Transcript ATLAS Status and Upgrade Programme Monica D’Onofrio (University of Liverpool) on behalf of ATLAS-UK PPAP meeting Birmingham, 17/09/12

ATLAS Status and Upgrade
Programme
Monica D’Onofrio
(University of Liverpool)
on behalf of ATLAS-UK
PPAP meeting Birmingham, 17/09/12
Outline
 ATLAS and LHC: achievements and
current status
 The high luminosity Phase

Physics motivations

Radiation and pile-up challenges
 ATLAS upgrades projects and UK
involvement
 Summary and outlook
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
A successful year: LHC and ATLAS
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
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Great performance of the LHC
 √s from 7 to 8 TeV (50 ns bunch crossing)
 peak lumi 7.73 x 1033 cm2 s-1
.. and the ATLAS experiment
 Total efficiency above 90% despite the
challenging conditions
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
A successful year: the Higgs boson

The discovery of a new Higgs-like boson
with a mass of 125-126 GeV marks a
milestone and opens a new chapter in the
history of particle physics
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Plenty of questions to be answered about
the nature of this new fundamental particle!
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Searching for New Physics
 Enormous programme to
search for SUSY, ExtraDimensions and several other
Beyond SM (BSM) particles
A total of 189 (394) papers (CONF notes) on collisions data and
much more to come with full 8 TeV dataset (Moriond 2013)
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17/09/2012
UK roles in ATLAS
 Strong contributions of UK Institutions in several areas
 The UK holds key positions in ATLAS at senior management level,
in Physics Coordination and data taking. Among them:
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Spokesperson: Dave Charlton (Birmingham – currently deputy)
Deputy Physics Coordinator: Bill Murray (RAL/STFC – starting 1/10/12)
PubCom Chair: Tony Doyle (Glasgow)
Inner Detector Project Leader: Steve McMahon (RAL/STFC)
(Deputy) Trigger Coordinator: Simon George (RHUL – starting 1/10/12)
L1Calo Project Leader: Steve Hillier (Birmingham)
Upgrade coordinator: Phil Allport (Liverpool)
Standard Model convener: Jon Butterworth (UCL – ending 30/9/12)
SUSY convener: Monica D’Onofrio (Liverpool – starting 1/10/12)
MC generators coordinator: Andy Buckley (Edinburgh)
In the past three years the UK has also provided convenors of the B-physics, Exotics and
Higgs physics working groups
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
The next decades: the ATLAS
upgrade from Phase 0 to Phase II
The Roadmap to 2030

Most recent schedule (ESPP-Cracow meeting)
LHC has still only delivered a small
fraction of the effective partonparton lumidiscovery physics
programme just getting started!
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Accelerator timescale
driven by several aspects:
 Radiation damage of
LHC components
 R&D and construction
of LHC upgrades
 Required schedule of
detector upgrades

Long Shutdown (LS)
periods to install upgrades

Possibility of an HE (High
Energy ) LHC still under
discussion (see back-up for
physics potential)
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17/09/2012
The highest priority should be to exploit fully the
physics potential of the LHC
Physics motivations and goals:

