??????? ? ATLAS LoI (1992)

1
21.May.2005 T. Kobayashi
ATLAS????????(??5) ?????????????(?????)
M1????
1)??????????? ??????? ? ATLAS
LoI (1992) 2)???choice??????performance ?
ATLAS Physics TDR (1999) 3)????????key
point(??????) H ? llll, gg, tt(VBF) SUSY
(SUGRA, GMSB, ?)
2
???????
???????????????? ??????????????? ??????
3
Physics Goals of ATLAS (as of 1992, LoI)
sensitivity to the largest possible Higgs mass
range detailed studies of top quark mass and
decays Standard Model studies (gauge boson
couplings) SUSY searches sensitivity to large
compositeness scales search for unexpected new
physics ????top???, mH lt 1TeV, SUSY or
DSB(techni-color), gauge unification(),
SUGRA () Ugo Amaldi, Wim de Boer,
Fuerstenau (1991) ????top???Higgs mass range,
GMSB, VBF(), ED, little Higgs, ? ()
Rainwater, Zeppenfeld, ?? (1998)
4
Examples of physics signatures
Higgs searches H ? gg from pp ? HX or
ttH, WH, ZH with e or m tags H ? ZZ ? eeee
or eemm or mmmm H ? ZZ ? as above, llnn, ll
jetjet (le,m) H ? WW ? lnl-n or ln
jetjet with forward jet tag A ? tt H
? tn Top quark physics tt ? WbWb ? ln jets
plus b-tag tt ? HbWb ? tn ln plus
b-tag Supersymmetry Main signatures for
squark and gluinos are missing ET plus jet
topologies (direct decays) plus W or Z (cascade
decays) Compositeness Deviations in the jet
cross section from the QCD expectation for very
high pT jets ? Sensitivity to a variety of
final state signatures is needed
5
Detector goals
Primary goal Balanced approach to electron,
gamma, muon, jet and missing transverse energy
measurements at high luminosity Additional
goals During initial lower luminosity, and to
as high a luminosity as practicable, more
complex signatures including tau detection and
heavy flavour tags Large acceptance in rapidity
and transverse momentum thresholds Homogeneous
detector layout with only the essential
components Design within realistic cost
constraints ? Detector performance goal
(see Table)
6
Global detector concept
Powerful inner detector in a 2T central solenoid
for accurate momentum measurement of isolated
leptons over a large rapidity span (-2.5 lt ? lt
2.5) and electron identification High quality
EM sampling calorimetry combined with fine
granularity preshower detection for electron and
gamma detection Hermetic hadron calorimetry for
jet and missing transverse energy measurements
(-5 lt ? lt 5) Air-core toroid muon spectrometer
with large acceptance (-3 lt ? lt 3) and
stand-alone momentum measurement capability High
precision vertex detector for (initial) lower
luminosity operation Modular and flexible
trigger, DAQ and analysis architecture
7
Detector component choice
Inner detector precision tracking -
silicon micro strip and pixel detectors
electron identification and continuous tracking
- straw tube with transition radiation
detection (TRT) Calorimetry electromagnetic
with Pb absorber - liquid Argon accordion
hadronic with Fe absorber - scintillator
tiles and liquid Argon(with Cu) very forward
calorimetry (3 lt ? lt 5) - liquid Argon
in tube/rod with Cu/W Muon measurements
momentum measurements - MDT and CSC
triggering and 2-nd coordinate measurements
- RPC and TGC
8
ATLAS Detector
EM Calorimeter (LAr)
Hadron Calorimeter (sci. tile, LAr)
Muon Spectrometer (MDT, CSC, RPC, TGC)
Toroid Magnets (air-core)
23m

(Weight 7000 ton)
42m
Inner Detector (pixel, SCT, TRT)
Solenoid Magnet (2T)
9
Compact Muon Solenoid (CMS)
? Solenoid???
10
ATLAS Inner Detector
Physics TDR (1999)
R4cm
50m(Rf)300m(Z)
R11, 20cm
80m pitch, 40mrad stereo
R30, 37,45,52cm
4mmf straw
R56107cm
(? 30m, continuous tracking, electron-id)
11
ATLAS Inner Detector

• Solenoid Magnet (2T field)
• Pixel Detectors (1.4108channels)
• Strip Detectors (6106 channels)
• Transition Radiation Tracker (4105 channels)

? s(pT)/pT 0.4 pT (pT in TeV)
12
B 2T
B 4T
s(pT)/pT 0.36 pT 0.013 (pT in TeV)
0.15 pT 0.005
Tracking ??
(ATLAS?KS-id??)
13
?????? Liq.Ar and Tile Calorimeters
ID?Liq.Ar?????????????? ??????????????(??1.5)?
14
ATLAS EM Calorimeter
4 X0
- preshower detector for particle id.(g/p0,
e/p) - precise h position measurement
16 X0
212 X0
for energy loss correction
15
back section
Barrel EM calorimeter
middle section
strip section
16
(No Transcript)
17
??????????
3 samplings for precision physics
???????
EndCap??????? (FCAL??3.2lt?lt4.9)
18
EM Calorimeter Performance

