Recent Results from the BESIII Experiment. Ryan Mitchell Indiana University Miami 2011 December 17, 2011

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1 Recent Results from the BESIII Experiment Ryan Mitchell Indiana University Miami 11 December 17, 11 1

2 The primary goal of BESIII: Use e + e collisions to produce charmonium states, then use their properties and their decays to learn about the strong force. (and the properties and the decays of their decay products, etc.) 3.8 MD "##(1 3 D1) "#( 3 S1) 3.6!c#( 1 S) MASS [GeV/c ] 3.4 hc(1 1 P1) $c(1 3 P) $c1(1 3 P1) $c(1 3 P) accelerator 3. charmonium QCD 3.!c(1 1 S) J/"(1 3 S1) c c E1-Dominated Transitions M1-Dominated Transitions phenomenology and theory %+ 1 %% 1 +% J PC

3 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 3

4 accelerator 4

5 BEPCII: Institute for High Energy Physics Beijing, China Collide e + e in the τ-charm region: R accelerator e + e Center of Mass Energy First collisions: March 8 Record luminosity: ~6 1 3 cm s 1 (~1 CESRc and ~5 BEPC) 5

6 aerial view of BEPCII at IHEP accelerator to Beijing 6

7 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 7

8 detector 8

9 The BESIII Detector detector Excellent tracking and calorimetry with a uniform acceptance: tracks: σp/p ~.6% at 1 GeV/c photons: σe/e ~.5% at 1 GeV 9

10 The BESIII Detector detector First Hadronic Event: July 8 Excellent tracking and calorimetry with a uniform acceptance: tracks: σp/p ~.6% at 1 GeV/c photons: σe/e ~.5% at 1 GeV 1

11 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 11

12 data 1

13 BESIII Data So far BESIII has collected: ~ 5 Million J/ψ ~ 16 Million ψ(s) ~.9fb 1 at the ψ(377) ~.5fb 1 at 41 MeV data 13

14 BESIII Data data So far BESIII has collected: ~ 5 Million J/ψ ~ 16 Million ψ(s) ~.9fb 1 at the ψ(377) ~.5fb 1 at 41 MeV BESIII will also collect: more J/ψ, ψ(s), ψ(377) + data at higher energies (for XYZ searches and Ds physics...) 14

15 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 15

16 Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 16

17 MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S)! $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) " J/"(1 3 S1)!c(1 1 S) %+ 1 %% 1 +% Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) For example: J PC analysis Properties of the hc (PRL 14, 13 (1)) 17

18 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 18

19 3.8 MD "##(1 3 D1) "#( 3 S1) 3.6!c#( 1 S) MASS [GeV/c ] 3.4 hc(1 1 P1) $c(1 3 P) $c1(1 3 P1) $c(1 3 P) 3. J/"(1 3 S1) 3.!c(1 1 S) E1-Dominated Transitions M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture 19

20 3.8 MD "##(1 3 D1) "#( 3 S1) 3.6!c#( 1 S)!!"#!!$#!!%#! c1,!" J/#$ MASS [GeV/c ] 3.4 hc(1 1 P1) $c(1 3 P) $c1(1 3 P1) $c(1 3 P) &'()))#*+,-./.1+# % c 3. J/"(1 3 S1) photons from ψ(s) decays 3.!c(1 1 S) E1-Dominated Transitions M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture

21 A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) 3.8 MD 3.6!c#( 1 S) "##(1 3 D1) "#( 3 S1) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) MASS [GeV/c ] 3.4 hc(1 1 P1) $c(1 3 P) $c1(1 3 P1) $c(1 3 P) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions 3. J/"(1 3 S1) Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) 3.!c(1 1 S) E1-Dominated Transitions M1-Dominated Transitions Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later %+ 1 %% 1 +% J PC a bigger picture 1

22 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis

23 QCD phenomenology and theory 3

24 Quantitative Comparisons with Lattice QCD e.g.: charmonium masses radiative transitions open charm decay constants Decay Dynamics e.g.: the ρπ puzzle J/ψ or ψ(s) ρπ QCD The Structure of Mesons e.g.: gluonic excitations? phenomenology and theory 4

25 detector data accelerator QCD phenomenology and theory MASS [GeV/c ] 3.8 MD "##(1 3 D1) "#( 3 S1)!c#( 1 S) $c(1 3 P) hc(1 1 P1) $c1(1 3 P1) $c(1 3 P) J/"(1 3 S1) E1-Dominated Transitions!c(1 1 S) M1-Dominated Transitions %+ 1 %% 1 +% J PC a bigger picture Events / 1MeV Events / 1MeV BESIII E1 photon tagged Inclusive! recoil mass (GeV/c ) analysis 5