With data taken in coming years at or near to the design energy of 14 TeV, a
broader picture of physics at the TeV scale will emerge. Amongst the
essential inputs:
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Precision measurements of the properties of the Higgs boson
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Spin/CP nature
Higgs couplings and self-couplings
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VV scattering : understanding electroweak symmetry breaking
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Direct searches for new physics up to multi-TeV scale
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SUSY particles
High mass resonances (Z’, KK ...)
Their properties, if found
Challenges:
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Accurate reconstruction and identification of physics objects (leptons
including the τ, heavy flavour tagging, photons, jets, missing transverse
energy)
Broad coverage in momentum and rapidity: e.g. to characterise events
from vector boson fusion
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Physics motivations
Based on the preliminary document submitted to
Cracow meeting (final version:15/10/2012):
https://cdsweb.cern.ch/record/1472518
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Higgs spin/CP properties
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Establish the nature of this particle by determining the spin/CP quantum
numbers  already possible with 30 fb-1 @ 8 TeV if it is a pure state
Better separation between spin 1 and spin 2 with large datasets and high
c.o.m. energy. Similarly with 300 fb-1 @ 14 TeV spin/CP quantum numbers of
non-mixed states can be established with a significance > 5 sigma
With 3000 fb-1, clean channels and rare couplings can be studied
ttH, H  gg for top yukawa couplings
Rare decays: H  mm
Small signal-to-background ratio (~ 0.2%) but narrow signal
peak  expected signal significance > 6
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Higgs couplings parameters
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For a given production and decay mode, s x BR is assumed to be
proportional to GiGj/GH
The coupling fit parameters are chosen as:
Expected precision on ratios
of Higgs partial widths
Expected precision
on signal strength at
300 and 3000 fb-1
Phase-I: 10-60 (80)%
Phase-II: 10-30%
(*)
(*)
(*)
Studies on trilinear selfcoupling (lHHH ) relevant to
determine SM parameters
and nature of higgs
mechanism:
• Most promising channels:
HH  bbgg and HH  bbtt
(*) only vector boson fusion
taken into account
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Also in progress (see back-up):
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Weak boson (VV) scattering
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HL-LHC upgrade can have a major impact in discovering extended EWK
symmetry breaking sector beyond SM higgs mechanism
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Preliminary studies on WW scattering: based using a reference model with unitarised amplitudes (a4,
a5 = numerical coeff of two new operators), if 0.01 – 0.001 compatible with precision EWK constraints
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Experimental signature: WW + 2 forward jets (renmant)
Studies on dileptonic and semi-leptonic channels
HL-LHC can probe the parameter space
interesting for EWK precision constraints
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Searches for SuperSymmetry
• Very stringent constraints from LHC on strongly produced sparticles (1st, 2nd generation
mass degenerate squarks, gluinos)  can be quite heavy (multi-TeV)
• Direct production of 3rd generation squarks and weak gauginos is becoming accessible
as the amount of integrated luminosity increases (low cross sections)
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If No deviations from the SM
observed in 300/fb
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Extension of sensitivity (mass &
cross section reach) with 3000/fb
Deviations from the SM
observed in 300/fb
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Signal characterization with
3000/fb
• Determination of masses by measuring
endpoints of visible mass distributions
• Measurement of couplings and spin (via
angular analysis)
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Weak gauginos and 3rd generation
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Low cross sections (≈ fb) expected for stop and chargino/neutralino pair
production
Possibly the only sparticles with mass below 1-2 TeV because of naturalness
Factor of 10 in integrated luminosity will extend the reach considerably
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Resonances
 Several BSM predicts i.e. new gauge bosons (Z’)
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Explore ditop resonances, as well as dileptons.
Di-top
Di-lepton
 Sensitivity up to about 8 TeV
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Challenges: sub-detectors
and trigger system upgrades
Based on:
Phase II
Phase I
In preparation: end of 2012
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17/09/2012
Upgrade goals
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The studies presented assume detector and trigger performance similar to
(or better than) those of the present detector, despite the extremely
challenging environment for data rate and radiation
Ensuring such performance is crucial and requires
 Upgrade/replace selected elements of the apparatus (due to radiation
damage) and associated readout, trigger, data acquisition and
computing systems to exploit fully the new phases of LHC running at
instantaneous luminosities up to ~5×1034 cm-2 s-1 in Phase II
 Maintain infrastructure efficient and operational over decades
ATLAS UK: Work packages (WP) on
- Tracker upgrade (Strips + Pixels)
- Trigger upgrades (L1Calo, L1Track, HLT)
- Computing and simulation studies
For both
Phase I and II
built on heritage from construction and operation
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase 0 and I
 Phase
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0: 2013-2014, planned since few years:
long list of maintenance, consolidations &
repairs
4th pixel layer installation (IBL)
new chambers in muon spectrometer to
improve coverage
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Phase I: 2018 (in Phase I LoI, TDRs and MoUs 2013/14):
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New muon inner endcap Wheels (due to high
occupancy of current ones at HL)
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Expect better fake rejection and efficiency
Calorimeter electronics & trigger upgrades
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Higher-granularity L1Calo trigger
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Fast tracker (FTK) input to LVL2 triggers
HLT upgrades
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UK contributions
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Computing & software
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Forward proton detectors (AFP, 210 m)
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase I - L1 Calo&trigger upgrade
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UK institutes are engaged in upgrade of Level 1
Calorimeter Trigger, crucial to mantain trigger
acceptance
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For Phase I: the UK is building the electron
Feature Extractor (eFEX) to mantain electron
trigger thresholds at the current level (25-30 GeV)
Fundamental step for Phase II as well
fake rate for electron rate
Without eFEX
From LoI
<m>=46
L=2 x 1034
With eFEX
+had isolation
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WP7, April 2013 – March 2019
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase I – the High Level Trigger
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Significant investment and on-going commitment of UK institutes in HLT selection
software, data-flow and processor farms (WP9: April 2013 – March 2019)
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Increase Data Throughput
Provide for new detectors (Inner Pixel and muon wheel)
