New Physics and Rare B Decays
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New Physics and Rare B Decays
• New Physics in Loops (Motivation) • bs Penguins (2 or 3 examples)• Decays with “Large Missing Energy”• How the Super B Factory fits in
Tom Browder (University of Hawaii)
Apologies: Will aim at HEP physicists in other subfields. “If I could remember all the decay modes I would have been a botanist”
Only a small subset of possible topics from Belle and BaBar are covered; a few of the results are ~ 1year old.
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New Physics
Are there new particles beyond those in the SM, which have different couplings (either in magnitude or in phase) ?
Supersymmety is an example (~40 new phases)
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How to find New Physics Phases
Example:Vts: no KM phase
SM: sin21 = sin21 from BJ/ K0 (bc c s)
unless there are other, non-SM particles in the loop
eff
Vtd
Vtd
+
1
B B
, ’,
1
, ’,
_
*
*
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How New Physics may enter in bs
0SK
0B
b
s
s
sd d
0SK
0B
b
s
s
sd d
Many new phases are possible in
SUSY
New physics in loops?
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Extra dimensions (by Randall + Sundrum)
New Kaluza-Klein (K.K) particles are associated with the extra dimension.
(“Tower of states”)
Some may induce new phases and flavor-changing neutral currents.
e.g. K.Agashe, G. Perez, A. Soni, PRD 71, 016002 (2005)
Model: K.K. Gluon near 3 TeV
RS1
SM
++CPV in D decay
e.g. G. Burdman, Phys Lett B 590, 86 (2004)
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Belle 2006: tCPV in B0 K0
“sin21” = 0.50 0.21(stat) 0.06(syst) “sin21” = 0.50 0.21(stat) 0.06(syst)
KS and KL combined background subtracted good tags t –t for KL
t distributions and asymmetry
_535M BB
Consistent with the SM (~1lower) Consistent with Belle 2005
(Belle2005: “sin21” = +0.44
Consistent with the SM (~1lower) Consistent with Belle 2005
(Belle2005: “sin21” = +0.44
unbinned fitSM
hep-ex/0608039, PRL 98, 031802(2007)
hep-ex/0608039, PRL 98, 031802(2007)
a.k.a sin(2β)
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K0: sin2eff = +0.12 ± 0.31(stat) ± 0.10 (syst)K0: sin2eff = +0.12 ± 0.31(stat) ± 0.10 (syst)
BaBar: K0 using B0 K0
measurement (not sin2)
[hep-ex/0607112] _347M BB
a.k.a. sin(2 φ1)
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unbinned fitSM
“sin21” = 0.64 0.10 0.04“sin21” = 0.64 0.10 0.04
535M BB 5.65.6
’K0
“sin21” = 0.58 0.10 0.03 “sin21” = 0.58 0.10 0.03
>5>5
’Ks ’KL
_347M BB
[hep-ex/0608039]PRL 98,031802(2007) [hep-ex/0607100], PRL+Sept 28 press conf
1st Observation of tCPV in a bs mode
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2006: Hints of NP in b s Penguins ?
Smaller than bccs in all of 9 modes
Smaller than bccs in all of 9 modes
Theory predicts positive shifts
Naïve average of all b s modes
sin2eff = 0.52 ± 0.052.6 deviation from SM
Naïve average of all b s modes
sin2eff = 0.52 ± 0.052.6 deviation from SM
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Results on Radiative and Electroweak Penguins
Example discussed here: modifications to the rate for bs γ
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Measurement of inclusive b s
Measure primary only:monochromatic E spectrum
Important to measure low E to reduce model dependence
Huge Background (semi-log) experimental challenge
Background suppression• continuum: event shape• veto
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Nakao
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NNLO calculation
(29826) x 10-6
M. Misiak et al, hep-ph/0609232, PRL 98,022002(2007)
Theory News
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Error on BF
Central value of BF
95% CL lower limit on charged Higgs mass from exp and NNLO
M. Misiak et al, hep-ph/0609232, PRL 98,022002 (2007)
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Right-handed currents in b s
• tCPV in B0 (Ks0)K*
– SM: is polarized, the final state almost flavor-specific.
S(Ks0 ~ 2ms/mbsin21
– mheavy/mb enhancement for right-handed currents in many new physics
models
e.g. LRSM, SUSY, Randall-Sundrum (warped extra dimension) model
– LRSM: SU(2)LSU(2)RU(1)
• Right-handed amplitude mt/mb : is WL-WR mixing parameter
• for present exp. bounds (WR mass > 1.4TeV)
|S(Ks0 ~ is allowed.
