ALICE Experiment Highlights and Status Rene Bellwied (ALICE-USA - - PowerPoint PPT Presentation
ALICE Experiment Highlights and Status Rene Bellwied (ALICE-USA Coordinator) University of Houston (bellwied@uh.edu) USLUA Meeting, Chicago, November 2015 R. BELLWIED * 1 Topics to be discussed Status of ALICE Run-1 analysis LS1
University of Houston
(bellwied@uh.edu)
USLUA Meeting, Chicago, November 2015
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Status of ALICE Run-1 analysis LS1 activities Run-2 update Upcoming Heavy Ion Run The Future of ALICE
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A significant scientific output: 139 ALICE papers on arXiv High impact papers: average of 75 citations Several 100 presentations at international conferences each year 29 talks and ~70 posters at QM 2015 alone
LHC physics publications by number of citations
ALICE-USA comprises about 8% of the ALICE members ALICE-USA members give about 10% of all ALICE presentations ALICE-USA members have contributed to 30% of all ALICE publications ALICE-USA members have reviewed 44% of all ALICE publications
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ALICE-USA highlights Jet analyses with the calorimeters Full jet RAA (PLB 746 (2015) 1) Di-jet correlations (PLB 746 (2015) 385) Hadron-jet correlations (arXiv:1506.03984) Event shape engineering (arXiv:1507.06914) Hyper-nuclei and exotica (arXiv:1506.08453) Strangeness in small systems (see lightning round talk) Mass difference between nuclei and anti-nuclei (Nature article) Anti-matter production (arXiv:1506.08951) Focus on pp and p-Pb Flow in pPb (arXiv:1506.08032) Charm in pPb (arXiv:1405.3796)
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Full jet RAA measurement
Results in agreement with high pT hadron reconstruction and with several energy loss models Results with bigger jet cones and larger kinematic range to follow soon
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Di-jet acoplanarity in pPb
No strong modification of kT due to cold nuclear matter with respect to event multiplicity or the PYTHIA reference
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VHMPID
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ALI-PUB-72522
Anti-4He is the heaviest anti-nucleus ever observed
arXiv:1506.08951
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The ratio nuclei / anti-nuclei is compatible with one, as for all
A large fraction of the systematic uncertainties on the determination of the ratios is due to the limited knowledge of the cross sections of anti-nuclei interacting with the material
arXiv:1506.08951
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CERN Press Release, Nature Physics (2015)
measurement of mass difference in the nuclei sector
earlier measurements
violation improved by a factor 2 for deuteron. First measurement for (anti-)3He
Mass difference Binding energy difference
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Very loosely bound, BE < 150 keV Identified as
Fit to the differential yield in different ct bins extract the lifetime: Yields well described by thermal model fits arXiv:1506.08453
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Search for LL and Ln bound states (arXiv:1506.07499)
No evidence for H-Dibaryon at a rate of about a factor 50 below thermal model predictions
Search for strange pentaquarks (arXiv:1406.3206)
The f(1860) penta-quark was announced in 2004 by the NA49 collaboration (in the X-p+ channel in pp collisions) No evidence in our data Strange (NA49) = X-p+ , Charm (LHCb)= J/yp
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0-20% 60-100%
near-side jet correlations away-side jet correlations near-side ridge
Subtraction of jet correlations reveals double ridge structure Clear indication for mass ordering in p-Pb Resembles Pb-Pb Ridge extends out to |Dh|=5 and |h|=4 Collective flow? arXiv:1506.08032
arXiv:1405.3796
RpPb vs y RpPb vs pT
Suppression of charmonia in p-Pb is an indication of initial state nuclear matter effects y(2S) suppression stronger than for J/y, especially at low-pT Model w/ co-mover interactions + EPS09 describes ALICE data
