Near-term ProspectNear-term Prospectof 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 mindunder the subject “near-term prospect”...
overlaps... unavoidableoverlaps... 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
ProloguePrologue 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
““Think different!”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
ContentsContents
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
What do we expect in a What do we expect in a few years?few years?
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...
-- 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...
What do we expect in a What do we expect in a few years?few years?-- by the time LHC turns on
Once upon a time, there Once upon a time, there was LEPwas LEP
What to anticipateWhat to anticipatein CP violationin CP violation
- still, mostly stat.-limited
BB00 and and 22(())
Milky Way
Babar New!
We hope to see this being resolved...We hope to see this being resolved...
Belle vs. BaBar on Belle vs. BaBar on 33 (Dalitz)(Dalitz)
new
CPV of non-CKM typesCPV of non-CKM types
CPV in di-leptons (++ CPV in di-leptons (++ vs. --)vs. --)
~ O(10-3) in the SM
)%56.060.013.0(
NN
NN
0028.00030.00006.1 p
q 85M BB
biggest syst. err. from track selection and continuum subtraction
B B X Xsstruly amazing progress in ~10 years
CLEO 1993
Belle 2003
CPV in b CPV in b ss
CPV in b CPV in b ss
CP asymmetry in B CP asymmetry in B XXss 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 Xd (ACP can be large)
but negligible in the current measurements
152M BB
89M BB015.0050.0025.0)( sbACP
030.0050.0002.0)( sbACP
CKM sideCKM side
- esp. Vub
VVubub from inclusive B from inclusive B XXuu l l
Using full-recon. tagging
The lesson: no single dominant error, i.e. need to beat down every error sourcestat. / background / shape / theory, etc.
VVubub from exclusive B from exclusive B XXuu l l
all about tagging ...
VVubub from exclusive B from exclusive B XXuu l l
VVubub using using ll w/ high-q w/ high-q2 2 & L-& L-QCDQCD
The error is dominated by exp. stat. and L-QCD error a good sign, isn’t it?
2 4BaBar: LCSR, low-q2
Belle: L-QCD, high-q2
Shape Shape functionfunction
made possible by E spectrum in b s
a theorist’s a theorist’s call ...call ...In an illuminating talk by Bigi
yesterday,
Rare B decaysRare B decays- B l () modes - B Xd
B B l l ( ())Mode BF (SM) BF (Expt.)
B ~ 10-4< 2.9x10-4 (Belle,
prelim.)
< 3.3x10-4 (BaBar)
B ~ 5x10-7< 2.0x10-6 (Belle,
prelim.)
< 6.6x10-6 (BaBar)
B (2~5)x10-6
< 2.3x10-5 (Belle, prelim.)
B e < 2.2x10-5 (Belle, prelim.)
Grinstein, FPCP2004 : “Double Ratio”
B B X Xdd
How about then ? )/()(
)/()(*
*
KDD
KBB
2
tdts /VV
Distributions that Distributions that we needwe need
or to watch out ...
Important Important distributionsdistributions q2 in exclusive B Xu l q2 in B Xs l+l- (excl. & incl.) AFB(q2) in B Xs l+l- E in B Xs
etc.
Background errors are Background errors are
not negligible, eithernot negligible, either
What shall we do?
Do we understand b Do we understand b c ? c ?
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” ...
Belle-Conf-0126 (submitted to LP-01)
A new tool to explore A new tool to explore missing modesmissing 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?
(Ex1)(Ex1) BBDD l l with full with full recon.recon.
Exclusive B SL decays in PDG2004
nothing much is known except for D and D*
Exclusive measurements w/ B/B ~ O(10%) are feasible
(Ex2)(Ex2) flavor-specific flavor-specific inclusive inclusive
Never forget “crazy” Never forget “crazy” modesmodes
We should not regret for not having tried...
(Ex)(Ex) “ “Neutrinoless 2Neutrinoless 2 decay” in B?decay” in B?
CLEO
SummarySummary
Went through a list of subjects which might be interesting in a near-future in B physics– Belle vs. BaBar : TCPV in B0 + -
– 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