Presentation on theme: "Results from B-factories ByungGu Cheon Sungkyunkwan University Presented at ACFA LC workshop (15-17 Dec 2003, TIFR, Mumbai, India)"— Presentation transcript:
Results from B-factories ByungGu Cheon Sungkyunkwan University Presented at ACFA LC workshop (15-17 Dec 2003, TIFR, Mumbai, India)
outline Belle and BaBar CP violation in B meson decays New Physics search in B factory Toward >10 35 lumonosity era Most of physics results shown today are based on LP03 presentations !
Luminosity frontier colliders Records by summer 2003, now data taking again!
Detectors Typical design : SVD+CDC+PID+ECL+KLM PID : TOF+ACC vs DIRC Belle BaBar
Time-dependent CP violation If either S or A is non-zero, B f CP has CP asymmetry. Mixing-induced CPV param. Direct CPV param.
CP eigenstates categoryCP modeprocessCP(x f )SM prediction SAPenguin charmoniumJ/y KSJ/y KS - x f sin2f 1 0negligible y(2S) K S c C1 K S hC KShC KS J/y K*(K S p 0 ) -1/+1 J/y KLJ/y KL +1 charmoniumJ/y p0J/y p x f sin2f 1 eff yes double charmD (*) -1/+1smallyes b s penguinf KSf KS - x f sin2f 1 smalldominant h’ K S K+K-KSK+K-KS +1 hhp+p-p+p- -1/+1 - x f sin2f 2 eff yes (x f CP eigenvalue )
e-e- e+e+ e - :8.0 GeV e + :3.5 GeV B CP DzDz B tag ¡(4S) bg ~ f CP Dz cbgt B ~ 200 mm Flavor tag 4 steps toward the CP violation measurement Reconstruct B f CP decays Determine the flavor of B tag Measure proper-time interval : Dt Evaluate asymmetry from the obtained Dt distributions How to measure CP violation?
B 0 (cc)K S vs. (ss)K S 68 signals 2716 signals
b ccs sin2f 1 : b ccs
Theoretically cleanest example : b sss sin2f 1 : b sss First Indication of New Physics in quark sector
Summary of sin2 f 1 NP? Stat. Fluctuation? more data: interesting S bs : 3.1 s away from S bc 2.1 s difference in S bs ( f K s ) 2.1 s S bs S bc
New Physics search in B decays Tree diagrams: New Physics(SUSY) effect ~negligible Loop diagrams: W, heavy quark loop in the SM Effect of NP particles in loop can be visible Processes with loop diagrams only sensitive to NP squark bs b b d d Penguin Box A obs = A SM + A NP deviation from A SM only |A obs | Branching fraction phase(A SM /A NP ) CP asymm. Many modes/ways in B-factory !
B/ t decays for NP search New CPV phase in Penguin : Time-dependent CPV Radiative & EW Penguin : b s g, b s l + l - LFV t decays : t mg, t mh DCPV in ff K- h c ff K interference(b s Penguin) b s nn, B l n, l + l -, B D (*) tn NP in B 0 -mixing by detailed ( r,h ) consistency study and so on…
s g,K * g B X s g,K * g No deviation from the SM Need reducing errors: theory : NLO to NNLO exp. : lower E (more data) All measurements agree. Need better theor. precision: debate on B K* form facor Inclusive Exclusive
b s g
b s l + l - Penguin + Box diagram contribution Additional dimension: Mass(l + l - ) [l + l - angle helicity] More opportunity to distinguish New Physics effect/models B Kl + l - : first observed by -1 (LP 2001) B K*l + l - : first evidence by -1 (EPS03) Now Belle/BaBar updated with 140fb -1 /113fb -1 data ! (exclusive)
B X s l + l - 60 fb -1 Semi-inclusive analysis ( pseudo-reconstruction ) Xs=(K + or Ks)+0~4 (0,1 ) (covers 81%) M Xs <2.1 GeV/c 2 [PRL 90, (2003)] Inclusive b s l + l - : better theoretical prediction 60.1 13.9 ev. 5.4 hep-ex/ (BaBar) w/ 81fb -1
M ll and M Xs distributions Mass distribution SM prediction observed M ll spectrum Model by A.Ali et al. M l l (GeV/c 2 ) M(X s ) (GeV/c 2 ) observed M(X s ) spectrum ~ consistent with SM prediction [PRD 66, (2002)] SM acceptance corrected
b s l + l - [A.Ali, et al. PRD 64, (2000)] K* BF K* A fb More data towards SUSY M Started to see signals (consistent with SM)
Rare B decays
If we’ve more data…
t decays B-factory : also excellent t -factory Promising mode to see New Physics effect t mg decay forbidden in the SM (very small even with mixing) SUSY, L-R symmetry model … allow LFV decays Br( t mg ) ~ 10 -9~-7 [~ xBr( m eg )] SUSY particles (~1M t -pairs/fb -1 )
Search for t mg Reconstruction E = E +E -E beam M inv = Mass( ) 2D unbin’d extended Max. Likelihood fit Result ： Br( t mg )< 3.1x10 Signal MC sideband (78.5M -pairs) region sel = 0.11) CM CM CM hep-ex/
t mg (New)
The mystery meson
KEK B-factory upgrade strategy Present KEKB L= L=2x10 35 L~10 36 ∫Ldt =350fb -1 I LER =1.5A I LER =9.4A I LER =20A Constraint: 8GeV x 3.5GeV wall plug pwr.<100MW crossing angle<30mrad L=2x10 34 I LER =1.5A Crab crossing One year shutdown to: install ante chamber increase RF modify IR Increase RF data set (158fb -1 ) in 1 week L =5 (New)
Optimal scenario: NP found at Tevatron/LHC/LC –Super-B to measure its parameters(flavor mixing, CPV,…) precisely. If NP is SUSY, the interest is in its breaking mechanism. Even if no deviation from SM is found, that is very interesting. (No effect of existing particles?) Intriguing scenario: deviation from SM found in flavor physics (has already started?) –Super-B to measure it more precisely. Frustrating scenario: SM looks fine even after LHC/LC –Super-B to search for NP, competing with LHC/LC. Some words on Super-B project HL05
Super B Factory Workshop in Hawaii January 19-22, 2004 East-west Center, Honolulu To discuss physics, accelerator and detector assuming N BB, N >1billion, L>10 35.
Comparsion with the previous results Belle BaBar ?
B Kppg K K c.m.s New possibility to measure helicity or CPV (more sensitive to NP than Br) SM: ~left-handed ~ no Time-dependent CPV Helicity : B Xs , Xs 3-body [K 1 (1400) K ] SUSY,LR-symm.: right-handed Sizable CPV CPV: B 0 K 1 (1270) Ks Ks [M.Gronau et al., PRL, 88, 5(2002)] [D.Atwood et al., PRL, 79, 185(1997)]
B Kppg ∫L dt = 29 fb -1 [PRL 89, (2002)] B(B + K + + - ) = (24 5 )x 2 A big step towards -helicity meas., Time-dep CPV ! First Observation ! Bump : M K =1.3~1.4 GeV K*(892), peaks seen Need more data to extract K 1 (1270),K 1 (1400)
Search for t mg Signature(topology): [signal side] + opposite sign track (not ) (+ ’s) [tag side] p miss > 0.4GeV( ) M miss ~ 0 tag