1. Misura di R

2. Importanza di R QED (M Z ) (g-2) Test di CVC nei decadimenti del Regole di somma di QCD e S

3. Hadronic contributions to a had 12 - 5 - 12 (+ )3.7 - 5 (+J/, ) 1.8 - 3.7 4 3 (+, )2 > 4 (+KK) < 1.8 GeV a had 2 [ a had ] <1.8 GeV 1% Calculations based on Davier, Eidelman, Höcker, Zhang e+e- data only! 2 contrib. a had 8% [2m p - 0.5 GeV] 54% [0.6 - 1.0 GeV] 10% [Rest<1.8 GeV] r 2 contrib. a had 8% [2m p - 0.5 GeV] 34% [0.6 - 1.0 GeV] 31% [Rest< 1.8 GeV] > 1GeV r

4. Contribution to had from F. Jegerlehner

5. Comparison of different evaluations of had had MethodRef 0.0280 0.00065 data<12 GeVS.Eidelman F.Jegerlehner 95 0.02777 0.00017 data<1.8 GeVJ.H.Kuhen, M.Steinhauser 98 0.02763 0.00016 data<1.8GeVM.Davier, A.Höcker 98 0.027730 0.000148 Euclidean>2.5 GeVF.Jegerlehener 99 0.027426 0.000190 scaled data, pQCD 2.8-3.7, 5- A.D.Martin et al. 00 0.027896 0.000391 data<12 GeV (new data CMD2 & BES) F.Jegerlehner 01 0.02761 0.00036 data<12 GeV (new data CMD2 & BES) H.Burkhardt,B.Pietrzyk 01 ( 05) 0.00007 (0.00005) up to J/ up to )

6. magnitudeerrors Burkhardt & Pietrzyk 2001 Contributions to had Including KLOE results, a preliminary analysis of B.& P. found a value of (5) (m Z 2 ) which confirms their 2001 estimate: (5) (m Z 2 ) =0.02761±0.00036

7. Results on R from scan at s<12 GeV PlaceRingDetectorE cm (GeV)ptsYear NovosibirskVEPP-2M VEPP-2 CMD2,SND Olya,ND,CMD <1.4 12897-99 79-85 BeijingBEPCBESII2-58598-99 OrsayDCIM3N,DMI,DM21.35-2.133378 FrascatiAdone 2,MEA, Boson,BCF 1.42-3.093178 SLACSpearMarkI2.8-7.87882 HamburgDorisDASP PLUTO C.Ball LENA 3.1-5.2 3.6-4.8,9.46 5.0-7.4 7.4-9.4 64 27 11 95 79 77 90 82 NovosibirskVEPP-4MD-17.23-10.343091

8. Recent Results from… 01 03 128<1.4CMD2,SNDVEPP-2MNovosibirsk 05, … <10 Gev (via ISR) (0.5-4.5 GeV) Babar PEPIISLAC 05<1 (via ISR)KLOE DA NE Frascati YearptsE cm (GeV)DetectorRingPlace Future Projects or Upgrades PlaceRingDetectorE cm (GeV)ptsYear NovosibirskVEPP-2000Upgrades of CMD2 and SND <2 08? BeijingBEPCIIBESIII2-5 06? CornellCESRCLEO-C3-505

9. Data at 95

10. Data at 05

11. After 95 main results were published from CMD2 and SND @VEPP-2M and BESII@BEPC: 1)VEPP-2M, Novosibirsk (exclusive measurements) 0.4 <E cm <1.4 GeV –New results on e + e - + - + -, + - o o ( syst ~7%), e + e - + - o ( syst ~12%), e + e - K S,K L, e + e - + -, + - ( syst ~15%) from CMD2 and SND – e + e - + - from CMD2 with syst ~1.4% published on 99 and with syst ~0.6% ( 0.61<E<0.96 GeV) published on 01 – e + e - + - from SND with syst ~1.3%(hep-ex/0506076) 2)BESII @ BEPC, Beijing (inclusive measurement) 2 <E cm <5 GeV –New result on R in 2 <E cm <5 GeV from BESII coll., with R /R~7% (improvement of a factor 2) - New results on 4 from BES with R /R~10% (presented on Oct 2005 in Frascati) Recent results with energy Scan:

12. BES: 4 E cm L L 2.00 45.8 1.4 2.80 89.0 1.8 2.20 123.5 3.7 2.90 94.0 2.6 2.40 61.0 1.6 3.00 947 22 2.50 47.0 1.0 3.07 2272.8 36.4 2.60 1231.0 14.8 3.65 6450.4 90.3 2.70 71.6 2.1 Luminosity (nb -1 ) 2( + - )

13. 1)KLOE: – e + e - + - with syst ~1.3% (0.35<E<0.95 GeV 2 ) published on 05 – e + e - + - at threshold is under way (0.1 GeV 2 bin width (5-20 MeV)) 2)BABAR: - e + e - + - 0 between 1. and 3 GeV with syst ~5%-10%published on 05 (25 MeV bin width) - e + e - 4h ( + - + -, + - + -, + - + - ) between 0.6 and 4.5 GeV published on 05: - syst ( + - + - ) is 12% ( 3 GeV) - syst ( + - + - ) is 15% (1.5-4.5 GeV) - syst ( + - + - ) is 20% (2.0-4.5 GeV) - e + e - 6h (3( + -, 2( + - ) 0 0, 2( + - ) + - ) between 1.5 and 4.5 GeV with syst between 6 and 10% –e + e - + - with syst <=1% is under way Recent/expected results with ISR:

14. Babar: 3 + - 0

15. Babar: 4h

16. Babar: 6 3( + - ) 2( + - ) 0 0 Total systematic: ~6-8%Total systematic: ~11%

17. Babar: 2K4 2( + - )K + K - Total systematic: ~7%

18. Proiezione a 10 anni Con cosa deve essere competitiva una misura tra 10 anni? Babar... BES... VEPP 2000... Altro? La regione 1-2 GeV particolarmente interessante: lerrore attuale ( 15%) contribuisce con un 40% allerrore totale su had

19. Open issues Buco nella sezione durto multiadronica vicino a soglia p bar-b narrow vector meson resonance, with a mass M 1.87 GeV and a width 10-20 MeV, consistent with an N bar-N bound state

20. Open issues Buco di FOCUS nella sezione durto dei 6 Babar conferma in entrambi i canali

21. Errore percentuale R/R Punti con errore ~3% dalla misura inclusiva di BES ZOOM PRL 84, 594 (2000) – PRL 88, 101802 (2002)