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S. Stone Syracuse Univ. May 2003. Heavy Quark Physics. Far too much interesting Material to include in 40 min. Apologies in advance. Physics Goals.

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S stone syracuse univ may 2003
S. StoneSyracuse Univ.May 2003

Heavy Quark Physics

Far too much interesting

Material to include in 40 min.

Apologies in advance.

Physics goals
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

The basics quark mixing the ckm matrix
The Basics: Quark Mixing & the CKM Matrix

d s b









  • A, l, r and h are in the Standard Model fundamental constants of nature like G, or aEM

  • h multiplies i and is responsible for CP violation

  • We know l=0.22 (Vus), A~0.8; constraints on r & h

The 6 ckm triangles
The 6 CKM Triangles

  • From Unitarity

  • “ds” - indicates rows or columns used

  • There are 4 independent phases: b, g, c, c (a can be substituted for g or b)






All of the ckm phases
All of The CKM Phases

  • The CKM matrix can be expressed in terms of 4

    phases, rather than, for example l, A, r,h:

  • a= p-(b+g), not independent

  • a, b & g probably large, c small ~1o, c smaller

Required measurements
Required Measurements

  • |Vub/Vcb|2 = (r2+ h2)/l2 use semileptonic B decays

  • Dmd and Dms 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-r)2+h2

  • eK is a measure of CP violation in KL decays, a function of h, r and A

  • Asymmetries in decay rates into CP eigenstates f (or other states) measure the angles a, b, g & c, sometimes with little or no theoretical model errors



V ub a case study
|Vub | a case study

  • Use semileptonic decays

    • c >> u, so difficult exp

    • Also difficult theoretically

  • Three approaches

    • Endpoint leptons: Clear signal seen first this way; new theory enables predictions

    • Make mass cuts on the hadronic system; plot the lepton spectrum. Problems are the systematic errors on the experiment and the theory.

    • Exclusive B pln orrln decays. Data are still poor as is theory. Eventually Lattice Gauge calculations should be able to remove this problem

V ub from lepton endpoint
Vub from lepton endpoint


  • Vub both overall rate & fraction of leptons in signal region depends on model. Use CLEO b sgspectrum 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)x10-3theory errs : Vub formula, using sg

  • Luke: additional error >0.6x10-3 due to:

 Y(4S) data

bcln +



 buln

Shape from

b sg

subleading twist, annihilation

V ub using inclusive leptons
Vub Using Inclusive Leptons

  • ALEPH & DELPHI, OPAL select samples of charm-poor semileptonic decays with a large number of selection criteria

  • Mass < MD  b  u

  • Can they understand b  cln feedthrough < 1% ?

  • |Vub|=(4.090.370.44 0.34)x10-3


S stone syracuse univ may 2003

Problem According to Luke


  • LQCDmB and

  • mD2 aren’t so different!

  • kinematic cut and singularity are perilously close …

    SOLUTION: Also require q2>~7 GeV2

V ub using reconstructed tags babar
Vub using reconstructed tags - BABAR

  • Use fully reconstructed B tags

  • |Vub|=(4.520.31(stat)0.27(sys)


    0.27(1/mb3)) x10-3


V ub from belle
Vub from Belle

  • Two techniques (Both Preliminary)

“D(*)ln tag”

|Vub| = 5.00  0.60  0.23  0.05  0.39  0.36  10-3






“n reconstruction and Annealing uses Mx < 1.5, q2 > 7”

|Vub| = 3.96  0.17  0.44  0.34  0.26  0.29  10-3






V ub from exclusives b p l n b r l n


Vub from exclusives:Bpln & Brln


  • Use detector hermeticity to reconstruct n

  • CLEO finds rough q2 distribution

  • BABAR finds

V ub summary
|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

B d mixing in the standard model
Bd Mixing in the Standard Model

  • Relation between B mixing & CKM elements:

  • F is a known function, hQCD~0.8

  • BB and fB are currently determined only theoretically

    • in principle, fB can be measured, but its very difficult, need to measure Boln

    • Current best hope is Lattice QCD

B s mixing in the standard model
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=A2l4[(1-r)2+h2]  1/fBBB2

    • |Vtd|2/ |Vts|2=[(1-r)2+h2]  fBsBBs2/fBBB2

    • Circle in (r,h) plane centered at (1,0)

  • Lattice best value for



Upper limits on d m s
Upper limits on Dms

  • P(BSBS)=0.5X


  • To add exp. it is useful to analyze the data as a function of a test frequency w

  • g(t)=0.5 GS



4s discovery limit


Status of sin 2 b
Status of sin(2b)

No theoretical

uncertainties at

this level of error

sin2b = 0.7410.0670.034 BABAR

sin2b = 0.7190.0740.035 Belle

sin2b = 0.73  0.06 Average

B0 fCP

B0 fCP

78 fb-1

fCP=J/yKs, yKs, etc..

