1 s. stone syracuse univ. may 2003 heavy quark physics far too much interesting material to include...
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S. StoneSyracuse Univ.May 2003
Heavy Quark Physics
Far too much interestingMaterial to include in 40 min.Apologies in advance.
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Physics Goals
Discover, or help interpret, New Physics found elsewhere using b & c decays - There is New Physics out there: Standard Model is violated by the Baryon Asymmetry of Universe & by Dark Matter
Measure Standard Model parameters, the “fundamental constants” revealed to us by studying Weak interactions
Understand QCD; necessary to interpret CKM measurements
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The Basics: Quark Mixing & the CKM Matrix
A, , and are in the Standard Model fundamental constants of nature like G, or EM
multiplies i and is responsible for CP violationWe know =0.22 (Vus), A~0.8; constraints on &
2 3 2
2 2 4 2 2
3 2
1 11- λ λ Aλ -i 1- λ
2 2
1V= -λ 1- λ -i A λ Aλ 1+i λ
2Aλ 1- -i -Aλ 1
η
η
ρ
η
ηρ
d s bu
c
t
mass
mass
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The 6 CKM Triangles
From Unitarity“ds” - indicates
rows or columns used
There are 4 independent phases: ( can be substituted for or )
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All of The CKM Phases
*cdcb
*tdtb
VV
VVarg
cd*cb
ud*ub
VV
VVarg
tb*ts
cb*cs
VV
VVarg
cs*cd
us*ud
VV
VVarg
The CKM matrix can be expressed in terms of 4 phases, rather than, for example , A, ,
not independent& probably large, small ~1o, smaller
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Required Measurements
|Vub/Vcb|2 = (2+ 2)/2 use semileptonic B decaysmd and ms are measured directly in Bd and Bs mixing.
There is a limit on the ratio which is a function of Vtd/Vts and depends on (1-)2+2
K is a measure of CP violation in KL decays, a function of , and A
Asymmetries in decay rates into CP eigenstates f (or other states) measure the angles & , sometimes with little or no theoretical model errors
Bo Bo
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|Vub | a case study
Use semileptonic decaysc >> u, so difficult expAlso difficult theoretically
Three approachesEndpoint leptons: Clear signal seen first this way; new
theory enables predictionsMake mass cuts on the hadronic system; plot the lepton
spectrum. Problems are the systematic errors on the experiment and the theory.
Exclusive B or decays. Data are still poor as is theory. Eventually Lattice Gauge calculations should be able to remove this problem
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Vub from lepton endpoint
Vub both overall rate & fraction of leptons in signal region depends on model. Use CLEO b sspectrum to predict shape
CLEO: Vub=(4.08±0.34 ±0.44±0.16 ±0.24)x10-3
BABAR: Vub=(4.43±0.29 ±0.25±0.50 ±0.35)x10-3 theory errs : Vub formula, using s
Luke: additional error >0.6x10-3 due to:
CLEO
Y(4S) data bccontinuum
Shape fromb s
bu
subleading twist, annihilation
CLEO
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Vub Using Inclusive Leptons
ALEPH & DELPHI, OPAL select samples of charm-poor semileptonic decays with a large number of selection criteria
Mass < MD b uCan they understand b c
feedthrough < 1% ? |Vub|=(4.090.370.44
0.34)x10-3
DELPHI
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Problem According to Luke
PROBLEM: QCDmB and mD
2 aren’t so different!kinematic cut and singularity are perilously close …SOLUTION: Also require q2>~7 GeV2
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Vub using reconstructed tags - BABAR
Use fully reconstructed B tags
|Vub|=(4.520.31(stat)0.27(sys)
0.40(thy)0.09(pert)
0.27(1/mb3)) x10-3
Preliminary
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Vub from Belle
Two techniques (Both Preliminary)
|Vub| = 5.00 0.60 0.23 0.05 0.39 0.36 103stat. syst.
|Vub| = 3.96 0.17 0.44 0.34 0.26 0.29 103
bc bu
stat. syst. bc bu
“D(*) tag”
“ reconstruction and Annealing uses Mx < 1.5, q2 > 7”theor.
theor.
