Toward%20the%20LHC-ALICE%20experiment

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Toward the LHC-ALICE experiment

• Hideki Hamagaki
• Center for Nuclear Study
• University of Tokyo

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CNS group

• Staff Members
• Hideki Hamagaki (Group leader)
• Taku Gunji (Deputy leader)
• Kyoichiro Ozawa
• Students
• 4 students for PhD (Doctoral course)
• 3 for RHIC-PHENIX, 1 for LHC-ALICE
• 4 students for Diploma (Master course)
• 2 for LHC-ALICE, 2 for RD of GEM detectors

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Activity of CNS in ALICE

• ALICE-TRD collaboration since 2002.
• Natural choice, based on the CNS group activities
  at RHIC-PHENIX
• Prototype TRD beam test _at_ CERN (2002)
• optimize the radiator, study the basic
  characteristics (dE/dx, TR, gain, space charge,
  resolution) and improve analysis technique
  (Likelihood, neural network) for eID
• First realsize TRD beam test _at_ CERN (2004)
• performance test (chamber, readout electronics,
  material budget)
• Final TRD beam-test (2007) and data analysis
• 2 diploma thesis from CNS (2004, 2006)
• many NIM papers

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Current Activity in ALICE-TRD

• Development of Detector Control System (DCS)
• PVSS
• User interface
• FS/CE/libTRD
• Handle MCM/SCSN/ORI
• distribute configuration pars.
• read results, status and publish to upper layer.
• Applications (hardware access functions)
• Testbench at CNS (DCS/ROBs/Other infra.)
• Commissioning (installation/tests) _at_ CERN

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Physics Strategies in ALICE

• Current major physics topics of the CNS group
• Quarkonia in pp/pA/PbPb via di-electron decays
  
• Open heavy flavor measurement via electrons
  and/or hadrons
• Multiplicity measurement in pp and PbPb with
  TPC
• Possible (near-future) topics
• Extensive study of gluon PDF at small x --- CGC
• New forward EMCal for direct g, p0, J/y, U
• (Exotic) hadrons with multiple heavy quarks
• Upgrade CsI-GEM in HMPID

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Color Glass Condensate

• High gluon density -gt non-linear gluon-gluon
  fusion
• Sizable A dependence
• End of independent particle description of
  partons
• Gluon PDF at x lt 10-2 is very uncertain -gt LHC
  could be an ideal machine to investigate CGC

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A Hint from RHIC data

• Saturation hint at RHIC
• hadrons from d Au by BRAHMS RdAu 0.8 for h
  3.2, pT 3 GeV/c ( x 10-3)
• Sizable PDF modification could be possible even
  at central rapidity in LHC
• y 0, pT 3 GeV/c ( x 10-3)
• RdAu 0.8 -gt RPbPb (0.8)2 0.6
• pA data is crucial, probably more than at RHIC
• uncertain gluon PDF at low x
• interpretation of RAA needs RpA

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Hard Collisions

• Many jets in central PbPb collisions at LHC
• Dnjet/Dh 1.7 x N(coll) 1700
• Dn/Dh 0.2 x N(coll) for RHIC
• gluon shadowing is not taken into account
• Most of them have low energy
• stopped in short-distance, and heat up the system
• Energetic jets
• fraction grows with energy
• jet quenching -- need some distance, before
  stopping

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Hard Collisions (cont.)

• Complication of initial state
• With much larger number of energetic partons,
  time needed for thermalization may become longer
  at LHC?
• Space-time evolution may also become complicated
• A honeymoon between QGP and Hydro may be
  disturbed more often at LHC with intruding jets
• a part of lost energy may be used to heat up the
  fluid, while other part may simply escape the
  system
• This should be a quantitative question hopefully
  to be answered before having collisions at LHC

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Outlook

• Situation at LHC is NOT a mere extension of RHIC
• Tools and knowledge, both experimental and
  theoretical, acquired at RHIC can be utilized to
  challenge the new problems.
• Surely new findings at LHC
• although I cannot guarantee it, since it is
  beyond my imagination.

