1/29/2008 1

Frederick A. HarrisFrederick A. HarrisUniversity of HawaiiUniversity of Hawaii

BES CollaborationNew BESIII Initiative MeetingNov. 7, 2006Washington, DC

1/29/2008 2

OUTLINEOUTLINE

• Introduction: physicsof tau charm region.

• History• BESI/II Collaboration• BESIII Collaboration• Summary

IHEP

CM Energy ranges from 2 to 5 GeV

Luminosity at J/ψ ~ 5 x 1030 cm–2 s -1

A unique e+e- machine in the τ-charm energy region since 1989 – until CLEOc.

Beijing, China

BESII

The Beijing Electron Positron Collider (BEPC)

1/29/2008 4

Physics of tau – charm regionTremendous variety: taus at threshold, R, charm,

charmonium, transition region between perturbative and

non-perturbative QCD, etc.

Many new particles: X, Y, Z, etc. Hybrids? Glueballs?ψ(3770) charm threshold

1/29/2008 5

Tau mass measurementBESI measurement:

10X better precision

225.018.017.021.0 MeV/c96.1776 ++

−−=τm

J. Z. Bai et al, PRD53, 20 (1996).

79 citations

1/29/2008 6

BESI -- Tau mass measurementLifetime, leptonic branching ratio, and mass: Γ~ (mτ)5.

Status 1992 (2.4 σ)

and 1994 (1.3 σ)

Status 2006

A. Pich, Charm06 talk

1992

1994

1/29/2008 7

R Below 10 GeV

Before BES R Scan After BES R Scan

BES reduces R errors from 15 – 20 % to an averageof 6% in the 2 – 5 GeV region. Important region!

PRL 84, 594PRL 88, 10180267 + 137 citations

1/29/2008 8

R measurementR measurementNeeded to improve precision of α(M2

Z):Uncertainties in α introduced when it is extrapolated to the

Z-pole:

Dominant uncertainty due to hadronic vacuum polarization.This is determined from R values using a dispersion

relation.

The Higgs mass determined from radiative corrections in the SM is very sensitive to α(M2

Z).

1/29/2008 9

SM Fit to mH

GeVmGeVm

H

H

17062 53

30

<= +

−

(95% C.L.) GeVmGeVm

H

H

21298 58

38

<= +

−

Burkhardt and Pietryzk, Phys. Lett. B513, 46 (2001).]

(95% C.L.)

Without BES dataWith BES data

Data from tau-charm mass region

important for standard model fits.

1/29/2008 10

History1979 First US/PRC HEP meeting1984 BEPC approved1988 first electron positron

collisions1991 US/China BESI

Collaboration formed1992 tau mass measurement

published1993 Hawaii joins1995/96 BESII Upgrade1998/99 R Scan (91 energy points)2000/01 J/psi data (58 M)2002 psi’ data (14M)2003 BEPCII/BESIII approved2006 BESIII collaboration

formed

1/29/2008 11

US Groups and ContributionsBESI and BESII

Boston UniversityCaltechUC IrvineColorado State UniversityUniversity of HawaiiMITSLACUniversity of Texas at DallasUniversity of Washington

Hardware ContributionsMDCII endplates & feed throughsTOF Calibration SystemVertex Chamber (MarkIII)Preamps for VCLuminosity MonitorMDCIII, Outer Cylinder, & preamps

OtherPhysics analysesRefereeingStudentsPublication policyPolishing papers

1/29/2008 12

BESIII Collaboration

Institute of High Energy PhysicsUniversity of Science and TechnologyPeking UniversityTsinghua UniversityShangdong UniversityNankai UniversityCentral China Normal UniversityUniversity of AnhuiUniversity of ZhejiangUniversity of ZhengzhouNanjing Normal UniversityNanjing UniversityShanxi UniversitySichuan UniversityHenan Normal University

University of HawaiiUniversity of WashingtonUniversity of TokyoJoint Institute of Nuclear

Research, DubnaGSIUniversity of BochumUniversity of Giessen

Need more here!

1/29/2008 13

BESIII CollaborationOrganization progressing nicely:

o Governance rules adopted at Jan. 2006 meeting.• IB constituted and IB Chair elected.• Spokepersons elected.• IB committees established.

o Management Plan adopted at June 2006 meeting.o Analysis Infrastructure – decided at Jan. 2007 meeting.

•Input from CLEOc groups important.

Organized like any other internationalcollaboration.

1/29/2008 14

BESIII Overall Structure

Spokespersons(Represent and

run collaboration)

Executive Board(advisory – scientific,

technical, andmanagement.)

Institutional Board(organizational issues,

admission of new institutions,author list, etc.)

Management Team

Committees:Nominating,

membership, etc.

CollaborationMeeting (votes on

important matters)

2008-1-29 15

Management structureSpokespersonsEB

Technical coordinator

Run coordinator

Software and Computing coordinator

Physics coordinators

Speakers bureau

Publicationcommittee

Technical board

Computing board

PCC

SCC

2008-1-29 16

Physics coordinators• Appointment procedure

– Nominated by spokespersons and ratified by EB – Term: 1 year as deputy coordinator and 1 year as coordinator

• Responsibilities– Organize physics analysis and physics tools groups, recommend their

conveners to EB after consultation with the physics coordinationcommittee (PCC).

– Organize and chair analysis meetings, arrange parallel and plenary physics sessions at collaboration meetings.

– Organize discussions on physics priorities, running plans, Monte Carlo production priorities, etc.

– Allocate resources (computing, man power,…) for physics analysis– Organize efforts, in coordination with the software coordinator, for

data quality checks, performance tests, calibration verification, …– Organize efforts to provide common analysis tools, methods, standards,

and data (such as luminosities, bad runs, …) – Responsible for high quality and efficient publication of physics papers,

including tracking analysis progress, appointing paper referees, …

1/29/2008 17

BESIII TOF Monitoring System

TOF endcap 48 fibersTOF endcap 48 fibersLaser Light splitter

TOF barrelPMT PMT

Ref. PMTTDC startADC gate

Fiber

TOF barrel 176 fibersTOF barrel 176 fibers

Electronic switch

fiber

Fiber bundles

connector

Monitor the amplitude and time performance of each channel including PMTs and electronics. Being built by University of Hawaii (F. Harris, S. Olsen, G. Varner, M. Rosen, Lucas Nguyen):

Use mirror to steer beam – like BESII.Purchase fiber cable bundles (2 cables).

2008-1-29 18

Fiber Bundle Cables (need 2)Barrel TOF

EC TOF

1/29/2008 19

Summary• BES has had a long productive history.• US participation has been extremely important

but needs to be strengthened for BESIII. • BESIII Collaboration formed, much of the

governance structure decided.• Analysis structure details remain.• Commissioning expected in late 2007.• Rich physics after CLEOc. 10 billion J/ψ events

per year• New US groups should join now to have impact on

software, computing, physics analysis, and upgrades.