Oct.28-Nov.1,2006 高能物理学会第 7 届年会，桂林 1 Yajun Mao （ School of Physics, PKU...

Oct.28-Nov.1,2006 高能物理学会第7届年会，桂林 1

Yajun Mao（ School of Physics, PKU）

for BESIII Collaboration

Oct 31 ， 2006

Extracting Physics From BESIII Experiment


Outline

Preparation of Physics Analysis

Introduction

Some Physics Reach @ BESIII

Summary

BESIII Physics Book


Why BEPCII/BESIII?

High precision experiment ： higher lumi/statistics + better detector => higher precision for rare process

Test SM and search for new PhysicsCKM elements J/ decayLepton University D meson decay

Basic QCD ParametersLight hadron spectroscopyCharmonium Physics


Physics Channel

Energy (GeV)

Luminosity (1033 cm–2s –1)

Events/year

J/ 3.097 0.6 1.0×1010

3.67 1.0 1.2×107

’ 3.686 1.0 3.0 ×109

D* 3.77 1.0 2.5×107

Ds 4.03 0.6 1.0×106

Ds 4.14 0.6 2.0×106

*D production cross section is taken as 5 nb

Events Expected at BESIII


Hints for New Spectroscopy-Challenge QCD

2003 20042005

Belle

BaBar

BESII J/ pp

M=1859 MeV/c2

< 30 MeV/c2 (90% CL)

+3 +510 25

J/ ’

Are they the same particle?

X(3872)

DsJ(2317) DsJ(2458)

Y(3940) Z(3930)X(3940)

Y(4260)

X(1835) mass is consistent with the mass of the S-wave resonance X(1860) indicated

by the pp mass threshold enhancement.2

2

MeV/c 7.73.207.67

MeV/c 7.21.67.1833

54264

M

Nobs

410)4.04.02.2()()( XBXJB59.1

8.0 10)4.00.7()()(:.. ppXBXJBfc

X(1835)X(1860)

A detail angular analysis will definitely tell us the JPC of X(1835) at BESIII: 35 104 events in J/ pp ( = 50%) 24 104 events in J/ ’ ( = 12%) 10 billion J/

Particle Zoo from R. Faccini

ISR

B decaysB decay

Continuum

J/ccbar

Glueball, hybrid or exotic search in J/ (10109) @ BESIII f0(600)

f0(980)

f0(1370)

J/ (, , , ) + f0(1500) and also Tensor candidates

f0(1710) and Many threshold enhancements

f0(1790)

J/ ppbar +X probe excited and exotic baryon states by B. Zou

Partial Wave Analysis will be the KEY tool in the study of spectroscopy, some of Key issues should be solved in the future.


Scan of the resonance @ 3.7 - 4.6 GeV to probe spectroscopy

)(),(

)/(),(

))((),/(

),(),( (*)(*)

eeKKee

Jeeee

eeJee

DDeeDDee

cJ

SS Test QCD @ 3.7 - 4.6 GeV

Search for exotic ccbar, Y(4260)

Probe gluon enhanced hidden ccbar states

A detail plan to take data @ BESIII should be made based on the study of R&D in Physics book.

CLEO-c Preliminary

D*D Enhancement at D*D* threshold

Plateau in D*D*

Very little DD


Dalitz Analysis at BESIII•K-π+π0, Ksπ+π- vs CP tags, measure strong phase of Kρ, K*π

•K-π+π0, Ksπ+π- vs flavor tags, measure Br of DCSD

•Ksπ+π-, π-π+π0 vs CP tags, search for CP Violation (via same sign CP Tags)

• Strong phase measurement : Measurements of /3 in BD(*)K(*)

•CP asymmetries across Dalitz Plots

–Ksπ+π-, π-π+π0 vs flavor tags

–D+ K-K+ π+

Light spectroscopy in D Dalitz analysis: (K) s-wave, () s-wave, many isoscalars M. Pennington’s talk at Charm2006


