x. c. lou, snowmass 20011 charm physics potentials at b-factories xinchou lou, university of texas...
Post on 15-Jan-2016
215 Views
Preview:
TRANSCRIPT
X. C. Lou, Snowmass 2001 1
Charm Physics Potentials at B-factories
XinChou Lou, University of Texas at Dallas
• Introduction
• Physics Topics: branching fractions, leptonic decays, mixing
• Extrapolations from CLEO-B• Initial State Radiation Production of Charm
Events at B-Factories• Measurements with ISR Charm at B-factories
• Summary
0 0D D
X. C. Lou, Snowmass 2001 2
Introduction
• BaBar projection 32 fb-1 by end of August 2001
~400 fb-1 by end of 2004
• CLEO-c plan Data-taking in Spring 2003 around charm thresholds, a few fb-1
Physics soon after
• Super B-factory after 2010?
Look at physics of BaBar and CLEO-c in near term Super B-factory longer term
X. C. Lou, Snowmass 2001 3
CLEO-B Extrapolations
0 * *
0 * *
0
0
( )
( )
s
s
s tag
tag s
B D D
B D D
N
ND
D D
D
• Leptonic Ds decays, fDs 4.8 fb-1
CLEO, PRD 58,032002(1998)
• Method
current fDs=(280 29 28 34) MeV
(7stat10sys 12B)%
with 400 fb-1 (<1 (3-6) 2)% (4-7)%
main sys. error: PID, tracking
Model Dependent
• 2.5 fb-1 clns95-1387
current (21.5stat13.4sys)%=24%
main sys. errors: random and eff.BR
with 400 fb-1 (1.73)%3.5%
main sys. Error: tracking
Model Dependent
( )sB D
*
*
( )
( )
s s
s s
N D D
N D D
X. C. Lou, Snowmass 2001 4
CLEO-B Extrapolations
• 4.7 fb-1
CLEO, PRD 62,072005(2000)
• methods: , B-decays, SL/Lifetime
current B=(5.0 0.5 0.12)%
(10stat15 12 8 8 5)%
main sys. errors: p tag, modeling, Dp bkg,
c/D spectra, c /D ID
with 400 fb-1 (1.1 (2-5) 2)% (3-6)%
main sys. error: same as above, tracking
Model Dependent
• 1.79 fb-1
CLEO PRL 72, 2328 (1994)
continuum data
with measured
current (3.25.4 5.0)%8.6%
main sys. errors: R+, eff., B(D0K)
with 400 fb-1 (21.5 1.5)%3%
main errors: R+, eff., B(D0K)
Model Dependent
( )B D K
0
0
*
*
( )
( )K
KN D D
N D D
* 0
* 02.21 0.07
( )( )D D
RD D
BB
( )cB pK
|
|
([ ] )( )
cN p DN p D
X. C. Lou, Snowmass 2001 5
CLEO-B Extrapolations
• Mixing 9 fb-1 CLEO Conf 01-1
Standard Model 10-8, Beyond SM 10-(3-4)
Method
current best limits (5-9)10-3 (E791, ALEPH)
Sentivity with 400 fb-1 data: for rmix (BaBar Phys. Book)
0 0D D
0
0
*
*
( )(
( ( )
)
)K
KN D D
N D D
t
t
Mode rD
(10-3)
rW
(10-3)
N0
(106)
Sensivity
(10-4)
K 7.2 1.5 2.6 1.3
K 2.5 1.5 3.1 0.8
K0 2.8 1.5 5.8 0.6
0
45
D Wr reN
X. C. Lou, Snowmass 2001 6
The ISR Method at B-factories
M. Benayoun et. al.
Spectroscopy at B-factories Using
Hard Photon Emission
Modern Phys. Lett. A Vol. 14,
No. 37, 2605-2614 (1999)
form factors, R scan, Upsilon states
X. C. Lou and W. Dunwoodie
Physics with ISR Events Produced
at B-factory Experiments
Presented at Hadron 99, Sept, 1999
Nucl. Phys. A675, 253 (2000)
charmed hadrons, charmonia, exotics
X. C. Lou, Snowmass 2001 7
Production of Charm near Thresholds via ISR
• ISR production cross section
ISR = 0
1 f(s,k)(s´)dk J. P. Alexander et. al. SLAC-PUB-450
• Narrow resonance approximation
(s´) = (3/s´) ee0 .
( s´-MR)2+02/4
Example: e+e- (2S) ISR=13.3 1.1 pb
provides a way to determine leptonic width ee
X. C. Lou, Snowmass 2001 8
Observation of ISR (2S) signal by BABAR (8.9fb-1)
208 ±15 events
M()-M() (GeV) M() (GeV)
events
Momentum (GeV) Fitted Momentum (GeV)
DPF 2000
X. C. Lou, Snowmass 2001 9
Estimate of ISR Charm Rates
Production interact.
(GeV)
fraction of sampling fun.
cross-section(Coupled-channel
model)
produced events in 400
fb-1 of data (1000)
(all) 3.94 4.33 0.00167 ~1 nb ~670
(charged + neutral) 4.0 4.6 0.00273 ~6 nb ~6,000
4.57 5.09 0.00284 ~0.4 nb ~450
J/(2S)
~3.096
~3.767
~38 pb
~13 pb
15,200
5,200
* 4.6D D GeV
c c c Dp
s
s s sD D D DK
Source: J. M. Izen, W. Dundoodie, X. C. Lou, MKIII
( )e e e e X
X. C. Lou, Snowmass 2001 10
Estimate of ISR Signal Events
Decays
Produced events in 400 fb-1 of data (1000)
B.R.Det. Eff.
(%)
Events reconstructed
Relative
stat. error (%)
Super
B-factory ?
(%)
Ds branching fraction
~670 0.024 163
8 0.8
Ds leptonic decays
~670 0.039
260
4.5
(fDs)
0.5 ?
(fDs)
D+
leptonic decay
~2,800 0.001 40
16 1-2
~2,800 0.22 6,230
~1.3 ~0.1-0.2
c branching fraction
~450 0.025 112 ~9 ~1
J/(2S)
leptonic width
15,200
5,200
0.3
0.067
45600
3,500
0.5
1.7
0.05
0.2
| KD
Source: J. M. Izen, X. C. Lou
X. C. Lou, Snowmass 2001 11
Charm Cross-sections near Thresholds
all Dtotal 6 nb
all Dstotal 1 nb
all ctotal 0.4 nb MKIII
X. C. Lou, Snowmass 2001 12
Summary
• Much improved charm measurements with CLEO methods and 400 fb-1 of data around Upsilon(4S) B.R. measurements will be systematics limited
• New ISR technique brings potentials for B-factory experiments
charm physics before CLEO-c turns out physics results
continuous e+e- data below Upsilon(4S) over all
• The ISR approach at a Super B-factory may enable exploration
of physics between 10 > s > 0 GeV at ~1033 cm-2•s-1
s
top related