Status of the LHCb experiment

Andrei Golutvin ( Imperial & CERN & ITEP )on behalf of the LHCb Collaboration

Outline:

Introduction Detector Subsystems Trigger/Online/Computing Cost and funding issues Collaboration matters Physics goals in 2010

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The installation of LHCb is fully completed, including M1 station

All detector elements are commissioned and ready for data taking Read out at 1 MHz successfully tested

Full Experimental System Test (FEST), which is able to inject MC data to Event Filter Farm, is used for the HLT commissioning Strategy for trigger and subsequent physics analysis of the 2009-2010 Run is prepared LHCb is fully operational for the Physics Run in 2010

RRB October 2009

Brief Summary

LHCb Collaboration

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700 members15 countries52 intitutes

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Beam Pipe (CERN)23 m long beam pipe consisting of 3 Be and 1 stainless steel sections

• The procurement of a replacement beam pipe UX85/3B is underway It is fully budgeted by CERN

• Design of optimized beam pipe supports with reduced material is ongoing

Magnet (CF)Warm dipole magnet with 4 Tm bending power

along the beam axis

• Magnet was powered in July and September 2009 to perform a survey on the support of TT and RICH-1 shielding using CCD cameras. Much improved stability no other intervention on the support structures needed

VErtex LOcator (CH,DE,GB,NL) 2×21 pairs of Si sensors arranged in 2 halves; each pair consists of one sensor with R-

and one sensor with -strips

5RRB October 2009

VELO is now ~100% operational

– LV and HV system are operating stable

LV spares situation substantially improved due to delivery of spares from CAEN

– DAQ read out at 1 MHz– Online and offline monitoring finalized – Vacuum and cooling systems fully operational

Until September 2009 the temperature was kept at -5°C.

Lowered to the nominal -30°C for the recent TED RUN (completed Yesterday) in readiness for full data taking

– VELO interlock box ready (including spare)– The build of the VELO replacement continues. ~50% of

modules,

capton cables and vacuum feedthroughs complete

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TI8

LHC

- Transfer line External beam Dump - Shots every 48 seconds - Joint work with TT/IT/ST and SPD - Typical occupancy of 7 clusters/sensor/event

• The procedure to tune the timing tested with data

• Timing accuracy < 2 ns can be achieved with ~ 100 clusters/sensor/step

• Timing is monitored online

VELO experience with TED runs

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Results with 255 tracks: Histogram 2.163

mm( = 0.080 mm)

Milliepede 2.156 mm

The halves were moved by a “secret” amount (450 m).

Results with 852 tracks: Histogram 2.611

mm ( = 0.087 mm)

Milliepede 2.601 mm

Very Preliminary

Very Preliminary

VELO was moved by 445 ± 10 m

Evaluation of the distance between 2 VELO halvesusing TED data

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Outer Tracker – OT (CERN,CF,CN,DE,NL,PL)Three stations with each 4 stereo layers of straw tubes 5 mm diameter and 5m length; 55k channels

OT

CaloMuon

Outer Tracker is ready for data taking

• Installation and test of FE electronics completed

• OT read out at 1.11 MHz

• HV test continued, 99.9% channels ok! Likely a large fraction of remaining 0.1% can be recovered

• The anti-ageing treatment of detector modules at 40°C in situ has been completed. Gas system modified to allow an oxygen admixture if necessary

• Initial time and space alignment within expectations The procedures for further offline improvements give expected results. High level data quality monitoring is being finalized

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- 2 FE boxes show high rate issues- 3 FE boxes (at the edge of acceptance) dismounted

Status of the Front End electronics (9 / 2009)

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without alignment with alignment

T1 T2 T3

OT spatial alignment using cosmics(using drift time information)

Alignment accuracy better than 100 musing only 10k tracks

ST: Trigger Tracker & Inner Tracker(CERN,CH,DE,ES,UA)

TT covers area of 1.41.2 m2; 4 stereo layers with ladders consisting of 3 or 4 chained Si- sensors with strip pitch 183 micron; 143k channelsIT: 3 stations with 4 boxes each arranged around beam pipe; each box has 4 stereo layers x-u-v-x, modules with one or two chained Si-sensors; strip pitch 198 micron; 130k channels

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ST is ready for data taking

• After repair work during shutdown 99.7% IT channels and 98.6% TT channels are operational

• Both detectors successfully read out at 1 MHz

• Detailed studies of detector performance using TED data; IT ladders aligned to < 20 m precision

• Remaining concern is the broken bonds appearing on seven TT modules. Four of the effected modules replaced with spares; three left in situ to study the evolution in the pit. Order new hybrids in the next months.

