Aurelio BayInstitut de Physiquedes Hautes Energies

Aurelio.bay@iphe.unil.ch

July 13-25, 2000, Hanoi, Vietnam

SM

~Vub

from BXu+l

from m:

B0B0

B0

J Ks

W Wt

t

CP Asym ~ sin[2(new )]

t

d

b

tW W

b

d

~

~Vtd

The Unitary TriangleThe Unitary Triangle

Im

Re

+ New FCNC

= cte

from BXu+l

from m: + rnew

new

B0

Wt

t

~

d

b

b

dNEWFCNC

Unchanged

rnew

NEW

new

+

SM + New FCNC

~Vub

from BXu+l

from m:+rnew

new

B0B0

B0

J Ks

W Wt

t

CP Asym ~ sin(2(new))

t

d

b

tW W

b

d

~

d

b

b

dNEWFCNC

Unchanged

rnew

NEW

The Unitary TriangleThe Unitary Triangle

Im

Re

from Bd D*-n+, D*+n-, etc.

Idem with Bs decays:Idem with Bs decays:

snew from CP in Bs J

snew from CP in Bs Ds

K, Ds

K

compare the two determinations(then combine them)

Bd D*nvs Bd D*n

Bd D*n vs Bd D*n

From 2(new) +

CP in BJ/Ks ~ 2(+new)

We want to measure , we need to select hadronic decay channels,

we want to study the Bs system, have K/ separation, access to Br < 10….

• BABAR, BELLE, CLEO-III, CDF, D0, HERA-B will test CKM at the O(3) level.

• LHCb is a second generation experiment for CP violation studies in the B and Bs meson systems. The goal is to obtain precise and overconstrained determination of CKM elements, including terms beyond O(3). This will permit to detect deviations from the Standard Model description and thus to probe New Physics.

• Second generation means:

– High statistics is needed to study Bu,d,s decays with Br < 107

– Excellent proper time resolution

– Excellent particle identification

– Efficient and flexible triggering scheme, including a selection on hadrons.

• High statistics can be obtained by LHCb because

– B production cross section at 14 TeV:

– LHCb running luminosity:

fi

LHCb overlook

Rate(bb) = 105 sec1 : 0.5% total inelastic Rate(bb) = 105 sec1 : 0.5% total inelastic

bb ≈ 500 bbb ≈ 500 b

cm s cm s

LHCb

LHC beamscollide here

Magnetdipole

Vertex Locator

Œ[15, 300]mrad

Œ4.91.9

x

z

20 m10 m

Open geometry with (quite) easy access to (almost) all components

non-bendingplane view

LHCb bending plane

Vertex Locator (VELO)

Design work on front-end chip (DMILL and sub-micron technolgies) in progressprototype of R measuring 1/2 plane

-20

80 cm

0

toward

spectrometer

retract by3 cm duringbeam setup

0 0.8 4 cm• ≈ 200 m Si single-side• R and measuring planes• 220 kchannels, analogue R/O, S/N =15

z ≈ 40 m resolution on

interaction point

Z

impact parameter

100

10

[m]

0.1 1 10Pt [GeV]

RICH

Threshold [GeV/ c ]

Aerogel C4F10 CF4

.6 .6 4.4K . 9. 5.6

K– separation > 3 1<p< 100 GeV/c

largeaerogelrings

smallC4F10 CF4 rings

pixel HPD

Gas CF4

Gas C4F10

Aerogel

pedestal

1 p.e.

2 p.e.

3 p.e.

4 p.e.

