allow more powerful and more cost effective detectors
> instead, in many cases, of just replacing originally planned devices.
> This is much more important taking to account that a vigorous program
> of machine development is planned for the LHC, leading to a continuous
> increase of luminosity over time. This is good for the scientific
> results, but places increasing stress on the detector performance. The
> detector upgrades will allow ATLAS to exploit fully the high
> luminosity running of the LHC, and will be chosen to profit from the
> best new ideas and techniques, with examples given below. This will
> require substantial R&D, which should start in 2004 in order to be
> able to carry out the Upgrades in later years.
>
> The initial Inner Detector configuration will defer one of the three
> pixel layers and its associated read-out electronics as well as the
> outermost endcap TRT wheels. Full calorimeter coverage is required for
> the initial LHC physics and is also need mechanically to shield the
> muon chambers within the ATLAS air-core toroid system. The limited
> staging that has been implemented for the calorimeters concerns a
> reduction of the read-out drivers (RODs) and possibly a reduced
> redundancy in HV power supplies. The cryostat-gap scintillators used
> for energy corrections in the transition regions between the
> calorimeter barrel and endcaps will be deferred. For the muon system,
> some of the precision Monitored Drift Tube (MDT) chambers, including
> supports and electronics, in the transition region between barrel and
> endcaps will be staged, and part of the endcap end-wall MDT chambers.
> Only half of the planned Cathode Strip Chamber layers (mechanics and
> electronics) will be part of the initial detector. The higher level
> trigger and DAQ system will be initially designed to the reduced
> scope, in a way that can be readily upgraded, and the downstream
> processor farm will be implemented in an expandable way, starting from
> a reduced system.
>
> The full potential of the LHC will only be achieved in the high
> luminosity running of the machine, which is expected to be reached
> gradually starting in mid-2007. In order to cope with the expected
> background conditions, the full robustness and redundancy of the ATLAS
> detector will be required, according to its design criteria. This
> means restoring both the pattern recognition capabilities and the
> resolutions for the large variety of expected (and unexpected)
> signals. The staged components must therefore be installed in 2007
> after the initial run.
>
> The major upgrade activities we foresee in which NSF-supported groups
> will likely participate include the restoration of the full
> calorimeter ROD capability, the addition of the cryostat gap
> scintillators, the addition of approximately 80 muon spectrometer MDT
> chambers, and the completion of the full Trigger/DAQ system. There may
> also be a significant US involvement in upgrades of the silicon pixel
> and strip subsystem.
>
> (Further details...?)
>
> (Budgets include R&D costs, design, prototyping, fabrication, shipping
> and installation)

6.  **Education and Outreach**

> Many of the NSF-supported institutions in ATLAS have been active for a
> number of years in a wide range of Education and Outreach activities.
> Since its launch in 1999, the NSF- and DOE-funded QuarkNet program has
> been a natural focus for these diverse Outreach efforts. Of the
> thirty-four QuarkNet sites that are now active, twenty are US ATLAS
> institutions and eleven of these are groups that have been funded by
> the NSF.
>
> QuarkNet provides community high school science teachers with the
> opportunity to experience particle physics research at first hand.
> QuarkNet teachers spend their summer "assignments" working alongside
> physicists, technicians and students on tasks as varied as
> constructing and testing components for future detectors (such as
> ATLAS) or analyzing data from running experiments. At many
> institutions, the teachers also profit from "crash courses" in a wide
> range of topics in modern physics. One of the goals of the QuarkNet
> program is that the teachers return to their classrooms and pass on
> some of the excitement of forefront scientific research to their
> students, including aspects and examples of modern physics in their
> curriculum where possible. Feedback from many of the teachers in the
> program indicates that this has succeeded beyond their most optimistic
> hopes, and has led to an appreciable number of high school students
> getting interested, and participating, in the research work at
> QuarkNet sites around the country.
>
> The first three years of the NSF-ATLAS groups' involvement in QuarkNet
> have been a clear success, and we expect to build upon and extend our
> activities as we enter the Research Phase of the ATLAS Experiment. One
> example of a recent initiative to extend the reach of our Education
> and Outreach activities was the inclusion of four high school teachers
> from sub-Saharan Africa in our 2001 QuarkNet program. The ATLAS groups
> at Columbia and at Hampton University invited two teachers each to
> join their summer workshops, adding a very stimulating international
> dimension to the QuarkNet experience. Planning for follow-up in Africa
> is underway, and will initially include visits by US scientists and
> undergraduates to schools in South Africa, and a Traveling Lab of
> self-contained physics demonstrations suitable for high school
> students in South Africa. It is our hope that the QuarkNet program,
> and others like it, can play a part in bringing the latest advances in
> scientific research to all parts of the globe.
>
> Other activities that have been supported by NSF funding of ATLAS to
> date include the production of educational videos and CD-ROMs about
> the experiment, assistance in setting up and constructing
> demonstration experiments for high school classrooms, and lectures on
> topical scientific subjects for the general public.
>
> Aside from our activities aimed at high school populations and the
> public at large, essentially all of the NSF-ATLAS groups have
> significant undergraduate and graduate student involvement in their
> research and detector projects. Experience has shown that this is an
> invaluable way of giving students some of the research experience and
> technical training they will need in order to become our future
> scientists.

