Transcript Document 7518289

 Decays at CLEO
Steve Blusk
Syracuse University
for the CLEO Collaboration
Preview
 Introduction
 Measurements of B((nS)  m+m- )
 Electric Dipole Transitions
 (1S)  ( c c ) + X
 Summary
ICHEP’04, Beijing, China Aug 16-22,2004
Bottomonium
CLEO III
n2S+1LJ
J=L+S
 1-- (bb) states couple to virtual photon
Spin-orbit
3 P 3 P
J
0,1,2
 (1S)- (3S) too light to form B mesons
ggg and qq decays dominant, but suppressed.
Hyperfine
(spin-spin) splitting
 States are narrow !
 EM and hadronic transitions to
lower-lying bb states competitive
 (4S)BB; Weak Int. Physics
JPC
Photon Transitions
E1: |DL|=1, DS=0:   E3 | n f L f | R | n f L f |2
M1: DL=0, |DS|=1:   ( E3 / mb2 ) | n f L f | R | n f L f |2
 E1 >> M1
Detector & Data Samples
Analyses presented here make
extensive use of the excellent CsI
calorimeter, tracking and muon
systems
106
(1S)
30
25
20
CsI:
6144 crystals (barrel only):
sE/E ~ 4% at 100 MeV
~2.5% at 1 GeV
Tracking
CleoIII/c
CleoII
CUSB/CBAL
15
10
5
0
(3S)
(2S)
Measurement of B((nS)m+m- )
ICHEP ABS10-0774
 Goal: Extract tot.of (nS) .
 tot << dEbeam  cannot be extracted by scanning the resonance.
 Use: tot= ee / Bee = ee / Bmm
where Bll=B((nS)m+m-); (assumes lepton universality)
 B((nS)m+m- ) also important for (nS) EM & hadronic BF’s.
 We actually measure: Bmm  mm / had  N( nS )mm / N( nS )hadrons
 Which is related to Bmm by: Bmm  Bmm /(1 + 3Bmm )
(nS)m+m- Event Selection
 Exactly 2 back-to-back oppositely charged muons
 < 2 showers with E>50 MeV
(nS)m+m- efficiency: (65.2±0.2)%
(nS)hadrons Event Selection
 >2 charged tracks
 For Ntrk<5:
(Ecc> 0.15Ecm) & (Ecc<0.75Ecm or Eshmax<Ebeam)
 Evisible > 0.2Ecm
(nS)hadrons efficiency: (97-98)%
Background dominated by cascade decays:
e.g. (2S) (1S) 00/  
(2S) : (2.9±1.5)%
(3S) : (2.2±0.7)%
(2S) Data
Nsh  2
Nsh < 2
(2S)m+m-
(2S)(1S)X,
(1S)m+m-
Mmm/Ebeam
Results
(1S)
(2S)
(3S)
Nmm
344,908 ± 2485
119588 ± 1837
81179 ± 2660
mm
0.652 ± 0.002
0.652 ± 0.002
0.652 ± 0.002
Nhad
18,957,575 ± 11729
7,838,270 ± 8803
4,641,369 ± 12645
had
0.979 ± 0.016
0.965 ± 0.013
0.975 ± .014
Interference corr.
0.984
0.961
0.982
Bmm (%)
2.49  0.02  0.07
2.03  0.03  0.08
2.39  0.07  0.10
tot (keV)
52.8 ± 1.8
29.0 ± 1.6
20.3 ± 2.1
PDG tot (keV)
53.0 ± 1.5
43.0 ± 6.0
26.3 ± 3.4
(1S) mm in good
agreement with previous
measurements
(2S), (3S) mm
significantly larger than
current world average
values
B(%)
B(%)
B(%)
C. Davies, et al, PRL 92. 022001 (2004)
Electromagnetic
Transitions
Aim is to get precision measurements of masses and transition rates.
Tests of LQCD & effective theories, such as potential models or NRQCD.
 We present results on Inclusive Analyses of E1 transitions:
 (2S)cbJ(1P)
 (3S)cbJ(1,2P)
 Can be used to extract E1 matrix elements and extract relative importance of
spin-orbit and tensor interactions.
Inclusive
(2S)cbJ(1P)


Raw
Preliminary
e+e-
Background
m+msubtracted
(2S) 
Branching
Fraction (%)
Photon energy
(MeV)
 cb0(1P)
3.750.120.47
162.560.190.42
 cb1(1P)
6.930.120.41
129.580.090.29
 cb2(1P)
7.240.110.40
110.580.080.30
Dominant Systematics
B: Shower Simulation & Fitting
E: Calorimeter calibration
Inclusive
(3S)cbJ(1,2P)

