The The -charm Physics @ BESIII-charm Physics @ BESIII

SHEN Xiaoyan

Institute of High Energy Physics, CAS

International Review Meeting

Oct. 21, 2013, IHEP, Beijing

OutlineOutline

• Introduction

• Highlights from -charm physics

• Management structure of BESIII

• Future prospects

• Summary

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Standard Model (EW+QCD)Standard Model (EW+QCD) Many precision tests on SM, especially EW theory,

mainly in 4 exps. at LEP in CERN

Higgs discovered at LHC in CERN

Great success of EW theory !

QCD has been tested extensively at the high momentum transfer by lots of high precision experiments (> 10 GeV).

At low energy, QCD is difficult to be tested due to its non-perturbative nature.

• How does QCD work at low energy? Do the new forms of hadrons predicted by QCD exist ? How to calibrate QCD at low energy ?

• Does the physics beyond Standard Model exist? How to test EW theory precisely in -charm region? Where is the new physics in -charm sector ?

Fundamental questions need to be answeredFundamental questions need to be answered

What can we do at BEPC2/BESIII ?

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BESIII detector

LINAC

2004: started BEPCII upgrade, BESIII construction2008: test run2009 - now: BESIII physics run

Beijing Electron Positron Collider (BEPC)Beijing Electron Positron Collider (BEPC)

BEPCII/BESIII – unique facility at BEPCII/BESIII – unique facility at -charm -charm energy region in the word now.energy region in the word now.

Features of the BEPC Energy RegionFeatures of the BEPC Energy Region Rich of resonances: charmonia and charmed mesons Threshold characteristics (pairs of , D, Ds, …) Energy location of the glueballs, hybrids and multi-quark states Energy location of the XYZ’s Transition between smooth and resonances, perturbative and non-

perturbative QCD

6

6The Y’s are here ….

PDG

• How does QCD work at low energy? Do the new forms of hadrons predicted by QCD exist ? How to calibrate QCD at low energy ?

• Does the physics beyond Standard Model exist? How to test EW theory precisely in -charm region? Where is the new physics in -charm sector ?

Fundamental questions need to be answeredFundamental questions need to be answered

Search for the new hadrons and systematic study of the spectroscopy – a way of understanding the internal structure of hadrons.

Conventional hadrons consist of 2 or 3 quarks： Naive Quark Model：

QCD predicts the new forms of hadrons:• Multi-quark states ： Number of quarks > ＝ 4

• Hybrids ： qqg ， qqqg …• Glueballs ： gg ， ggg …

None of them is settled after many years’ efforts.

New forms of hadronsNew forms of hadrons

g

gg

g

None of the new forms of hadrons is settled !None of the new forms of hadrons is settled !

Precision measurement of CKM elements-- Test EW theory

Precision measurement of CKM elements-- Test EW theory

b

s

d

VVV

VVV

VVV

b

s

d

tbtstd

cbcscd

ubusud

'

'

' CKM matrix

Three generations of quark? Unitary matrix?

5% precision 10% precision

Expected precision < 2% at BESIII

BESIII + B factories + LQCD

Precision measurement of CKM matrix elements -- a precise test of SM model New physics beyond SM?

Precision measurement of CKM matrix elements -- a precise test of SM model New physics beyond SM?9

CKM matrix elements are fundamental SM parameters that describe the mixing of quark fields due to weak interaction.

BESIII + B factories + LHCb + LQCD

Hadron spectroscopy search for the new forms of hadrons meson spectroscopy baryon spectroscopy

Study of the production and decay mechanisms of charmonium states: J/, (2S), C(1S), C{0,1,2} , C(2S), hC(1P1), (3770), etc.

Calibrate QCD

Precise measurement of R values, mass, ...

Precise measurement of CKM matrix

Search for DD mixing, CP violation, etc.

