ECAL planning towards installation Compilation from planning by Alexander Aref

1
Sergey Barsuk CERN and ITEP,Moscow
On behalf of the LHCb collaboration
Assisi, June 2024, 2005
The LHCb experiment Status and expected physics
performance
2
Introduction

• LHCb is a dedicated experiment to study CP
  violation and other rare phenomena in B meson
  decays (and also c,t,jets,)
• Precision measurement of CKM parameters
• Test of Standard Model predictions / search for
  new physics
• Expect 1012 b-hadrons / year
• All b-species are produced Bu (40), Bd
  (40), Bs (10), Bc (0.1), ?b (10), ,
  Excited states,
• Bu, Bd are being explored in great detail
  (thanks to B-factories)
• gt Improve statistics (other sources of
  systematics)
• Bs time resolved studies (not accessible at
  B-factories)

3
b-production at LHCb

• LHC Luminosity _at_ LHCb
• 2-5 x 1032 cm-2s-1
• sbbar 500 µb
• sinelastic 80 mb

?b
beam
1 LHCb year 2 fb-1 1012 bb
4
Detector requirements
Decay Bs -gt Ds K, Ds -gt Fp Flavour tag
B -gt Dl?
Example
Exclusive B-decay reconstruction gt Kinematics
measurement gt Particle ID
Flavour tagging gt Particle ID
Proper time (L1cm) Fast Bs oscillations gt
Precise vertexing
Efficient trigger Control of systematics
5
The LHCb detector kinematic measurements
Charged tracks
?, po
Vertex LOcator Trigger Tracker Inner/Outer Tracker
Magnet
Calorimeter
-gtTalk by Matthew Needham
6
VErtex LOcator

• 21 stations in vacuum tank
• R/f sensors
• 180k R-O channels

VELO
Si sensor
1 m
Sensors sensitive area 8mm from beam line (30
mm during injection)
R-O chip
hybrid

• PVx position resolution
• x,y 8 µm
• z 44 µm
• IP precision 30 µm

• VELO in the TestBeam in 2006
• -gt study of pattern recognition, alignment,

Vacuum vessel arrived at NIKHEF in 04/2005
7
Magnet

• ?Bdl 4 Tm
• Warm dipole magnet (Al), Fe yoke 1600 t
• Daily reverse field to reduce systematics

Installed and commissioned in 2004 Field mapping
ongoing
8
Tracker
Sensors
Kapton cable

• Trigger Tracker
• Silicon Strip, 1.6 x 1.3 m2
• gt 144k channels
• Inner Tracker
• Silicon Strip, 1.2 x 0.6 m2
• gt 129k channels
• Outer Tracker
• Straw tubes, 5.6 x 4.6 m2
• gt 54k channels

Sensor ladders
60 of chambers produced
Electronics hybrid

• Efficiency 94 (pgt10 GeV/c)
• Ghost rate 3 (pTgt0.5 GeV/c)
• Momentum resolution 0.4

9
The LHCb detector particle ID
p/K/p
e, ?, po
µ
RICH system
µ -system
Calorimeter
-gtTalk by Tito Bellunato
10
RICH system
RICH2 15-120 mrad
RICH1 125-300 mrad
RICH1 Aerogel and C4F10 RICH2 CF4
p/K separation for true pions from B-gtpp events
ltp/K separationgt
Photon detectors Hybrid PhotoDiodes (HPD)
11
RICH system
Contract for 500 HPDs signed Delivery starting
from 07/2005
Installation of RICH1 shielding in the LHCb
detector
Entrance/exit windows of RICH2
12
Calorimeter

• Scintillator Pad Detector / Preshower (SPD/PS)
• Electromagnetic calorimeter (ECAL)
• Hadronic calorimeter (HCAL)

projective geometry, variable granularity
SPD/PS

• SPD/PS
• Sc-Pb-Sc 15mm-14mm-15mm
• 2 x 6k detector cells/R-O channels
• Deep groove design of cell
• 2.5 Xo depth
• Production ongoing

