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LHCb Project ReviewNeville Harnew3rd October 2006

Introduction to LHCb and Oxford’s work

Summary of work over the last year

Physics work and planning

Future plans

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LHCb introduction LHCb will:

1. Make precision measurements of CP violation in the decay of all flavours of B mesons

2. Search for New Physics in rare B decays e.g. B→μ+μ-

3. (Hopefully) discover NEW PHysics

LHCb will make measurements from day one

Low energy run in 2007 First physics run in 2008

Schematic of the LHCb experiment

2 Ring Imaging Cerenkovdetectors (RICHes) provide

particle ID over a wide range of momenta-key for hadronic B decays important for CP

studies

RICH electronics, mechanics and

software, along withphysics preparation

and Grid are Oxford’s LHCb activities

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The LHCb Oxford group

Faculty: N. Harnew & G. WilkinsonDept. Lecturer: J. LibbyPostdocs: R. Muresan & P. SpradlinStudents: V. Gligorov, A. Powell, S. Brisbane,

Lauren Martin, & Philip Xing Electronic Engineer: P. SullivanElectronic Technicians: N. RotoloDrawing office: R. SenanayakeSystem Engineer: S. Topp-JorgensenGrid programmers: C. Cioffi & A. Soroko

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The LHCb RICH1 detector

HPD plane:7 columns,

14 tubes each

Magnetic shield boxVertical

X-section

RICH1 is undergoing phased programme of design and construction

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RICH2 - in place in the LHCb pit

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Status of Oxford hardware projects

RICH Level-0 electronics

RICH-1 mechanics

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Status of the L0 electronics

Oxford’s responsibility is the front-end electronics for the RICH detectors

Hybrid Photo-Detectors (HPDs) detect the Cherenkov radiation by detecting photoelectrons on a 32×32 pixel detector encapsulated within the detector

readout pixel chip

silicon detectorSchematic of a HPD section

72 mm

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The production L0 board

PIXEL anodes

Kaptons

10 cm

16.5 cm

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Production status 300 boards to be

produced and tested in Oxford 242 boards required to

equip both RICHes The performance is

excellent Half of boards have been

produced and 1/3rd shipped to CERN for mounting in the RICHes [on time and within budget]

ECS and DCS in preparation

Andrew Powell, Nicolo RotoloSean Brisbane Phil Sullivan Stig Topp Jorgensen Jim LibbyNeville Harnew

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HPD column mounting @CERNAndrew Powell, Nicolo RotoloSean Bisbane Phil Sullivan

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RICH1 mechanics Collaboration with Imperial

- produced final design of the RICH1 gas enclosure

Produced final engineering drawings

Performed FEA to validate design

Responsible for procurement of gas enclosure - leak tested in Oxford

Designed mechanical support and lifting rig

Helped with installation with Imperial

Next – design of the photon detector region

Rohan Senanayake

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Physics work and planning

RICH calibration

measurement

Charm physics

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RICH calibration Using golden kinematics of D*+→D0π+ decays to select a

pure samples of D0 →K-π+ (and charge conjugate decays)

The charge of the tracks from the D0 decays define pure samples of π and K from which identification efficiencies can be derived solely from data

(GeV/c)

Raluca Muresan, Guy Wilkinson

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Getting at γ

LHCb will make direct measurements of the unitarity triangle angle γ

Classic channel B0s→DsK

suffers several problems with ambiguous solutions and limited statistics (14o precision in one year)

03825 )61(

We are exploring alternative channels to measure γ

From B factories:

Guy Wilkinson, Jim Libby, Andrew Powell, Neville Harnew

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γ is the weak phase between b→cus ( Vcb) and b→ucs ( Vub)

Very promising strategies for being pursued in Oxford Dalitz plot fit to 3 body decays D0 →Ksππ and also 4 body decays

exploits interferences between sub-resonances in decay current world best measurement from e+e- B factories LHCb expects ~2000 events to tape per year (3-body)

Atwood-Dunietz-Soni method with D0 →Kπ and D0 →Kπππ Sensitivities expected range from 4-14o (parameter dependent)

Measuring γ: B+→D0K+

cbV

*usV

ubV

*csV

D0 and D0 decay to a common final state

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Charm physics

Oxford are studying charm physics at LHCb (Oxford are the leading group in LHCb working on charm physics) Inclusive D* higher level trigger stream will

provide ½ a billion D0 decays a year Allows sensitivity to D0 mixing and CP violation in

charm system

Patrick Spradlin, Guy Wilkinson