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Vub from exclusives:BBUse detector
hermeticity to reconstruct
CLEO finds rough q2 distribution
BABAR finds
(GeV)
CLEO
exp thytheor -3
stat ρlν FFsys
+0.16 +0.533.17±0.17 ±0.03 ×10
-0.17 -0.39ubV
thy
-3
stat syst
+0.393.64±0.22 ±0.03 ×10
-0.56ubV
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|Vub | Summary
All measurements nicely clustered. RMS ~0.3x10-3
However, there are theoretical errors that might all have not been included (see Luke)
Also previous values may have influenced new values
Safe to say |Vub|=(4.0±1.0)x10-3
Future: More and better tagged data
from B-factories Lattice calculations
(unquenched) for exclusives in high q2 region
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Bd Mixing in the Standard Model
Relation between B mixing & CKM elements:
F is a known function, QCD~0.8BB and fB are currently determined only
theoreticallyin principle, fB can be measured, but its very
difficult, need to measure Bo Current best hope is Lattice QCD
td
222 m*2 2F t
B B tb t QCD2 2mWB B
m Gx B m V m F
6f V
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Bs Mixing in the Standard Model
When Bs mixing is measured then we will learn the ratio of Vtd/Vts which gives the same essential information as Bd mixing alone:|Vtd|2=A24[(1-)2+2] 1/fBBB
2
|Vtd|2/ |Vts|2=[(1-)2+2] fBsBBs2/fBBB
2
Circle in () plane centered at (1,0)
Lattice best value for
S S S S
222 m* 2s F t
s B B tb t QCD2 2m
2B B ts
Ws
m Gx m V m F
6B Vf
S S
d d
B B
B B
f B1.24 0.04 0.06
f B
Partiallyunquenched
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Upper limits on ms
P(BSBS)=0.5X
Se-St[1+cos(mSt)]
To add exp. it is useful to analyze the data as a function of a test frequency
g(t)=0.5 S
e-St[1+cos(t)]
4 discovery limit
LEP + SLD
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Status of sin(2)
B0 fCPB0 fCP
sin2 = 0.7410.0670.034 BABAR sin2 = 0.7190.0740.035 Belle sin2 = 0.73 0.06 Average
sin2 = 0.7410.0670.034 BABAR sin2 = 0.7190.0740.035 Belle sin2 = 0.73 0.06 Average
78 fb-1
fCP=J/Ks, Ks, etc..
( )
sin(2 )sin( )
BBCP
BB
d
N NA t
N N
m t
No theoretical uncertainties atthis level of error
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Current Status Constraints on & from Nir using Hocker
et al. Theory parameters exist except in
Asymmetry measurements, because we measure hadrons but are trying to extract quark couplings. They are allowed to have equal probability within a restricted but arbitrary range
Therefore large model dependence for Vub/Vcb, K and md, smaller but significant for ms and virtually none for sin(2). The level of theoretical uncertainties is arguable
sin(2)
sin(2) may be consistent with other measurements
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for s get K-
Bo+-
In principle, the CP asymmetry in Bo measures the phase . However there is a large Penguin term (a “pollution”) (CLEO+ BABAR+BELLE): (Bo +-) = (4.8 ±0.5)x10-6 (Bo K±) =(18.6±1.0)x10-6
ACP(t)=Ssin(mdt)-Ccos(mdt),
where SC
To measure , use Bo see Snyder & Quinn PRD 48, 2139 (1993))
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Results
Inconsistent Results!
S C S2+C2
Belle -1.23±0.42 0.77±0.28 2.1±2.2
BABAR 0.02±0.34 -0.30±0.34 0.1±0.3
-5 0 5 t (ps)
BABAREach exp~80 fb-1
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Progress on Best way to measure is
2nd best is
Another suggestion is DoK*±K (Grossman, Ligeti &
Soffer hep-ph/0210433)
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Currently available data
Belle signals (also B+)
Where is a strong phase &
These data do not constrain BABAR has similar results
0fD K
1 ,D K K
02 , , ,
,S S S
S S
D K K K
K K
signal
1,2 1,2
1,2 11
,2,2
( ) ( )
( ) ( )
B B D K B B D K
B B D K B BA
D K
2
2 sin( )sin( )
1 2 cos( )cos( )
r
r r
0
0
( ) ( )
( ) ( )
A B D K A b u
A B D K A b cr
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New Physics Tests
We can use CP violating or CP related variables to perform tests for New Physics, or to figure out what is the source of the new physics.
