Post on 07-Jan-2016
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Current Status of CP Violation, Rare Decays & Heavy Flavor Physics
D. MacFarlane
SLAC National Accelerator Laboratory
ICFA Seminar, October 2011
2Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Seeking new physics through quark flavor
Precision measurements of SM parameters» Quark flavor measurements have established a consistent
picture of the weak interaction sector of the SM» Consistency & increasing precision for CKM parameters offers
opportunities for discovering new physics CP violation and CP violating phases
» Interference of amplitudes required for CP inherently sensitive to introduction of new phases
Rare decays» Processes with new BSM amplitudes, phases and helicity
properties will produce final states with different BR, angular distributions, and phases
» There are many examples of SM-suppressed FCNC transitions where new physics effects can be large
3Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
The Players
B Factories, BES-III
Tevatron, LHC
Upgraded LHCb, Super Flavor Factories: Next talk
Much of the material for this talk drawn from LP2011 plenary talks
4Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Status of the quark flavor sector of the SM
SM is the dominant source of CP violation
5Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Hint of problem with current CKM measurements
Tension between observed values of and with predictions from fit» BF too high or sin2b
too low BF measurements are
consistent between BABAR & Belle
LQCD calculations for BF factor in good agreement with observation
sin(2 )cc( )BF B
2
d dB Bf B
6Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Seeking new physics in CP violation
Sources» CPV through interference of
decay amplitudes» CPV through interference
between mixing and decay amplitudes
» CPV through interference of mixing diagram
Sensitivity to new physics» Interference of amplitudes
required for CP inherently sensitive to introduction of new phases
2
wk sti iAe e
1AB f
stwk
( ) ( )f or 0 and 0B f B f
7Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
New physics by comparing like quantities
b ss
sd
d
W
g
, ,u c t
0SK
0 0 B K
0B
0SK
0B
b
s
s
sd d
SUSY contribution with new phases sin2b from penguin & golden modes should be and are consistent
8Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Search for NP in BS mixing phase
Bs mixing phase has been measured in both BsJ/ψ ϕ and BsJ/ψ f0 decays
NP can add large phases in the box: ϕsNP
0SB
DiCPA e
CPf
0SB
2 Miqe
p
Di
CPA e
9Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Dimuon charge asymmetry measurement at D0
b bb bbSl
bb bb
N NA
N N
Measurable: Like-sign dimuon charge asymmetry:
d sd Sl s SlC a C a
( 0.787 0.172( ) 0.093( ))%bSlA stat syst
0.0050.006( ) ( 0.028 )%b
SlA SM
D0 observes:
versus Standard Model expectation:
(3.9s difference)
V.M.Abazov, et al. (D0 Collab), FERMILAB-PUB-11-307-E
10Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Asymmetry measurement from D0
11Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
LHCb measurements of ϕs from BsJ/ψ ϕ
PS to VV final state:
Need full angular time-dependent CP analysis, performed in transversity basis
LHCb sample of 8300 BS signal events with superimposed fit results
12Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
LHCb measurements of ϕs from BsJ/ψ ϕ
Single most precise measurement of ϕs
» ϕs = 0.13 ± 0.18 (stat) ± 0.07 (syst) rad
» Consistent with SM 4σ Evidence for ΔΓs ≠0 :
» ΔΓs = 0.123 ± 0.029 (stat) ± 0.008 (syst) ps-1
» Γs = 0.656 ± 0.009 (stat) ± 0.008 (syst) ps-1
13Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Summary of ϕs from BsJ/ψ ϕ
LHCb (340/fb)
Combined 0/ , /J J f
14Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Exploiting redundancy in CKM constraints
Subset of tree-level processes that are not affected by new physics in mixing
Use to constrain new physics in box diagrams
, , , , ,
( )ud us cb ub
cc
V V V V
15Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
New physics in Bd0-Bd
0 mixing diagram
16Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
