Status of BES-III Experiment
Hai-Bo Li for BES-III Collaboration IHEP, Beijing HQkdLtHeavy Quarks and Leptons, 5 June-9 June 2008 School of Physics, The University of Melbourne Australia
2008－6－5Hai-Bo Li (李海波） 1 Outline
¾ BEPC-II/BES-III detectors ¾ Physics program at BESIII ¾ Summary
2008－6－5Hai-Bo Li (李海波） 2 Status of BEPC -II and BES -III
2008－6－5Hai-Bo Li (李海波） 3 BEPC II Storage ring: Large angle, double-ring RF SR RF Beam energy: 1.0-2.3 GeV Luminosity: 1×1033 cm-2s-1 Optimum beam energy: 1.89 GeV 0 . 1 Energy spread: c m 5.16 ×10-4 d 8ns ra No. of bunches: 1 2 m .5c 2 m 93 2.5m Bunch length: 1.5 cm Total current: 0.91 A SR mode: 0.25A @ 2.5 GeV 2008－6－5Hai-Bo Li (李海波） 4 IP Milestone of BEPCII storage ring commissioning
Nov. 2006 Beam stored in the storage ring Dec. 2006 Start to provide SR beams for users Mar. 2007 First e+e− collision, Lumi ~ 1030 cm-2 s-1 June 2007 Provide SR beams for users at 2.5GeV, 200mAwithalifetimeof55hr200 mA with a lifetime of 5.5 hr Aug. 2007 Beam current reached 500 mA Sep. 2007 SCQ moved to the interaction region Jan. 2008 BEPCII: collision with 500mA×500mA and 93 bunches in each ring，the luminosity is about 1110*1032cm-2s-1 June 20 2008 First physics collision
2008－6－5Hai-Bo Li (李海波） 5 Charm productions per year at BEPCII
Average Lum: L = 0.5×Peak Lum.; One year data taking time: T = 107s
σ × × Nevent/year = exp L T
Resonance Mass(GeV) Peak Lum. Physics Cross #Nevents/year CMS (1033cm-2s-1) Section (b)(nb) J/ψ 3.097 0.6 3400 10 × 109 τ+τ− 3.670 1.0 2.4 12 × 106 ψ(2S) 3.686 1.0 640 3.2 × 109 D0D0bar 3.770 1.0 3.6 18 × 106 D+D- 3. 770 101.0 282.8 14 × 106 DsDs 4.030 0.6 0.32 1.0 × 106 DsDs 4.170 0.6 1.0 2.0 × 106
2008－6－5Hai-Bo Li (李海波） 6 BES-III
Magnet: 1 T Super conducting current 3400 Amp MDC: small cell & Gas: He/C3H8 (60/40) σ =130 μm σxy p/p = 0.5% @1GeV dE/dx=6%
TOF: σ T = 100 ps Barrel 110 ps Endcap
Muon ID: 9 layers RPC 8 layypers for endcap EMC: CsI crystal Data Acquisition: ΔE/E = 2.5% @1 GeV Event rate = 4 kHz σz = 0.6 cm/√E Total data volume ~ 50 MB/s The detector is hermetic for neutral and charged particle with excellent resolution , PID, and large coverage. 2008－6－5Hai-Bo Li (李海波） 7 2008－6－5Hai-Bo Li (李海波） 8 BESIII Status 9 Finish the installation of all the detector components . Beam pipe, MDC, Barrel and endcap TOF, barrel and endcap EMC, all muon chambers. 9 Cosmic ray data from Dec. 2007 to March 15 2008, with DAQ, Trigger, and Slow control, fixing problems. 9 BESIII deecodetector into obe beam-line o n May 6, 2008 9 Starting another cosmic run on May 28, 2008 9 Physics run on July 20, 2008 9 Luminosity of BEPCII is expected to reach ~ 3 x 1032cm-2s-1 in the end of 2008. [The design Lum is 1 x 1033cm-2s-1] 9 Software and physics preparation in good shape.
