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Recent Charmonium Results from Ψ(2S) Decays at BESII. Changzheng YUAN IHEP, Beijing for the BES Collaboration. 2nd International Workshop on Heavy Quarkonium Sept. 20 – 22, 2003, Fermilab. BESII obtained 14 M (2S) events. Study of V T channels

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Recent Charmonium Results from Ψ(2S) Decays at BESII

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Recent charmonium results from 2s decays at besii

Recent Charmonium Results from Ψ(2S) Decays at BESII

Changzheng YUAN

IHEP, Beijing

for the BES Collaboration

2nd International Workshop on Heavy Quarkonium

Sept. 20 – 22, 2003, Fermilab


Recent charmonium results from 2s decays at besii

BESII obtained14 M

(2S) events

  • Study of V T channels

    inΨ(2S) decay

  • First observation of

    K0S K0LinΨ(2S) decay (and improved analysis of J/  K0S K0L )

  • First evidence of

      in cJ decay

14

1.5

01.11-02.3


Recent charmonium results from 2s decays at besii

pQCD rule and “ puzzle”

  • pQCD rule

    [the relation between J/ and (2S) ]

  • Violation was revealed by MARK-II ,

    confirmed by BES at higher sensitivity


Recent charmonium results from 2s decays at besii

VT Channel

  • BES-I results [PRL81(1998)5080]

    [PRD67(2003)052002]

† This value from DM2 only

12 % rule ( pQCD rule )

Suppressed!!


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

 f2

 

+–0 +–

+–+–0

 

 a2

  

 

 

+–+–0

 

Ψ(2S)

K* K*2

 

K K

K+K– + –

 f2'

 

K+K– KK

K+K–K +K –


Recent charmonium results from 2s decays at besii

Event Selection

Ψ(2S)  V T

  • Four charged tracks with net charge zero;

  • |cosθ|<0.80 for all tracks;

  • PartID using TOF+dE/dx

  • At least 2 photon candidates for π0 channels;

  • Remove ψ(2S) π﹢π﹣J/ψ background;

  • Kinematic fit (4C/5C), Prob>0.01.

χ2KF of ψ(2S) 5 π

Data/MC


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

M.C.

Data

B.G.(  )

f2 (1270)

B.G.(M.C.)


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

Data

M.C.

a2 (1320)

B.G.


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

Data

M.C.

K*(892)

K*2 (1430)

B.G.


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

M.C.

Data

f2'(1525)

f0(980)

B.G.


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

Systematic Errors (%)

*NO evidence of continuum production according to

study with a 6 pb-1 data sample at Ecm=3.65GeV.


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  V T

† This value from DM2 only

12 % rule ( pQCD rule )

Suppressed!!


Recent charmonium results from 2s decays at besii

Ψ(2S)  KS KL

Theoretical Background

  • pQCD rule & Phase Study

B(2S) Ks K L

Phase


Recent charmonium results from 2s decays at besii

Ψ(2S)  KS KL

The Relative Phase

J/ψ Decays:

1. AP: 90 ° M. Suzuki, PRD63, 054021 (2001)

2. VP: (106 ±10) ° J. Jousset et al., PRD41, 1389 (1990)

D. Coffman et al., PRD38, 2695 (1988)

N. N. Achasov, talk at Hadron2001

3. PP: (90 ±10) ° M. Suzuki, PRD60, 051501 (1999)

4. VV: (138 ±37) ° L. Köpke and N. Wermes,

Phys. Rep. 74, 67 (1989)

5. NN: (89 ±15) ° R. Baldini et al., PLB444, 111 (1998)

ψ(2S)VP

1. φ=180 °(90 ° ruled out!)

M. Suzuki, PRD63, 054021 (2001)

2. φ=﹣90 ° or φ=180 °(with continuum amplitude)

P. Wang, C. Z. Yuan and X. H. Mo, hep-ph/0303144.


Recent charmonium results from 2s decays at besii

Ψ(2S)  KS KL

The Relative Phase

Ψ(2S)  Pseudoscalar Pseudoscalar

A’ (π﹢π﹣) and

A’+B’ (K﹢K﹣) known,

KS KLis needed to extract

the phase

between A’ and B’.

φ


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  KS KL

–

+

–

+

–

+

KL


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  KS KL

  • Two Good charged tracks with net charge zero ;

  • Decay length in transverse plane greater than 1.0 cm for KS ID;

  • Total Energy of photon candidates less than 1 GeV.


