Lattice 2005
CLEO-c confronts
High Precision Lattice QCD
Jim Napolitano, Rensselaer Polytechnic Institute
for the CLEO-c Collaboration
XXIII International Symposium on Lattice Field Theory
School of Mathematics, Trinity College, Dublin
25th-30th July 2005
Outline
Focus on issues specific to Lattice QCD
•
Latest Results: D+→μ+νμ
★
Related and Brand New: Γee for ϒ(nS)
•
• Summary: Heavy quarkonium masses
• The Future
- Increased precision on D decays
- Data taking for D decays
- Glueballs revisited
Latest Results: D+,D0 semi-leptonic decay
S
Jim Napolitano (CLEO-c)
2
Lattice 2005
expected to be larger than for pions and kaons, as are
finite volume and statistical errors; computations with
these hadrons are not yet under control. Also, there are
many gold-plated quantities that we have not yet fully
week ending
P H Y S I Cand
A LsemilepR EVIEW LET T ERS
16 JANUARY 2004
VOLUME 92,
N UMBER 2 mixing amplitudes,
analyzed.
Heavy-quark
tonic decay form factors, for example, are essential to
high-precision experiments at CLEO-c and the B facto- formalism, are reliable and accurate tools for analyzing
ries; our lattice techniques for these require indepen- heavy-quark dynamics.
A serious problem in the previous work was the incondent tests.
sistency between light-hadron, B=D, and "= quantities.
The larger challenge facing LQCD is to exploit these Heavy-quark masses and inverse lattice spacings, for
new techniques in the discovery of new physics. Again, B example, were routinely retuned by 10%–20% when
and D physics offer extraordinary opportunities for new going from an " analysis to a B analysis in the same
physics from LQCD. There are, for example, gold-plated quenched simulation [14]. Such discrepancies lead to the
lattice quantities for every Cabibbo-Kobayashi-Maskawa results shown in the left panel of Fig. 1. The results in the
(CKM) matrix element except Vtb (Fig. 3). An immediate right panel for !, K, !, Ds , J= , Bs , and " physics mark
challenge is to predict the D=Ds leptonic and semilep- the first time that agreement has been achieved among
tonic decay rates to within a few percent before CLEO-c such diverse physical quantities using the same QCD
parameters throughout.
measures them.
Confrontations in this Talk
Results from recent CLEO
runs prior to taking data
at the ψ(3770).
The dominant uncertainty in our light-quark quantities
comes from our extrapolations in the sea and valence
light-quark masses. We used partially quenched chiral
FIG. 1. LQCD results divided by experimental results for
perturbation theory to extrapolate pion and kaon masses,
nine different quantities, without and with quark vacuum
and the weak decay constants f! and fK . The s-quark
polarization (left and right panels, respectively). The top three
mass required only a small shift; we estimated correcresults are from our a % 1=11 and 1=8 fm simulations; all
tions due to this shift by interpolation (for valence s
others are from a % 1=8 fm simulations.
quarks) or from the sea u=d mass dependence (for sea s
quarks). We kept u=d masses smaller than ms =2 in our fits,
so that low-order chiral perturbation theory was suffidifferent physical quantities. The right panel shows recient. Our chiral expansions included the full first-order
sults from QCD simulations that include realistic vacuum
contribution [15], and also approximate second-order
polarization. These nine results agree with experiment to
terms, which are essential given our quark masses. We
within systematic and statistical errors of 3% or less —
corrected for errors caused by the finite volume of our
with no free parameters.
lattice (1% errors or less), and by the finite lattice spacing
The quantities used in this plot were chosen to test
(2%–3% errors). The former corrections were determined
several different aspects of LQCD. Our results for f! and
from chiral perturbation theory; the latter by comparing
fK are sensitive to light-quark masses; they test our
results from the coarse and fine lattices. Residual discreability to extrapolate these masses to their correct values
tization errors, due to nonanalytic taste violations [7]
FIG.
3. chiral
Gold-plated
LQCDtheory.
processes
that bearsimulations
on CKM ma- that remain after linear extrapolation in a2 , were estiusing
perturbation
Accurate
another
quantity.
trix
"K is of
for elements.
a wide range
small gold-plated
quark masses
were essential
mated as32% for f! and 1% for fK . Perturbative match-
Very recent
results.
Goals of future
run plans.
Jim Napolitano (CLEO-c)
Lattice 2005
+
+
Results: D →μ νμ
Latest
c
μ+
D+
d¯
Γ=
A Difficult Measurement!
W+
G2F
8π
m2µMD+
!
Jim Napolitano (CLEO-c)
νμ
m2µ
1− 2
MD+
• Small branching ratio
• Need to reconstruct
“missing” neutrino
• Backgrounds from
"2
many sources
• Precision is important!
2
2
× fD+ |Vcd |
An opportunity almost
ideal for CLEO-c!