2008－6－5Hai-Bo Li (李海波） 9 Totally 37 institutions now Europe (5) USA (7) GSI, Germany University of Hawaii University of Bochum, Germany University of Washington University of Giessen, Germany Carnegie Mellon University Univ. of Florida JINR, Dubna, Russia Univ. of Minnesota Rensselaer Polytechnic Institute BdkiBudker instit tittute o fNf Nuc lear Ph Phiysics Japan (1) University of Rochester Russia China (24) Tokyo University IHEP, CCAST, GUCAS， Univ. of Sci. and Tech. of China Shandong Univ., Zhejiang Univ. Huazhong Normal Univ., Wuhan Univ. “Spectators”: Zhengzhou Univ., Henan Normal Univ. Peking Univ., Tsinghua Univ. , four institutes Zhongshan Univ.,Nankai Univ. Shanxi Univ., Sichuan Univ from Italy Hunan Univ., Liaoning Univ. Nanjing Univ., Nanjing Normal Univ. Guangxi Normal Univ., Guangxi Univ. HKUiitHong Kong University Chinese Univ. of Hong Kong 2008－6－5Hai-Bo Li (李海波） 10 Hot ppyhysics top ics at BES-III
2008－6－5Hai-Bo Li (李海波） 11 Hot topics at BES-III ¾ Light hadron spectroscopy: meson, baryon, hybrid, glueball and other exotics in J/ψ and ψ(2S) decays. η η ψ ψ χ ¾ Charmonium states: c((),1S), c((),2S), J/ , ((),2S), c, hc , ψ(3770), new ccbar states above 4.0 GeV
¾ Energy scan: R values, new resonances … ¾ Tau physics: precision tau mass ¾ Charm physics: D, Ds mesons Leptonic Charm Decays D→l+ν SilidSemileptonic decay rates & &f form-factors Charm Dalitz Decays, …… Charm Mixing. CP Violation and Rare charm decays …
¾ Rare charmonium decays: LFV, invisible decays , …… many more unexpected itiinnovations
2008－6－5Hai-Bo Li (李海波） 12 Light hadron spectroscopy With 1010 J/ψ events with the state of art detector , we expect to learn more on: • Baryon spectroscopy • Glueballs • Non-qqbar states
2008－6－5Hai-BoSpectrum of glueballs fromLi (李海波） LQCD 13 0++ resonances at BESIII σ κ , , f0(980), f0(1370), f0(1500) and f0(1710) are well established in PDG. B.S.Zou arXiv 0804.2756 J/ψ radiative decays
J/ψ hadronic decays
χ c02 hadronic decays
2008－6－5Hai-Bo Li (李海波） 14 States with Exotic quantum number Hybrid mesons and glueballs are always mixing with normal mesons with the same quantum numbers. It is hard to us to separate them from normal mesons . However: Quantum numbers offf fermi on-antifermi on EtiExotic 1−+ : quantum numbers 2s+1L JPC Meson J π η 1S (s-wave0-+ ) a 0 π JPC 0 πη π 3S (p-wave)1-- 1 ρ 0+- 1 πη 1 (d-wave)+- a2 -- P1 1 b1 0 3P 0++ a 1-+ 0 πρ (p-wave) π1 0 3 ++ +- P1 πf (s-wave)1 π a1 2 3 1 ++ 1 -+ P2 π 2 π a2 3 b1 (s-wave) 1
2008－6－5Hai-Bo Li (李海波） 15 Example + − + − X(1835) at BESIII via J /ψ → γη'π π ,η'→ηπ π
58M J/ψ data Phys.Rev.Lett.95:262001,2005 at BESIII at BESII 3×109 J/psi events (50 times of BESII) 2 years’ data taking
5.0σ >10σ
η ππ 2 M( ’ ) GeV/c 2 2008－6－5Hai-Bo Li (李海波） M(η’ππ) GeV/c16 Charmonium states below open charm
What can we do with 3 billion ψ(2S)?