Physics Topics at BESIIIPhysics Topics at BESIII

Int. J. Mod. Phys. A, Vol. 24 (2009)

10

TOFBTOF: two layersETOF: 48 crys. for each

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BESIII DetectorBESIII Detector MDC

R inner: 63mm ; R outer: 810mm Length: 2582 mm Layers: 43

CsI(Tl) EMC

Crystals: 28 cm(15 X0)

Barrel: |cos|<0.83Endcap: 0.85 < |cos| < 0.93 RPC MUC

BMUC: 9 layers – 72 modulesEMUC: 8 layers – 64 modules

BESIII Detector PerformanceBESIII Detector Performance

Exps.MDC

Spatial resolution

MDC

dE/dx resolution

EMC

Energy resolution

CLEOc 110 m 5% 2.2-2.4 %Babar 125 m 7% 2.67 %Belle 130 m 5.6% 2.2 %

BESIII (2013) 115 m <5%

(Bhabha) 2.2%

Exps.

TOF

Time resolution

CDFII 100 psBelle 90 ps

BESIII (2013)

68 ps (BTOF)98 ps (ETOF)

MUC: Efficiency ~ 96% BG level: < 0.04 Hz/cm2(B-MUC), < 0.1 Hz/cm2(E-MUC)

Data/Monte-Carlo ConsistencyData/Monte-Carlo Consistency• For tracking efficiency, data/MC difference < 1%• For particle identification efficiency, data/MC difference < 2%

BESIII Physics Results BESIII Physics Results

• Hadron spectroscopy– Search for non-qq, non-qqq states– Meson & baryon spectroscopy

• Charmonium physics – Transitions and decays

• Charm physics– Decay constant fD

– CKM matrix elements: Vcd, Vcs• Precision measurement of R, • Search for new physics

BESIIIBESIII Physics Results (since 2009)Physics Results (since 2009)

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• Papers published：– 53 papers published (PRL 12, PRD 37 ， PLB 1, CPC 3)

2010: 4 (PRL 2, PRD 1, CPC 1)

2011: 11 (PRL 3, PRD 8)

2012: 17 (PRL 5, PRD 10, PLB 1, CPC 1)

2013: 21 (PRL 2, PRD 18, CPC 1)

-- Submitted 6 (PRL 5, CPC 1) International conference talks

About 50 talks at the international conferences every year. Among them, about half are the invited talks.

Highlights from Highlights from -charm Physics-charm Physics

• Below open charm threshold

All charmonium states observed. No surprising found.

• Above open charm threshold:

many expected states not observed

many unexpected discovered

X(3872)

XYZ(3940)

X(3915)

X(4160)

Y(4008)

Y(4140)

Y(4260)

Y(4360)

X(4350)

Y(4660)

X(3915)

X(4160)

Y(4008)

Y(4140)

Y(4260)

Y(4360)

X(4350)

Y(4660)

Z(4430)Z(4250)Z(4050)Z(3900)

Charmonium spectroscopyCharmonium spectroscopy

Data taking at 4260 and 4360 MeV Data taking at 4260 and 4360 MeV for XYZ study for XYZ study

BESIII: Observation of the ZBESIII: Observation of the Zcc(3900) (3900) — a charged charmonium-like structure — a charged charmonium-like structure

BESIII: PRL110, 252001 (2013)

BESIIISignificance >8

What is Zc(3900)?

• Couples to cc• Has electric charge• At least 4-quarks

• DD* molecule?• Tetraquark state?• Cusp?• Threshold effect?• …

Many theoretical interpretations:

Submitted the paper on March 24, 2013. Already got 81 citations !

Impacts of the ZImpacts of the Zcc(3900) (3900)

PRL referee says: ”Since a chargedcharmonium-like state cannot be conventional ccbar meson, the Z(3900)may be the first indisputable example of a multi-quark meson.

81 citations PRL110, 252001 (2013)

Observation of ZObservation of Zcc(3900) in D(3900) in DDD*0*0

Any more decay modes for ZAny more decay modes for Zcc(3900) ?(3900) ?

Zc(3900) 6(Zc(3900) DD*0)

(Zc(3900) J/)

JP favors 1+

Very important in understanding ZVery important in understanding Zcc(3900) !(3900) !

arXiv: 1310.1163, submitted to PRL

Observation of ZObservation of Zcc(4020)(4020)

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Does the charged ZDoes the charged Zcc(3900)’s partner exist ? (3900)’s partner exist ?

What is Zc(4020)?

• Couples to cc• Has electric charge• At least 4-quarks

BESIII

arXiv: 1309.1896, submitted to PRL

BESIII confirmed X(1835) and observed X(2120) & X(2370) BESIII confirmed X(1835) and observed X(2120) & X(2370) BESIII: Phys. Rev. Lett. 108 (2011)112003

• Glueballs can be largely produced in J/ radiative decays.