Increase Computing Power
New readout Buffer Input design and Single-Node farm
Developing new framework
for L2 tracking (L2star)
 ½ ROBin boards for ROS built in UK
Current
ATLAS:
split
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase II
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Inner detector (ID) has limited lifetime:
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Now
aged mostly by high total radiation dose (fluence)
Very severe pile-up conditions expected: from 140
to 200 PV
Need finer segmentation to ensure pattern
recognition
 Complete construction of a new ID to be tested
on surface in 2021 and installed during LS3
 New calorimeter readout to provide higher
granularity information for the L1 Calo trigger
 L1 Track trigger
 Major change to trigger architecture, with use
of 2-stage (L0/L1) hardware trigger
 Changes in the very forward calorimeters
Phase-II TDRs and MoUs to be
prepared ~2016
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2022
140-200 collisions every 25ns
bunch crossing
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
New Inner Detector: performance
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Need of new ID (ITK) with excellent
tracking efficiency + low occupancy to
achieve low fake rate, preserving
performance up to 200 pile-up:
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Several algorithms and pile up
conditions compared
Lepton identification
Capability of identifying Primary and Secondary
Vertex of charged particle tracks
Identification of bjets (b-tagging)
Track finding efficiency in
several Pile-up conditions
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17/09/2012
Phase II R&D: tracker upgrade
 All-silicon inner detector (strips + expanded
 WPs 1-6: April 2013, March 2016
Long Barrel Strips Short Barrel Strips
pixel system)
Forward Strips
Forward pixel
Barrel pixel
Baseline layout of the new ATLAS inner tracker for HL-LHC
Aim to have at least 14 silicon hits everywhere (robust tracking)
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17/09/2012
R&D tracker upgrade: Short strip
 UK Institutes have a major involvement in many aspects.
 Deliverables for Short
strip tracker region:
based on a large area composite double-sided detector element (stave)
 Major goal: fully define the final stave using ASICs technology towards
development of mass-manufactoring processes
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Schematic of
short strip stave
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Schematic of short strip module
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Short strip program
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Two clusters of UK Institutes to be formed (Northern and Southern) capable
of the full production process
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Northern: Glasgow, Lancaster, Liverpool, Sheffield
Southern: Birmingham, Cambridge, Oxford, QMUL, RAL, UCL
Essential to guarantee sufficient production rates and quality control checks
Deliverables from current program
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Stave Prototypes and Powering Concepts
Concept based on single-sided
modules sandwiched around a
carbon fibre core with
integrated cooling
Full Length 12 Module Mock-up Stave
2.5V
0V
5V
7.5V
12.5V
10V
Glue
Glue
Serial Powered Chain of Hybrids
Extra Noise compared to Reference Data
H0
H1
H2
H3
Shield
H0
H1
H2
H3
100mm Cu
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60
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140mm Cu
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46
8
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ENC
ENC
ENC
ENC
Targets low
mass and
large-scale
production
DC-DC Stavelet
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17/09/2012
R&D tracker upgrade: Pixel
Development and construction of the forward pixel disk
 2013-2016: focus on R&D in preparation for mass manifacture
 deliverables: prototype disks and modules (sensor + 4 FE-I4 chips)
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4 FE-I4 compatible
sensors from IBL
project suitable for
prototyping
Schematic of pixel disk: to be
developed from current IBL modules
QUAD module
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Quad sensor masks
fabricated with Micron
Semiconductor (UK)
Ltd
R&D tracker upgrade: radiation
 Simulation studies for radiation levels and layout optimization
Detailed studies of beam radiation, expected occupancy
and fluences dependence
n-in-p Planar FZ Sensor Irradiations
Strip
Doses
900V
1.3×1015neqcm-2
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Higher voltages and
thinner sensors allow
even higher doses to be
survived
Pixel
Doses
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Computing for HL-LHC
phase-1 & phase-2
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UK effort reflect those of existing leadership and expertise
 Distributed computing system, ATLAS simulation, Software for tracking
system, visualization tools
WP10, April 2013-March 2018
All strands in current phase of the upgrade project  expect changes of
emphasis in the future planning:
 Significant effort in development of tracking software, simulation and
reconstruction for detector and trigger upgrades
 Cope with evolution in hardware and software technologies
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Usage of many-core processors along with onboard vector-like coprocessors
with application of memory-reduction methods (job-level and event-level
parallelism)
Evaluation of performance
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase II – Trigger upgrade
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Hardware trigger in two stages, Level-0 and Leve-1:
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Level-0 running at < 500 kHz in < 6 us
Level-1 running at <200 kHz in < 20 us
Level-1 Trigger from Phase I largely re-used to form Level-0 trigger at
Phase II;
Additional (new) L1Calo processing of full-granularity calorimeter data
and matching of track and calorimeter features;
Extensive changes to HLT – improved selections, work with improved
Level 1 information
L1 Track trigger
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase II - L1 track trigger
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WP8, April 2013 – March 2016
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Estabilished as essential R&D needed concurrently with new ID
development
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Several follow up projects for HLT:
(possible Phase II trigger architecture in back-up)
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17/09/2012
Summary & outlook
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The LHC and ATLAS are performing well, and recent achievements such as the
discovery of the Higgs-like particle demonstrate this
The luminosity upgrade will dominate the high energy discovery frontier in the next
two decades
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Strong physics motivation (properties of the new Higgs-like fundamental particle, searches for BSM physics
up to multi-TeV scale)
Using an established facility and experiment to its full potential is mandatory for the HEP community
Upgrades of the detectors required to cope with the high instantaneous and
integrated luminosity (high radiation and occupancy, 140-200 pile-up)
Major STFC investment has given the UK a leading role in the R&D for the ATLAS
Tracker and Trigger upgrades, crucial for Phase II and in coordination & planning of
the overall ATLAS upgrade programme
“Remarkably, the recent discovery came at half the LHC design energy, much more severe pileup, and onethird of the integrated luminosity that was originally judged necessary. This demonstrates the great value
of a bold early conceptual design, a systematic programme of development and construction, and a
detailed understanding of detector performance, in confronting challenging physics goals.” (ES document
ATLAS contribution, Cracow)
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Back up
New physics at 33 TeV