7.  **Project Management**

> We are proposing that that Columbia University continue to assume the
> financial responsibility for NSF funding contributions to the Research
> program of ATLAS, and that Columbia continue to serve as the NSF-ATLAS
> Project Office, working closely with the US ATLAS Project Office at
> BNL.
>
> Fourteen US ATLAS institutions, including Columbia University, have
> been supported to date by the NSF under Cooperative Agreement No. PHY
> 97-22537 for Construction of the ATLAS Detector. The fourteen groups
> have coordinated their activities during the construction phase of the
> experiment, with Columbia University assuming responsibility for the
> work, subcontracting to the other universities.
>
> Project Management for the US ATLAS Construction program has been
> provided by the US ATLAS Project Manager (Willis), and Project Offices
> at Columbia University (for the NSF) and Brookhaven National
> Laboratory (for the DOE). Project oversight has been provided by BNL
> and by the NSF/DOE Joint Oversight Group.
>
> Columbia has also administered and assumed financial responsibility
> for some of the initial NSF funding for the US ATLAS Physics and
> Computing project.
>
> The NSF-ATLAS Project Management role of Columbia University during
> the Construction Phase of the experiment has been functioning
> efficiently and smoothly. Columbia is currently managing more than 20
> subcontracts for the Construction, Computing and Education and
> Outreach components of the NSF-ATLAS program. The implementation of
> the US ATLAS Construction Project Management Plan and the US ATLAS
> Computing Project Management Plan included a number of features that
> were not very familiar to some of our collaborating institutions. For
> example the operation under defined Memoranda of Understanding, rather
> than a Grant, with a necessity of supplying detailed invoices for the
> subcontracts on a timely basis. On the technical side, we require
> regular progress reports for each activity in our Work Breakdown
> Structures with a firm deadline each month. Compliance with these
> requirements has continued to improve.
>
> The management system now in place at Columbia for NSF-ATLAS maintains
> close control over expenses and progress tracking, with a minimum
> burden on the Subcontractors. We have found our organization to be
> flexible while maintaining a tight managerial control. We expect that
> our model and our experience will prove valuable for the Research
> Phase of the ATLAS experiment.
>
> (There should be paragraph describing the general framework we expect
> to implement for the Research Phase... strong MOUs etc.)

## References

(Refs. need to be fixed)

1.  ATLAS Detector and Physics Performance TDR...

2.  K. Kodama *et al*. \[DONUT Collaboration\], hep-ex/0012035.

3.  D.E. Groom *et al*. \[Particle Data Group Collaboration\], Eur.
    Phys. J. **C15**, 1 (2000).

4.  R.N. Cahn, LBL-38649 (1996), submitted to Rev. Mod. Phys.

5.  P. Igo-Kemenes, report to the LEPC, November 2000.

6.  The LEP Electroweak Working Group, CERN-EP-2000-016.

7.  For a review see I. Hinchliffe, Ann. Rev. Nucl. and Part. Sci.
    **36**, 505 (1986).

8.  N. Arkadi-Hamed, S. Dimopoulos and G. Dvali, Phys. Lett. **B429**,
    263 (1998).

9.  L. Randall and R. Sundrum, Phys. Rev. Lett. **83**, 3370 (1999).

10. Revised US ATLAS Construction Project Management Plan, US-ATLAS
    99-20.

# Budget Justification

The budget request for Computing, Maintenance and Operations, Upgrades
(including Upgrade R&D), Education and Project Management is shown in
the table below. Also shown is the expected NSF funding for the
computing grid projects GriPhyN and iVDGL, although these are not part
of this Proposal.

(This table will be reformatted for the final Proposal)

![](media/image3.wmf)

(Yeck asked to show Computing support back to 1999 also?)

## 

## (General comments about AY\$, inflation, etc.?)

## Computing

For the Software budget line, approximately 3-4 FTE software
professional support is requested, assuming roughly \$170k\$/FTE. This
effort will support the US core software obligations.

The cost of completing the deployment of grid-related software tasks is
based on projections of one FTE at each of the prototype Tier 2 sites,
and some amount of hardware to support the prototyping efforts. The
hardware typically supports the establishment of routers, commodity
processor farms, and disk storage at a level commensurate with a
substantial fraction of the anticipated final capacity at the turn on of
the LHC.

The costing of the ramp up of the Tier 2 sites is based on the
hierarchical structure with the US Tier 1 regional center, wherein the
aggregate capacity of the Tier 2's taken together roughly equals the
capacity of the Tier 1 site.

## Maintenance and Operations

## Upgrades

**Education**

**Project Management**

We are proposing that Columbia University continue to assume the
financial responsibility for NSF funding contributions to the Research
program of ATLAS, and that Columbia continue to serve as the NSF-ATLAS
Project Office, working closely with the US ATLAS Project Office at BNL.

Based in part on our experience during the Construction phase, we
anticipate that of order twelve institutions will receive NSF funds for
M&O and Upgrade activities during this proposal period. We propose that
Columbia continue to coordinate this work, subcontracting to the other
collaborating institutions, building on the framework established in
order to manage the NSF-ATLAS Cooperative Agreement for detector
construction. For NSF-ATLAS Computing activities, we estimate that
roughly eight institutions may receive funding from this proposal, and
that there will be a small number of institutions (say, five) receiving
funding for Education and Outreach activities. In total, we estimate
that Columbia may be administering approximately 25 subcontracts during
the Research phase. The current indirect cost rate (ICR) overhead on
subcontracts issued by Columbia is \$15,875 per subcontract. Assuming 25
subcontracts, the total ICR is estimated to be approximately \$400,000.
We expect that these subcontracts will mostly be initiated in the first
or second year of this proposal period, and have allocated the overhead
charges accordingly in our budget table (\$150k in FY02, \$250k in
FY03). We are requesting 1 FTE administrative support to help manage the
subcontracts, and maintain financial records. This cost is estimated at
\$90k per year, including fringe and overheads.