Charmonium below open charm @ BESIII

1974

1974

1980

20022004

1977

1975

(2S) J/ really “pure” J/ sample a complementary of J/ peak data!

c,0,1,2 sample useful to understand the decay dynamics of ccbar and light hadron with same JPC! Q. Zhao, hep-ph/0508086c in (2S) KSK

(2S) C

with untagged gamma M. Voloshin hep-ph/0206240 B(C(2S) C ) = 5-10%

Detail study of hC at BESIII

2S – 1D mixing : “” puzzle J. Rosner PRD 64 (094002) 2001 P. Wang et al PRD70(114014)2004 Non-DD decay of (3770): N. Achasov hep-ph/0505146 The productions of D0D0, D+D

M. Voloshin hep-ph/0402171 C(1S) sample from J/ C(1S) used to study the light spectrum

What can we do with 3 billion (2S)?


*

)

CLEO-c Preliminary Ron Poling talk at Charm2006

Charmonium Decays of (4040), (4160), and Y(4260)

Scan Run will be crucial at BES-III: Scan Run will be crucial at BES-III: EECM CM = 3970-4260 GeV= 3970-4260 GeV

CLEO-c PRL 96, 162003 (2006)

From the current experimental indication!


BES III Charm Mixing (1) Quantum Correlations in DQuantum Correlations in D00DD00 decays from the decays from the (3770) allow measurement of strong phases (3770) allow measurement of strong phases and mixing parameters from BESIII:and mixing parameters from BESIII:Coherence simplifies study DCSD interfere away so not a backgroundUnmixed: D0 K+ D0 K+ mixing: D0 K+ D0 D0 K+ DD00DD00 (Kev Kev)

With 20fb-1(4-5 years running) at Ψ(3770) peak RM <104

K

K

BB

q

pyxKKDDKKDD

2

2

2

222

00

00

2)))((()))(((

• BESIII PID system

–dE/dx, resolution (6-7)%

–Two layer barrel TOF, time resolution ~100ps, ~83% solid angle coverage

–1 layer endcap TOF, ~110ps

• Selection efficiency is >20% with a K/π double mis-identification rate at < 10-4

level

•Two missing neutrinos in events

•Electron PID can suppress background

•The selection efficiency is similar as the Kπ channel

•Background level is also negligible while running a small MC data sample (~1% of 20fb-1). More detail study is needed.

2))(())(( 22

00

00 yxllDDllDD


BES III Charm Mixing (2)

BESIII

Be careful e+e DD( n)(m) no resonant contribution, TQCA will be lost!

Data 4160 MeV

DD

DD*

D*D*

D0 Momenta from CLEO-c Preliminary

Evidence for “multibody” (MB) events, e.g. Evidence for “multibody” (MB) events, e.g. ee++ee--→→DDDD**::


Estimated uncertainties (stat.) of Mixing parameters using TQCA

From PRD 73 034024 (2006) by Asner and Sun

Using single and double CP/flavor tags –

complicated analyses

parameter valueCLEO-c (3x106D0D0b) BESIII(20fb1)

C=-1 C=+1 C=-1 C=+1

y 0 ±0.015 ±0.007 ±0.003 ±0.002

x2 0 ±0.0006 ±0.0003 ±0.00013 ±0.0001

cosδKπ 1 ±0.15 ±0.13 ±0.035 ±0.04

xsinδKπ 0 ─ ±0.010 ─ ±0.003

Have to identify C=+1 ofD0D0bar and D0D0barπ0 from D*Dbar and D*D*bar decays

From Kanglin He


CP eigenstate Tags•CP +

–K+K- (3.89X10-3 )

–π+π- (1.38X10-3 )

–Ks π0π0

–π0π0 (8.4X10-4)

–KSKS (7.1X10-4)

–ρ0 π0 (3.2x10-3)

•CP –

–KSπ0(0.012)

–Ksη (3.9X10-3)

–KS η’ (0.0094)

–KSρ0 (0.0078)

–Ksω (0.012)

–KSφ (4.7X10-3)