There are also important methods using Rare Decays, described later
These tests can be either generic, where we test for inconsistencies in SM predictions independent of specific non-standard model, or model specific
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Generic test: Separate Checks
Use different sets of measurements to define apex of triangle
(from Peskin)
Also have K
(CP in KL system)
Magnitudes
Bd mixing phase
Bs mixing phase
Can also measure via
B-DoK-
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Generic Test: Critical Check using
Silva & Wolfenstein (hep-ph/9610208), (Aleksan, Kayser & London), propose a test of the SM, that can reveal new physics; it relies on measuring the angle .Can use CP eigenstates to measure BsJ/ Can also use J/but a complicated angular analysis is
requiredThe critical check is:
Very sensitive since 0.2205±0.0018Since ~ 1o, need lots of data
2 sin sinsin
sin( + )
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Rare b Decays
New fermion like objects in addition to t, c or u, or new Gauge-like objectsInclusive Rare Decays such as inclusive bs, bd, bs+Exclusive Rare Decays such as BBK*+: Dalitz plot & polarization
+-
A good place to find new physics
Ali et. al, hep-ph/9910221
SUSYexamples
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Inclusive bs
CLEO B(b s)=
(2.85±0.35±0.23)x10-4
+ALEPH, Belle & Babar
Average
(3.28±0.38)x10-4
Theory
(3.57±0.30)x10-4
CLEO
7 b 7 8 b 8
μν μν7 b L μν R 8 b
2 522 *F b
7 tb ts4
L μν R2
*Feff tb ts c (m )O c (m )O
e 1O = m s σ b F , O = m s σ b G
1
G αmΓ(b sγ)= c V
4
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GH
V in lowest order32π
V V2
π 4π
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Implications of B(b s ) measurement
Measurement is consistent with SM
Limits on many non-Standard
Models: minimal supergravity,
supersymmetry, etc… Define ala’ Ali et al.
Ri=(ciSM+ci
NP)/ciSM ; i=7, 8
Black points indicate various New Physics models (MSSM with MFV)
SM
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BK(*)+-
Belle Discovery of K+-
They see K+-
BABAR confirms in Ke+e-
Only u.l. on K*+-
0.25 60.21
(B K )
0.75 0.09 x10
B
0.24 0.11 60.20 0.18
(B K )
0.78 x10
B
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BXs+-
Belle finds B(b s+- )=
(6.1±1.4 )x10-6
Must avoid J/, ´Important for NP
+1.4
-1.1
Heff = f(O7, O9, O10)
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Tests in Specific Models:First Supersymmetry
Supersymmetry: In general 80 constants & 43 phasesMSSM: 2 phases (Nir, hep-ph/9911321)
NP in Bo mixing: D , Bo decay: A, Do mixing: K
Process Quantity SM New Physics
BoJ/Ks CP asym sin(2) sin2(D)
BoKs CP asym sin(2) sin2(DA)
DoK-+ CP asym 0 ~sin(K)
NP
Difference NP
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CP Asymmetry in BoKs
Non-SM contributions would interfere with suppressed SM loop diagramNew Physics could show if there is a difference between sin(2) measured here and
in J/ KsMeasurements: BABAR: -0.18±0.51±0.07
Belle: -0.73±0.64±0.22 Average: -0.38±0.41
2.7 away from 0.73 - bears watching, as well other modes
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relies onfinite strongphase shift
MSSM Predictions from Hinchcliff & Kersting
(hep-ph/0003090)
Contributions to Bs mixing
CP asymmetry 0.1sincossin(mst), ~10 x SM
BsJ
B-K-
Contributions to direct the CP violating decay
Asym=(MW/msquark)2sin(), ~0 in SM BABAR u.l Asy=(3.9±8.6±1.1)%
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Extra Dimensions – only one
Extra spatial dimension is compactified at scale 1/R = 250 GeV on up
Contributions from Kaluza-Klein modes- Buras, Sprnger & Weiler (hep-ph/0212143) using model of Appelquist, Cheng and Dobrescu (ACD)
No effect on |Vub/Vcb|, Md/Ms, sin(2)
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SO(10)ala’ Chang, Masiero & Murayama hep-ph/0205111
Large mixing between and (from atmospheric oscillations) can lead to large mixing between bR and sR.
This does not violate any known measurements
Leads to large CPV in Bs mixing, deviations from sin(2) in Bo Ks and changes in the phase
~ ~
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Revelations about QCD
BABAR discovery of new narrow Ds+o state
and CLEO discovery of narrow Ds*+o state
Double Charm BaryonsThe C(2S) and implications for Potential
Models (no time)The Upsilon D States (no time)
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The Dso state
“Narrow” state, mass 2316.8±0.4±3.0 MeV width consistent with mass resolution ~9 MeV found by BABARLighter than most potential modelsWhat can this be?