(3S)cbJ(2P)
(3S)cbJ(1P)
(3S)  cb(1P0) 
(3S)  cb(1P2)  +
(3S)  cb(1P1)  +
cb(1PJ)  (1S) 
(1DJ)cb(1Pj) 
(2S)cb(1PJ) 
50
100
E(MeV)
200
Preliminary
E(MeV)
(3S)
Branching
Fraction (%)
Photon energy
(MeV)
 cb0(2P)
6.770.200.65
121.550.160.46
 cb1(2P)
14.540.180.73
99.150.070.25
 cb2(2P)
15.790.170.73
86.040.060.27
 cb0(1P)
0.300.040.10
-
Summary of (2S) cbJ(1P) Results (Preliminary)
(2S)cb(1P2)
(2S)cb(1P1)
(2S)cb(1P0)
E
B
r
mc2 - mc1
mc1 - mc0
 0.57  0.01  0.01
Gives quantitative information on the relative
importance of spin-orbit & tensor forces
Summary of (3S) cbJ(2P) Results (Preliminary)
(3S)cb(2P1)
(3S)cb(2P2)
E
B
r
mc2 - mc1
mc1 - mc0
 0.58  0.01  0.01
(3S)cb(2P0)
Charmonium Production in (1S) Decay
ICHEP ABS10-0773
 History:
CDF observes J/y, y(2S) ~10x, 50x too large.
 Braaten & Fleming propose color-octet (CO) mechanism; J/y produced perturbatively in CO state
and radiates a soft-gluon (non-perturbatively) to become a color-singlet (CS); <ME> fit to data.
 Problems though: J/y polarization data from CDF, e+e-J/y+X from BaBar & Belle, J/y at HERA .
Suggestion by Cheung, Keung, & Yuan: If CO is important, the glue-rich decays of  should provide
an excellent labortatory for studying the role of the CO mechanism in y production.
 Distinct signatures in J/y momentum spectrum (peaking near endpoint).
Li, Xie & Wang show that the Y(1S)J/y+ccg may also be important (2 charm pairs)
Li, Xie & Wang,
PLB 482, 65 (2000)
B((1S)J/y+X)
Momentum Spectrum
6.2x10-4
Soft
Cheung, Keung & Yuan,
PRD 54 929 (1996)
5.9x10-4
Hard
Previous CLEO measurement based on ~20 J/ymm events: B=(11±4)x10-4
Event Selection & Signals
 Data Sample: 21.2x106 (1S) decays
 Reconstruct J/ym+m-, e+e Backgrounds:
 Radiative return: suppressed through Ntrk, Emax, and Pevmiss requirements
 Radiative Bhabha (ee only): veto events where either electron can form M(e+e-)<100 MeV.
 ccJ: Negligible after Ntrk and Pevmiss requirements.
 e+e-J/y+X continuum: Estimated using U(4S) data and subtracted.
 Efficiencies: ~40% (~50%) for J/ymm (J/yee); small dependence on momentum, cosq
(1S)J/y+X
e+e-J/y+X below Y(4S)
(1S)J/y+X
Continuum Background
BaBar
s(e+e-J/y+X)=1.9±0.2(stat) pb
BaBar: s(e+e-J/y+X)=2.52±0.21±0.21 pb,
PRL87, 162002 (2001)
+
Belle: s(e e J/y+X)=1.47±0.10±0.13 pb,
PRL88, 052001 (2002)
B((1S)J/y+X)=(6.4±0.4±0.6)x10-4
Normalization to (1S) Data
* Luminosity ratio
*s
9.46 GeV
e + e -  J /y + X
/s
10.56 GeV
e + e -  J /y + X
 (10.56 / 9.46)
* Phase space ratio: 0.78±0.13
2
 Spectrum much softer than CO prediction
 Somewhat softer than CS prediction
 Very different from continuum
First Observations/Evidence
(1S)y(2S)+X
(1S)ccJ+X
(4S) Continuum
B( (1S )  y (2S ) + X )
 0.41  0.11  0.08
B( (1S )  J / y + X )
CO & CS both predict ~20%
B( (1S )  c c 2 + X )
 0.52  0.12  0.09
B( (1S )  J / y + X )
B( (1S )  c c1 + X )
 0.35  0.08  0.06
B( (1S )  J / y + X )
B( (1S )  c c 0 + X )
 7.4
B( (1S )  J / y + X )
cc1, cc2 BF’s ~2x CO prediction
Summary
CLEO has the world’s largest sample of (1S),  (2S), and (3S)
data sets
Precision measurements in (bb) spectroscopy (rates, masses) provides
a unique laboratory for probing QCD.
 Glue-rich environment is ideal for studying color-octet predictions
Recent work also includes:
 Searches/limits for M1 transitions (hb)
 First observation of a (1D) state (first new (bb) state in 20 years!)
 Measurements of new hadronic transitions (e.g., cb1,2(2P)w(1S))
 Searches for anomalous couplings
Many other interesting topics are in the pipeline
 Exclusive 2 and 4 transitions in (3S) decays
 New measurements of ee for (1S), (2S), (3S)
 (1S,2S,3S)Open Charm
 (1S) r, K*K, etc (“r puzzle”)
 Searches for LFV
…
Backup Slides
The Physics
The (1S)- (3S) resonances are the QCD analogy of positronium
- bb are bound by the QCD potential: Coulomb-like behavior
from 1-g exchange
e.g. V(r)= – 4/3 s/r + kr
Long distance
behavior, confining
k~1 GeV/fm
Large b quark mass  (v/c)2 ~ 0.1  non-relativistic to 0th order
(In some models, relativistic corrections added to non-relativistic
predictions)
In much the same way that positronium allowed for a greater
understanding of QED, the masses, splittings between states and
the transition rates provide input into understanding QCD.
Tests of lattice QCD Important for flavor physics !
Test of effective theories, such as QCD potential models
Electric Dipole Transitions
In the non-relativistic limit, the E1 matrix element
is spin independent.
4
E1 (ni S  n f P )  eQ2 (2 J + 1) E3 n f P r ni S
27
2
After normalizing out the (2J+1)E3 between
different J’s, we obtain:
cb(2P):
(J=2) / (J=1)
(J=0) / (J=1)
(J=0) / (J=2)
1.000.010.05
0.760.020.07
0.760.020.09
cb(1P):
(J=2) / (J=1)
(J=0) / (J=1)
(J=0) / (J=2)
1.010.020.08
0.820.020.06
0.810.020.11
cc(1P):
(J=2) / (J=1)
(J=0) / (J=1)
(J=0) / (J=2)
1.500.020.05
0.860.010.06
0.590.010.05
 In NR bb system, (v/c)2~ 0.1  expect ratios ~ 1
 NR corrections O(<20%) for J=0
 Also shown are (cc), which show sizeable
differences (v/c)2~0.3; mixing between
23S1and 13D1 states may also contribute.
Using: E1=B(niSnfP)tot((nS))
We can extract
Uses new
CLEO tot
values
n f P | r | ni S
Comparison with various models
o = predictions (non-relativistic)
▲ = spin-averaged predictions (relativistic)
y