New physics in Bd0-Bd
0 mixing diagram
17Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
D0-D0 mixing
18Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
D0-D0 mixing measurements
19Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
CP violation in charm mixing
20Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Seeking new physics through rare decays
Diagrams with new BSM amplitudes, phases and helicity properties will produce final states with different BR, angular distributions, and phases
SM penguin
NP penguin
Example: BdK*μμ forward backward asymmetry in different SUSY models
21Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
AFB in BdK*μμ: experimental status
Early results have shown intriguing hints of deviations from SM but statistics were too poor to claim any evidence
250 events[PRL 103 (2009) 171801]
60 events [PRD 79 (2009) 031102
100 events[4.4 fb-1, CDF note 10047]
SMC7=-C7
SM
C9C10=-C9C10SM
AFB=-AFBSM
S [GeV2]
22Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
LHCb Preliminary
303 signal eventsafter mass cut
AFB in BdK*μ+μ-: enter LHCb at EPS11
Based on 309 pb-1 and 300 candidates: largest sample in the world, just as clean as at the B factories
Data are consistent with SM predictions within present sensitivity
LHC
b-C
ON
F-2
011-
038
Theory predictions: C. Bobeth et al, arXiv 1105.0376v2
23Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
B(d,s) μμ is the good way to constrain the parameters of the extended Higgs sector in MSSM, fully complementary to direct searches
Bs→µµ = (3.2±0.2)×10-9
Bd→µµ = (1.0±0.1)×10-10
Buras et al., arXiv:1007.5291 and references therein
Main SM diagrams
~ |Vts |2, CA
Search for NP in Bs,dμμ decays
FCNC & helicity suppressed in SM
+
Sensitive to NP contributions in the scalar/pseudo scalar sector
MSSM, large tanβ approximation
( ()2 )2
24Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Data set Limit
CDF 3.7 fb-1 4.3 x 10-8
D0 6.1 fb-1 5.1 x 10-8
LHCb 0.036 fb-1 5.6 x 10-8
Published Bsμμ limits @ 95% CL
L [pb-1]
Experimental results (before summer 2011)
SM prediction: (3.2±0.2) x 10-9
25Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Results based on 7 fb-1, improved muon acceptance & NN
1.9% compatibility with bkg+SM hypothesis
Barrel-barrel
Barrel-endcap
backgroundSignal
(SMx5.6)
0.46 x 10-8 < BR < 3.9x10-8 @ 90% CL or BR=(1.8+1.1-0.9) x 10-8
Mμμ distribution in Bs search window for different NN bins
New CDF result from July
26Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
LHCb search in the Bs mass window
Data in Boosted Decision Tree bins
Combinatorial background
Data
Bhh misid background0.1±0.1 events in each BDT bin
Signal with SM BR
27Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Background onlyhypothesis
Background + signalwith BR=BR(SM)
New LHCb preliminary limit with ~340 pb-1
90% CL 95% CL
LHCb 2011 only 1.3x10-8 1.6x10-8
LHCb 2011 & 2010 1.2x10-8 1.5x10-8
28Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
LHCb-CMS combination
Combination has been performed by LHCb just adding 2 CMS bins (1 for barrel, 1 for endcap):
BR(Bsμμ) (LHCb+CMS) < 1.1 x 10-8 @ 95% CL (3.4xSM)Excess seen by CDF not confirmed
[LHCb-CONF-047, CMS-PH-11-019-pas]
29Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Conclusions & Outlook
Flavor physics remains an essential window into new physics through quantum loop processes» Some recent hints for deviations from the SM seem to have
been resolved, but other anomalies remain» Still room for new physics in rare decay, CP violation and
mixing processes Many other areas of important work not covered here
» Spectroscopy, new measurements of gamma and other rare B decays, tau and charm physics
Renaissance of contributions from hadron collider experiments and LHCb» Promise significant sensitivity improvements in the near term
Super Flavor Factories and upgrades to LHCb offer order-of-magnitude reductions in errors for many of these processes
30Current Status of CP Violation, Rare Decays & Heavy Flavour Physics: D.MacFarlane
Conclusions & Outlook
x50-75 sample size at Super Flavor Factories in early 2020’s