20-sept-2011stan bentvelsen programme: 2005-2010 group composition: 16 staff, 8 postdoc, 24 phd....

20-sept-2011 Stan Bentvelsen

Stan Bentvelsen

Programme: 2005-2010

Group composition: • 16 staff, 8 postdoc, 24 PhD.

Publications:• 18 theses• 296 publications

University partner: UvA, RUN

Investment in experiment:• 11.911 kE (2.7% ATLAS)

Physics at the TeV scale: ATLAS


ATLAS group • Exploitation phase ATLAS

– Permanent staff ~ constant – Decrease technical staff– Increase of PhD student

and postdocs

• D∅ activity is closed down– After period with activity in

top-quarks and SM Higgs.• In-kind contribution:

production of Monte Carlo samples

• Reached goal: excellent preparations for LHC


Mission and research questions

• Our current research topics– Top quark physics

• Top-quark production and properties• Observation of single top

– Supersymmetry• Inclusive searches with missing energy• Flavour tagging in supersymmetry

– Higgs particle• H→ZZ→4 leptons• H→WW→2l±+2ν

Mission: To find and study the Higgs particle(s) responsible for the generation of mass. To search for physics beyond the Standard Model, such as supersymmetry, large extra space-time dimensions, or unexpected phenomena.

ATLAS Origin of mass XXX Antimatter X Quark-gluon plasma Supersymmetry XXX Dark matter X Dark energy Nature of neutrino’s Extra dimensions XX Gravitational waves Magnetic monopoles

X

Origin of cosmic rays Early universe X Unexpected phenomena

XXX

Groesbeek April 22 4

Atlas program - Stan

Bentvelsen - SAC April 17,

20087

End-cap toroidsIn-kind contribution

Semi Conducting TrackerInstallation End-cap

Trigger/DAQMuon Read Out System/Drivers

Muon precision chambers96 MDT BOL chambers

Top quark physics Supersymmetry Higgs physics

Muon tracking ID trackingCombined Tracking


Highlights …• Leadership roles

– in period 2005-2011• Awarded funding

• Conferences organised– 2nd Trigger workshop in Amsterdam (2010)– Particle Physics Symposium: experiment meets theory

(2011)

S Bentvelsen

Higgs or no Higgs at the LHC 2007-2011

FOM project

N de Groot Muons as a probe of supergravity 2006-2011

FOM project

S de Jong ASAP Higgs 2008-2012

FOM project

S Klous Chasing the Higgs boson with a distributed trigger 2008-2011

NWO-VENI

AP Colijn Radiating Top Quarks 2005-2010

NWO-VIDI

I van Vulpen Top quarks and fundamental physics 2006-2011

NWO-VIDI

O Igonkina Lepton flavour violation: 2011-2016

NWO-VIDI

S Bentvelsen

Beyond the top; a new era in particle physics 2007-2013

NWO-VICI

P de Jong Between bottom and top: supersymmetry searches with flavour

2009-2014

NWO-VICI

E Koffeman R&D training network 2009-2012

EU

E Koffeman AIDA detector R&D 2011-2014

EU

N Hessey sLHC: prepatory phase 2007-2010

EU

S Bentvelsen, P Ferrari, W. Verkerke

Top-quark physics group convenor

I Van Vulpen Top quark reconstruction coordinator

P de Jong SUSY physics group convenor

O Igonkina Trigger menu coordinator

W Liebig, P Kluit Combined muon reconstruction convenor

P Werneke SCT End-cap project engineer

K Bos Computing coordinator

N Hessey Upgrade Coordinator

P Ferrari Speakers committee


Tracking in ATLAS

6

Point at 2.36 TeV by Kayl (cum

laude)

Nikhef

reconstruction

• First collisions in 2010-2011– Track density determination– Drell-Yan with muons

• Status SCT/MDT detectors– Excellent performance

• both in efficiency, noise, and reliability

• Plans:– Complete muon software

reconstruction, including taggers


Top quark physics• Top anti-top quark pairs

– Why?• Precision tests Standard Model• Searches for New Physics• Background to supersymmetry

– Production cross section• Single lepton final state

– Nikhef contributions to paper editor,fake lepton estimates and W+jets from data

– Mass of top-anti-top quarks

• Ongoing and plans:– New physics searches in top; tau leptons in top-events– Observe and study single top production