26 A Few Highlights from the BESIII Experiment A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) 3.8 MD 3.6!c#( 1 S) "##(1 3 D1) "#( 3 S1) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) MASS [GeV/c ] 3.4 hc(1 1 P1) $c(1 3 P) $c1(1 3 P1) $c(1 3 P) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions 3. J/"(1 3 S1) Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) 3.!c(1 1 S) E1-Dominated Transitions M1-Dominated Transitions Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later %+ 1 %% 1 +% J PC a bigger picture 6

27 Study of Light Quark States A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later Types of Meson States Allowed by QCD q q MESON q q HYBRID MESON GLUEBALL q q q q FOUR QUARK q q q q 7

28 The X(186) in J/ψ γ(pp) at BESIII First observed by BESII Now confirmed by BESIII in ψ(s) π+π J/ψ J/ψ γpp using 16 million ψ(s) decays Event/.1GeV/c Also recently confirmed by CLEO-c (with lower statistics) in the same reaction M(pp)(GeV/c ) No clear evidence in: ψ(s) γpp (BESII) J/ψ ωpp (BESII) J/ψ π pp (BESIII) ϒ(1S) γpp (CLEO III) ) Events/(.5GeV/c X(186) phase space etc. Possibly baryonium? M pp -m p (GeV/c ) acceptance 8

29 J PC of the X(186) (NEW) perform amplitude analyses using decay angular distributions... J/ψ γpp + (186) ++ phase space fj(191) fj(1) ψ(s) γpp arxiv:111:94 X(186) has J PC = + X(186) is now seen in ψ(s) decays (~5% of J/ψ decays) 9

30 The X(1835) in J/ψ γ(η π + π ) at BESIII First observed by BESII: (58 million J/ψ decays) PRL95, 61 (5) Confirmed by BESIII: (5 million J/ψ decays) X(1835) PRL16, 7 (11) bg + phase space predicted bg Rich Substructure! But with surprises: (an amplitude analysis could help with interpretation) 3

31 The X(187) in J/ψ ω(ηπ + π ) at BESIII One more surprise... f1(185) η(145) Look at M(ηπ + π ) from J/ψ ω(ηπ + π ) X(187) after selecting a ± ηπ ± A new signal appears at a mass of 187 MeV/c with a width of ~8 MeV/c! PRL17, 181 (11) In general, amplitude analyses will be needed to learn more about these new states... and then we need a global comparison between experiment and theory... 31

32 Study of Charmonium Decays A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later ψ(s) ψ(s) γη ( ) η or η ideally, study the η η mixing angle, but ψ(s) γη is anomalously suppressed... ψ(s) γπ γ* ψ(s) π possibly study the γ* γ π form factor for timelike γ* γ γ 3

33 Analysis of ψ(s) γ(π,η,η ) at BESIII ψ(s) γη (First Observation) η π + π π ψ(s) γη η π + π η ψ(s) γπ (First Observation) π γγ strange depletion! η π π π η γπ + π (Branching fractions in units of 1 6 ) 33

34 The Suppression of ψ(s) γη? For J/ψ, J/ψ γη ( ) = (1.1 ±.9) % consistent with other measurements of the η η mixing angle. J/ψ γ η or η But for ψ(s), = (1.1 ±.38 ±.7) % ψ(s) ψ(s) γη ( ) γ η or η Why the difference? interference with the continuum? contributions of other processes? something related to the ρπ puzzle? 34

35 Study of Charmonium Spectroscopy A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) 3.8 MD 3.6!c#( 1 S) "##(1 3 D1) "#( 3 S1) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) MASS [GeV/c ] 3.4 hc(1 1 P1) $c(1 3 P) $c1(1 3 P1) $c(1 3 P) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions 3. J/"(1 3 S1) Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) 3.!c(1 1 S) E1-Dominated Transitions M1-Dominated Transitions Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later %+ 1 %% 1 +% J PC 35

36 Measuring the Mass of the ηc(1s) the ηc(1s) is the ground state of the charmonium system, but its properties are not well-known: MASS WIDTH some of the problem appears to stem from measurements using ψ(1s,s) γηc(1s)... 36