RICH R&D

DEP prototype pixel HPDDEP prototype pixel HPD

Photodetectors options:HPDs and multianode PMTs

• single photoelectron resolution•QE = 17% @ 400 nm• spatial resolution ~1 mm• large area ~2.9 m2, active: ~ 70% 325 kchan. binary readout• B stray field up to 100 gauss• radiation dose < 3kRad/year

Pion beam:large rings in aerogeland small rings in C4F10

threshold

Other Systems Magnet: Warm dipole 4 Tm - 4.2 MW - 1450t TDR ok Tracker

Inner: (40x60 cm2) triple GEM , Si 3 stations

Outer: straw-tube drift chambers p/p = 0.3 % [5 , 200] GeV/c

(MB) =15 MeV/c2

(MD) = 4 MeV/c2

Calorimeter (design completed)

Pre-shower sandwich Pb - scintillators

ECAL Shashlik type, 25 X0

HCAL Fe + scintillating tiles, 5.6R/O by wave-length shifting fibers and PMTs MUON

Resistive Plate Chambers (RPC) + Wire and Cathode Pad Chambers (WPC/CPC) for high rate regions

HCAL Fe+scintillating tiles

ECAL Shashlik

Joint Calorimeter Test

0 20 40 GeV

30

20

10

0

HCAL resolution %

0 50 100 150 200 GeV

preshowerECAL resolution %

LHCb Trigger Efficiency

L0(%) L1(%) L2(%) Total(%) e h all

BdJ/(ee)KS + tag 17 63 17 72 42 81 24BdJ/()KS + tag 87 6 16 88 50 81 36BsDsK + tag 15 9 45 54 56 92 28BdDK Bd + tag 14 8 70 76 48 83 30

for reconstructed andcorrectly tagged events

where the hadron trigger is important

where the leptontrigger is important

Tags considered (so far): – muon or electron from other b-hadron b lepton

– charged kaon from other b-hadron b c s

Overall tag efficiency = 40% Overall mistag rate = 30%

Tags considered (so far): – muon or electron from other b-hadron b lepton

– charged kaon from other b-hadron b c s

Overall tag efficiency = 40% Overall mistag rate = 30%

Trigger System

~30 %

~10%

Running luminosity

2 x 1032

Running luminosity

2 x 1032

LHC: 40 MHz L0:1 MHz L1:40 KHz Output:200 Hz

High PT electronsHigh PT hadrons

High PT muons

Pileup Veto

L0decision

unit

L1 Trigger3D reconstruction

of secondary vertices

L2+L3 TriggerFull event

information

Latency: 4 s < 2 ms

B0

Inelastic pp interactions

hadron triggerthreshold

DsK

Ds

5.2 5.3 5.4 5.5 GeV/c2

Mass, decay time resolutions and particle ID

Measurements of ms

with a significance >5: up to4psxs5

Bs-Bs oscillations with BsDs

ms 30 ps

Bs DsKseparation from

Bs Ds

Bs DsKseparation from

Bs Ds

DsK

Ds

5.2 5.3 5.4 5.5 5.6 GeV/c2

m = 11 MeV/c2m = 11 MeV/c2Mass(DsK)

with RICHwithout RICH

LHCb CP Sensitivities in 1 year

Parameter Channels+c.c. No of events (1 year)

Bd 5k @P/T = 30°, |P/T|=0.200.02, =90° 2-5

Bd0 1k @ =50° 5

2+ Bd D*(incl.) 260k @2+=0 12

BdJ/Ks 100k <0.6

-2 Bs DsK 2400 8(ms=15ps-1) - 12 (45ps-1)

Bd DK* 400 10

Bs J/ 50k 0.6

Bs oscillations

xs Bs Ds 35k up to 75 (5)

Rare Decays

Bs 11 s/b=3.5

Bd K0* 4500 s/b=16

Bd K* 26k s/b=1

See yellow Book CERN 2000-004 !

2000

2001

2002

2003

Inner Tracker

Vertex Detector

RICH, Calorimeters

Muon System

L0 & L1 Trigger, DAQ

Computing

Outer Tracker

Magnet installation

LHCb schedule (and conclusion)

2004

2005

Magnet

1998 Technical Proposal 1999 LHCb approved

LHCb ready for LHC « day one »and for many years of B physicsat “nominal LHCb luminosity”

TechnicalDesignReports

Detector and DAQ installation