Current status
Current Status

sin(2b) may be consistent with other measurements

  • Constraints on r & h 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, eK and Dmd, smaller but significant for Dms and virtually none for sin(2b). The level of theoretical uncertainties is arguable







B o p p

for s get K-


  • In principle, the CP asymmetry in

    Bop+p- measures the phase a.

    However there is a large Penguin

    term (a “pollution”) (CLEO+


    B(Bop+p-) = (4.8 ±0.5)x10-6

    B(BoK±p) =(18.6±1.0)x10-6

  • ACP(Dt)=Sppsin(DmdDt)-Cppcos(DmdDt),

    where Spp2+Cpp2<1

  • To measure a, use Borp (see Snyder & Quinn PRD 48, 2139 (1993))


Inconsistent Results!

Spp Cpp Spp2+Cpp2

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


Each exp

~80 fb-1

-5 0 5 Dt (ps)

Must be < 1

Progress on g
Progress on g

  • Best way to measure g is

  • 2nd best is

  • Another suggestion is DoK*±K (Grossman, Ligeti & Soffer hep-ph/0210433)

Currently available data
Currently available data


  • Belle signals (also B+)

    Whered is a strong phase &

  • These data do not constrain g

  • BABAR has similar results

New physics tests
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

Generic test separate checks
Generic test: Separate Checks

  • Use different sets of measurements to define apex of triangle

    (from Peskin)

  • Also have eK (CP in KL system)

Bd mixing phase


Bs mixing phase

Can also measure g via


Generic test critical check using c
Generic Test: Critical Check using c

  • 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 c.

    • Can use CP eigenstates to measure c

      BsJ/yh() ,hgg,hrg

    • Can also use J/yf, but a complicated angular analysis is required

    • The critical check is:

    • Very sensitive since l =0.2205±0.0018

    • Sincec~ 1o, need lots of data

Rare b decays

New fermion like objects in addition to t, c or u, or new Gauge-like objects

Inclusive Rare Decays such as inclusive bsg, bdg, bsl+l-

Exclusive Rare Decays such as Brg, BK*l+l-: Dalitz plot & polarization

Ali et. al, hep-ph/9910221

Rare b Decays

  • A good place to find

    new physics





Inclusive b s g
Inclusive b Gauge-like objectssg

  • CLEO B(bsg)=


  • +ALEPH, Belle & Babar






Implications of b b s g measurement
Implications of Gauge-like objectsB(bsg ) measurement

  • Measurement is consistent with SM

  • Limits on many non-Standard

    Models: minimal supergravity,

    supersymmetry, etc…

  • Define ala’ Ali et al.

    Ri=(ciSM+ciNP)/ciSM ; i=7, 8

  • Black points indicate various New Physics models (MSSM with MFV)


B k l l
B Gauge-like objectsK(*)l+l-

  • Belle Discovery of Kl+l-

  • They see Km+m-

  • BABAR confirms in Ke+e-

  • Only u.l. on K*l+l-

B x s l l
B Gauge-like objectsXsl+l-

  • Heff = f(O7, O9, O10)

  • Belle finds

    B(bsl+l- )=


  • Must avoid J/Y, Y´

  • Important for NP



Tests in specific models first supersymmetry

Difference Gauge-like objects

 NP


Tests in Specific Models:First Supersymmetry

  • Supersymmetry: In general 80 constants & 43 phases

  • MSSM: 2 phases (Nir, hep-ph/9911321)

  • NP in Bo mixing: qD ,Bodecay: qA,Do mixing: fKp

Cp asymmetry in b o f k s
CP Asymmetry in B Gauge-like objectsofKs

  • Non-SM contributions

    would interfere with

    suppressed SM loop diagram

  • New Physics could show

    if there is a difference between sin(2b) measured here and in J/y Ks

  • Measurements: BABAR: -0.18±0.51±0.07

    Belle: -0.73±0.64±0.22

    Average: -0.38±0.41

  • 2.7s away from 0.73 - bears watching, as well other modes

Mssm predictions from hinchcliff kersting hep ph 0003090

relies on

finite strong

phase shift


Asym=(MW/msquark)2sin(fm), ~0 in SM



MSSM Predictions from Hinchcliff & Kersting (hep-ph/0003090)


  • Contributions to Bs mixing

CP asymmetry  0.1sinfmcosfAsin(Dmst), ~10 x SM

Extra dimensions only one
Extra Dimensions – only one Gauge-like objects

  • 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|, DMd/DMs, sin(2b)