4
Lattice 2005
The Special Contribution of CLEO-c
Decays of “Tagged” D-mesons using ψ(3770) Data Runs
e+e−→D+D−
π+ π+
νμ
e+
π−
D+→KSπ−π+π+
*
π+
π+
π−
KS
KS→π+π−
e−
D−→μ−νμ
μ−
Jim Napolitano (CLEO-c)
μ−
5
Lattice 2005
Number of Events/0.01 GeV
Results (Preliminary)
D+→μ+νμ
120
15
D+→π+KL
100
10
80
60
With 280 pb-1 of data,
we observe 50 events
with a background of 3.
5
-0.05
0
Other
backgrounds
0.05
40
Branching Ratio
+
+
B(D → µ νµ)=
+29
−4
.
(4.45 ±.67−36
. )×10
Decay Constant
fD+ =
20
0
2
0.25
2
(Missing Mass) (GeV2)
2
MM (GeV
)
0.50
MeV
More data to come!
using D− tags and one additional opposite sign charged track and no extra energetic
6
xt). The insert shows the signal region for D+ → µ+ ν enlarged; the defined signal
Jim Napolitano (CLEO-c)
+7
(223 ± 16−9)
Lattice 2005
Related and Brand New: Γee for ϒ(nS)
(b)
e−
Not
e+
{
W
B
u, d
(a)
...but
b
{
(b)
b
e−
γ
Y(nS)
e process whose probability
is measured by Γee , (b) the process
e+
b
{
Tour de force of statistical
and systematic precision!
b
W
B
u, d
Preliminary Results
FIG. 1: Feynman diagrams for (a) the process whose probability is measured by Γee , (b) the process
for fB .
Get widths by measuring
Υ(1S), Υ(2S), and Υ(3S) measures the coupling of the bb̄
the total
in
In the absence
of other Υ cross
decays, Γ section
would be the inverse
at half-maximum of the Υ’s rest mass distribution. Since
+ Γ,−andannihilation:
, Γ =eB e
represents about 1 keV of the Υ’s 50
Γee(1S)=1.336±0.009±0.019 keV
keV
ee(2S)=0.616±0.010±0.009
The di-electron width, Γ , of Υ(1S), Υ(2S), and Υ(3S)Γ
measures
the coupling of the bb̄
resonance to a two-electron state. In the absence of other Υ decays, Γ would be the inverse
lifetime of the Υ and the full-width at half-maximum of the Υ’s rest mass distribution. Since
sed to determine Γ.
Γeeabout
(3S)=0.425±0.009±0.006
keV
Υ does decay to other final states, Γ = B Γ, and represents
1 keV of the Υ’s 50
I.
INTRODUCTION
ee
ee
ee
ee
ee
ee
ee
of two steps: firstkeV
thefull
two
b quarks
other Γ.
width.
Given Bmust
is usedeach
to determine
ee , Γee find
+ −
The Υ →through
e e process
consists of
two steps:
first the two b quarks must find each other
duced electromagnetically
a virtual
photon
(see
and annihilate, then e+ e− are produced electromagnetically
through ee
a virtual photon (see
ee
well-understood QED,
and
can
be
used
as
a
probe
of
the
Figure 1-a). This second step is well-understood QED, and can be used as a probe of the
ance, the bb̄ spatialQCD
wavefunction,
at the
involve in the evaluated
first. For instance,
theorigin,
bb̄ spatial wavefunction, evaluated at the origin,
can be
!
!
" calculated from
2ee"
ee
2
3M
Υ
2
3M
Υ
|ψ(0, 0, 0)| =
(1)
, 0, 0)|2 =
Γee
(1) QED 2 Γee
16πα
2
16παQED
Cross
Section
Γ (2S)/Γ (1S) =0.461±0.008±0.003
Γ (3S)/Γ (1S) =0.318±0.007±0.002
Γ (3S)/Γ (2S) =0.690±0.019±0.006
because the two b quarks must fluctuate to the same ee
point in space before
ee annihilation [1].
givesin
us space
some idea
of the annihilation
width of the wavefunction
in space, and therefore the strength
ctuate to the sameThis
point
before
[1].
of theinforce
that and
bindstherefore
the two quarks.
h of the wavefunction
space,
the strength
Most importantly, Γee can test the newly “unquenched” lattice QCD calculations [2]
arks.
because it can be calculated to high accuracy (2–5%). This anticipated theoretical accuracy
t the newly “unquenched”
QCD
calculations
is better thanlattice
the current
experimental
precision[2]
of Γee (for the Υ(2S) and Υ(3S) at least), so
Jim
Napolitano
(CLEO-c)
a
new
set
of
high-precision
measurements
would
test
h accuracy (2–5%). This anticipated theoretical accuracy the7predictive power of the unquenched
Center of Mass Energy
Lattice 2005
Latest
+
Results: D→{π,K}e νe
+
e
W
D
A Key Measurement!
