The Impact of BaBar ISR data on the SM Muon Anomaly Prediction 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
Goals of the BaBar ISR Program Precise measurements of cross section for all significant processes, e+e hadrons, from threshold to ~4-5GeV Measure , KK 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
Exclusive Channels with BaBar 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 ISR H is radiation function
BaBar ISR: e+ehadrons Reactions for which results have been published : pp PRD 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+Kp0, KSKp+, K+Kh, subm. to PRD arXiv:0710.xxxx [hep-ex] LL , LS0 , S0S0 subm. to PRD arXiv:0709.1988 [hep-ex] +pp BaBar Preliminary 2p+2pp0,2p+2ph, KK p+pp0, KKp+ph accept. by PRDarXiv:0708.2461 [hep-ex] Work in progress: , K+K, p+p3p0 Inclusive R
BaBar ISR: errors include systematics huge discrepancy with DM2 SND BaBar DM2 contribution to ahad (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 x1010
BaBar ISR: 22 contribution to ahad (<1.8 GeV) : all before BaBar 14.20 0.87 0.24 all + BaBar 13.09 0.44 0.00 x1010
BaBar ISR: 33 BaBar contribution to ahad (<1.8 GeV) : all before BaBar 0.10 0.10 all + BaBar 0.108 0.016 x1010
BaBar ISR: 222 BaBar contribution to ahad (<1.8 GeV) : all before BaBar 1.42 0.30 0.03 all + BaBar 0.890 0.093 x1010
Only statistical errors plotted BaBar ISR: +00 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
BaBar ISR: +00 --substructure Intermediate states: 0 +- large and first seen 0 f0(980) a1(1260) BaBar preliminary MC
BaBar ISR: ++0 Cross sections of sub-mode: +- 0 X = 3 + 0 3 : from subtraction /+- 0 3
BaBar ISR: +p- BaBar,3 1.35 0.03 0.45 0.14 1.66 0.01 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
BaBar ISR: p+-+p- ~4,300 events selected first measurement BaBar preliminary
BaBar ISR: KSK , K+K-p Dominant states: K*(980)K and K2*(1430)K K+K-p Isoscalar channel dominates over isovector Parameters (1680): PDG m=172320 MeV, 168020 = 37175 MeV, 15050 ee= 58060 eV, B/BK*K 1/3
BaBar ISR: KK , K+K-pp Substructure in the final state K*(892) - 1 per event K+K-0 p0 K+K-0 p0 K1(1270),K1(1400) – 1+ K+K-p+ p- ~ 1500
BaBar ISR:KKKK,KKppp,KKpp jK+K- dominated J/Y K+K-+p-p K+K-+p- First measurement !
BaBar ISR: KKpppp Cross section Substructures K*0(892) j J/y first measurement
Present BaBar Measurements only statistical errors syst. 5-10% to obtain R in the energy range 1-2 GeV the processes +-, +-30, +-40, K+K-, KSKL, KSKL, KSK+ -0 remain to be measured
Conclusions program underway with BaBar to measure all significant exclusive cross sections for ee 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