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Innermost bond row affectedEffect not reproduced in the lab(despite of extensive studiesapplying vibrations & thermalcycling)

Possible causes:

• Initial cracks due to the bonding process, typically occur at first bonds• Loop height (should be > 25%)

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Three modules left in situ in order to study progress of the problemOrder for new hybrids to be placed

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ST analysis of TED data

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• IT ladders aligned to precision of ~14 m

• TT alignment requires better understanding of VELO seeds

• Expect from the analysis of recent TED run:

- Improved quality of VELO-TT & IT-TT tracks - Improved timing

RICH (CERN,CF,GB,IT)RICH1 and RICH2 with 3 radiators covers momentum rRecent highlighange 2-100 GeV; RICH1: 5cm aerogel with n=1.03 & 4m3 C4F10 with n=1.0014; RICH2: 100m3

CF4 with n=1.0005; ~500 HPD to readout

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Both RICH1 and RICH2 are complete, commissioned and waiting for data

• Recent highlight is the observation of Cherenkov rings from the aerogel and gas ( C4F10 ) radiators using cosmic rays convincing test of the online monitoring and offline reconstruction software.

• Estimate of lifetime is well established process for each HPD. The details of repair process of all degraded tubes agreed with DEP-PHOTONIS. Tubes expected to fail in RICH-2 in 2009/2010 are being replaced (14 HPD available).

• Timing alignment, in particular for RICH-2.

• RICH-1 Magnetic Distortion Monitoring System tested.

• Some HV supplies were showing short saturation glitches. Cause identified by the manufacturer. All HV suppliers repaired. Overall stability is now satisfactory

LHCb RICH1 sees rings with cosmic rays(RICH1 has two radiators: aerogel and gas)

Ratio of the rings radiicorresponds to the ratio of the gas and aerogelrefractive indexes

Aerogel ring

Gas ring

17RRB October 2009

• Excellent Signal/Noise of HPD (only a few out of ~105 active channels were noisy). • Number of detected Cherenkov photons agree with expectations

18RRB October 2009

Calorimeters (CERN,CF,ES,FR,RO,RU,UA) PS/SPD: 12k scint. tiles readout by WLS; ECAL:

6k shashlik cells; HCAL: TILE Calo, 1.5k channels

19RRB October 2009

The four calorimeters system SPD/PS/ECAL/HCAL is fully operational

• Much improved stability of the 6000 ECAL channels modified during 2008/2009 shutdown. PMT gain measurements agree within 5% with earlier test measurements ~10% inter-calibration at the start-up

• HCAL is inter-calibrated to <4% using the Cesium source

• All calorimeters are successfully read out at 1 MHz

• SPD/PS/ECAL/HCAL time aligned within 3 ns Further improved using TED data

• Emphasis on ECAL calibration procedures and data quality controls

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Timing inside crate & Front End card

PS / ECAL / HCAL aligned to < 1ns using TED dataFast improvement expected with a few millions events

Improved CALO timing using TED data

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(G(LED) – G(HAM)) / G(LED)

Mean: 2.3%

R.M.S.: 11.4%

Comparison of the ECAL PMT gain measured in situ with previous measurements (@ LAL and Hamamatsu)

PMT gain can be measured in situ using LED calibration system

Taking into account that all moduleshave been measured at cosmics beforethe installation ECAL is inter-calibratedto ~ 10% at the start-up

Several methods to reach 1% levelusing 0 signals have been tested with MC data

Muon (CERN,CF,IT,RU)Arranged in 5 SuperLayers; M1 consists of 12 double triple GEM

chambers and 264 MWPC’s; M2-M5 consists of 1104 MWPCs

22RRB October 2009

• The installation of M1 station completed in time by July 7 M1 commissioning is nearly completed; M1 included in the global DAQ

• HV systems operational

• Commissioning of M2-M5 stations completed Faulty readout channels fixed

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02 March 2009: cables and pipes…

July

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Sept

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first

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M1 history in brief

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Hardware level (L0)

Search for high-pT μ, e, γ and hadron candidates

Software level (High Level Trigger, HLT)

Farm with O(2000) multi-core processors

HLT1: Confirm L0 candidate with more complete

info, add impact parameter and lifetime cuts

HLT2: B reconstruction + selections

Trigger & Online &Computing(CERN,CF,CH,DE,FR,ES,GB,IT,NL)

Hig

h-L

ev

el T

rig

ge

r

2 kHz

Le

vel -

0

L0 e,

40 MHz

1 MHz

L0 had

L0

ECALAlley

Had.Alley

Global reconstruction30 kHz

HLT1

HLT2

MuonAlley

Inclusive selections, +track, topological,

charm, ϕ

& Exclusive selections

Storage: Event size ~35kB

(L0) (HLT1) (HLT2)

Electromagnetic 70 %

> ~80 % > ~90 %Hadronic 50 %

Muon 90 %

Trigger is crucial as σbb is less than 1% of total inelastic cross section and B decays of

interest typically have BR < 10-5

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• L0 trigger rechecked following improvements in the MUON, CALO and DAQ The integration of M1 underway.