In 20fb-1 Ψ(3770) data, we can get> 4.5x105 CP+ tags and > 3.6x105 CP- tags

With large sample of CP tags, we will definitely improve the measurements

of strong phase, probe the direct CP, and other mixing parameters


CP Violation at ψ(3770) at BESIII

K

K

ππ

0D

0D

K+K-, , Ks0 ,

•CP violating asymmetries can be measured by searching for events with two CP odd or two CP even final states:

)ψCP(1)()CP()CP()CP(

ψ ofdecay for theL

2121

21

ffffff

ACP sensitivity 10-2 - 10-3 K K vs

Beam constraint Mass

)cos()Re(2)sin()Im(2

212*1

22

21

212*1

22

22

AAAAAA

AA

AAA

ff

ffCPFind:


Leptonic and Semileptonic decays at BESIII

BESIII:Integrate Lumi. 20fb DDbar MC simulation

2

2222 2

218

lFl cdD D

D

mGD l f m M V

M

223

322

24qf

pVGPlD cqF

Vcd/Vcd 1.7% Vcs/Vcs 1.6%lD

lD


BESIII Physics Yellow Book

Part One: The BES-III Experiment and its Physics Conveners: Jian-Ping Ma and Ya-Jun Mao Part Two: e+e collision at BEPC-II Conveners: Xiao-Yuan Li and Yuan-Ning Gao Part Three: Light Hadron Physics Conveners: Bing-Song Zou and Xiao-Yan Shen Part Four: Charmonium Physics Conveners: Cong-Feng Qiao and Chang-Zheng Yuan Part Five: Charm Physics Conveners: Zhi-Zhong Xing and Hai-Bo Li Part Six: Tau Physics Conveners: Toni Pich and Chang-Zheng Yuan Part Seven: Comparison with other facilities and future prospects Conveners: Cai-Dian Lu and Shan Jin


Chapters of the Yellow BookPart One: The BESIII experiment and its physics Jian-Ping Ma and Ya-Jun Mao Chapter 1. Physics goal of BESIII Jian-Ping Ma Chapter 2. The BESIII detector Ya-Jun Mao Chapter 3. Offline Software Ya-Jun Mao and Wei-Dong Li Chapter 4 Analysis tools Kang-Lin He

Part Two: e+e- collision at BEPC-II Yuan-Ning Gao Chapter 5. Physics Processes Ping Wang and Da-Hua Zhang Chapter 6. Hadron Production and Fregmentation Hai-Ming Hu Chapter 7. R values Xiao-Yuan Li Chapter 8. QCD studies at sqrt(s) = 2-5 GeV H.M. Hu and Y.N. Gao Chapter 9. Production cross section of DD and DsDs Kang-Lin He Chapter 10. Measurements of Parameters of Charmonium Resonances Yuan-Ning Gao and Gang Rong Part Three: Light hadron physics Bing-Song Zou and Xiao-Yan Shen Chapter 11. Hadron spectroscopy: status and prediction Q. Zhao, C. Liu and Y.Chen Chapter 12. Meson spectrum Qiang Zhao Chapter 13. Baryon spectrum Bing-Song Zou Chapter 14. Glueball searches Qiang Zhao Chapter 15. Hybrid, Multi-Quark and Molecule candidate searches Shi-Lin Zhu


Chapters of the Yellow Book Chapter 16. Two-photon physics Bing-Song Zou and Hai-Bo Li

Chapter 17. Soft pions and a0-f0 mixing Han-Qing Zheng

Part Four: Charmonium Physics Cong-Feng Qiao and Chang-Zheng Yuan Chapter 18. Charmonium transition C.Z. Yuan

Chapter 19. Leptonic decays P.Wang

Chapter 20. Radiative decays Cong-Feng Qiao and C.Z.Yuan Chapter 21. Hadronic decays X.H. Mo, C.Z.Yuan

