Inclusive  Production at Y(1S) Sheldon Stone Jianchun Wang Syracuse University CLEO Meeting 09/13/02

Jianchun (JC) Wang2 Motivation  B (B  X) measurements with P  > 2 GeV, where background from b  c processes are suppressed:  CLEO: PRL 81,1786(1998),  BaBar:  A majority of events lie at large recoil mass (M>1.8 GeV).  Atwood & Soni proposed that the large  yield is associated with the gluonic content of the  via the sub-process b  s(g   g  ). The form factor remains constant up to q 2  m b 2 (momentum transfer of g  ). This explains the large recoil mass and large  yield ( B ~ 8  10  ).

09/13/02Jianchun (JC) Wang3 Motivation  Hou and Tseng suggest that  s be running and evaluated at the scale of momentum transfer through the gg  vertex, which introduces a mild logarithmic suppression (slowly falling):  The pQCD predicts that the leading form factor contribution falls like 1/q 2 (by Kagan & Petrov). The form factor can be parameterized as (pQCD):  KP also construct a purely phenomenological form factor for comparison (intermediate):

09/13/02Jianchun (JC) Wang4 Motivation  Y(1S)  gg(g   g  ): large overlap on the region of q 2 relevant for fast  production with that in b  s(g   g  ).  A. Kagan: “ the  spectrum in Y(1S) decay could potentially constrain the g  g  form factor, and at the same time tell us if the sub-process b  s(g   g  ) can account for the  yield in B decay”.  ARGUS measurement (w/o continuum subtraction) extracted by Kagan to be: n Z>0.7 < (6.5  1.3)  10 .  Model prediction:

09/13/02Jianchun (JC) Wang5 Reconstruction of  Photon:  E > 30 MeV  | cos  | <  E9/E25  Not fragment  Angcrt > 20  : (Mass constraint)  Multi-bump cut  Mass cut: –3.0  to 3.0  Track:  TNG approval  Good primary track  Impact point (0.005,0.03 for p>0.25, 0.01,0.05 for p<0.25)  3  dE/dX consistence  :  For Z<0.5,  veto on  photons      ( B =44.3%)  B =39.3%) Z = E  /E beam

09/13/02Jianchun (JC) Wang6 The     Invariant Mass Spectra a)Y(1S) data (~80 pb  ) : 1S1  3 (  10 6 Y(1S) ) b)Continuum data (~1200 pb  ): 4S2  7, E  G a)b) N = 1486  137N = 4062  174

09/13/02Jianchun (JC) Wang7 The     Invariant Mass Spectra Z > 0.7 a) b) N = 41  7N = 241  20

09/13/02Jianchun (JC) Wang8 Signal Sources  The sources of  production in 1S data:    qq   X:  ~ 4 nb 2)Y(1S)  qq   X:  ~ 2 nb 3)Y(1S)  ggg   X:  ~ 18 nb 4)Y(1S)  gg    X:  ~ 0.5 nb  Use qq and ggg generator respectively  The gg  is treated as ggg throughout the study

09/13/02Jianchun (JC) Wang9 Breakdown of Signal Events Number of Signal before efficiency correction

09/13/02Jianchun (JC) Wang10 Z Mapping for Continuum Data For continuum data, Z= E  /E beam is not good, it needs remapping Simple one: Linear with Z min (10.52)  Z min (9.46), 1  1 Sophisticated one: P4 fit

09/13/02Jianchun (JC) Wang11 Reconstruction Efficiency  Event shape is more spherical in 3g event:  3g /  qq,9.46 ~ 1.15  Event is more jetty at GeV:  qq,10.52 /  qq,9.46 ~ 0.93  Beam energy also affects  production: n qq,10.52 /n qq,9.46 ~ 1.07 No  vetoWith  veto

09/13/02Jianchun (JC) Wang12 Y(1S) data   ° veto applied for Z < 0.5.  Mass fixed to average over all Z.  Width determined from MC.

09/13/02Jianchun (JC) Wang13 Off-resonance data   ° veto applied for Z < 0.5.  Mass fixed to average over all Z.  Width determined from MC.

