first high p t physics prospects with the photon spectrometer at alice
Download
Skip this Video
Download Presentation
First High p T Physics Prospects with the Photon Spectrometer at ALICE

Loading in 2 Seconds...

play fullscreen
1 / 14

First High p T Physics Prospects with the Photon Spectrometer at ALICE - PowerPoint PPT Presentation


  • 118 Views
  • Uploaded on

First High p T Physics Prospects with the Photon Spectrometer at ALICE. Kenta Shigaki (Hiroshima University ) for the ALICE Collaboration 3 rd Joint Meeting of DNP’s of APS and JPS October 14, 2009 Waikoloa, Big Island, Hawaii. Most Relevant Members.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' First High p T Physics Prospects with the Photon Spectrometer at ALICE' - lei


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
first high p t physics prospects with the photon spectrometer at alice

First High pT Physics Prospectswith thePhoton Spectrometer at ALICE

Kenta Shigaki

(Hiroshima University )

for the ALICE Collaboration

3rd Joint Meeting of DNP’s of APS and JPS

October 14, 2009

Waikoloa, Big Island, Hawaii

most relevant members
Most Relevant Members
  • + all PHOS and PWG4 (jet/photon) collaborators

Kenta Shigaki Aya Hiei Hisa Torii

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

presentation outline
Presentation Outline
  • LHC/ALICE/PHOS status and schedule
  • high pT neutral mesons in first year of ALICE
    • statistics and pT reach
    • technical challenges and resolutions
  • first high pT physics prospects
    • p0 in Pb+Pb run in 2010
    • more work in progress
  • summary and concluding remarks

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

lhc alice phos status schedule
LHC/ALICE/PHOS Status & Schedule
  • collisions in 2009/12; physics awaited in 2010
  • ALICE under commissioning
    • cosmic data taking ongoing
    • LHC beam (p and Pb) also seen
  • 3(/5) PHOS modules installed; being cooled down

September, 2009

Pb beam injection oriented

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

jet quenching at lhc
Jet Quenching at LHC
  • higher pT reach + stronger suppression than RHIC
    • clearer measurement of quark energy loss
      • e.g. quark flavor/spin dependent suppression?
  • “day-1” ALICE physics program
    • enough acceptance with initial 3 PHOS modules

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

statistics p t reach in 1 st p p run
Statistics + pT Reach in 1st p+p Run
  • assumptions:
    • 10 TeV p+p;

5×1028 cm-2s-1;

180 days×10%

    • p0 in NLO/CTEQ6M/KKP;

particle ratios from PYTHIA

    • 3/5 PHOS geom. coverage

(~ high pT limit) only

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

statistics p t reach in 1 st pb pb run
Statistics + pT Reach in 1st Pb+Pb Run
  • assumptions:
    • 3.9 TeV Pb+Pb;

5×1025 cm-2s-1;

30 days×10%;

~ 10% central (b < 5 fm)

    • NLO pQCD×PYTHIA

×N-N binary scaling

(1,150 for central Pb+Pb)

×suppression (0.1)

    • 3/5 PHOS geom. coverage

(~ high pT limit) only

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

lhc first year versus years at rhic
LHC First Year versus Years at RHIC
  • statistics not really an issue

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

and more

Technical Experiences

and More
  • multi-photon decay channels challenging
  • kinematic cut optimization to improve S/B
  • careful combinatorial background subtraction
  • PHOS: highest resolution ever in RHI experiments

PHENIX example wp0g

PHENIX wp0g

Au+Au peripheral (cent 60~92 %)

3.5 < pT < 4.5 [GeV/c]

WA98

13 GeV Pb+Pb

nucl-ex/0108006

PHENIX

200 GeV Au+Au

run 2

ALICE

14 TeV p+p

GEANT simulation

after cut optimization

S/√B (significance)

w

before cut optimization

pT(w) [GeV/c]

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

feasibility evaluation ingredients
Feasibility Evaluation Ingredients
  • single particle simulation
    • NLO pQCD×PYTHIA×N-N binary scaling×suppression
    • mass reconstruction in ALICE analysis framework
      • acceptance for multi-photon decays
      • two-cluster resolution (merging effect)
      • photon identification
  • 1 M central Pb+Pb HIJING at 3.9 TeV
    • locally generated at Hiroshima
  • “hybrid” approach
    • multiplicity effects in next steps
      • embedding study by combining the two

h

p0

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

s b and s s b
S/B and S/(S+B)
  • better S/B, not necessarily S/(S+B), at higher pT
  • p0 in ~ 10% central Pb+Pb at 3.9 TeV; RAA = 0.1
  • 5×1025 cm-2 s-1, 30 days, 10% uptime
  • feasible up to >> 10 GeV/c
  • more species (h, w, K0s) under study

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

proof of hybrid approach applicability
Proof of Hybrid Approach Applicability
  • p0 peak visible in central Pb+Pb HIJING
  • consistent S/B in NLO/HIJING hybrid evaluation
    • multiplicity effects to be tested by embedding

pT = 3 GeV/c

pT = 4 GeV/c

pT = 5 GeV/c

pT = 6 GeV/c

pT = 7 GeV/c

pT = 8 GeV/c

pT = 9 GeV/c

pT = 10 GeV/c

with gID

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

summary and concluding remarks
Summary and Concluding Remarks
  • new physics prospects at very high pT at LHC
  • ALICE at LHC starting in months (finally!)
  • neutral meson yields in first year very promising
    • both for p+p and Pb+Pb runs
  • real issue: S/B ratio, significance S/(S+B)
    • especially for multi-body decays (e.g.w, K0s) in Pb+Pb
  • p0 feasible even in central Pb+Pb
  • work in progress: h, w, K0s
    • solid basis on RHIC experiences
  • physics from very beginning of LHC operation!

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

famous kinematic cut asymmetry
Famous Kinematic Cut: Asymmetry
  • discard highly asymmetric pairs to reduce BG
    • background concentrated at high a ( asymmetry)
    • acceptance only at low a at low pT
    • optimized for p0: a < 0.7 at pT 3 GeV/c
    • two photon separation only at high a at very high pT
      • minimum a cut option
  • more complicated cuts for > 2 body cases
    • e.g.p0–p0 energy asymmetry in K0s case

Hawaii ’09 – First High pT Physics Prospects with PHOS at ALICE – K.Shigaki

ad