4 PHOS SM DCAL FULL TRD
– 5 TRD modules – 8 DCal modules (approved in 2010, US led project) – Add 1 PHOS module
ALICE-USA contributions: Electromagnetic calorimeters
Run1: PHOS: lead-tungstate, |h|<0.13, 260<ϕ<320 EMCal: lead-scintillator, |h|<0.7, 80<ϕ<187 Run2: DCal calorimeter installed back-to-back to EMCal: 0.22 < |h| < 0.7, 260 < ϕ < 320. |h| < 0.7, 320 < ϕ < 327. 4th PHOS module + charged particle veto detector installed Readout upgrade (100kHz readout as foreseen for run3) New trigger system allowing EMCAL, PHOS and DCal to act as a single trigger detector
EMCAL DCAL
Fast calibration and reconstruction Quasi-online data processing
Without backlog
Accumulation of raw data in Run 2
1.83 PB of data, 1,338,895,095 events reconstructed
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dN/dη measured for two normalisation classes: INEL: inelastic events INEL>0: events having at least one charged particle in |η|<1
arXiv:1509.08734 CMS, 1507.05915
Energy dependence in fair agreement with expectations from low energy extrapolations
INEL: dN/dη in |η|<0.5 INEL>0: dN/dη in |η|<1.0
Energy dependence fitted with power-low function asb
arXiv:1509.08734
arXiv:1509.08734 arXiv:1509.08734
ALICE-PUBLIC-2015-004
Gas mixture in TPC changed from Ne–CO2 (90:10) to Ar–CO2 (90:10):
flux generated during p-Pb and Pb-Pb running
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ALICE-PUBLIC-2015-004
ALICE-PUBLIC-2015-004
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Collected statistics in pp at 13 TeV: Minimum-bias: 600M High-multiplicity: 1.8 pb-1(V0) and 0.24 pb-1(SPD) Muon triggers: 4.3 pb-1 Plans for pp reference at 5.02 TeV in 2015 (2 days): Integrated luminosity: O(100 nb-1) Muon triggers: O(100 nb-1) Plans for Pb-Pb at 5.02 TeV in 2015 (3 weeks): Integrated luminosity: O(300 ub-1) EMCAL/DCAL/PHOS triggers: O(200 ub-1) Central barrel UPC triggers: O(200 ub-1) Muon triggers: O(300 ub-1)
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So far: The future: RUN2 (2015, 2016, 2017) : will allow to approach the 1 nb-1 for PbPb collisions, with improved detectors and double energy RUN3 + RUN4 (2021, 22, 23 and 27, 28, 29): 10 nb-1 of PbPb at full field in the ALICE magnet plus a dedicated low-field run and pPb with major detector improvements So: three phases, each jumping one order of magnitude in statistics and progressively improving the detectors year system energy √sNN TeV integrated luminosity 2010 Pb – Pb 2.76 ~ 0.01 nb-1 2011 Pb – Pb 2.76 ~ 0.1 nb-1 2013 p – Pb 5.02 ~ 30 nb-1
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1. Completely new Silicon Inner Tracking System 2. New or upgraded readout for all detectors to cope with the higher rate, new CTP and Trigger Detectors 3. New readout chambers for the Time Projection Chamber 4. New Silicon Tracker in front of Muon Absorber 5. New Data Acquisition System and High Level Trigger to handle the continuous readout, new Offline
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New Inner Tracking System (ITS)
Time Projection Chamber (TPC)
readout chambers
electronics MUON ARM
readout electronics Muon Forward Tracker (MFT)
Data Acquisition (DAQ)/ High Level Trigger (HLT)
compression
TOF, TRD, ZDC
New Trigger Detectors (FIT) New Central Trigger Processor
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1. Readout Pb-Pb MB collisions at 50 kHz 2. Unique Physics Program with x100 larger statistics
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The DOE funded BTU (Barrel Tracking Upgrade) project Contribution to Silicon Tracking (ITS) Contribution to TPC Upgrade (TPC) Contribution to Readout and Trigger System (via calorimeters) Contribution to Online/Offline (O2) computing Upgrade project supported by all U.S. institutions (Creighton, UHouston, UTennessee,
UT Austin, Yale, Wayne State, LBNL, ORNL) under the leadership of LBNL and ORNL
Successful Technical, Cost, Schedule and Management review in April 2015 Main areas of scope: 1. Design, assemble, test and commission new Readout Chambers (ROCs) for Inner
TPC sectors (IROCs) utilizing GEM detectors as charge amplifiers (ORNL, UT Austin, UTennessee, WSU, Yale).