09/13/02Jianchun (JC) Wang14 Breakdown of Signal Events  The total number is the sum of small Z bins.  Z-dependent reconstruction efficiency used   120 Y(1S)  ggg,qq 21.5   11 Continuum qq 10.6   5 Y(1S)  qq 13.9   120 Y(1S)  ggg   130 Off-resonance 46.0   120 Y(1S) data Z > 0.7All Z Sample

09/13/02Jianchun (JC) Wang15 Branching Ratio  Inclusive branching fraction for All Z:  Inclusive branching fraction for Z > 0.7:  At 90% C.L. the upper limit of B (Y(1S)  (ggg)   X) / B (Y(1S)  (ggg)) for Z > 0.7 is 3.4    B (Y(1S)  X)  B (Y(1S)  (ggg)   X) / B (Y(1S)  (ggg))  B (Y(1S)  (qq)  X) / B (Y(1S)  (qq))  B (Y(1S)  X)   B (Y(1S)  (ggg)   X) / B (Y(1S)  (ggg))   B (Y(1S)  (qq)  X) / B (Y(1S)  (qq))  

09/13/02Jianchun (JC) Wang16 Systematic Errors Total systematic error   Z mapping   Y(1S)   Ratio of integrated luminosity  B (Y(1S)  qq)  B          Total number of Y(1S)  Number of  from fit  Reconstruction efficiency of   Reconstruction efficiency of   All othersqq Sampleggg Sample (Z>0.7) Sources

09/13/02Jianchun (JC) Wang17 The Differential Branching Fraction  Systematic errors are not shown ( ~ 10%).  Detailed study on excess at 0.6<Z<0.7 reveals no narrow structure (corresponding to 5.3 < M recoil < 6.1 GeV ). There could be more than one processes. ?!

09/13/02Jianchun (JC) Wang18 Comparison with Theoretical Predictions The measured dn/dZ spectrum of Y(1S)  (ggg)   X.  Theoretical predictions with a) A slowly falling form factor. b) A rapidly falling form factor. c) An intermediate form factor.  The measurement favors rapidly falling q2 dependence of the g*g  form factor predicted by pQCD.

09/13/02Jianchun (JC) Wang19 Summary  We measured the inclusive  production rate from Y(1S) data and ggg, qq samples.  Small B (Y(1S)  X) at high energy strongly favors rapidly falling q 2 dependence of the g  g  form factor predicted by pQCD.  CBX ready for comment.

09/13/02Jianchun (JC) Wang20 Z Spectra Generated Z redefined for GeV qq data

09/13/02Jianchun (JC) Wang21 Signal Reconstructed  ° veto applied for Z < 0.5

09/13/02Jianchun (JC) Wang22 Breakdown of Z Spectrum

09/13/02Jianchun (JC) Wang23 Cross-section and Branching Fraction  Sources: 1.PRD39, 3528 (1989), CLEO (muonic branching fractions at 1S and 3S).   (   (1S)  1.12 nb (by QED)   (Y(1S)  (0.555  0.022) nb   (Y(1S)  hadrons  (20.39  0.04) nb  Br(Y(1S)  0.07  0.07)%  2.PRD57, 1350 (1998), CLEO (hadron cross section at GeV).  R  3.56  0.01  PRD55, 5273(1997), CLEO (direct photon spectrum at 1S).   (Y(1S)  gg  )/  (Y(1S)  ggg)  (2.75  0.04  0.15)% 4.RPP2000.  Br (Y(1S)  )%  Br (Y(1S)  ee  0.11)%  Br (Y(1S)  0.06)%  Calculation here    qq)  (1.12  3.56)  (3.99  0.08) nb  (Y(1S)  qq)  (0.555  3.56)  (1.98  0.09) nb 3)Br(Y(1S)  qq)  (2.48  3.56)  (8.83  0.28)%  (Y(1S)  ggg/  )  (20.39  1.98)  (18.41  0.09) nb 5)Br(Y(1S)  ggg/   (Y(1S)  ggg)  (17.92  0.09) nb  (Y(1S)  gg  ( 0.49  0.03) nb