Chapter 22. Rare and forbidden Charmonium Decays X-M Zhang, J-P Ma, Hai-Bo LI Chapter 23. Charmonium spectroscopy close to open charm threshold Chapter 24. Exotic decays of Psi(4030), Psi(4160) and Psi(4415) Steve Olsen

Part Five: Charm Physics Zhi-Zhong Xing and Hai-Bo Li

Chapter 25. Leptonic D (Ds) Decays Ya-Dong Yang and Gang Rong

Chapter 26. Semileptonic D(Ds) decays and CKM matrix M-Z Yang and G. Rong

Chapter 27 Hadronic D(Ds) decays Yue-Liang Wu and Kang-Lin He

Chapter 28. Charm baryon production and decays H. Y. Chen

Chapter 29. DDbar mixing and CP violation D. Asner, I. Bigi, K. He, H. Li, Z-Z. Xing

Chapter 30. Rare and forbidden charm decays Ya-Dong Yang and Hai-Bo Li


Chapters of the Yellow Book

Part Six: Tau Physics Toni Pich and Chang-Zheng Yuan Chapter 31. Tau mass near threshold Chapter 32. Hadronic tau decays Chapter 33. Leptonic and semileptonic tau decays Chapter 34. Search for CP violation in tau decays

Part Seven: Comparison with other facilities and future prospects Cai-Dian Lu and Shan Jin Chapter 35. Tau-Charm physics at B factories Alex Bondar and Steve Olsen Chapter 36. Opportunities of Tau-Charm physics at Super-B factories D. Asner and I. Bigi Chapter 37. Do we need a super-charm factories D. Asner and Alex Bondar


Status of The Book• Proposed in Jun, 2005 • 1st meeting: Mar 6, 2006, in Xiamen:The primary content lists were approved; Some examples were shown on the meeting; Latex Style was fixed;• 2nd meeting: Apr10, 2006, IHEP, in Beijing: The editorial board was ratified and editor-in-chiefs were approved; The structures of the book were adjusted; Conveners for each part and each chapter.• 3rd meeting: May 10, 2006, IHEP, in Beijing: Most of the conveners joined the meeting, a detailed plan was discussed. Convener of each part/chapter presented their own schedule.• 4th meeting: Aug 5, 2006, in Beijing, progress review of the book• 5th meeting: Nov. 4, 2006, in Beijing, second review of the progress

6th meeting: Dec, 2006, The Proofread


Analysis Preparation

PhysicsAnalysis

EventSimulation

Detector Response

Recon.+ PID

Detector R&D Mass Production

DataAcquisition

RealCollision

Software +Physics

Hardware


Overview of BESIII Offline Software

GEANT4 GAUDI ROOT

BOOST BOSS

Eve

ntG

ener

ato

r Det

ecto

rSi

mul

atio

n

Rec

onst

ruct

ion

Phys

ics

Ana

lysi

s

Phys

ics

Ana

lysi

s

Eve

nt

Dis

play


Software Environment• Underlying framework

– GAUDI (originally developed by LHCb)• Simulation

– GEANT4• Other external LIBs:

– CERNLIB, CLHEP, ROOT, AIDA, XercesC, GDML …• Database: PGSQL/MySQL• Software configuration management

– CMT and CVS • Computer language: C++ (BESII legacy code written in Fortran )• Operation system:

– Redhat 7.3/gcc3.2 (now), SLC3/ gcc3.2.3 (in the future)• Reused code from Belle, BaBar, ATLAS,GLAST …


Main Drift Chamber Software • Simulation

– Stereo cells are described by G4TwistTube.– Digitization is based on parameters from test

beam data. • The calibration algorithm contains

correction to – X-T relation, spatial resolution,T0, wire

position, time walk. • Reconstruction algorithms are: TrkReco

and MdcPatRec. For single 1 GeV muons, both of them obtain:– Efficiency: ~99% – Spatial resolution: ~110 μm

• dE/dx resolution: ~6% consistent with detector design report.


TOF Software

• Simulation – Two-layered structure for Barrel– Digitization takes into account: light

production, light propagation and PMT response etc.