HCAL
ECAL
SPD/PS modules with 144, 64 and 16 detector cells
100 outer type modules produced
13
Calorimeter ECAL

• Shashlyk technology
• 6k detector cells/R-O channels
• Volume ratio PbSc 24 (mm)
• 25 Xo , 1.1 ? depth
• Production completed

• Light yield 3000 ph.e./GeV
• Cell-to-cell spread r.m.s.lt7
• Energy resolution s(E)/E 10/VE 1

Lateral scan of ECAL module with 50 GeV e-beam
ADC channels
Spread across the module for beam parallel
to module axis lt 1.3 for beam at 200 mrad
lt 0.6
mm
X
14
Calorimeter ECAL

• Wall size is within measurement error to design
  value
• x,y-positions of module are known to 0.5 mm
• z-position all modules within 2 mm

15
Calorimeter HCAL

• Fe-Scintillator tile calorimeter
• 1.5k detector cells/R-O channels
• 5.6 ? depth
• Production completed
• Cell-to-cell spread r.m.s. lt 5

Assembly of HCAL module
1/2 HCAL is installed in the detector
16
Muon detector

• 5 stations with projective pad R-O
• Production at 6 sites
• In total 1368 MWPCs
• Produced and tested 450 MWPCs (30)

PNPI2
Poliuretanic foam
Cathode PCB
Cathode pads
20 ns
2mm pitch wire R-O

• Efficiency 95
• p-misID rate lt1

17
A very busy time in the LHCb cavern
18
Trigger
-gt talk by Frederic Teubert

• Level 0 (40 MHz -gt 1 MHz)
• -gt hardware
• high-pT e, ?, po, µ, h
• gt CALO, MUON
• pile-up veto
• gt VELO
• Level 1 (1 MHz -gt 40 kHz)
• -gt software
• large IP and pT tracks
• gt VELO, TT
• High Level Trigger
• -gt software
• complete event info
• gt ALL
• offline selection
• -gt 2 kHz on tape
• -gt systematics and data mining

Large pT
b-physics topology Mb 5 GeV/c2 ß?ct 1 cm
Large IP
L0 L1 L0xL1
19
Baseline measurements

• Bs oscillations frequency, phase and ?Gs
• Bs -gt Ds p
• Bs -gt J/? F, J/? ?, F ?c

• Measurement of ?-Arg Vub
• Bs -gt Ds K
• only tree diagrams -gt no NP
• Bd -gt pp, Bs -gt KK
• U-spin symmetry, NP in gluonic penguins
• Bd -gt Do K, Do K, DCP K
• Dunietz-Gronau-Wyler method, NP in DD-mixing

• Rare decays, search for NP
• Bd -gt K?, ??, Bs -gt F ?
• Bs -gt FF, Bd -gt FKs
• Bd -gt K µµ
• Bs -gt µµ

20
Event generator PythiaQQ Full detailed Geant
simulation of detector pile-up and spill-over
included Realistic digitization and
reconstruction with full pattern
recognition Realistic L0, L1 trigger
simulation Assumption Major background
bb-inclusive events large pT, IP,
secondary vertices, multiplicity Toy MC used for
sensitivity studies acceptance and resolutions
parameterized from full MC Reconstruction/analysi
s software environment
-gt talk by Patrick Koppenburg
21
?ms measurement Bs -gt Dsp
Ds -gt KKp
Proper time resolution 40 fs
LHCb 1 year
?ms 25 ps-1

• 82k events/year
• B/S 0.32 0.10

• 5s measurement in 1 year of running for ?ms up
  to 68 ps-1
• (far beyond Standard Model expectation ?ms lt
  26 ps-1)
• Once oscillations are established, determine
  ?ms with s(?ms) 0.01stat ps-1

22
? measurement Bs -gt DsK
Ds -gt KKp
K/p !!!

• 5.4k events/year
• B/S lt 1

Bs -gt DsK
Bs -gt Dsp

• Measures ?-2?

