Highlights from BESIII Yaqian Wang Johannes Gutenberg University Mainz, Germany 14th International Conference on B-Physics at Hadron Machines 8-12 th April, Bologna BEAUTY 2013 Highlights from BESIII 04/10/2013 1
BESIII Experiment e + e - BEAUTY 2013 Highlights from BESIII 04/10/2013 2 To Tian anmen Square (~10 km)
BEPC II Storage Ring Beam energy: 1.0-2.3 GeV Design luminosity: 1 10 33 cm -2 s -1 Optimum energy: 1.89 GeV Energy spread: 5.16 10-4 No. of bunches: 93 Bunch length: 1.5 cm Total current: 0.91 A Circumference: 237 m 65% achieved double ring BEAUTY 2013 Highlights from BESIII 04/10/2013 3
The BESIII Detector Magnet yoke SC magnet, 1T RPC TOF, 90ps Be beam pipe MDC, 120 μm BEAUTY 2013 CsI(Tl) calorimeter, 2.5 %@ 1 GeV Highlights from BESIII 04/10/2013 A total weight of 730t, ~40000 readout channels, data rate 6000Hz ~50Mb/s, ~1000 man*year, 30 M$ 4
BESIII Collaboration US (6) Univ. of Hawaii Univ. of Washington Carnegie Mellon Univ. Univ. of Minnesota Univ. of Rochester Univ. of Indiana ~360 members 52 institutions from 11 countries BEAUTY 2013 Europe (12) Germany: Univ. of Bochum, Univ. of Giessen, GSI Johannes Gutenberg Univ. Helmholtz Ins. In Mainz Russia: JINR Dubna; BINP Novosibirsk Korea (1) Italy: Univ. of Torino,Frascati Lab Seoul Nat. Univ. Netherland:KVI/Univ. of Groningen Sweden: Uppsala Univ. Turkey: Turkey Accelerator Center Pakistan (2) China(30) Univ. of Punjab COMSAT CIIT Highlights from BESIII 04/10/2013 Japan (1) Tokyo Univ. IHEP, CCAST, GUCAS, Shandong Univ., Univ. of Sci. and Tech. of China Zhejiang Univ., Huangshan Coll. Huazhong Normal Univ., Wuhan Univ. Zhengzhou Univ., Henan Normal Univ. Peking Univ., Tsinghua Univ., Zhongshan Univ.,Nankai Univ. Shanxi Univ., Sichuan Univ., Univ. of South China Hunan 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. Hong Kong Univ., Hong Kong Chinese Univ. 5
Data Samples Y(4360) Y(4260) ψ(4040) ψ ψ ~500 pb -1 ~500 pb -1 ~500 pb -1 ~2.9 fb -1 106 M + 2013 J/ψ 225 M + 2009 BEAUTY 2013 Highlights from BESIII 04/10/2013 6
Physics Program @ BESIII Light hadron physics -meson & baryon spectroscopy -multiquark states -threshold effects -glueballs & hybrids -two-photon physics -p & n form-factors Charmonium physics: - precision spectroscopy - transitions and decays QCD & τ -physics: - precision R-measurement - τ decays Charm physics: - semi-leptonic form factors - f D & f D decay constants. s - CKM matrix: V cd, V cs - D 0 -D 0 mixing and CPV - strong phases XYZ meson physics: -Y(4260) ππj/ψ & other decays - searches for new states BEAUTY 2013 Highlights from BESIII 04/10/2013 7
Recent Results on Light Hadron Physics PWA of J/ψ γηη PWA of J/ψ γωɸ BEAUTY 2013 Highlights from BESIII 04/10/2013 8
PWA of J/ψ γηη arxiv:1301.0053 Search for glueballs, hybrids and multi-quarks LQCD: the lowest mass glueball with 0 ++ is in the mass region from 1.5-1.7 GeV Difficulty: mixing with qq nonet mesons Radiative J/ψ decay is a gluon-rich process J/ψ radiative decay to two pseudoscalar mesons offers a very clean laboratory to search for scalar and tensor glueballs Clear peak f 2 (1910)? f 2 (1950)? ~1 order larger than f 0 (1500) f 2 (2300)? BEAUTY 2013 Highlights from BESIII 04/10/2013 9
PWA of J/ψ γωφ X(1810) was observed in J/ψ γωɸ by BESII [PRL96,162002] PWA: 0 ++ favors (>30σ) doubly OZI suppressed process Possible interpretations: a tetraquark state, a hybrid, or a glueball state, a dynamical effect arising from intermediate meson rescattering, or a threshold cusp of an attracting resonance. PRD 87, 032008 (2013) BEAUTY 2013 Highlights from BESIII 04/10/2013 10
Charmonium Spectroscopy First observation of ψ γη c Properties of h c Mass and width of η c BEAUTY 2013 Highlights from BESIII 04/10/2013 11
η c (1S) The S-wave spin-singlet charmonium ground state, found in 1980 Mass and width measurements: -J/ψ radiative transitions: M ~ 2978.0 MeV, Γ ~ 10 MeV -γγ processes / B Kη c : M = 2983.1±1.0 MeV/, Γ = 31.3±1.9 MeV _ γγ, pp, B decay Mass ψ(1s, 2S) γη c width C.L.=0.0014 C.L.<0.0001 BEAUTY 2013 Highlights from BESIII 04/10/2013 12