χ sample Ψ(2S) Æ π+π−J/ψ (31%) c,0,1,2 useful to understand really “pure” J/ψ sample 1977 thdhe decay dynam ics o f cc bar a complementary of and light hadrons J/ψ peak data! 1974 Q. Zhao, hep-ph/0508086 2002 η ′ ψ γ π 2004 1975 c in (2S) Æ KSK ψ γπ+π−η (2S) Æ C with untagged gamma M. Voloshin hep-ph/0206240 “ρπ”l” puzzle η π+π−η B( C(2S) Æ C ) = 5-10% Kuang et al. J. Rosner PRD 64 (094002) 2001 Detail study of hC at BESIII P. Wang et al PRD70(114014)2004 Non-DD decay o f ψ(3770): 1980 N. Achasov hep-ph/0505146 η ψ ψ) γη The productions of D0D0, D+D− C(1S) sample from (2S) (J/ Æ C(1S) 1974 used to study the light spectrum M. Voloshin hep-ph/0402171
2008－6－5Hai-Bo Li (李海波） 17 Scan will be crucial at BES-BES-III:III: ECM = 3773-3773-46004600 MeV Opportunity at BESIII to look for new states above the o pen charm region. )
*
CLEO-c Preliminary Ron Poling talk at Charm2006 CLEO-c PRL 96, 162003 (2006) 2008－6－5Hai-Bo Li (李海波） 18 Rare and forbidden quarkonium decays
No any evidence beyond SM is found on the accelerators. No any indication beyond SM in Quarkonium decays.
Rare and forbidden Charmonium decays : (1) Lepton Flavor/baryon number violating decays; (2) Invisible decays .
2008－6－5Hai-Bo Li (李海波） 19 Lepton flavor violating processes in J/ψ decays
Lepton flavor violating (LFV) processes are strongly suppressed in the Standard Model by power of (small) neutrino masses. Such decays signal new physics. PRD63, 016003, S. Nussinov, R.D. Peccei and X.M. Zhang
ψ → μτ τ → ν ν ψ → τ τ → μν μν J / , e e τ J / e , τ BESII upper limit BR(J/ψ Æ eμ)<11) < 1.1×10−6 BR(J/ψ Æ eτ) < 8.3×10−6 BR(J/ψ Æ μτ) < 2.0×10−6 with 58M J/ ψ sample BESII PLB561,,( 49 (2003) μ momentum distribution PLB598, 172(2004) J/ψ Æ eμ, eτ, τμ, the sensitivity can be 10−8 –10−9 at BES-III with 1010 J/ψ events per year J/ψ Æ e− pp,roton +c.c, J/ψ Æ μ− proton +c.c can also be searched for. 2008－6－5Hai-Bo Li (李海波） 20 Invisible quarkonium decays
WithiWith in SMthiSM, the inv iiblisible quar kon ium decays are pre ditdbdicted by: hep-ph/9806487, L.N Chang, O.Lebedlev and J. N. Ng
With 2-3% uncertainty!
One get: Br(Y(1S) Æνν) = 1.0×10−5 Theoretical clean process can be used to test model Br(J/ψ Æ νν) = 2.69 ×10−8 and probe new physics! New physics may enhance the production rate of the invisible dfkiFlMVdkttdidtdecays of quarkonia. For example, MeV dark matter candidates.