One extra dimension
One Extra Dimension Gauge-like objects

  • Precision measurements needed for large 1/R




So 10 ala chang masiero murayama hep ph 0205111
SO(10) Gauge-like objectsala’ Chang, Masiero & Murayama hep-ph/0205111

  • Large mixing between nt and nm (from atmospheric n 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(2b) in Bof Ks and changes in the phase g



Possible size of new physics effects
Possible Size of New Physics Effects Gauge-like objects

  • From Hiller hep-ph/0207121

Revelations about qcd
Revelations about QCD Gauge-like objects

  • BABAR discovery of new narrow Ds+po state and CLEO discovery of narrow Ds*+po state

  • Double Charm Baryons

  • The hC(2S) and implications for Potential Models (no time)

  • The Upsilon D States (no time)

The d s p o state

* Gauge-like objects



The Dspo state



  • “Narrow” state, mass

    2316.8±0.4±3.0 MeV

    width consistent with

    mass resolution ~9 MeV

    found by BABAR

  • Lighter than most potential models

  • What 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…


D s states
D Gauge-like objectss** 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 Dspo 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 Dsg, Ds*g and Ds p+p- are not seen. If the 2317 were 1+ then it could decay strongly into Ds p+p- but it cannot if it’s 0+






S stone syracuse univ may 2003

CLEO Sees Two Mass Peaks Gauge-like objects



Dm=349.3±1.1 MeV

s=8.1±1.3 MeV

Dm= 349.8±1.3 MeV

s= 6.1±1.0 MeV

Ds* signal region

  • These two states can reflect into one another

  • DspoDs*po not to bad, ~9%, because you need to pick up a random g

Ds* sideband region

Feed down d s 2460 signal reconstructed as d s 2317
Feed Down: D Gauge-like objectss(2460) Signal, Reconstructed as Ds(2317)

All events in the Ds*p0 mass spectrum are used to show the Ds(2460) signal “feed down” to the Ds(2317) spectrum.

Feed down rate is 84%

Unfolding the rates
Unfolding the rates Gauge-like objects

  • 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

Upper limits on other d s 2317 modes
Upper Limits on other D Gauge-like objectss(2317) modes

Mode Yield Efficiency(%) 90% cl Theory

  • Corrected for feed across

  • Theory: Bardeen, Eichten and Hill

Belle confirms both states
Belle Confirms Both States Gauge-like objects

M=(2459±1.9) MeV

s=(7.0 ±1.7) MeV

M=(2317.2±0.5) MeV

s=(8.1 ±0.5) MeV

Also see “feed up”

M(Ds*+π0 )

M(Ds+π0 )

Conclusions on d s s
Conclusions on D Gauge-like objectss**’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 model

    • Seen modes and u.l. are consistent with these assignment; except 1+ Dsp+p- is above threshold for decay, predicted to be 19% but is limited to <8.1% @ 90% c. l.

Selex two isodoublets of doubly charmed baryons

X Gauge-like objectscc+








Selex: Two Isodoublets of Doubly Charmed Baryons

Consider as (cc)q - BEH

The future
The Future Gauge-like objects

  • Now & near term

    • Continuation of excellent new results from Belle & BABAR

    • Bs physics, especially mixing from CDF & D0

    • CLEO-c will start taking data in October on y

  • LHC era

    • Some b physics from ATLAS & CMS

    • Dedicated hadronic b experiments: LHCb & BTeV (at the Tevatron) – enhanced sensitivity to new physics

Summary of required model independent measurements for ckm tests
Summary of Required Gauge-like objectsModel Independent Measurements for CKM tests

Cdf measures b s d s p needed for b s mixing

o Gauge-like objects


CDF measures BsDsp-needed for Bs mixing

  • For fs/fd = 0.27±0.03, B(Bs)/B(Bd)=1.6±0.3

Btev lhcb
BTeV & LHCb Gauge-like objects

  • Dedicated Hadron Collider B experiments

  • Tevatron LHC



Could find narrow Bs** states

Btev lhcb1
BTeV & LHCb Gauge-like objects

  • Physics highlights

    • Sensitivity to Bs mixing up to xs ~80

    • Large rare decay rates BoK*om+m- ~2500 events in 107 s

    • Measurement of g to ~7o using BsDs K-

    • Measurement of a to ~4o using Borp (BTeV)

    • Measurement of c to ~1o using BoJ/yh (BTeV)

Conclusions Gauge-like objects

  • There have been lots of surprises in Heavy Quark Physics, including:

    • Long b Lifetime

    • Bo – Bo mixing

    • Narrow Ds** states

  • We now expect to find the effects of New Physics in b & c decays!