• Search for W-t channel, close collaboration with Nikhef theory

W Verkerke, P Ferrari, S Bentvelsen

After >1 year data approaches Tevatron precision; more top quarks collected


Search for supersymmetry• Cascade decay of SUSY particles

– Signatures with large missing energy from LSP• Searches at Nikhef with

zero, one or two leptons– Sweep phase space with

incoming data• No ‘easy’ supersymmetry

observed

• Plans– Study more difficult

regions of supersymmetry• with less missing energy

and focus on 3rd generation:top, sbottom, stau

– Benefit from 14 TeV runs

2010→2011

P de Jong


Higgs searches• Effort in two decay channels

– H→WW*→lνlν• The most sensitive process for 130 < mH < 200 GeV

– Challenging: reconstruction invariant mass of this system not possible

• Nikhef in ‘cut and count’ method, and multivariate analysis – H→ZZ*→llll

• Very clean, but small rates • Nikhef contributes in muon reconstruction

calibration, efficiency optimisation, baseline analyses

10


Higgs combined limits• Combined ATLAS results

– Combination ofmany Higgs decaychannels

• RooFit package– Implements combination s/w,

statistical analysis– Used throughout ATLAS,

CMS, LHCb and others

• Plans– Observe or exclude SM Higgs

in WW and ZZ final states

Standard Model Higgs boson mass excluded at 95% CL:

146 < mH < 232 GeV256 < mH < 282 GeV296 < mH < 466 GeV

Verkerke

11


Upgrade plans: physics

• Clarify the Electro-Weak symmetry breaking– What happens if there is no light Higgs...

• Some mechanismto prevent WW scatteringto violate unitarity

– Exploration at Nikhef started

– Check properties of Higgs (in case it exists)• Higgs “self couplings”, branching fractions to various

decay modes

• Search for new physics at the TeV scale– Explore all reachable regions of supersymmetry

Need ~ 3000 fb-1

First make full use of 14 TeV run

12


Upgrade plans: technical case• Shutdown 2013-1014

• Increase cm energy to 14 TeV run– Install “b-layer” in existing pixel detector

• Development front end chips & readout• CO2 cooling

• Shutdown 2018• Luminosity tot 2.2 1034 cm-2s-1

– Upgrade muon system• Muon read-out system• Fast track trigger & track finder

• Shutdown 2021-2022• Luminosity levelling to 5 1034 cm-2s-2

– Installation entire new Inner Detector• Inner tracker layout and mechanics• Possible with GOSSIP detector? services

13


Points of attention & remarks• Nikhef in ATLAS

– One of the larger institutes• Hardware responsibilities, leading roles in

muon performance, top quarks, Susy, Tier-1– Big group with many responsibilities

• Continue to keep group focused to coherent set of activities

• Upgrade plans– Further away, and maybe less concrete

than other LHC experiments• Make sure that Nikhef resources will

remain to be available for ATLAS

• For individuals difficult to stand out in large collaboration – At CERN supervision for PhD students – Make sure postdoc positions remain available

14


Conclusion and schedule physics• Thanks to the LHC for delivering so well and so fast

• Eagerly waiting the 14 TeV runs

• Higgs hunting approaches the moment of truth• Closing on Higgs masses - moderate excess• Measurement of quantum numbers and couplings of the

Higgs further away

• Unfortunately, New Physics was not “around the corner”• Experimental challenges as we enter further the Multi-TeV

world.

• Funding for FOM ATLAS program ends January 1st, 2016 • Research program continues beyond

2 fb-1 down; 2998 fb-1 to go!

15


Output 2010• The scientific

output of ATLAS– 21 ATLAS papers

submitted• 3042 authors

– 9 papers withvisible Nikhefcontribution

• 99 conference notes

• 432 internal notes

16


Highlights• Appeal to the imagination!

• General public– Numerous outreach presentations– Higgs movie, Newspapers– Annual open days– ...

– Starting collisions

The Dutch know about LHC

SAC April 2006P

• Construction of 96 large ‘muon chambers’

• Construction of 96 large ‘muon chambers’

18


Semi Conducting Tracker • Responsible one endcap

– Construction SI modules– Mounting all modules– Assembly endcap

• Installation in ATLAS– 4 space-points on track

19


Top quarksEvent display of a top pair e-μ dilepton candidate with two b-tagged jets. The electron is shown by the green track. The two b-tagged jets are shown by the purple cones.

20


20-sept-2011stan bentvelsen programme: 2005-2010 group composition: 16 staff, 8 postdoc, 24 phd....

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