• L0×HLT1×HLT2 tuned to give an output rate below 2 kHz (for MC data produced at nominal LHCb conditions @ 2×1032).

• HLT farm has been increased to 550 processing units sufficient to receive 1 MHz trigger rate at nominal event size.

• The readout network expanded to nominal capacity. Completion of the farm to reach its full CPU power will be decided in the beginning 2010.

• New MC09 data sample prepared to mimic 2010 conditions. A total of 109

min. bias and 100’s billion signal events run on the GRID. Many improvements in the production system.

• MC09 is being used to tune the trigger settings to the start-up and first physics. Trigger is capable to efficiently select charm in addition to the core B-physics programme.

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Cost and FundingOverall cost remains unchanged at 75 MCHFThe underfunding in 2005 of 2.6 MCHF for the DAQ CPU Farm, hasbeen covered through extra contributions (BMBF Brazil, France,MPI Germany, Spain, UK, US and CERN)

Budget forecast for M&O Cat. A for this year is correct for all the itemsexcept Online and Power estimates

Collaboration Matters• Two new applications for Technical Associates:

- Catholic University of Rio de Janeiro, Brazil - Tier-1 centre CCIN2P3, Lyon, France

Final decision is expected at the next CB in December 2009 Guy Wilkinson (University of Oxford) elected as the next PhysicsCoordinator starting from January 2010

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Physics goals in 2010Early measurements - Calibration signals and minimum bias physics: 108 eventsKey channels available in min bias data with simple trigger: - Ks ππ 95% purities achievable using - Λ pπ kinematical & vertex cuts ~ 40 mins @ 1031

With 2 kHz random trigger

- J/ψ trigger on single muon with pt cut (600k ev./pb-1) one muon unbiased for PID studies and momentum calibration

- J/ψ physics & production cross-sections: ~ 1-5 pb-1

Measure diff. cross-section for promptJ/ψ and bb production cross-section(from secondary J/ψ) in regioninaccessible to other experiments

Λpπ

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Physics goals in 2010

Charm physics: 20 pb-1 and upward ( Exciting possibilities even with low luminosity)

An example: flavour tagged D0KK events for measuring yCP

y = τ(D0 Kπ) / τ(D0 KK) – 1and corresponding CP asymmetry LHCb can collect ~ 105 flavour tagged KK events with 20 pb-1 (same statisticsas BELLE with 540 fb-1 ). Similar data sets for many related channels:

D0ππ, KKππ, KSππ, KSKK, D+ KKπ …

Detailed studies of Dhh (rehearsal for Bhh) - Separate Kπ, KK, ππ and DCS Kπ - Vertex and mass resolutions - LifetimesAccumulate samples of BD(Kπ)π(“ADS” control mode) - Study background environment - Look for any evidence of B+ / B- asymmetries

Analysis commissioning in hadronic modes

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Prospects for most competitive measurements in 2010

With data sample of ~200 pb-1

LHCb should be able to improveTevatron sensitivity for Bs μμ and ϕs

(present ‘central’ value from Tevatron wouldbe confirmed at 5σ level)

Bs μμ

ϕs

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Conclusion

LHCb is ready for data taking

First data will be used for calibration of the detector and trigger in particular. First exploration of low Pt physics at LHC energies. Some high class measurements in the charm sector may be possible with 50 pb-1

With ~ 200 pb-1 data sample LHCb will reach Tevatron sensitivity in a few golden channels in the beauty sector

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Calorimeter hardware status

Non working channels

Non working LED

ECAL 2/6016 none 17 PMT changedLED fixed

HCAL 1/1448 none 4 PMT changed

PS 0/6016 20 Cables plugged Patch Panel

SPD 0/6016 10% channels

Cables cured

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M2 M3 M4 M5

2008

2009

Noi

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hann

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G. Graziani

M2-M5 channel map: 2008 vs 2009A few missing logical channels in 2009 map due to wrong settings (too high threshold)