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Prospects of rare B decays at high luminosity B factories

Prospects of rare B decays at high luminosity B factories. Nobu Katayama KEK. High luminosity B factories. 4.4  10 33 cm - 2 s - 1 (KEKB, peak luminosity) gives 5  10 7 BBbar pairs/year Luminosity goal of HLBF:10 35 cm - 2 s - 1 10 9 BBbar /year

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Prospects of rare B decays at high luminosity B factories

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  1. Prospects of rare B decays athigh luminosity B factories Nobu Katayama KEK

  2. High luminosity B factories • 4.4  1033 cm-2s-1 (KEKB, peak luminosity) • gives 5 107 BBbar pairs/year • Luminosity goal of HLBF:1035 cm-2s-1 • 109 BBbar/year • Competition with the hadron collider experiments • 1032 cm-2s-1 gives 1011 BBbar/year • a factor of 100 will be overwhelming for rare B decays? • Yes and no Nobu Katayama

  3. Possible Belle run plan Nobu Katayama

  4. How I estimated • Many conventional measurements on the sides of the triangle are already systematically limited • Measurements on the phase and branching fractions and other parameters that are sensitive to New Physics are not yet systematically limited • Estimations of the measurement accuracy based on the current Belle analyses are given • Will not quote the central values of the Belle measurements but discuss the errors only Nobu Katayama

  5. Rare B decays • Modes for angle measurements • not covered by this talk • Modes for “beyond the SM” search are discussed • BXs,dg • BXs,dll • BXs,dnn • Exclusive decays of the above • Bll,ln • BD*tn Nobu Katayama

  6. BXsg • Theory(SM): (3.29  0.21  0.21)10-4 • By P. Gambino and U. Haisch • Experiment: (3.21  0.40)10-4 • CLEO, ALEPH, BELLE combined • CLEO: (2.85  0.35  0.23)10-4 • E.Thorndike@BCP4, inclusive spectrum • using 9.7M BBbar Nobu Katayama

  7. Inclusive BXsg @B factories • dBr(BXsg) <0.310-4with 30 fb-1 • ~10% error (statistical + systematic) from the semi exclusive measurements • Experiments at the B factories take only 10% off-resonance data and they must be clever about the subtraction • dBr(BXsg) < 0.110-4 (dBr/Br ~ 3%) by 2006 • By summing all exclusive measurements ? • Inclusive photon spectrum above 2GeV (The new CLEO measurement) ?? • Most likely, B factories do better than hadron machines Nobu Katayama

  8. Exclusive BKxg decays • dBr(BK*(832)g)=0.310-5with 30 fb-1 • <10% error (statistical + systematic) • dBr(BKxg)=0.610-5with 30 fb-1 • BKpg and BKppg are now being analyzed • resonance structure, spin analysis • dBr(BK*(832)g)=0.110-5by 2006 • ~3% error • dBr(BKxg)=0.210-5by 2006 • 5~20% error on higher resonances • Modes involving neutrals will also be understood very well Nobu Katayama

  9. BXsg CP asymmetry • dAcp(BXsg)=0.1~0.2 with 30 fb-1 • dAcp (BK*(832)g)=0.1~0.2 with 30 fb-1 • S.E.S.(BK1g)~10-5with 30 fb-1  • dAcp(BXsg)=0.03~0.06 by 2006 • dAcp (BK*(832)g)=0.03~0.06 by 2006 • dAcp(BK1g, indirect) =~0.3 by 2006 Nobu Katayama

  10. Inclusive BXdg • BXdg:Large background from bsg • very good particle identification devices in order to separate Xd from Xs • understanding the performance of the PID devces • qqg and continuum backgrounds are much larger than sg case. BXdg inclusive branching fraction semi-exclusively by 2011? • Need to study more Nobu Katayama

  11. BXsll • Theory(SM): • Inclusive (5.7  1.2)10-6 • Br(BK*mm) = (2.0  0.7)10-6 • Experimental limits (CLEO 2001) • 9.6M BBbar • Br(BKll) < 1.7 10-6 • Br(BK*(892)ll)mll>0.5GeV/c2 < 3.310-6 Nobu Katayama

  12. BXsll • Single event sensitivity/10fb-1(107 BB), Belle • K+p-mm 1.21  10-6 • K+mm 4.41  10-7 • K+p-ee 1.56  10-6  • 10~30% error on exclusive b.r. by 2006 • 3~10% error on exclusive b.r. by 2011 • Inclusive measurements, Afb, mll will have similar fractional errors • B factories are better for low mll region Nobu Katayama

  13. Bll andBln • Theory(SM): • Br(Bmm)= 810-11 • Br(Btn)= (1~10)10-5 • Br(Bmn)= (0.5~5)10-7 • Experimental limit (CLEO 2000) • Br(Bmm) < 6.110-7 • Br(Bmn) < 2.110-5 Nobu Katayama

  14. Bll andBln • SES with 30 fb-1, Belle • Bmm 0.8  10-7 • Belle on Br(Bmn) with 20 fb-1 • dBr(Bmn) ~ 210-6  • No chance to observe if SM but if the b.r is ~10-8 we can observe by 2006 and 10-9, 2011 • If SM, we might be able to observe mn by 2011 Nobu Katayama

  15. BXsnn , Btn , BD*tn • One side of the event (B) must be reconstructed. Efficiency ~ 10-3 • The same analysis technique • Single event sensitivity/10fb-1(107 BB) • Xsnn , tn 10-4 • D*tn 10-3  • ~30% error on Br(Xsnn) by 2011 • ~10% error on Br(tn) by 2011 • D*tn ~100 events by 2006 Nobu Katayama

  16. BfKs • Single event sensitivity/10fb-1(107 BB), Belle • fKs 2  10-6 • fK+ 6  10-7  • 10~20% error on Br(fKs) by 2006 • 5~10% error on Br(fKs) by 2011 • Asymmetry error: < 0.2 by 2011 Nobu Katayama

  17. Summary • Belle has started analyses of many decay modes/asymmetries discussed here. Most of estimations are based on the numbers we already measure (but have not announced!) • Others are just wild guesses. Sorry, if they are wrong by more than factor 3 • There could be a discovery of new physics with < 500 fb-1 but even with 4000 fb-1, some parameters may not distinguish new physics from the SM Nobu Katayama

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