2008－6－5Hai-Bohep-ph/0506151 Li (李海波） Bob McElrath 21 Invisible decays of mesons η η ψ φη η ¾ Search for / ’ ÆInvisible Decays in J/ Æ / ’ 58 m illion J/ψ
BR(η → invisible) − <1.65×10 3 @90%C.L. ηBR(η →γγ )
BR( '→ invisible) − η < 6.69×10 2 @90%C.L. BR( '→γγ )
BES, Phys.Rev.Lett.97:202002,2006
¾ Search for J/ψ Invisible Decays byyg using ψ(()2S)Æπ+π− J/ψinvisible 14 million ψ(2S) B(J /ψ → invisible) − <1.0×10 2 @90%C.L. ψ → μ + μ − B(J / ) ψ(2S) BES, Phys. Rev. Lett. 100: (2008)
−6 − −7 ψ χ η η η The sensitivity at BESIII will be 10 10 for J/ , C , C , ’Æ Invisible 2008－6－5Hai-Bo Li (李海波） 22 Charm physics at BES-III
2008－6－5Hai-Bo Li (李海波） 23 DD Pairs at different Experiments 128 M is expected at BES-III with 4 years’ luminosity. 5 M is expected at CLEO-c until 2008. 700M 800
600 500M
400 128M 200 02M0.2 M 5M5 M
0 BESII CLEO- c BES- III BaBar Belle
ψ(3770) peak Υ(4S) Peak Background free Higher statistics
2008－6－5Hai-Bo Li (李海波） 24 Impact of Charm Physics
• Precision CKM
+ν – Leptonic Charm Decays D→l – Semileptonic decay rates & form-factors – Hadronic Charm Decays - B→Charm is dominant • Possib le New Ph ysics in Charm Sect or
– Rare Charm Decays (HilGIMHeavily GIM suppressedBF(d: BF(c→ull)10)~10-8) – Charm Mixing. – CP Violation
2008－6－5Hai-Bo Li (李海波） 25 fD+ and challenge of QCD
CLEO-c Preliminary : 818 pb -1 4.3% 2.0%
2.0%
PRL 100, 062002(2008) BES-III reaches 2% with 20 fb−1 data @ psi(3770).
2008－6－5Hai-Bo Li (李海波） 26 Precise determination of fDs –challenge LQCD H.B.Li ,J.H.Zou arXiv:0804.1822 See Hewett [hep-ph/9505246] & Hou, PRD 48, 2342 (1993).
CLEO-c, Belle and BaBar:
3.2% HPQCD+UKQCD PRL 100, 062002(2008) 1.2% 1.1% 4.0 sigma discrepancy between LQCD and experimental determination in the SM. 2008－6－5Hai-Bo Li (李海波） 27 Probing new physics in leptonic decays In the Standard model:
H.B.Li ,J.H.Zou arXiv:0804.1822 CLEO-c determination:
HPQCD+UKQCD: PRL 100, 062002(2008)
−1 At BES-III, Rμ : 2.0% with 20fb da ta at 4170 M eV .
2008－6－5Hai-Bo Li (李海波） 28 The D-meson Unitarity triangle
2008－6－5Hai-Bo Li (李海波） 29 Precise test of CKM in D decays
2008－6－5Hai-Bo Li (李海波） 30 Quantum Correlation
PRD 73, 034024 (2006) Asner and Sun I.I.Bigi SLAC report-33, 1989 page 169
(C=−1) e+e− → ψ(()3770) → D D Forbidden if no mixing K−π+ K−π+ Forbidden if no mixing K−l+ν K−l+ ν FbiddbCPForbidden by CP conserva tion CP+ CP+ Forbidden by CP Conservation CP− CP− Interference of CF with DCS K−π+ CP± Special menu at BES-III:
¾ The mixing rate RM can be measured at the first order; δ → π ¾ Strong phase Kπ is from CP tagged D K ; ¾ CP violation is measured in a production rate. 2008－6－5Hai-Bo Li (李海波） 31 Mixing rate RM from ± ± 2 + 2 π m π m = x y = N[(K π )(K )] R ± ± − M 2 N[(K m )(K mπ )] Sensitivity in 20 fb 1 data × -4 at BES-III: RM < 1.5 10 2 events in the signal region due to mis-ID. (the mis-ID rate for pi as a Kaon is 1%).
