frederick a. harris 1/29/2008 1 university of hawaiifah/bestalks/new_initiative.pdf · frederick a....
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1/29/2008 1
Frederick A. HarrisFrederick A. HarrisUniversity of HawaiiUniversity of Hawaii
BES CollaborationNew BESIII Initiative MeetingNov. 7, 2006Washington, DC
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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)
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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
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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
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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
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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
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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).
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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.
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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
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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
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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!
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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.
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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)
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Management structureSpokespersonsEB
Technical coordinator
Run coordinator
Software and Computing coordinator
Physics coordinators
Speakers bureau
Publicationcommittee
Technical board
Computing board
PCC
SCC
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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, …
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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).
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Fiber Bundle Cables (need 2)Barrel TOF
EC TOF
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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.