37 Measuring the Mass of the ηc(1s) BESIII observed a shift in mass due to a distortion of the ψ(s) γηc(1s) lineshape... Events / 1 MeV/c Events / 1 MeV/c data other " decays! X i cont sig non-reso int data other " decays 8 6 4! X i cont sig non-reso int M(KsK!) GeV/c M(KsK3!) GeV/c Events / 1 MeV/c Events / 1 MeVc data other " decays! X i cont sig non-reso int data other " decays! X i cont sig non-reso int M(KK! ) GeV/c M(K!! ) GeV/c Events / 1 MeV/c Events / 1 MeV/c 16 data other " decays ! X i cont sig non-reso int data other " decays ! X i cont sig non-reso int M(!!#) GeV/c M(6!) GeV/c Attributing the distortion to interference with non-resonant radiative decays... FIG. 1: The M(X i ) invariant mass distributions for the decays K S K + π, K + K π, ηπ + π, K S K + π + π π, K + K π + π π and 3(π + π ), respectively, with the fit results (for the constructive solution) superimposed. Points are data and the various curves are the total fit results. Signals are shown as short-dashed lines; the non-resonant components as long-dashed lines; M = ±.6 ±.6 MeV and Γ = 3. ± 1. ± 1. MeV and the interference between them as dotted lines. Shaded histograms are (in red/yellow/green) for (continuum/π X i /other ψ decays) backgrounds. The continuum backgrounds for K S K + π and ηπ + π decays are negligible. 37

38 Study of Open Charm A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later ψ(377) Use ψ(377) DD to produce two quantum correlated D mesons (almost) at rest. Tag one D meson to learn about the other. Powerful tool for studying: mixing and CP violation hadronic decays (e.g. Dalitz analyses) semileptonic decays (form factors) leptonic decays (decay constants) etc. BESIII has ~.9fb 1 (~3 CLEO) D D 38

39 Open Charm at BESIII Examples of a few D-tag modes... +,-... /#"(1(%$ +,-... /#"(1(%$! "!#!! $!#!! +,-... /#"(1(%$ +,-... /#"(1(%$ M $ E % p BC beam D very clean C#'D"E*(D%B&?F5&G#H excellent ~1.3 MeV 1DI#'J for pure charged?fk&g#h ~1.9 9(*:&D%#&! with a π! "! "!#!!!! "!#!! " M BC = E beam p D (using only 4 pb 1...) 39

40 Study of Charmonium Above Open Charm Threshold A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later the spectrum of charmonium states above open charm threshold is richer than once thought... State m (MeV) Γ (MeV) X(387) ±. 1.3±.6 1 (<.) X(3915) ± 3.1 8±1 X(394) G(39) 3943 ± 1 5±11 Y (48) ±97 Z 1 (45) Y (414) ± X(416) Z (45) Y (46) 463 ± 5 18±14 Y (474) X(435) Y (436) 4353 ± 11 96±4 Z(443) X(463) Y (466) 4664±1 48±15 Y b (1888) ± arxiv: [hep-ex] 4

41 The Y(46) and Y(436) States potential hybrid meson states discovered in ISR at Belle and BaBar... Discovery of the Y(46) by BaBar The Y(436) in π + π ψ(s) at Belle/BaBar PRL 95, 141 (5) arxiv: [hep-ex] These states could be produced directly at BESIII. 41

42 Summary A Selection of Recent Results from BESIII: Light Quark States X(186) in J/ψ γ(pp) (Chinese Physics C 34, 4 (1) and NEW: arxiv:111.94) X(1835) in J/ψ γ(η π + π ) (PRL 16, 7 (11)) X(187) in J/ψ ω(ηπ + π ) (PRL 17, 181 (11)) a (98) f (98) mixing (PRD 83, 33 (11)) η ηπ + π matrix element (PRD 83, 13 (11)) Charmonium Decays ψ(s) γπ, γη, γη (PRL 15, 6181 (1)) χ cj π π, ηη (PRD 81, 55 (1)) χ cj γρ, γω, γφ (PRD 83, 115 (11)) χ cj 4π (PRD 83, 16 (11)) Charmonium Spectroscopy and Transitions Mass and width of the η c (arxiv: ) Properties of the h c (PRL 14, 13 (1)) Multipoles in ψ(s) γχ c (arxiv: ) Open Charm results very soon Charmonium Above Open Charm Threshold results a little later BESIII is now fully operational and many analyses are underway (as well as many systematic studies) BESIII has already made many contributions beyond the reach of CLEO-c Many more results are on their way! (including analyses of open charm) 4