+
qµ
νe
• Needed to “climb the
{π,K}
ladder” to Vub
• Form factors are the
2
GF
!
!2 3
dΓ
!Vc{d,s}! p
=
{π,K}
2
3
dq
24π
!
!2
! {π,K} 2 !
(q )!
!f
Jim Napolitano (CLEO-c)
main uncertainties
• CLEO-c eventually
aims for precision
form factor results
8
Lattice 2005
The Need for Tagged D Mesons
D0→K−e+νe
800
Mid q2 Bin
C.L. = 52%
0.17
0.22
0
0.12
M (GeV)
0.22
You can make lots of D’s at
high energy, but they are
difficult to isolate cleanly.
0.32
3070404-004
2
Fraction of Events / 0.75 GeV
Recent result from CLEO-III
(e+e− annihilation at 10 GeV)
G.S. Huang, et al, PRL 94(2005)011802
200
400
0
0.12
3070404-003
Candidates / 4 MeV
Candidates / 2 MeV
1200
Mid q2 Bin
C.L. = 28%
D0→π−e+νe
Data
Quark mod.
MD*(s) pole
0.6
Light Cone SR
LQCD (APE)
LQCD (FNAL)
Small signal with lots of
different kinds of background.
ISGW2
0.4
Another excellent
opportunity for CLEO-c
0.2
0
0.75
1.50
1
0
q2 (GeV2)
Jim Napolitano (CLEO-c)
2
3
9
Lattice 2005
100
The signal
( c+→
)
D
10 π0e+νe
is cleanly
separated
5
from the
background 0
5
miss-cPmiss
( eU=E
)
200
20
150
15
100
10
Events / 10 MeV
Events / 10 MeV
Results (Preliminary)
0
50
0
15
50
(da+) →
)
(D
KSe+νe
1
1
50
5
00
0.25
0
0.25
15
-cPmiss
U =( cEU=E
Pmiss
(GeV)
)miss miss
10
4
3
Branching Ratios (%)
2
+ν
5
D→πe+νe
D→Ke
e
1
0
0
D+ 0.44±0.06±0.03
8.71±0.38±0.37
0.25
0
0.25 5
(e)
U
=
E
P
(GeV)
0
4
miss
miss
D 0.262±0.025±0.008
3.44±0.10±0.10
3
10
Jim Napolitano (CLEO-c)
Lattice 2005
2
More Results (Preliminary)
Values derived from branching ratio measurements
B(D0→π−e+νe) ⁄ B(D0→K−e+νe)=0.076±0.008±0.002
Γ(D0→K−e+νe) ⁄ Γ(D+→K0e+νe)=1.00±0.05±0.04
Γ(D0→π−e+νe)
⁄
2×Γ(D+→π0e+νe)=0.75
+0.14
−0.11 ±0.04
Form factor measurements are on the way.
Note: All these results based on 56 pb-1 data sample.
Jim Napolitano (CLEO-c)
11
Lattice 2005
Summary: Heavy quarkonium masses
All these results are based on non ψ(3770) running
•
• First observation of an ϒ(1D) state
• Observation of η and η' in the two photon
Observation of the 1P1 charmonium state hc
c
c
annihilation reaction
• New measurements of radiative transition
rates for ψ(2S)→γχcj and γηc
Jim Napolitano (CLEO-c)
12
Lattice 2005
Eve
M(
2.8
Observation of 1*P1 Charmonium
(h
c)
2.5
I
0140504-002
D1
DD Threshold
(Isospin
3
1
c S0
e+e
3500
π0 violating)
1
1
I
Mass (MeV)
3700
S
hc P1
1
0
γ
3300
2
3100
1
1
c S0
I
Several Modes
Jim Napolitano (CLEO-c)
1+
I
I
I
I
2900
1
4
Generic
MC
Data
( chc)
2
5
4
3
2
1
Exclusive and Inclusive average
e+e
0 +
6
Exclusive
0
3.40 3.46 3.52
M( 0 recoil) (GeV)
3
S
Events / 2 MeV
I
3
Events / 9 MeV
DD Threshold
3900
M(h )=3524.4±0.6±0.4 MeV
ΔMHF(1P)=1.0±0.6±0.4 MeV
0, 1, 2++ c
13
Lattice 2005
First observation of an ϒ(1D) state
3
1
10400 3 S 3 S1
0
Mass (MeV)
2 D2 2 DJ
13DJ
21P1
1
10000
3
1
23PJ
10200
2 S0
Events / 2.5 MeV
3 P1 3 PJ
1 D2
13PJ
11P1
9800
8
“Method #1”
6
4
2
0
1
23S1
(a)
10
2MB
3
1
Events / 1.0 MeV
43S1
10600
1630304-051
12
(b)
6
4
“Method #2”
2
0
10100
10125
10150
10175
Mass (MeV)
10200
9600
1
9400
1 S0
13S1
e+
+
M[ϒ(13D2)]=10161.1±0.6±1.6 MeV
e
Jim Napolitano (CLEO-c)
14
Lattice 2005
ηc and η'c
ψ(2S)→γχcj (and γηc)
1601203-016
70
CLEO II Data
60
Number of photons / 2% bin
Number of Events / 8 MeV
50
40
30
20
10
0
70
60
50
40
30
20
10
0
1630804-071
45000
CLEO III Data
35000
25000
15000
10000
5000
0
70 80
100
200
300
E (MeV)
2.6
2.8
3.0 3.2 3.4 3.6
M(K S K ) (GeV)
3.8
Yields E1 transition rates
with 5-7% uncertainties,
limited by systematics.