– Intrinsic time resolution: 85 ps

• Calibration & reconstruction– Calibration algorithm contains time

correction, effective velocity and attenuation calibration.

– Reconstruction results have been used in particle identification


EM Calorimeter Software

4E/E=[(p0/E) (p1/ E) p2]%

• Simulation– End-cap is described by

G4IrregBox.– Full simulation of readout

electronics is included in digitization.

• Energy calibration– Digit calibration: converting ADC

channels into energy.– Cluster calibration: correcting non-

linearity of readout signals.

• Reconstruction– ΔE/E = ~2% @ 1GeV– σz = 0.6 cm @ 1GeV


Muon Chamber Software

Ext track

Fired strips

Window

• Simulation – RPC as sensitive

detector– Detailed to each read-

out strip• Reconstruction

– Tracking algorithm is seeded by the tracks extrapolated from MDC.

– Searching for hits gap by gap within predefined windows.

• Reconstruction efficiency: ~ 99% @ 1GeV


Calibration calibUtil interface

Data (persistent)Metadata (persistent)

Dead chns(XML)

CAL calibs(ROOT)MySQL rdbms

Write/registerSearchRead

Signifies “uses” or “accesses”

Status Developed MDC, TOF and EMC calibration prototype algorithms Defined calibration data for each sub-detector Reconstruction algorithms are able to retrieved calibration constants

through the framework.


Event Display Tool: BesVis

• Based on ROOT, OpenGL, X3D and XML• Support both 2D and 3D view• Operations and controls available through menu

and toolbar items• First version was released in December 2005.


Analysis Software Preparation

• Analysis Tools – Particle ID– Composition Tools

• Event Data Model• Analysis Framework• Event/Physics Tags

– Event Tag– Physics Tags

• Physics Tools– RooFit

• Invariant mass fit and etc

– Charm Dalitz Analysis• In planned

– Statistic Analysis• In planned


Status of Particle ID

• DedxPID– Ready now

• TofPID– Barrel inner TOF PID

• Ready now

– Barrel outer TOF PID• Ready now

• MuonID– Ready now

• EmcPID– Ready now

• Endcap TOF PID– Ready now

• TOFQ PID– Ready now

Combined method for each sub-detector still in study


Combined Particle ID

• The probability method– Standard BESII, combined 2 distribution, simple but need

correction, ready now

• The maximum likelihood method– Combined PDF for each sub-detectors, ready now, still need

optimization on weight factor

• ANN method– Variables from all 4 subdetectors ： p, charge, pT, normPH,

numGoodHits, m2, Q, z, Q0, E1, E9, E25, depth, totHits, ready now but not MUC


Status of Composition Tools

• Telesis– Kinematic Fit

• BKlamsVTX– Ks/Λ reconstruction

• Vertex fitting– Vertex fit– Kinematic fit– 2ndVertex fit

All composition tools package worked smoothly


M

ρπJ/ψ

No 4C fit

ρπJ/ψ

After 4C fit

ρπJ/ψ


M

γγπ0

γγπ0 From (3770)


~3MeV

~1.2MeV

ππKS

pπ

, Ks From (3770)


KKφ

0πππω

From (3770)


KπK*0

πKK S*

From (3770)


πKD0 πππKD0

π

00 ππKD ππKD S0

D0


0S ππKD

πKD S

πππKD S

ππKD

D+


J/ψππψ

recM

Oct.28-Nov.1,2006 高能物理学会第7届年会，桂林 4250K Ψ’ MC data

Inclusive photon Energy0cχ

1cχ2

cχ

γJ/ψχ Jc

E

μμJ/ψ


Performance Check

• Reconstruction efficiency of hadron• PID efficiencies• X2 distribution• Photon Detection efficiencies• Efficiencies from Physics channels• Summary