An energy increase to 33 TeV, with an assumed integrated luminosity of
300/fb has been also considered:
 It will substantially enhance the sensitivity to SUSY and BSM particles,
particularly to strongly produced ones
Relative event yield
Model
14TeV
33TeV
Sparticle with
O(αs) coupling
3.5
7.5
This compares favorably with an
increase of about 500 GeV from a tenfold increase in integrated luminosity to
3/ab at constant √s=14TeV
HE-LHC needs substantial advance in
many domains from an accelerator side
(physics, beam injection&dumping...)
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Higgs spin/CP in ‘golden’ channel ZZ*
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Higgs self-couplings
Relevant to determine the SM
parameters and higgs mechanism as
responsable for EWK symmetry breaking
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Trilinear self-coupling lHHH can be determined via direct Higgs pair
production from gluon fusion:
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So far, studies on two specific channels:
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Expected (NLO) s = 34 fb
Enhanced at low lHHH (71 to 16 fb for lHHH 0 or 2)
HH  bbWW* channel: 25% BR but large top background
HH  bbgg channel : 0.27% BR, irreducable bkg from ttH and other SM
processes, for a maximum S/sqrt(B) of about 3
Promising: HH  bbtt under study
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Search for squark/gluinos
 An increase of integrated luminosity from 300 fb-1 to 3000 fb-1
improves the sensitivity to sq/gl by approximately 400-500 GeV
 Higgs boson in complex SUSY decay chain can be identified
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Flavor Changing Neutral Currents
 Several BSM predicts FCNC couplings in the top sector
 Example: studies of top decay BR in Z/g
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Phase I – L1 Calo architecture
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Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012
Possible Phase II architecture
HLT upgrade work in UK
Optimize the event selection
for higher luminosities
•Incorporate new Pixel
layer in tracking
6 ms
Muon Tracks
< 20 ms
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L1 trigger
< 200kHz.
•Integrate FTK inputs to
HLT event selection
•Explore the use of
GPUs to speed up
pattern recognition
Monica D'Onofrio, PPAP Meeting, Birmingham
17/09/2012