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 activities Run-2 update Upcoming Heavy Ion Run The Future of ALICE 2 R. BELLWIED
ALICE Physics output 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 contributions to scientific output 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 5/35 R. BELLWIED
ALICE Run 1 analysis highlights ALICE-USA highlights Jet analyses with the calorimeters Full jet R AA (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) 6/35 R. BELLWIED
Measurements including neutral jet component from calorimeters Full jet R AA measurement Di-jet acoplanarity in pPb Results in agreement with high pT No strong modification of kT due to hadron reconstruction and with cold nuclear matter with respect to several energy loss models event multiplicity or the PYTHIA reference Results with bigger jet cones and larger kinematic range to follow soon 7/35 R. BELLWIED
Event Shape Engineering 8/35 R. BELLWIED
Event Shape Engineering (2) VHMPID 9/35 R. BELLWIED
An antimatter factory ALI-PUB-72522 arXiv:1506.08951 Anti- 4 He is the heaviest anti-nucleus ever observed 10/35
Nuclei/Anti-nuclei abundance ratio The ratio nuclei / anti-nuclei is compatible with one, as for all other particle species 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 of the detector. 11/35 arXiv:1506.08951
Mass Difference of Nuclei and anti-Nuclei CERN Press Release, Nature Physics (2015) Binding energy difference Mass difference • Highest precision measurement of mass difference in the nuclei sector • Improvement by 1-2 orders of magnitude compared to earlier measurements • Constraint on CPT symmetry violation improved by a factor 2 for deuteron. First measurement for (anti-) 3 He 12/35
(Anti-)Hyper-triton Very loosely bound, BE < 150 keV Identified as Fit to the differential yield in different c t bins extract the lifetime: Yields well described by thermal model fits 13/35 arXiv:1506.08453
No evidence for strange exotica Search for LL and L n bound Search for strange pentaquarks states (arXiv:1506.07499) (arXiv:1406.3206) The f (1860) penta-quark was announced in No evidence for H-Dibaryon at a rate of about a factor 50 below thermal model 2004 by the NA49 collaboration (in the X - p + channel in pp collisions) predictions No evidence in our data Strange (NA49) = X - p + , Charm (LHCb)= J/ y p 14/35
Focus on small systems: Double ridge in p-Pb near-side jet away-side jet correlations correlations - = near-side ridge Phys. Lett. B 719 (2013) 29 60-100% 0-20% 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
Focus on small systems : y (2S) production in p-Pb R pPb vs y 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-p T Model w/ co-mover interactions + EPS09 describes ALICE data R pPb vs p T arXiv:1405.3796
ALICE detector installations in LS1 • New installations FULL TRD – 5 TRD modules – 8 DCal modules (approved in 2010, US led project) – Add 1 PHOS module DCAL 4 PHOS SM
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. 4 th 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
Run-2 progress Steady data taking Accumulation of raw data in Run 2 Fast calibration and reconstruction Quasi-online data processing Without backlog 1.83 PB of data, 1,338,895,095 events reconstructed 19/35
Charged-particle density at 13 TeV • INEL: b = 0.104(2) • INEL>0: b = 0.107(5) CMS, 1507.05915 arXiv:1509.08734 arXiv:1509.08734 dN/d η in | η |<0.5 INEL: dN/d η measured for two INEL>0: dN/d η in | η |<1.0 normalisation classes: Energy dependence fitted with power-low function as b INEL: inelastic events Energy dependence in fair agreement with INEL>0: events having at least one expectations from low energy extrapolations charged particle in | η |<1
P T distributions at 13 TeV arXiv:1509.08734 - Spectrum significantly harder than at 7 TeV - Shapes depend strongly on charged-particle multiplicity - In fair agreement with event generators. arXiv:1509.08734
ALICE performance at 13 TeV: TPC and TOF Gas mixture in TPC changed from Ne – CO 2 (90:10) to Ar – CO 2 (90:10): • ensure a more stable response for the high particle flux generated during p-Pb and Pb-Pb running • no degradation of momentum and dE/dx resolution 22/35 ALICE-PUBLIC-2015-004
The Particle Zoo: strangeness… f L X K* 0 K s ALICE-PUBLIC-2015-004
… and charm 24/35 ALICE-PUBLIC-2015-004
Collected statistics and plans 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 ) 25/35
The future of ALICE So far: year system energy √s NN integrated TeV luminosity ~ 0.01 nb -1 2010 Pb – Pb 2.76 ~ 0.1 nb -1 2011 Pb – Pb 2.76 ~ 30 nb -1 2013 p – Pb 5.02 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 26/35
The ALICE Upgrade: status • Five Pillars (each in a Technical Design Report), all approved by LHCC, UCG and RB, the latest this past September: 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 27/35
The LS2 ALICE upgrades New Inner Tracking System (ITS) Muon Forward Tracker (MFT) • improved pointing precision • new Si tracker • less material -> thinnest tracker at the LHC • Improved MUON pointing precision MUON ARM • continuous Time Projection Chamber (TPC) readout • new GEM technology for electronics readout chambers • continuous readout • faster readout electronics New Central Trigger Processor Data Acquisition (DAQ)/ High Level Trigger (HLT) • new architecture • on line tracking & data compression TOF, TRD, ZDC New Trigger 28/35 • 50kHz Pbb event rate • Faster readout Detectors (FIT)
The ALICE Upgrade: status 1. Readout Pb-Pb MB collisions at 50 kHz 2. Unique Physics Program with x100 larger statistics • Low momentum heavy flavor • Heavy flavor jets • Low mass di-leptons • Heavy nuclei and exotica 29/35
Recommend
More recommend