By X.B. Ji, G. Li, S.S. Sun, J.Y. Zhang and Yang Ming etc


Efficiencies from physics channels

J/Ψ→ρπ ~50%Ψ’π+π-J/Ψ, J/Ψμ+μ- ~50%Ψ’π0π0J/Ψ, J/Ψμ+μ- ~12%D0Kπ ~60%D0Kπππ ~28%D0Kππ0 ~25%D+K0π ~16%D+Kππ ~48%Ds KKπ ~40%Dsη’π ~8%

The physics efficiencies have been in a reasonable range


Highlight of Software Preparation

Simulation, Reconstruction/Calibration and Analysis software are in a good shape and reasonable status

We are ready to start physics study with current version of BESIII software


Important Steps Towarding PhysicsSimulation before data is ready

Extracting Physics from data

Selection of physics topics ( yellow book, work with theorists）Final state particles (, hadrons, leptons)Rough estimate of cross-section/branch ratio=> expected statisticsPrepare event generator for the interested channels, backgound channels Go though EventGenSimulation ReconstructionAnalysis chainto finalize feasibility study ( Determine cuts, efficiency study, background suppression etc.)

Calibration/alignmentData Production, data quality checkData sampling for interested channels MC with calibration/alignment database Extracting physics observables, MC/Data comparison Error study


Light Hadron Charmonium Charm R Tau

Calibration

Production

Quarlity Check

Analysis Tools

Expectation to Analyzers

MC/DataEach Analyzer should contribute to service in some form sometime


Institution 1

Institution 2

Institution 3

Institution 4

Institution 5

… …

Light Hadron

Charmonium

Charm

R

Tau

… …

Calibration

Production

Quarlity Check

Analysis Tools

IHEP PhysicsGroup 1

… …

IHEP PhysicsGroup 2

IHEP PhysicsGroup 3

IHEP PhysicsGroup 4

IHEP PhysicsGroup 5

Structrue of BESIII Analysis


How If One Wants to Contribute?

Help on selection of physics topicsHelp on development of event generatorsHelp on elucidation of experimental resultsHelp on paper drafting if you are BESIII members?

Expectations to theorists

Help on services, as hardware, software, calibration, data production, quality check, MC, etc.

Physics analysis

Expectations to analyzers


SummaryBESIII offline software are in good shape and reasonable status, intensive test and check arebadly needed to optimize and improve the software

The physics yellow book is undergoing, we need to hurry up to provide proofread as scheduled

The analysis structure has been discussed and weare going to organize our efforts accordingly

Contributions from theorists play very an important role in our analysis, support and suggestions from them are very much welcome


THANK YOU！


The Probability method

)n,(obPrP

)TofQ,Emci)(pdf(gauss

)dx/dE,tofi(xx

2i

2i

2

1i

measure

ectedexpmeasurei

BESII standard PID, simple but lots of work on corrections

For Emc deposit energy and Q of TOF, need a inverse Gassian to get xiApply histogram method to extract the p.d.fThe first working PID package, by Dr. Wang Liangliang

Kπ

PPP

K

K


The Likelihood method

j

j

iii

)j,p(w)j,x,p(L)h,p(w)h,x,p(L)h,x,p(F

)j,x,p(L)h,x,p(L)h,x,p(F

)h,x,p(pdf)h,x,p(L sub detector p.d.f

momentumMeasurement

Particle hypothesis

Likelihood ratio

WeightedLikelihood ratio

Weighted factorAdditional work on weighted factor

Dr. Huang Bin is working on


Neuron Network PID• Training variables

– Tracking: p, charge · pT– dE/dx: normPH, numGoodHits– Tof: m2, Q, z– TofQ: Q0– Emc: E1, E9, E25– Muc: discuss with PKU people

• Output:– Return a Value between 1-5, e,μ,π,K, p

Ready after BOSS 6.0.0 release, by Dr. Qin Gangwill be in next BOSS release including all sub-detector information


NN Pid SchemedEdx Tof1 Tof2 TofQ Emc Muc

Barrel

123456

Endcap

1234


Physics Topics Under Study

Oct.28-Nov.1,2006 高能物理学会第 7 届年会，桂林 1 Yajun Mao （ School of Physics, PKU...

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