1 / 21

Hadronic Contributions to aQED(MZ) Measured by Tests in Particle Decays

Explore the importance of hadronic contributions in aQED(MZ) through tests in particle decays. Dive into key calculations and comparisons for precise measurements. Review recent results and future projects in high-energy physics.

lara-bond
Download Presentation

Hadronic Contributions to aQED(MZ) Measured by Tests in Particle Decays

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Misura di R

  2. Importanza di R • aQED(MZ) • (g-2)m • Test di CVC nei decadimenti del t • Regole di somma di QCD e aS

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

  4. Contribution to Da(5)had from F. Jegerlehner

  5. Comparison of different evaluations of Da(5)had

  6. Burkhardt & Pietrzyk 2001 Contributions toDahad magnitude errors Including KLOE results, a preliminary analysis of B.& P. found a value of Da(5)(mZ2) which confirms their 2001 estimate: Da(5)(mZ2) =0.02761±0.00036

  7. Results on R from scan at s<12 GeV

  8. Recent Results from… Place Ring Detector Ecm(GeV) pts Year Novosibirsk VEPP-2M CMD2,SND <1.4 128 ’01 ‘03 Frascati DAFNE KLOE <1 (via ISR) ’05 SLAC PEPII Babar <10 Gev (via ISR) (0.5-4.5 GeV) ’05,… Future Projects or Upgrades

  9. Data at ‘95

  10. Data at ‘05

  11. Recent results with energy Scan: • After ’95 main results were published from CMD2 and SND @VEPP-2M and BESII@BEPC: • 1)VEPP-2M, Novosibirsk (exclusive measurements) 0.4 <Ecm<1.4 GeV • New results on e+e-p+ p- p+ p-, p+ p- po po (ssyst~7%), e+e-p+ p- po • (ssyst~12%), e+e-KS,KL, e+e-w p+ p-,hp+ p- (ssyst~15%) from CMD2 and SND • e+e-p+ p-from CMD2 with ssyst~1.4% published on ’99 and with ssyst~0.6% ( 0.61<E<0.96 GeV) published on ’01 • e+e-p+ p-from SND with ssyst~1.3%(hep-ex/0506076) • 2)BESII @ BEPC, Beijing (inclusive measurement) 2 <Ecm<5 GeV • New result on R in 2 <Ecm<5 GeV from BESII coll., with sR/R~7% • (improvement of a factor 2) • - New results on 4p from BES with sR/R~10% (presented on Oct 2005 in Frascati)

  12. BES: 4p Luminosity (nb-1) 2(p+p-)

  13. Recent/expected results with ISR: • 1)KLOE: • e+e-p+ p- with ssyst~1.3% (0.35<E<0.95 GeV2) published on ’05 • e+e-p+ p-at threshold is under way • (0.1 GeV2 bin width (5-20 MeV)) • 2)BABAR: • - e+e-p+ p- p0 between 1. and 3 GeV with ssyst~5%-10%published on ’05 • (25 MeV bin width) • - e+e- 4h (p+ p-p+ p-, p+ p-K+ K-, K+ K-K+ K-) between 0.6 and 4.5 GeV published on ’05: • - ssyst(p+ p-p+ p-) is 12% (<1GeV), 5%(1.-3 GeV), 16% (>3 GeV) • - ssyst(p+ p-K+ K-) is 15% (1.5-4.5 GeV) • - ssyst(K+ K-K+ K-) is 20% (2.0-4.5 GeV) • - e+e- 6h (3(p+ p-), 2(p+ p-)p0p0, 2(p+ p-) K+ K-) between 1.5 and 4.5 GeV with ssyst between 6 and 10% • e+e-p+ p-with ssyst<=1% is under way

  14. Babar: 3p p+p-p0

  15. Babar: 4h

  16. Babar: 6p 3(p+p-) 2(p+p-)p0p0 Total systematic: ~6-8% Total systematic: ~11%

  17. Babar: 2K4p 2(p+p-)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: l’errore attuale (15%) contribuisce con un 40% all’errore totale su Da(5)had

  19. Open issues • Buco nella sezione d’urto 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 d’urto dei 6p • Babar conferma in entrambi i canali

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

More Related