• First observed the resonant structures in the 2.4 GeV/c2 region in J/

radiative decays.

• LQCD predicts the lowest lying 0-+ glueball at around 2.4 GeV/c2.

• What is the nature of X(2120)/X(2370) ?

0-+ glueball ? excited /’ state ?

• Is X(1835) the same state as pp enhancement?

Measurement of fMeasurement of fDD from D from D++

Japan (1)Tokyo Univ.

US (5)Univ. of Hawaii

Carnegie Mellon Univ. Univ. of Minnesota Univ. of Rochester

Univ. of Indiana

Europe (13)Germany: Univ. of Bochum,

Univ. of Giessen, GSI Univ. of Johannes Gutenberg

Helmholtz Ins. In MainzRussia: JINR Dubna; BINP Novosibirsk

Italy: Univ. of Torino ， Frascati Lab, Ferrara Univ.Netherland ： KVI/Univ. of Groningen

Sweden: Uppsala Univ. Turkey: Turkey Accelerator Center

China(29)IHEP, CCAST, GUCAS, Shandong Univ.,

Univ. of Sci. and Tech. of ChinaZhejiang Univ., Huangshan Coll.

Huazhong Normal Univ., Wuhan Univ.Zhengzhou Univ., Henan Normal Univ.

Peking Univ., Tsinghua Univ. ,Zhongshan Univ.,Nankai Univ., Beihang Univ.

Shanxi Univ., Sichuan Univ., Univ. of South ChinaHunan Univ., Liaoning Univ.

Nanjing Univ., Nanjing Normal Univ.Guangxi Normal Univ., Guangxi Univ.Suzhou Univ., Hangzhou Normal Univ.

Lanzhou Univ., Henan Sci. and Tech. Univ.

Korea (1)Seoul Nat. Univ.

Pakistan (2)Univ. of Punjab

COMSAT CIIT

~400 members52 institutions from 11 countries

The BESIII CollaborationThe BESIII Collaboration

25~180 members from IHEP

BESIII Management StructureBESIII Management StructureSpokespersons (3, 3 years term)EB(~9)

Run coordinator

Software and Computing coordinator

Physics coordinators

Speakers bureau

Publicationcommittee

Shift committee

Membershipcommittee

IB(~51)

Convener-1 Convener-2 ………

Similar to other International Collaborations

Rules and policiesRules and policies• BESIII Collaboration Governance Rules • BESIII membership rules• Publication Policy• Responsibilities of the Speakers Bureau

……..Data TakingData Taking

• Data taking proposals presented and discussed at CM, decision made by EB and collaboration

• Adjust the data taking plans accordingly taking into account the importance of the physics, the competitions from other exps.

• Run coordinator, weekly run coordinators, chief shifters, shifters, on-call people, …. to ensure the high quality data.

IHEP Contribution IHEP Contribution

MDC & electronics

EMC & electronics

BTOF

ETOF & electronics MUC MUC

electronicsTrigger & DAQ

IHEP IHEP IHEP USTC IHEP USTC IHEP

MDC EMC TOF MUC Physics tools

IHEP+SDU IHEP IHEP PKU+IHEP IHEP+USTC

• BESIII softwareBESIII software

• The design, construction & operation of BESIIIThe design, construction & operation of BESIII

• BESIII papersBESIII papers

Total IHEP IHEP supervisors + univ. students Universities

59 30.5 13.5 15

IHEP ManpowerIHEP Manpower

• Currently, 57 faculties (16 profs. ) and 42 Students & post-docs for the maintenance, operation, upgrade of BESIII, and for the software and physics analysis.

Leading scientistsLeading scientists• WANG Yifang (Spokesperson from 2005 to Nov. 2011)• SHEN Xiaoyan (Spokesperson from Dec. 2011)• LOU Xinchou (EB member, IHEP IB)• ZHU Kejun, HE Kanglin (Run coordinators)• YUAN Changzheng (Physics coordinator)• LI Weidong (Software coordinator, EB member)• LI Haibo, JIN Shan (Were physics coordinators)• DONG Liaoyuan, ZHANG JIngzhi, FANG Shuangshi, MO Xiaohu, LIU Huaimin, …… (conveners)

BESIII data taking status & planBESIII data taking status & plan

Previous data

BESIII present & near future

Goal

J/ BESII: 58M 1.2 B 20* BESII 10 B

’ CLEO: 28 M 0.5 B 20* CLEOc 3B” CLEO: 0.8/fb 2.9/fb 3.5*CLEOc 10/fb

4040)/4170)/4260) ….