4.0
M(η'c)=3642.9±3.1±1.5 MeV
Jim Napolitano (CLEO-c)
15
Lattice 2005
The Future
Increased precision on D decays
•
Current data sample based on 280 pb-1
running at the ψ(3770)
• Precision so far is limited by statistics
• Expect ≈500 pb in the 2005/2006 run cycle
D production when we take data
• Additional
at higher energies for D sample
-1
S
uncertainties should come down
• Systematic
as we increase our statistical precision
Jim Napolitano (CLEO-c)
16
Lattice 2005
We thank the staff of the BEPC Acc
IHEP Computing Center for their effor
2
dersson
for helping in the developmen
S
1
generator. We also acknowledge usef
2
3
4
5
M. Davier, B. Pietrzyk, T. Sjöstrand,
Ecm (GeV)
e+e− Annihilation Cross Section
M. L. Swartz. We especially thank M
5
contributions not only to BES but als
(b)
R DSDS
D*SD*S
What
is theduring
cross
of the BEPC
the section
R scan. This
4
in part
by the National
for
producing
DS? Natural Scie
China under Contracts No. 19991480,
No. 19825116; the Chinese Academy
3
Contracts No. KJ95T-03, and No. E
*
Isbythere
a resonance?
D SDS
the Department
of Energy under
2
FG03-93ER40788 (Colorado State Un
3.8
4
4.2
4.4
4.6
AC03-76SF00515 (SLAC), No. DE
Ecm (GeV)
(University of Hawaii), No. DE-FG03
versity of Texas at Dallas), and by the
3. (a) A compilation of measurements of R in the
is set upofatKorea
CLEO
Move
ΔRrange from
and Technology
under Con
energy
1.4down
to 5 GeV. (b) R values from thisA run
(Korea).
iment in the resonance
by 140 region
MeV?between 3.7 and 4.6 GeV. thisI-03-037
August/September
to
R Value
Data taking for D decays
answer these questions
and to plan for next year.
02-4
ECM (GeV)
Jim Napolitano (CLEO-c)
17
Lattice 2005
Glueballs revisited
The final year of CLEO-c (2007/2008) was first proposed
for running at the J/ψ, for J/ψ→γ+glueball.
However the interpretation of the scalar mesons is now
murky, and the evidence for the tensor glueball has gone.
What are the most definitive statements that the lattice
can make about glueballs? Will mixing ever be calculable?
The CLEO-c collaboration is presently considering how
to configure the third year of running in light of all new
information. Any suggestions??
Jim Napolitano (CLEO-c)
18
Lattice 2005
CLEO-c and CLEO-III References
•
Improved Measurement of B(D+→μ+ν) and the Pseudoscalar
Decay Constant fD+, CLEO-CONF 05-5
•
Absolute Branching Fraction Measurements of Exclusive D0
Semileptonic Decays, CLNS 05/1906, hep-ex/0506052
•
Absolute Branching Fraction Measurements of Exclusive D+
Semileptonic Decays, CLNS 05/1915, hep-ex/0506053
•
Observation of the hc(1P1) State of Charmonium, CLNS 05/1919,
hep-ex/0505073
•
•
First Observation of a ϒ(1D) State, Phys.Rev.D70(2004)032001
•
Photon transitions in ψ(2S) Decays to χcJ(1P) and ηc(1S),
Phys.Rev.D70(2004)112002
Observation of η'c Production in γγ Fusion at CLEO,
Phys.Rev.Lett. 92(2004)142001
Jim Napolitano (CLEO-c)
19
Lattice 2005
Conclusion
Lots of CLEO-c physics is inspired by
confrontation with Lattice QCD.
Results from CLEO-c will continue
to come and precision will improve.
Hamilton
2005
Jim Napolitano (CLEO-c)
Our collaboration looks forward to
continued interactions with the
community of Lattice QCD.
Thank You!!
20
Lattice 2005