2. Design, fabricate, test and commission new Front-end Electronics for TPC sectors
with continuous, free streaming readout (ORNL, UHouston and UTennessee).
3. Design, construct, assemble and test two out of seven layers of the ITS (LBNL and
UT Austin).
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(GeV/c)
T
p
10 1 10
m) m Pointing resolution (
50 100 150 200 250 300 350 400
ALICE Current ITS, Z (Pb-Pb data, 2011) Upgraded ITS, Z (Pb-Pb data, 2011) j Current ITS, r j Upgraded ITS, rTotal weight 1.4 grams
(GeV/c)
T
p
10 1 10
Efficiency (%)
20 40 60 80 100
ALICE Current ITS Upgraded ITS = 0.8% = 0.3%; OB: X/X IB: X/X
Pointing Resolution Tracking efficiency x 3 X 7
<X/X0> = 0.3%
To operate at the 50 kHz rate => no gating grid => need to minimize Ion Back Flow to keep space charge distortions at a tolerable level Replace wire-chambers with GEMs
New readout electronics Keep all other subsystems Replace wire chambers with quadruple-GEM (full scale prototypes tested in beam in late 2014)
World Largest TPC ALICE key tracking and PID instrument 500 million pixels
UCG exercise in June 2015 TDR approved by RB in October 2015
Data of all interactions shipped from detector to online farm in triggerless continuous mode Data volume reduction by cluster finder No event discarded Average factor 2.2(factor 2.5 for the TPC data) Asynchronous event reconstruction with final Calibration with a delay of few hours.
HI run 1.1 TByte/s
Data Storage: 1 year of compressed data
90 GByte/s
Tier 0
20 GByte/s
Tiers 1 and Analysis Facilities Data volume reduction by tracking All the events go to data storage Average factor 5.5 (factor 8 for the TPC data)
500 GByte/s 90 GByte/s
Paradigm shift
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ALICE is progressing at an enormous pace Run-1 Physics analysis yields exciting results for the RHI
and HE communities
LS-1 Upgrades push ALICE into new territories for Run-2 Run-2 startup very successful, eagerly awaiting heavy
ions
LS-2 Upgrades are on schedule for an exciting program in
Run-3
ALICE-USA is crucial for the experiments success based
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LHC Schedule
PHASE I Upgrade ALICE, LHCb major upgrade ATLAS, CMS ‚minor‘ upgrade PHASE II Upgrade ATLAS, CMS major upgrade Heavy Ion Luminosity from 1027 to 7 x1027 HL-LHC, pp luminosity from 1034 (peak) to 5 x1034 (levelled)
Jan-Feb 2019: open experiment + remove TPC/ITS/beampipe 19 Oct 2015: ITS pixel chip EDR - done 4 Nov 2015: TPC GEM and chamber EDR start of production Nov 2015: ITS stave EDR Mar-Oct 2019: TPC upgrade in cleanroom Nov 2019-Jul 2020: install TPC/new ITS/MFT/FIT beampipe + close experiment Aug-Dec 2020: ALICE re-commissioning EYETS: O2 EL and CV infrastructure in place Q3-2018: O2 installed Nov-2017: ITS IB assembled Aug-2018: ITS OB assembled
Dec-2015: SAMPA final prototype submission Dec-2018: TPC chamber production finished
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