ψ γηc, ηc Exclusive Decays PRL 108, 222002 (2012) KsKπ K+K π0 KsK3π 2K2ππ0 π+π η 6π Interference with non-resonant background is significant!! Relative phase φ values from each mode are consistent within 3σ, common phase in the simultaneous fit. BEAUTY 2013 M: 2984.3 ± 0.6 ± 0.6 MeV/c2 Γ: 32.0 ± 1.2 ± 1.0 MeV φ: 2.40 ± 0.07 ± 0.08 rad Highlights from BESIII 04/10/2013 13
First Observation of ψ γη c PRL 109, 042003 (2012) B(ψ γη c γkkπ)= With B(η c KKπ)= BaBar B(ψ γη c )= Potential models: BEAUTY 2013 Highlights from BESIII 04/10/2013 14
Charm Physics (Preliminary) D + μ + ν D 0 K - / π - e + ν BEAUTY 2013 Highlights from BESIII 04/10/2013 15
D μν(besiii: 2.9 fb -1 ) Tag side reconstruction: 9 decay modes Kinematic variables: E E D -E beam M bc 2 2 (1.57±0.2) M tags found Beam-constrained mass of tag D BEAUTY 2013 Highlights from BESIII 04/10/2013 16
D μν(besiii: 2.9 fb -1 ) Signal side reconstruction: One charged track only Kinematic variable: M 2 miss ( ) 2 ( p tag p μ ) 2 0 = E Beam E μ 425 candidates BES III preliminary: N(D + μ + ν) = 377.3 ± 20.6 BEAUTY 2013 Highlights from BESIII 04/10/2013 17
D 0 K/π e + ν Partially blind analysis (0.9 fb -1 analyzed so far. Full 2.9 fb -1 later for final results) Tag side reconstruction: 4 decay modes 0.77 M tags found Signal side reconstruction: two oppositely-charged tracks Kinematic variable: U = E P miss miss 0 Systematic uncertainties are preliminary Good consistency with CLEO-c, statistical precision is comparable with only 1/3 data analyzed BESIII Preliminary D 0 -> K e ν N sig = 18460+/-143 BESIII Preliminary D 0 -> π e ν N sig = 1677+/-45 BEAUTY 2013 Highlights from BESIII 04/10/2013 18
Studies of XYZ at BESIII e + e ηj/ψ @ s=4.009 GeV e + e ππj/ψ @ s=4.26 GeV BEAUTY 2013 Highlights from BESIII 04/10/2013 19
e + e η/π 0 J/ψ@4.01GeV First observation: e + e - ηj/ψ (significance > 10σ) Measured Born cross section: (32.1±2.8 ±1.3) pb Assume η/π 0 J/ψ from ψ(4040): Br(ψ(4040) ηj/ψ)=(5.2 ±0.5±0.2±0.5) 10-3 Br(ψ(4040) π 0 J/ψ) <2.8 10-4 @90% CL Consistent with the theoretical calculation (Q.Wang et al., arxiv:1206.4511) J/ψ μμ J/ψ ee Partial width of ψ(4040) ηj/ψ: ~400keV (> two times ψ(4040) π + π J/ψ) Similar to the hadronic transition of Υ(4S) (admixture of a four-quark state in the wave function, M. B. Voloshin, Mod. Phys. Lett. A 26, 773 (2011)) J/ψ μμ BEAUTY 2013 Highlights from BESIII 04/10/2013 20
e + e π + π J/ψ@4.26 GeV Belle: PRL99, 182004 (2007) BaBar: PRD86, 051102 (2012) BEAUTY 2013 BESIII: arxiv:1303.5949 Highlights from BESIII 04/10/2013 BESIII: σ(e + e - π + π - J/ψ) = (62.9±1.9±3.7) pb Agree with BaBar & Belle! Best precision! 21
Dalitz Plots & 1D Projections BESIII: arxiv:1303.5949 BEAUTY 2013 Highlights from BESIII 04/10/2013 22
The Z c (3900) Signal Significance>8σ χ 2 /ndf=32.6/37 BESIII: arxiv:1303.5949 307 ±48 events Couples to cc Has electric charge At least 4-quarks What is its nature? BEAUTY 2013 S-wave Breit-Wigner with efficiency correction Mass = (3899.0±3.6±4.9) MeV Width = (46±10±20) MeV Fraction = (21.5±3.3±7.5)% Highlights from BESIII 04/10/2013 23
Summary BEPCII and BESIII are operating in good status. PWA results about ψ γηη and ψ γωφ are reported. Mass and width of η c are precisely measured; ψ γη c is first observed. With world s largest sample, precision measurements of f D, V cs, and V cd are in progress. Observation of Z c (3900) in e + e π + π J/ψ @4.26GeV, more precise measurements are underway. With excellent detector and machine, interesting programs of physics are expected! BEAUTY 2013 Highlights from BESIII 04/10/2013 24
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PWA of J/ψ γηη arxiv:1301.0053 BEAUTY 2013 Highlights from BESIII 04/10/2013 26
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