• ????????????? H????4e
• ??? 4????(E,p) or (t,x)???????????Kamiokande
• ATLAS Liquid Argon ???????????????!
• ???????? s/E10/?E ? 200(400)MeV/E ? 0.7
• ????? 4-6 mrad/?E (????Middle Layer(?2?))
• 50 mrad/?E (????StripMiddle Layer?Z
  vertex???)
• ????? 100 ps (1ns at 1GeV)
• ???? e/jets, ?/?0 gt 3 at ET50GeV
• Linearity lt 0.1
• Dynamic range 20MeV(MIP????????) -
  2TeV(?????????)
• ATLAS Liquid Argon???????
• ?/????????????????????(????????)
• Azimuthal?2p(??????)????????? ?lt3.2 (FCAL
  lt4.9)?????
• Liquid Argon??intrinsic?rad-hard?
• ?????????????

sx,y(IP) 15m
sz(IP) 5.6cm
19
CMS ECAL PbWO4
ATLAS
20
ATLAS Hadron Calorimeter
gt11l in front of Muon system ? reduction of
punch-through 10l active calorimeter(incl.
1.2l of EM) ? good E-res. for HE jets
LAr, rod tube geometry
21
TileCal
PMT
WLS fiber
10k channels
22
FCAL
LAr gap 250m, 375m
(9.5l)
Cu
W
W
23
FCAL
4 rod are ganged for readout ? 4k channels
24
The ATLAS Muon Spectrometer
ATLAS A Toroidal LHC ApparatuS

• Muon Spectrometer
• toroidal magnetic field ltBgt 4 Tm
• ? high pt-resolution independent
• of the polar angle
• size defined by large lever arm to
• allow high stand-alone precision
• air-core coils to minimise the
• multiple scattering
• 3 detector stations
• - cylindrical in barrel
• - wheels in end caps
• coverage ? lt 2.7

• Trackers
• fast trigger chambers TGC, RPC
• high resolution tracking detectors MDT,CSC

25
(No Transcript)
26
Muon Detection and Magnet System
h lt 2.7 air-core
h lt 2.4 Fe
27
Muon Detector
Monitored Drift Tubes (? lt 2) with a single
wire resolution of 80 µm Cathode Strip Chambers
(2 lt ? lt 2.7) at higher particle fluxes
Precision chambers
(p-meas.)
Resistive Plate Chambers (? lt 1.05) with a
good time resolution of 1 ns Thin Gap Chambers
(1.05 lt ? lt 2.4) at higher particle fluxes
Trigger chambers
(trigger, 2-nd coord.)
28
sagitta measurement
point-angle measurement (1.4 lt h lt 2.7)
29
Momentum measurement
ID
? muon stand alone ? ? inner detector ?
ATLAS 2.5 _at_100GeV 3.8
CMS 8 _at_ 100GeV 1.6
30
4 Muon final state

• H?mmmm

? GH
(1.5 )
31
Discovery Potential of SM Higgs
32
H???
ATLAS better uniformity and angular resolution
CMS better energy resolution

33
Combined H???0j and H???1j Analysis
H???1j
H???0j
B.Mellado (University of Wisconsin) _at_Higgs WG
meeting 30/03/05
34
(No Transcript)
35
Vertex Correction
Z Beam Axis O (0,0,0) of Atlas coord.
system O Event Interaction Point C shower
center in calorimeter RC radius of shower center
We use the shower depth parameterization to
calculate shower center
36

• Application of vertex correction (correction of
  photon angles using position of vertex) improves
  Higgs mass resolution by 27

MC_at_NLO MH130GeV DC1/7.0.2
Before Vertex Correction
After Vertex Correction
?/M1.04
?/M1.42
37
Gauge mediated SUSY breaking models
M(gravitino) lt 1 GeV NLSP ? gravitino ?
(SUSY breaking scale of messenger sector )2/Mm
Messenger mass
? short lifetime
? long lifetime
? NLSP
38
GMSB G2b point
c1
? stable heavy charged leptons
c2
c4
hlt1
Reconstructed slepton mass sM / M 4
ATLAS MDT ? st 1ns
? ??????????
39
A Possible Gauge Mediation Signal
ct O(1m)
tg (arrival time)
L
Gravitino???????
40
EM Calorimeter Performance

• ????????????? H????4e
• ??? 4????(E,p) or (t,x)???????????Kamiokande
• ATLAS Liquid Argon ???????????????!
• ???????? s/E10/?E ? 200(400)MeV/E ? 0.7
• ????? 4-6 mrad/?E (????Middle Layer(?2?))
• 50 mrad/?E (????StripMiddle Layer?Z
  vertex???)
• ????? 100 ps (1ns at 1GeV)
• ???? e/jets, ?/?0 gt 3 at ET50GeV
• Linearity lt 0.1
• Dynamic range 20MeV(MIP????????) -
  2TeV(?????????)
• ATLAS Liquid Argon???????
• ?/????????????????????(????????)
• Azimuthal?2p(??????)????????? ?lt3.2 (FCAL
  lt4.9)?????
• Liquid Argon??intrinsic?rad-hard?
• ?????????????

f????
????
41
4th ATLAS Physics Workshop (Athens, May
2003) LAr EM Calorimeter Results from Beam
Tests F. Djama - CPPM Marseille
Time resolution
(ps)
Resolution 70 ps _at_70GeV
42
A Possible Gauge Mediation Signal
ct O(1m)
? missing-ET ??
100 lg events ? sM/M (slepton, neutralino) 3
PRD69(2004)035003
43
???????
???????????????? ??????????????? ??????
(CMS?????ATLAS?????????????) Motivation??????
?????????? (???????????) ????MC
simulation????????????????????!