time
 Relativistic corrections needed for (cc)
 In (bb) system, NR calculations in
reasonable agreement with data.
Spin-Orbit & Tensor Interactions
Responsible for splitting the P states 3PJ
Can express:
MJ=2 = Mcog + aLS - 0.4aT
MJ=1 = Mcog - aLS + 2aT
MJ=0 = Mcog - 2aLS - 4aT
where
Spin-Orbit Coeff. aLS 
Tensor Coeff.
aT 
1
1 d
nP
|
(2V2 - 0.5V0 ) | nP
mb2
R dR
1
nP | V3 | nP
12mb2
V0= static potential; V2,3= spin-dependent potentials
(both model-dependent)
Data on mass-splittings can be used to extract aLS and aT,
 Experimentally, the mass splittings are most precisely determined using
r
mc2 - mc1
mc1 - mc0
CLEO3
CLEO2
r (1P)
0.570.010.01
0.540.020.02
r (2P)
0.580.010.01
0.570.010.01
Our results indicate that there is no difference between the
different radial excitations of the P waves in (bb) system.
Search for hb in
(3S)  hb(1S)  and (2S)  hb(1S) 
(2S)  hb(1S) 
U(2S) Data
(3S)  hb(1S) 
U(3S) Data

Hindered (ninf) M1
transition suppressed by
1/mb2
Large differences among
models
cb(1PJ)  (1S) 
(2S)  hb(1S) 
cb(2PJ)  (1S) 
(3S)  hb(1S) 
(3S)  hb(2S) 
CUSBII(PRD46,1928(1992)) vs CLEOIII
£(3S)~200/pb
~10% (poor segmentation of calorimeter)
£(3S)~1300/pb
~60%
Also it seems that they had worse energy resolution.
We are very surprised that they claimed comparable accuracy to ours.
(3S)  cb(2PJ) 
e+e-J/y+X using on Y(4S) Data,
pJ/y>2 GeV
Y(1S) & Y(4S) Overlayed