Beam constraint mass
2008－6－5Hai-Bo Li (李海波） 32 The first order sensitivity to strong phase CP even: = 1 ( 0 + 0 ) D1 D D 2 CP odd : 1 ()0 0 D2 = D − D 2
CP tagged Kπ decay: δ Δcos Kπ < 0.06 γ φ The model indeppgpendent strong phase determination is useful for / 3 A. Bondar, A.Poluektov, Eur. Phys. J. C47 347-353 (2006), hep-ph/0510246]. 2008－6－5Hai-Bo Li (李海波） 33 CP Violation at ψ(3770) at BESIII
+ K
0 CP violating asymmetries can be measured by − K D searching for events with two CP odd or two CP even final states:
0 D + π − π+π−, + - π0 π0, π0 π K K , Ks , ′′ → for the decay of ψ f1 f 2 CP( ) =CP( ) ⋅CP( ) ⋅( −1) L= − f f1 2 f 1 f 2 CP(ψ ′′) = +
Δ -3 ACP sensitivity : A ~10
2008－6－5Hai-Bo Li (李海波） 34 Sensitivities (20 fb-1 at psi(3770) peak ) • Mixing parameters –R =(x2+y2)/2 < 10-4 in Kπ and M BESIII Keν channels
– Probe y: ΔyCP < 0.7%, δ –Δcos Kπ < 0.06 •CP Violation -3 + –ΔACP~10 in D decays (direct CPV), φ γ • Improvement to 3/ measurement in BÆ D(*)K<2o (CLEO-c: ~5o) 2008－6－5Hai-Bo Li (李海波） 35 Rare and forbidden Charm Decays Charm FCNC decays heavily GIM suppressed in SM:
Burdman et. al., PRD66(2002)014009 New Physics can contribute in loop, which is different from the cases in B and Kaon mesons. Lepton decays: D0 → l+l− (l = e,μ); GIM suppressed decays: D0(±) →M0(±) l+l− (M is meson allowed); LFV decays: D0 → e+ μ − , D0(±) →M0(±)e+ μ − ; LNV decays: D± →M± l+ l + (l = e, μ; the same signed-di-lepton) ; 2008－6－5Hai-Bo Li (李海波） 36 D→hl+l− Like Rare Decays BBBaBar Inpu t ICHEP06 288 fb−1 @Y(4S)
CLEO-c 0.8 M (0.281 fb−1)
L 288 BaBar = = 960 LCLEO−c 0.3
Background free at a charm factory @psi(3770) peak!
2008－6－5Hai-Bo Li (李海波） 37 Sensitivity of LFV
Improve the limits by more than order magnitude!
BES-III(20 fb-1) -8 CLEO-c(1fb-1) 10 BaBar(288fb-1)
8.3 37 + + − + 0 + − → 0 +μ− B(D → e e ) 370 D B(DK→ee e ) 5.9 π 26.4 + + − + 590 D → e μ
4.3 ± 69 0 → μ m 81 D e
17 69 0 → μ + μ − 130 D
2.4 69 0 + − + − → 100B(D0 →Be (eD) e e )
LFV and LNV are “smoking gun” , any indication of deviation from zero will indicate New Physics (NP). 2008－6－5Hai-Bo Li (李海波） 38 Summary 9 Tests of QCD at low energy in various way: light hadron spectrum, charmonium decays and spectrum, light hadron decays, decay constants; ¾ Precise measurements: test of SM (R values, tau mass); ¾ New Physics probe at BES -III: (0) Rare and forbidden decays of quarkonia (1) Rare decays of Charm meson (2) D0-D0bar mixing (3) CP violation in D meson decays (4) Lepton Flavor/baryon number violated decays We expect to locate the search of tiny contributions from new ppyhysics at heav y flavor sector after an ythin g new can be found at LHC! 2008－6－5Hai-Bo Li (李海波） 39 Thank you!
BESIII in beam line ! 2008－6－5Hai-Bo Li (李海波） 40 Back up
2008－6－5Hai-Bo Li (李海波） 41 Be beam pipe
• Two Be cylinders (0.8 mm and 0.5 mm thick, 0.8mm gap), cold by paraffine-1 • 14.6 μm gold at the inner surface. • The beam pipe was put in the place on March 27, 2008, it is the last component of the BES-III detectors.
