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 , 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

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+ehadrons 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+Kp0, KSKp+, K+Kh, subm. to PRD arXiv:0710.xxxx [hep-ex] LL , LS0 , S0S0 subm. 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

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

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

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

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

Only statistical errors plotted 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

BaBar ISR: +00  --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=172320 MeV, 168020  = 37175 MeV, 15050 ee= 58060 eV, B/BK*K 1/3

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

BaBar ISR: KKpppp 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 +-, +-30, +-40, K+K-, KSKL, KSKL, KSK+ -0 remain to be measured

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