5 LHCb years
Bs -gt DsK
1 LHCb year
Bs -gt Dsp
?ms, (ps-1 ) 20 25 30
s(?), (o) 14.2 16.2 18.3
23
Bd -gt pp, Bs -gt KK
Bd -gt pp
Bs -gt KK
K/p !!!
24
? measurement Bd -gt pp, Bs -gt KK

• Measures ?
• Time-dependent asymmetries for Bd-gtpp and
  Bs-gtKK
• ACP(t) Adir cos(?m t) Amix sin(?m t)
• Parameters ?, fd(fs), P/T d e i?
• Take fd(fs) from other measurements
• U-spin symmetry Fleischer
• dpp dKK and ?pp ?KK
• gt 4 measurements, 3 unknown
• gt Solve for ?
• s(?) 5o in 1 LHCb year
• Uncertainty from U-spin assumption
• Sensitive to new physics in penguins

• Bd -gt pp 25k events/year
• Bs -gt KK 37k events/year

LHCb 1 year
Contours 68 CL 95 CL
25
Bs -gt J/? F
J/? -gt ll F -gt KK

• Non-CP state gt partial waves
• Measures fs -2 ? ?0.02 is small
• Simultaneous measurement of ?Gs in SM
  ?Gs/Gs0.1

Annual yield B/S
100k lt 0.3
7k lt 5.1
3.2k lt 1.4
gt 5 years sensitivity s(fs)0.02
26
Rare decays
Test of SM/QCD search for NP
Bs -gt F?
Bs -gt FF
Gluonic penguin
E/W penguin
9.3k events/year B/S lt 2.4
1.2k events/year B/S lt 0.2
Bs -gt µµ
Bd -gt Kµµ
E/W penguin
LHCb 5 years
4.4k events/year
AFB
17 events/year
27
Bc -gt J/? p
LHCb 1.5 month
CDF 2005
Yield 14k events/year B/S lt 0.8
28
Flavour Tagging
Determine the flavour of the signal B-meson at
production

• Quality of the flavour tagging
• tagging efficiency etag (RW) / (RWU)
• wrong tag fraction ? W / (RW)
• effective tagging efficiency eeff etag
  (1-2?)2
• (after passing trigger and offline cuts)

• Algorithms
• Opposite side
• leptons from semileptonic decays
• K from b-gtc-gts chain
• inclusive vertex charge
• Same side
• K from fragmentation accompanying Bs meson

In the LHCb, measure ? using control channels
with similar topology
29
Summary of principal physics channels
Nominal year 1012 bb pairs produced (107 s at
L2x1032 cm-2s-1 with sbb500µb) Yields include
factor 2 from CP-conjugated decays Branching
ratios from PDG or SM predictions
30
Performance after 1 LHCb year (2 fb-1)
channel yield precision
? Bs -gt Ds K Bd -gt pp, Bs -gt KK Bd -gt Do K Bd -gt Do K Bd -gt DCP K 5.4k 26k, 37k 0.5k 3.4k 0.6k s(?) 14o s(?) 6o s(?) 8o
? Bs -gt J/? F 120k s(?) 2o
Vtd/Vts Bs -gt Ds p 80k ?ms up to 68 ps-1
rare decays Bd -gt K ? 35k s(ACPdir) 0.01
-gt talk by Guy Wilkinson
systematics !
31
Summary

• LHCb detector is optimized for precise
  measurement of CP violation and search for new
  phenomena
• Exploit 1012 b-hadrons / year with all
  b-species
• -gt B(s,c)-factory
• Complementary/competitive to (Super)-B(d,u)-fact
  ories and Tevatron
• Detector construction is advancing well
• To be ready for the first LHC collisions in
  2007
• Physics potential can be fully exploited with
  the initial LHC luminosity
• More on LHCb in Wednesday/Thursday talks
• -gt M.Needham Status of the LHCb tracking
  system
• -gt T.Bellunato Status of LHCb RICH and HPD
  
• -gt F.Teubert LHCb trigger development
• -gt G.Wilkinson LHCb strategy to understand
  systematics
• -gt P.Koppenburg Reconstruction and analysis
  software environment of LHCb

32
To conclude
Historically, competitions on Beauty involve the
famous apple the Apple of Discord
33
and in a few years