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  KS KL

14M ψ(2S)

Bkg

MC

signal

Ks mass sidebands


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  KS KL

Systematic Errors

Lxy

Eγtot

cosθ

VC

trigger


Recent charmonium results from 2s decays at besii

BES Preliminary

Ψ(2S)  KS KL


Recent charmonium results from 2s decays at besii

BES Preliminary

J/Ψ  KS KL

58M J/ψ

signal

MC Bkg

K*0KS+c.c.

Ks mass sidebands


Recent charmonium results from 2s decays at besii

BES Preliminary

J/Ψ  KS KL

~4σ diff.

PDG2002: BJ/ Ks K L = ( 1.08 ± 0.14)10 – 4


Recent charmonium results from 2s decays at besii

J/Ψ , Ψ(2S)  KS KL

B(2S) Ks K L= (5.25± 0.45± 0.63 )  10 – 5

BJ/ Ks K L = (1.86 ± 0.04± 0.14 )  10 – 4

Ψ(2S) enhanced!


Recent charmonium results from 2s decays at besii

B ((2S) KS KL )

=5.2510 – 5

Ψ(2S)  KS KL

K+K– & +

 inputs ;

Input 1:DASP;

Input 2:BESI ;

Input 3: K+K–

from BESI &

+ by form

factor.

PLB567 (2003)73

–80°

120 °


Com for cj b b bar

COM for cJB B-bar

  • B(cJ pp-bar) fromBES, PRL81, 3091 (1998);

  • E760, NPB373, 35 (1992); R704, PLBB172, 455 (1986)

  • Nucleon wave function at small Q2:

J.Bolz, P. Kroll, Z. Phys. A356, 327 (1996)

J.Bolz, P. Kroll, Eur. Phys. J. C2, 454 (1998)

For each s quark,

introduces

S. M. Wong, Eur. Phys. J. C14, 643 (2000)


Event selection

Event Selection

Final states: γπ+π-pp-bar

γ


Signal in p mass

Λ signal in πp mass

Monte

Carlo

Data

Clear

Λ Λ-bar

Signal


Cj signal

cJ Signal

Data/Monte Carlo

χc2

χc1

χc0


Really

Really ΛΛ?

Yes!

we have p/p-bar!

Yes!

we have

long decay

length!


Remaining backgrounds

Remaining backgrounds

Monte Carlo Simulation:

Monte Carlo prediction

and a best fit


Fit the mass spectrum

Fit the mass spectrum

MC efficiencies

χc1

χc2

χc0

ΛΛ-bar Mass (GeV)


Number of 2s events

Number of ψ(2S) events

To achieve

high precision

&

cancel out

systematic bias

=14.9(1±8%)M


Systematic errors

Systematic Errors

Extensive

Comparison

Between

Data and

Monte Carlo

Simulation!

(Thanks for

The Large

Data sample!)

~20%!


Recent charmonium results from 2s decays at besii

– 3.1

– 3.4

– 4.0

–1.2

–0.9

–1.3

PRD67, 112001 (2003)


Recent charmonium results from 2s decays at besii

Eur. Phys. J. C 14, 643–671

–1.2

–0.9

–1.3

* The results on c1 and c2 decays only agree

marginally with model predictions.

* No prediction for c0 .


Discussions

Discussions

Checked with BESII data,

no serious discrepancy!

  • B(χcJp p-bar)?

    NO!

  • COM?

    Possible!

    Hints from other

    experiments!

  • wave functions?

    Possible!

    Need other

    experiment test!

E866

BELLE


Recent charmonium results from 2s decays at besii

Summary

  • Ψ(2S) VT channels f2 ,  a2 , K* K*2 and  f2'

    are first observed and branching ratios measured.

    The suppression of VT is confirmed.

  • First observation of K0S K0Lin Ψ(2S) decay.

    Improved measurement of J/ψ K0S K0L .

    Ψ(2S) is enhanced relative to 12% rule.

    The phase for ψ(2S) PP is ﹣80°or 120°.

  • First evidence of   in cJ decay .

    Results disagree with

    “COM+baryon wave function” calculation.

  • More results expected from BESIIΨ(2S) sample.


Recent charmonium results from 2s decays at besii

Thanks a lot !

谢谢!


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