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Low pT photon production at LHC, pT 2 GeV/c
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M. G. Song, D. H. Lee, B. K. Kim, B. S. Chang,
Y. Kwon, J. H. Kang Department of Physics,
Yonsei Univ., Korea
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Old human record says

• Genesis
• In the beginning God created the heaven and the
  earth.
• And the earth was without form, and void and
  darkness was upon the face of the deep. And the
  Spirit of God moved upon the face of the waters.
• And God said, Let there be light and there was
  light.
• And God saw the light, that it was good and God
  divided the light from the darkness.
• And God called the light Day, and the darkness he
  called Night. And the evening and the morning
  were the first day.

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Direct ? production

• Direct ? production in pp
• ? One of the best known QCD process

Really?
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Multiple collision in factorization? Higher twist?
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Saturation scale? Qs
RHIC Qs 1 GeV ? LHC Qs 2-3 GeV
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Why very low mass dileptons?

• ? ? ? ? ee- , R H Dalitz 1951 Proc. Phys. Soc.
  A 64 667-669
• AND we can avoid ?0 background!

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Dalitz pair mass distribution
invariant mass of virtual photon
invariant mass of Dalitz pair
invariant mass of Dalitz pair
invariant mass of virtual photon
phase space factor
form factor
phase space factor
form factor
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web pages created by  Pier-Luigi Barberis  for  ALICE  Experiment
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Particle identification by ALICE
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TRD(Transition Radiation Detector)
?lt0.9, 45lt?lt135 18 supermodules in F
sector 6 Radial layers 5 z-longitudinal
stack ? total 540 chambers ? 750m² active
area ? 28m³ of gas In total 1.18 million
read-out channels
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Tsukuba group activities for LHC-ALICE
Transition Radiation Detector(TRD) Construction/In
stallation/Commissioning/ Detector-control/Test-ex
periment/Analysis with Heidelberg, GSI,
Frankfurt, Muenster groups

• Outside of TPC, inside of TOF
• Electron ID high pT hadron measurement
• Online tracking higher-level online trigger
• J/y, U, jet, di-jet, mini-jet trigger

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Final Test Beam experiment for TRD just before
installation in ALICE
Transition Radiation photon
M. Konno (P.D.) D. Sakata (M2) M. Sano (M2)
e p
amplitude
Neural Network Method
e p
Amplification region
time bin
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Development of Detector Control System for TRD
H.V. control, Front- end Electronics (FEE)
control and error log
Super Module
M. Konno (P.D.) R. Tanabe (D2) K. Watanabe
(D1) H. Yokoyama (M1)
Chamber with read-out electronics
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Hadron Calorimeter Project (JCAL) for ALICE from
Particle Identification to Parton Identification
Total Energy measurement of Jet Jet Trigger
capability Gluon/Quark Jet separation This
Project is approved to do the detector RD and
and to make a small proto-type for ALICE.
PRL 94 (2005) 171802
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Jet-Tomography hadron-hadron, direct
gamma-hadron,
electron-hadron, identified hadron correlation,
two-particle,
three-particle correlation,
mach-cone, ridge analysis,
jet-reconstruction,
jet-identification Single (identified) spectra
(RAA), event anisotropy (v1, v2) analysis
reaction plane QGP in pp collisions ltpTgt,
v2, HBT, Jet-shape,
fluctuation, correlation, etc
vs Multiplicity,
Geometry
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Univ. of Tsukuba (High-Energy Heavy-Ion
Experimental) Group
Staff ???? Yasuo Miake ???? ShinIchi
Esumi ???? Tatsuya Chujo ??? Motoi
Inaba ???? Masahiro Konno(technical) ???? S
umio Katou (secretary) ???? Hatsume
Sakai Doctor course students ???? Maya
Shimomura ????? Kentaro Miki ???? Yoshimasa
Ikeda ?? ? Rei Tanabe ???? Kengo
WatanabeMaster course students ???? Dousatu
Sakata ???? Masato Sano ???? Hiroki
Yokoyama ??? Midori Kajigaya ????? Eitaro
Hamada ???? Naoki Shiohara ???? Mizuki
Kimura ???? Takahito Todoroki Undergraduate
students ?? Chang Peng ???? Yuki
Sekine ???? Toshimasa Takeuchi