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Near-term Prospect

Near-term Prospect. of B physics. Y. Kwon (Yonsei Univ.). What I said in FPCP2003, to announce “FPCP2004 in Korea”. and, this might be the sort that the organizers had in mind under the subject “ near-term prospect ”. overlaps... unavoidable.

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Near-term Prospect

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  1. Near-term Prospect of B physics Y. Kwon (Yonsei Univ.)

  2. What I said in FPCP2003, to announce “FPCP2004 in Korea”... and, this might be the sort thatthe organizers had in mind under the subject “near-term prospect”...

  3. overlaps... unavoidable • With so many good talks in B physics at this conference; on both present & future • “Agent Provocateur” on hot topics • “CKM summary” • “New physics in B decays” • “Super B Factories” • as well as prospects for B physics @ hadron machines • and all the excellent experimental result talks It’s very hard to avoid much overlaps... if I want to give a standardized talks on “Near-term prospect” • So, I will just focus on personal favorites which I want/expect to see in B physics in the near future • And, this talk will in no way be theoretical

  4. Prologue • Tomorrow (Oct.9) used to be a national holiday, in celebration of the invention of “Han-gul” (Korean alphabet system); a very successful system esp. in the modern digital era • It was a national project initiated (and finished) by the Great King Sejong in 15th C. • Before Han-gul, Koreans did not have its own alphabets, but borrowed Chinese characters for writing; not a very convenient choice, because they are two totally different languages • The best thing King Sejong did was to have thought differently; instead of imitating Chinese characters, Han-gul was based on 28 (now 24) character elements that have one-to-one (and onto) correspondence to phonetic sounds in Korean

  5. “Think different!” • During the last decade (plus more), everyone worked real hard in an anticipation of great things to come – preparing for the B-factories • And now, we are all enjoying a great success of B physics – in both experiment & theory • The next obvious path will be “Super-B”, but... Realistically, we still have a formidable task of convincing the tax-payers for one “Great, you now have your CP violations. Congratulations on a great job well ‘done’!” • So, we should not be afraid of searching for “crazy” things

  6. Contents • CPV & CKM • Rare B – esp. in leptonic modes • overlapping w/ my own talk here on Monday  will be very brief • Personal list • Distributions • Ordinary, but missing modes • Never ignore “crazy” modes

  7. What do we expect in a few years? -- by the time LHC turns on • Obviously, statistics will increase • Let’s aim at 1/ab per each B-factory • i.e. approx. factor 4 from current sample • stat. err.  ~½ x (now) • Better understanding of generic B & charm decays • some analyses are (somewhat) limited by background systematics • help from CLEO-c & BES? • Improved theory • L-QCD • Other improvements • And a few surprises, hopely...

  8. What do we expect in a few years? -- by the time LHC turns on • Obviously, statistics will increase • Let’s aim at 1/ab per each B-factory • i.e. approx. factor 4 from current sample • stat. err.  ~½ x (now) • Better understanding of generic B & charm decays • some analyses are (somewhat) limited by background systematics • help from CLEO-c & BES? • Improved theory • L-QCD • Other improvements • And a few surprises, hopely...

  9. Once upon a time, there was LEP

  10. What to anticipatein CP violation - still, mostly stat.-limited

  11. MilkyWay Babar New! B0 p+p- and f2(a) We hope to see this being resolved...

  12. Belle vs. BaBar on f3 (Dalitz)

  13. new

  14. CPV of non-CKM types

  15. CPV in di-leptons (++ vs. --) ~ O(10-3) in the SM biggest syst. err. from track selection and continuum subtraction 85M BB

  16. CLEO 1993 Belle 2003 B  Xsg truly amazing progress in ~10 years

  17. CPV in b  sg

  18. CPV in b  sg

  19. 152M BB 89M BB CP asymmetry in B  Xsg • CP asymmetry is expected to be small (<1%) in SM • some non-SM models allow large (~10%) ACP without changing the BF • possible contamination from Xdg (ACP can be large)  but negligible in the current measurements

  20. CKM side - esp. Vub

  21. Vub from inclusive B  Xu l n Using full-recon. tagging The lesson: no single dominant error, i.e. need to beat down every error source stat. / background / shape / theory, etc.

  22. Vub from exclusive B  Xu l n all about tagging ...

  23. Vub from exclusive B  Xu l n

  24. Vub using pln w/ high-q2 & L-QCD The error is dominated by exp. stat. and L-QCD error  a good sign, isn’t it?

  25. 2 4 BaBar: LCSR, low-q2 Belle: L-QCD, high-q2

  26. Shape function made possible by Eg spectrum in b  s g

  27. a theorist’s call ... In an illuminating talk by Bigi yesterday,

  28. Rare B decays - B  l n (g) modes - B  Xdg

  29. B  l n (g)

  30. How about then ? B  Xdg Grinstein, FPCP2004 : “Double Ratio”

  31. Distributions that we need or to watch out ...

  32. Important distributions • q2 in exclusive B  Xu l n • q2 in B  Xs l+l- (excl. & incl.) • AFB(q2) in B  Xs l+l- • Eg in B  Xs g etc.

  33. Background errors are not negligible, either What shall we do?

  34. Do we understand b  c ? Belle-Conf-0126 (submitted to LP-01) • Flavor-specific inclusive K using K-lepton corr. • Original motivation (Kagan, ’97) was to look for excess prompt Kaon from b  sg type decays • In interpretation, we were not sure whether we understand Kaon yield from b  c  s • We have to find out “missing modes” ...

  35. A new tool to explore missing modes • Full-recon. tagging is so powerful to constrain the kinematics of signal B • Then, why don’t we apply it to explore b  c modes that have not (or poorly) been measured because of missing neutrinos?

  36. (Ex1)BDp ln with full recon. Exclusive B SL decays in PDG2004  nothing much is known except for D and D* Exclusive measurements w/dB/B ~ O(10%)are feasible

  37. (Ex2) flavor-specific inclusive

  38. Never forget “crazy” modes We should not regret for not having tried...

  39. CLEO (Ex) “Neutrinoless 2b decay” in B?

  40. Summary • Went through a list of subjects which might be interesting in a near-future in B physics • Belle vs. BaBar : TCPV in B0 p+p- • Belle & BaBar vs. SM : TCPV in b  s vs. b  c • Many potentially interesting measurements are still stat.-limited, but... • For some parameters, esp. Vub, we do not have much budget for error in any source • Details, e.g. background understanding shall be important  explore missing, ordinary modes • We shall never give up searching for “crazy” things

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