– No need for a new CPV phase
b
b
Ls
Rs
mb
mb
msms
D.Atwood, M.Gronau, A.Soni, PRL79, 185 (1997)D.Atwood, T.Gershon, M.H, A.Soni, PRD71, 076003 (2005)
Photon polarization measurementvia time dependent CPV !
Photon polarization measurementvia time dependent CPV !
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_232M BB
Status of B KS 0γ tCPV Status of B KS 0γ tCPV
Yield = 176+/- 18
535M BB M(Ks 0) < 1.8 GeV
(C)hep-ex/0608017, PRD-RC 74, 111014(2006)hep-ex/0608017, PRD-RC 74, 111014(2006)
No new physics but errors on S are large
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Rare Decays with Large “Missing Energy”
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Motivation for B++ν
Sensitivity to new physics from charged Higgs if the B decay constant is known
The B meson decay constant, determined by the B wavefunction at the origin
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Why measuring νis non-trivial
(4S)B- B+
e+
e
B++, +e+e
B-X
The experimental signature is rather difficult: B decays to a single charged track + nothing
Most of the sensitivity is from tau modes with 1-prong
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Example of a B ν candidate
Tag: BD0 ,
D0 K
Very difficult or impossible at a hadron collider
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Evidence for B+ ν (Belle)
Find signal events from a fit to a sample of 54 events.
4.6 stat. significance w/o systematics,
449 106 B pairs BtagD(*)[,a1,Ds(*)] 680k tags, 55% pure. 5
decay modes
5.34.717.2
MC studies show there is a small peaking bkg in the 0 and modes.
After including systematics (dominated by bkg), the significance decreases to 3.5σ
Extra Calorimeter Energy
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B+ ν (BaBar preliminary)
Awaiting BaBar’s analysis with hadronic tags
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Direct experimental determination of fB • Product of B meson decay constant fB and CKM
matrix element |Vub|
• Using |Vub| = (4.39 0.33)×10-3 from HFAG
fB = 216 22 MeV (an unquenched lattice calc.)
[HPQCD, Phys. Rev. Lett. 95, 212001 (2005) ]
36 3431 37229Bf MeV
( Belle)
1.6 1.3 41.4 1.4(10.1 ) 10B ubf V GeV
Theory:
(PRL 97, 251802 (2006))
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Constraints on charged Higgs mass
rH=1.130.51
Use known fB and |Vub |
Ratio to the SM BF.2
2 22
(1 tan )BH
H
mr
m
excluded
excl
uded
449M
Compare to direct searches for H+
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B K(*) : Motivation
b s with 2 neutrinos
SM: B(BK* ) ~1.3 x 10-5 B (BK ) ~4 x 10-6 (Buchalla, Hiller, Isidori)
PRD 63, 014015
DAMA NaI 3Region
CDMS 04
CDMS 05
No sensitivity to M<10 GeV in direct searches
• New Physics in Loop• Light Dark Matter (M~1GeV)
_
_
_
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B0 K*0 : Belle (preliminary)
_
535M BB
Exp. technique similar to B
Full-rec. tag & K + nothingFull-rec. tag & K + nothing
3.12.64.7Yield
(1.7σ stat. significance)
Sideband = 19MC expectation = 18.73.3
460K tags
[hep-ex/0608047]
Super B Factory LOI: 5σ observation of BK will be possible with 50 ab-1
SM
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Comments on Super B Factories
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Recent Developments for the Super B Factory Accelerator
SuperKEKB design luminosity is now 8 x 1035/cm2/sec
Low emittance/ILC inspired INFN/SLAC design is ~10 x 1035/cm2/sec
To address the full array of new physics searches, require ~50 ab-1 of integrated luminosity
c.f. Current KEKB luminosity is 1.7 x 1034/cm2 /sec
c.f. Current KEKB integrated lumi 0.6 ab-1
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Interaction RegionCrab crossing
=30mrad.y*=3mm
New QCS
Super B Factory at KEK
Linac upgrade
More RF power
Damping ring
New Beam pipe
Ante-chamber & solenoid coilsto reduce photo-electron clouds
L = 81035/cm2 /sec
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Question: 12 nanometer beam spot in y, 2.7 microns in x. Is this possible in a real 2-3 km circumference multi-orbit machine ?
Conceptual Design Report will be submitted to INFN soon.
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First step towards Super B: Crab crossing
. Superconducting crab cavities (1 LER and 1 HER) have been installed and now are being tested at KEKB.
