Two Photon Physics at Belle Augustine E. Chen BELLE Collaboration National Central University June 6, 2006 Charm 2006

Two Photon Physics   R  hh   hh R :  c,  c0,  c2 … DKV, BL, BC No tag events J = 2 or 0

   hadron pair ( e.g.  +  -, K+K-,..)   CMS W   or W : E cm (  ) or Mass(hh) Cos   : production angle of h hadron pair at  CMS

Status of    hh hh Int L [fb -1 ] W [GeV]  +  PLB 615, 2005  K+K- 883 – 4 PLB 615, 2005 PP PLB 621, 2005 DD PRL 96, 2006 KsKs P hoton05 [preli.]  /  4642 – 4 in progress

   K+K- analysis   Pt (K+K-)

Invariant Masses of K+K- or 

Cos θ* (W : 2.4 – 4.0 GeV) K+K-/  +  - sin -4   (theory)

Cross Sections of K+K- and  Theory  = a*W -6 (solid lines) N = 7.3± 0.3 ± 1.5 N = 7.9± 0.4± 1.5

Ks sample for KsKs analysis

Invariant Mass (KsKs ) 981 events χ c0  KsKs 164 ± 14 events χ c2  KsKs 44 ± 7 events

Cross Section of KsKs  (W) = a*W -n N = 9.9 ± 0.4 DKV: Diehl, Kroll, Vogt BL: Brodsky, Lepage BC: Benayoun,Chernyak Naïve prediction of  (KsKS)/  (K+K-) ~ 2/25

Invariant Masses of DD & New Resonance DºDº (K-  +, K-  +  º, K-  +  -  +) D+D- (K-  +  +) D+D- + DºDº

Invariant Mass (DD) and Cos  New resonance Z(3930) J = 2 Candidate of χ’ c2 state

Widths of   charmonia  meson pairs Process Γ  B (eV) Z(3930)  DD 180 ± 50 ± 30 PRL (2006) χ c0   15.1± 2.1 ± 2.3 PLB (2005) χ c2   0.76±0.14±0.11 PLB (2005) χ c0  K  K  14.3± 1.6 ± 2.3 PLB (2005) χ c2  K  K  0.44±0.11±0.07 PLB (2005) χ c0  KsKs 7.07±0.61±0.62 Photon2005(priliminary) χ c2  KsKs 0.30±0.05±0.03 Photon2005(priliminary) PDG   (χ c0 ) = 2.6±0.5 KeV   (χ c2 ) = 0.52±0.07 KeV

Cross Section of PP (36,094 events)  (W) = a*W -n (89 fb -1 )

Cos  * (PP) GeV GeV GeV

 c  pp  c (1S)  pp 157 ± 33 events

   analysis  P t (  inclusive )  º  p   º   º  (~100%) E  = 74 MeV

Invariant Mass (1628  candidates)

 c   (MC simulation)

Invariant Mass (1628  candidates)

Invariant Mass (  as      DATA )

Widths of    c  Baryon pairs Process N Γ  B (eV)  c   103 ± ± 1.1 (preli.)  c   32 ± ± 2.3 (preli.)  c  pp 157 ± ± 1.5 PDG   (  c ) = 7.4±2.6 KeV

Cross Sections of  and  (very preliminary)

Summary Γ  ->R Br (R  hh) for charmonia and for different spices of hadron pairs are measured. Studies of total cross section  (W) and cos  * distributions over a W range of 2-4 GeV reveal their dynamical variations. These need further investigation of how QCD calculation transits from low energy to high energy. Two photon processes have demonstrated to be an excellent test bed for QCD, with help of high luminosity provided by KEKB. Belle has collected 0.6 ab -1, we expect more two-photon physics results are to come.

   M(P-  +) vs M(P+  -)

        M(    ) vs M(    )

Ratio of  (KsKs)/  (K+K-) DKV: Diehl, Kroll, Vogt BL: Brodsky, Lepage BC: Benayoun,Chernyank

Transition between Charmonium states χ c2  J/ , J/   ll Γ  B (eV) = 13.5 ± 1.5 (33 fb-1) Belle colla. PLB 540, 33 (2002) 4 hadrons final states Proceedings of HEP2005 (Lisbon)