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hadrons

. The Impact of BaBar ISR data on the SM Muon Anomaly Prediction. Michel Davier Laboratoire de l’Accélérateur Linéaire, Orsay. Muon Magnetic Moment Workshop October 25 - 26 , 200 7 , University of Glasgow. . . . hadrons. davier@lal.in2p3.fr. Goals of the BaBar ISR Program.

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hadrons

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  1. The Impact of BaBar ISR data on the SM Muon Anomaly Prediction Michel Davier Laboratoire de l’Accélérateur Linéaire, Orsay Muon Magnetic Moment Workshop October 25 - 26, 2007, University of Glasgow    hadrons davier@lal.in2p3.fr

  2. Goals of the BaBar ISR Program Precise measurements of cross section for all significant processes, e+e hadrons, from threshold to ~4-5GeV • Measure , KK channels with high precision • Summing up exclusive cross sections==>Improve the precision of R • Study spectroscopy of JPC=1−− states and their decays M. Davier et al., 2003 Ös

  3. Exclusive Channels with BaBar ISR ISR • systematic program underway using ISR from (4S) energies, taking • advantage of high luminosity (B-factory) • statistics comparable to CMD-2/SND for Ecm<1.4 GeV, much better than • DM1/DM2 above • full energy range covered at the same time • channels identified using particle ID and kinematic fitting • systematic uncertainties at 5-10% level • large acceptance for hadronic system (boosted opposite to ISR photon) X = 2E /Ecm H is radiation function

  4. BaBar ISR: e+ehadrons • Reactions for which results have been published : • ppPRD 73, 012005 (2006) • p+p-p0 PRD 70, 072004 (2004) • 2p+2p-, K+K-p+p-, PRD 71, 052001 (2005) • K+K-p+p- K+K-p0p0 , 2K+2K- PRD 76, 012008 (2007) • 3p+3p-, 2p+2p-p0p0, K+K-2p+2p- PRD 73, 052003 (2006) • New results presented last Summer : • K+Kp0,KSKp+,K+Kh, subm. to PRD arXiv:0710.xxxx [hep-ex] • LL , LS0 , S0S0subm. to PRD arXiv:0709.1988 [hep-ex] • +ppBaBar Preliminary • 2p+2pp0,2p+2ph,KK p+pp0, KKp+ph accept. by PRDarXiv:0708.2461 [hep-ex] • Work in progress: • ,K+K, p+p3p0 • Inclusive R

  5. BaBar ISR:  errors include systematics huge discrepancy with DM2 SND BaBar DM2 contribution to ahad (1.05-1.8 GeV) : • all before BaBar 2.45  0.26  0.03 • all + BaBar 2.79  0.19  0.01 • all – DM2 + BaBar 3.25  0.09  0.01 x1010

  6. BaBar ISR: 22 contribution to ahad (<1.8 GeV) : • all before BaBar 14.20  0.87  0.24 • all + BaBar 13.09  0.44  0.00 x1010

  7. BaBar ISR: 33 BaBar contribution to ahad (<1.8 GeV) : • all before BaBar 0.10  0.10 • all + BaBar 0.108  0.016 x1010

  8. BaBar ISR: 222 BaBar contribution to ahad (<1.8 GeV) : • all before BaBar 1.42  0.30  0.03 • all + BaBar 0.890  0.093 x1010

  9. BaBar ISR: +00 Only statistical errors plotted BaBar preliminary ψ ->p0p0J/ψ(->mm) J/ψ • Previous situation chaotic • Preliminary syst. error: 8% in peak 5% • Good agreement with SND <1.4 GeV • Huge improvement >1.4 GeV • First measurement >2.5 GeV

  10. BaBar ISR: +00--substructure • Intermediate states: • 0 • +- large and first seen • 0 f0(980) • a1(1260) BaBar preliminary MC

  11. BaBar ISR: ++0 Cross sections of sub-mode: +-  0  X =  3 + 0 3 : from subtraction /+-  0 3

  12. BaBar ISR:+p- BaBar preliminary BaBar,3   BaBar preliminary f0(980) 1st measurement 1.35  0.03 0.45  0.14 1.66  0.01 0.22  0.04 BaBar,3

  13. BaBar ISR: p+-+p- • ~4,300 events selected • first measurement BaBar preliminary

  14. BaBar ISR:KSK, K+K-p KSK-++- Dominant states: K*(980)K and K2*(1430)K K+K-p Isoscalar channel dominates over isovector Parameters(1680): PDG m=172320 MeV, 168020  = 37175 MeV, 15050 ee= 58060 eV, B/BK*K 1/3

  15. BaBar ISR: KK, K+K-pp K+K-p+p- Substructure in the final state K*(892) - 1 per event K+K-0p0 K+K-0 p0 K1(1270),K1(1400) – 1+ K+K-p+p- ~ 1500

  16. BaBar ISR:KKKK,KKppp,KKpp K+K- K+K- jK+K-dominated J/Y K+K-+p-p K+K-+p- First measurement !

  17. BaBar ISR: KKpppp Cross section Substructures K*0(892) j J/y first measurement

  18. Present BaBar Measurements only statistical errors syst. 5-10% to obtain R in the energy range 1-2 GeV the processes +-, +-30, +-40, K+K-, KSKL, KSKL, KSK+-0 remain to be measured

  19. Conclusions • program underway with BaBar to measure all significant exclusive cross sections for ee  hadrons using ISR • many channels already published; more underway • should allow reconstruction of R from threshold to 2 GeV • will match inclusive data from BES from 2 to 5 GeV • important input for VP calculations and QCD analyses • BaBar will be the only experiment able to provide the whole input in the low-energy region, with good accuracy

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