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Backup Slides
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The Super B Factory is part of a Unified and Unbiased Attack on New Physics
Newphysics
Quark sectorLepton sectorPr
opag
ator
s
expts accel, reactor,g-2, e, etc.
Super B Factory, LHCb, Rare K expts, BESIII…
LHC, ILC
mass and mixing,CPV, and LFV
Higgs boson massand couplings. New particle searches
Flavor mixing,CPV phases
LFV, CPV
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Are there New Physics Phases and New sources of CP Violation Beyond the SM ?
Are there right-handed currents ?
Are there new flavor changing neutral currents ?
Are there new operators with quarks enhanced by New Physics ?
Fundamental Questions in Flavor Physics
Experiments: bs CPV, compare CPV angles from tree and loops
Experiments: AFB(BK*l l), BK rates and asymmetries
Experiments: bs CPV, B->VPγ or BV V triple-product asymmetries
Experiments: bs ννbar, D-Dbar CPV+mixing+rare, τγ
These questions can only be answered at a Super B Factory.
Why three generations ?
String Theory ? (e.g. P.Binetruy et.al.,
hep-th/0509157; J.Phys G.32: 129 (2006)); Larger Symmetry Groups ?
Experiments with quarks or heavy leptons?
This question is probably too hard – more tractable questions…..
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Lessons of History New Physics is usually discovered first in loop
processes, which involve high mass virtual particles. (Heisenberg Uncertainty Principle)
Beautiful and precise measurements of the top quark mass at the Tevatron. However, the couplings |Vts|, |Vtd,| and most importantly the phase of (Vtd) cannot be measured in direct top production.
Example I: Absence of KL allowed theorists to deduce the existence of the charm quark. The rate of K mixing allowed a rough determination of the charm mass.
Example II: The absence of bs decays and the long B lifetime ruled out topless models. Large Bd mixing showed the top was heavy contrary to theory prejudices of the time. Radiative corrections from Z measurements determined the rough range of the top mass.
Vtd
Vtd
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http://www.jahep.org/hec/doc/jahep_tenbou_eng_final.pdf
....
(An excerpt)
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“Dai-repoton keikaku”
K. Oide (Leading Japanese Accelerator Physicist)
Official Announcement from KEK director A. Suzuki on Super B expected in 2007
Budget of Japanese
accelerator physicists
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As in bs γ, heavy particles in the loops can be replaced with NP particles (e.g.W+ H+)
The Hunt for the EW Penguin:BXs l+ l-
Note contributions from virtual γ* , W, Z*
and internal t quark.
Discovered by CLEO in 1994
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B → XB → Xsγ from a sum of 38 exclusive decay modes
Eγ>1.9 GeV
hep-ex/0508004, 88.9 MBB
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b s : Belle result140fb-1Efficiency corrected spectrum
E >1.8 GeV (cover 95.2%)
B(B s ) = (3.55 0.32 ) x10-4 +0.30 +0.11
0.31 0.07(Stat) (sys) (theo)
<E> = 2.292 0.0260.034 GeV
<E> <E> = 0.0311 0.0730.063 GeV
[hep-ex/0403004, PRL xxx]
Moments:
useful for Vcb,Vub
An update with much more data (x 3) is in progress
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SuperKEKB Projection for B Ks0 and other b smodes
Possible deviationO(1): Warped extra dim.O(1): L-R symmetric modelO(0.1): SUSY SU(5)
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B K0, ’K0, KsKsKs projection for SuperKEKB
total errors(incl. systematicerrors)
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“Golden” mode:K0
• Obtain CP parameters for 2-body and 3-body modes simultaneously by time-dependent Dalitz fit
KKKS
KKKS
KKKL
1516 65 KKK0signal
1516 65 KKK0signal
[hep-ex/0607112]
B0 K0 Dalitz tCPV B0 K0 Dalitz tCPV
M
_347M BB
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b s : Bkg subtraction
Continuum use OFF-resonance data (ECM 60 MeV lower)
B background B X: measured by data include in MC
backup
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B K(*) : Motivation
b s with 2 neutrinos
SM: B(BK* ) ~1.3 x 10-5 B (BK ) ~4 x 10-6 (Buchalla, Hiller, Isidori)
PRD 63, 014015
No sensitivity in direct searches
• New Physics in Loop• Light Dark Matter (M~1GeV)
_
_
_
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The Super B Factory will face tough competition from LHCb, which is now a real experiment.
LHCb
There is considerable complementarity: photon, neutral detection and inclusive channels are considerable easier at the Super B Factory while time-dependent Bs studies are superior at LHCb.
J. Libby
10 fb-1 for LHCb
50 fb-1 for SuperB