2008－6－5Hai-Bo Li (李海波） 42 Drift chamber • To measure the momentum of charged particles • Design spec.: Single wire reso. dE/dx reso. CLEO: ~110μm, 5.7% Babar: ~110μm, 6.2% Belle: ~130μm, 5.7% BESIII ~120μm 6%6 %
• Rin = 63mm; Rout = 810mm; length = 2400 mm • 7000 Signal wires: 25(3% Rhenium) μm gold-plated tungsten • 22000 Field wires: 110 μmAl
• Gas: He + C3H8 (60/40) • Momentum resolution@1GeV: 0.5% σ Pt = 0.32% ⊕ 0.37% Pt
2008－6－5Hai-Bo Li (李海波） 43 Separate cosmic ray test：meet design
90 hits 800 dr 25.025 phi0 3.23820 dz -326.564 tanL -0.60083 600
400
200
0
-200
-400
-600
-800 -800 -600 -400 -200 0 200 400 600 800
resrevoverall 35000 Entries 781908 Mean -2.772e-05 RMS 0.123 30000 χ2 / ndf 2234 / 154 Prob 0 p0 ± 25000 σ=120μm 5551 24.2 p1 9.471e-05 ± 1.416e-04 p2 0.07865 ± 0.00022 20000 p3 2245 ± 23.5 p4 -0.000392 ± 0.000456 VL=60, VH=80 p5 0.1854 ± 0.0008 15000 T T
10000
5000 2008－6－5Hai-Bo Li (李海波） 44 0 -1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8 1 Residual (mm) U3 BESIII CsI(Tl) crystal calorimeter • To measure the energy of electromagnetic particles • Barrel: 5280 crystals，Endcap: 960 crystals Babar: 2.67% @1GeV • Cryy(stal: (5.2x 5.2 – 6.4 x 6.4) x 28cm3 • Readout: ~13000 Photodiodes, 1cm×2cm, BELLE: 2.2% @1GeV • Energy range：20MeV – 2 GeV CLEO: 2.2% @1GeV • position resolution :6: 6 mm@1GeV BES2%@1GSIII: 2.5%@1GeV • Tiled angle: theta ~ 1-3o, phi ~ 1.5o
2008－6－5Hai-Bo Li (李海波） 45 Slide 45
U3 250rad/year 28 cm long electronic noise less than 200keV 0.5 MeV noise. User, 5/30/2008 Installation of barrel and endcap EMC
Crystal calorimeter without supporting wall between crystals 2008－6－5Hai-Bo Li (李海波） 46 PID: Time-Of-Flight counters • DbllDouble layers a tblf88t barrel of 88 count ers /layer, read dttbthdout at both ends, endcap each has 48 counters, readout at the inner end. Barrel TOF Endcap TOF
High quality plastic scintillator: 2.4 m long, 5cm thick
2008－6－5Hai-Bo Li (李海波） 47 TOF • All scintillator bars arrived from Bicron. BC408 at barrel, BC404 at endcap, PMT:R5924; • LlihtittLaser light monitor system; • All counters are assembled, tested and installed. • Cosmic ray test shows the system works. Test beam at IHEP electron Proton Pion
(94±3) ps (70±2) ps (104±11) ps 2008－6－5Hai-Bo Li (李海波） 48 μ system : RPC • 9 layer, 2000 m 2 • Special bakelite plate w/o linseed oil • 4cm strips, ~10000 channels • Noise less than 0.1 Hz/cm2
螺栓M36
螺栓M20
2008－6－5Hai-Bo Li (李海波） 49 U4 Magnet reached 1 tesla （3364A）, sep. of 2006. Mapped the field with machine magnet together Aug. of 2007
4 x 10
1.025
1.02
1.015
1.01
1.005 Bz (Gauss) Bz 1
0.995
0.99 2000 1000 3 300 0 250 200 150 -1000 100 50 -2000 0 Z (mm) phi (degr ee)
2008－6－5Hai-Bo Li (李海波） 50 Slide 50
U4 The maximum fluctuation is about 1.5%. User, 5/30/2008