CLEO: 0.6/fb @ 4160)

2011: 0.5/fb @ 4040)2013 ： 2/fb@4260, 0.5/fb@4360

5-10 /fb

R scan BESII

Prospects of BESIIIProspects of BESIII

• In 2013-2014 physics run, R scan above 3.8 GeV. The goal: reach the precision of ~2% for R values.

• More results on XYZ particles will come understand the nature of XYZ

• Search for glueballs, hybrids,… with huge J/ data.

• Precision measurement of CKM elements• mass Expected to have an error of 0.1MeV.

Prospects of BESIIIProspects of BESIII

fD

Summary Summary • Observed Zc(3900), Zc(4020) at BESIII, opened a new

window big impact. More results on XYZ particles will come understand the nature of XYZ

• Produced many important results on charmonium physics, hadron spectroscopy, ….

• BESIII will run another 7-10 years Upgrade of BESIII on going– MRPC for ETOF– New inner drift chamber– CGEM for drift chamber

• More data will come, more physics output• Keep the leading role in -charm physics in these years.

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Backup slidesBackup slides

36

Matters are made of leptons and quarks:

Interactions are mediated by: photons — electromagnetic W± and Z — weak gluons — strong QCD

Origin of masses Higgs (Discovered at LHC in 2012)

e

e

bsd

tcu

Electroweak theory (EW)

Standard Model Standard Model (SM)(SM)

37

Pure leptonic decays

• All quantities are well measured except fD.• Use world average |Vcd| to extract fD

• Compare fD with LQCD for the validation of LQCD

Preliminary study of D+ at BESIII• 9 singly D- tag modes

The error is still statistical dominated.

Comparison of fD with theories

fD (MeV)

ZZcc(4020)’s other decay mode ?(4020)’s other decay mode ?

Observation of ZObservation of Zcc(4025) in D*(4025) in D*DD*0*0

arXiv: 1308.2760, submitted to PRL

Standard Model and BES PhysicsStandard Model and BES Physics• Three generations of quarks and leptons

• Interactions– Electromagnetic interaction– Weak interaction– Strong interaction

BES -charm Physics

｝ EW theory

QCD theory

Y.B. Yang, et al, Phys. Rev. Lett. 111, 091601 (2013)

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10)9(8.3 ,)8(35.0)/(

tot

keVGJ

• The widths of J/ radiatively decay to glueballs are calculated directly in lattice QCD .

• This result can be compared to the production rates of scalar mesons f0(1710), f0(1500)

3

0

40

100.3)(1.5 )1710(/

100.321.01 )1500(/

fJ

fJ

Support fSupport f00(1710) to be dominantly a scalar glueball.(1710) to be dominantly a scalar glueball.

Scalar glueball production in Scalar glueball production in J/J/ radiative decays from LQCD radiative decays from LQCDScalar glueball production in Scalar glueball production in

J/J/ radiative decays from LQCD radiative decays from LQCD

Tensor glueball production Tensor glueball production in J/in J/ radiative decays from LQCD radiative decays from LQCD

Tensor glueball production Tensor glueball production in J/in J/ radiative decays from LQCD radiative decays from LQCD

• The tensor glueball production rate in J/ radiative decay

2

21 0)2(1.1/)/( t o tGJ

• With the largest J/psi events sample, the LQCD results can provide useful information for BESIII to identify the tensor glueballs.

L. Gui, et al, Phys. Rev. Lett. 110 (2013) 021601

Paper submission proceduresPaper submission procedures• Talk at the group meeting, get approval by the group and group convener, get the analysis memo ready.

• Talk at the phys. & software meeting, get approval

• Physics coordinators assign 3 internal referees to review the analysis, memo draft be approved

• Collaboration wide review

• Spokespersons’ approval

The time from the submission to the journal to finally being accepted for publication is short.