DK molecule Barnes, Close & Lipkin hep-ph/0305025“Ordinary” excited cs states: D**, narrow because isospin is violated
in the decay. Use HQET + chiral symmetry to explain. Bardeen, Eichten & Hill hep-ph/0305049
Etc…
Ds* New
BABAR
+
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Ds** States
Ds** predicted Jp: 0+, 1+, 1+ & 2+. One 1+ & 2+ seen. Others predicted to be above DK threshold and have large ~200 MeV widths, but this state is way below DK threshold
The Dso decay from an initial cs state violates isospin, this suppresses the decay width & makes it narrow. So the low mass ensures the narrow width
Decays into Ds, Ds* and Ds +- are not seen. If the 2317 were 1+ then it could decay strongly into Ds +- but it cannot if it’s 0+
+
+
+ + +
+
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CLEO Sees Two Mass Peaks
These two states can reflect into one another
DsoDs*o not to bad,
~9%, because you need to pick up a random
Ds* signal region
Ds* sideband region
Ds*o Dso
m=349.3±1.1 MeV=8.1±1.3 MeV
m= 349.8±1.3 MeV= 6.1±1.0 MeV
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Feed Down: Ds(2460) Signal, Reconstructed as Ds(2317)
All events in the Ds*0
mass spectrum are used to show the Ds(2460) signal
“feed down” to the Ds(2317) spectrum.
Feed down rate is 84%
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Unfolding the rates
We are dealing with two narrow resonances which can reflect (or feed) into one another
From the data and the MC rates can be unfolded
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Upper Limits on other Ds(2317) modes
Mode Yield Efficiency(%) 90% cl Theory
Corrected for feed acrossTheory: Bardeen, Eichten and Hill
Dso 150±49 13.1±0.7 - 1
Ds -22±13 18.4±0.9 <0.057 0
Ds* -2.0±4.1 5.3±0.4 <0.078 0.08
Ds+- 1.6±2.6 19.6±0.7 <0.020 0
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Belle Confirms Both States
M(Ds+
π0 ) M(Ds*+
π0 )
M=(2317.2±0.5) MeV
=(8.1 ±0.5) MeV
M=(2459±1.9) MeV
=(7.0 ±1.7) MeV
Also see “feed up”
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Conclusions on Ds**’s
CLEO confirms the BABAR discovered narrow cs state near 2317 MeV, measures mDs(2320)-mDs =350.4±1.2±1.0 MeV
CLEO has observed a new narrow state near 2463
mDs(2463)-mDs*=351.6±1.7±1.0 MeV Belle confirms both states The mass splittings are consistent with being equal (1.2±2.1 MeV)
as predicted by BEH if these are the 0+ & 1+ states The BEH model couples HQET with Chiral Symmetry and makes
predictions about masses, widths and decay modes. These results provide powerful evidence for this modelSeen modes and u.l. are consistent with these assignment;
except 1+ Ds+- is above threshold for decay, predicted to be 19% but is limited to <8.1% @ 90% c. l.
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Selex: Two Isodoublets of Doubly Charmed Baryons
cc
++
(J=1/2+)?
cc
++
(J=1/2-)?
cc
+
(J=1/2+)?
cc
+
(J=1/2-)?
Consider as (cc)q - BEH
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The Future
Now & near term Continuation of excellent new results from Belle
& BABARBs physics, especially mixing from CDF & D0CLEO-c will start taking data in October on
LHC eraSome b physics from ATLAS & CMSDedicated hadronic b experiments: LHCb &
BTeV (at the Tevatron) – enhanced sensitivity to new physics
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Summary of Required Model Independent Measurements for
CKM testsPhysics Quantity
Decay Mode Vertex Trigger
K/ sep
det Decay time
sin(2) Bo
cos(2) Bo
sin() BsDs K
sin() BoDo K
sin(2) Bs J/ J/
sin(2) Bo J/Ks
cos(2) Bo J/Ko, Ko
xs BsDs
for Bs Bs
J/ K
K Ds
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CDF measures BsDs-
needed for Bs mixing
For fs/fd = 0.27±0.03, B(Bs)/B(Bd)=1.6±0.3
0.060.o + -
d d
o + -S S
7S
0
( )0.42 0.11 0.11
( )f B
f π
D π
B DB
B
+o
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BTeV & LHCb
Dedicated Hadron Collider B experiments Tevatron LHC
LHCb
Could find narrow Bs** states
PbWO4
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BTeV & LHCb
Physics highlightsSensitivity to Bs mixing up to xs ~80
Large rare decay rates BoK*o+- ~2500 events in 107 s
Measurement of to ~7o using BsDs K-
Measurement of to ~4o using Bo (BTeV)Measurement of to ~1o using BoJ/ (BTeV)