Paper Committee: Moneti(chair?), Danko, Ehrlich, Galik 1 OCT 21, 2006

History/Bibliography: Most germane previous CLEO publication: Direct Photon Spectrum from Upsilon(1S),Upsilon(2S) and Upsilon(3S) Decays Phys. Rev. D 74, (2006) Last plenary presentation by Shawn at Sept. meeting (almost No changes since. Conference paper:Measurement of Upper Limits for Upsilon to gamma + Resonance Decays, J. Rosner et al. Presented at 33rd International Conference on High Energy Physics, July 26- August 2, 2006, Moscow (ICHEP06) hep- ex/ CBX, Draft at Y_GammaRes_CBX.ps( or PDF), Y_GammaRes_PRD.ps( or PDF) Intended for PRD publication 2 OCT 21, 2006

3 OCT 21, 2006 Motivation  s extraction in gg analysis: Exp’t and theory assume a continuous direct photon spectrum in determining BR(Y—> gg )/BR(Y—> ggg) Two-body radiative  decays comprise a systematic uncertainty in gg analysis (“bumps” in gamma spectrum!) This is especially true near the kinematic end-point (x  ~ 1, low M  ). We DO see (small) Y—>  + f 2 (1270) Resonant enhancements could explain why estimates of  s from  decays are systematically lower than the world average

4 OCT 21, 2006 Look for a Resonance Signal Above suggests a search for   + ,   4 charged tracks using same hadronic event selection as published ggg analysis. A two-body radiative  decay will produce a monochromatic  in the lab frame, leading to ''bumps'' in the otherwise smooth predicted theoretical gg spectrum. Goal: try to determine upper limits on (narrow)resonance contribution to gg rate. Complication: bkg’d (ISR + hadron fakes) NOT subtracted

5 OCT 21, 2006 MC Example: BIG SIGNAL !

Brief Analysis Orientation Remember: XE/E beam, M(res) = 2E beam sqrt(1- X) For Y(1S), X = 0.2 means M ~ 1 GeV, (E) ~ 20MeV X= 0.9 means M ~ 4.3 GeV, (E) ~ 60MeV We can be largely sensitive to resonances of ~ this width or narrower. Fixed resolution at each X 1) step along X -spectrum in steps of 0.5 (E), taking a ± 10  range of X X in which to fit for gaussian signal on polynomial background; bin size is 0.2* 2) Extract Area, A(X )of gaussian at each step, plot. 6 OCT 21, 2006

Method (cont.) 3) Convert to upper limit contour with height=A(x  )+ 1.645* A (x  ) where  A (x  ) is the gaussian fit area sigma. 4) Negative points 1.645* A (x  ) 5) Study continuum data, too. Look for evidence of bumps common to Y(nS) and continuum. ''etc…? 6) apply estimate (conservative) of efficiency to give BR limits. 7) We use            efficiency and 0 - (or 0 + ) 1+cos 2  for  angular distribution. 8) re-plot with M R as abcissa 7 OCT 21, 2006

8 OCT 21, 2006 Y(1S)

Y(1S) binned vs. M R 9 OCT 21, 2006 

Efficiency corrected BR’s 10 OCT 21, 2006

Y(1S), scaled <Y(1S) comparison Correlated? ISR? 11 OCT 21, 2006

12 OCT 21, 2006 Monte Carlo Check Easy way to check procedure: input known *+,  4  MC signal at various sensitivities and check that which we reconstruct reliably. In this check, we construct all signals above our upper limit floor (~10 -4 ) within our accessible recoil mass range See Plot

13 OCT 21, 2006 if >BR then recovered MC with 10 embedded R’s

14 OCT 21, 2006 Our sensitivity is of order across all accessible values of M We measure for all M  : B ((1S)+,4 charged tracks) < 1.26 x B ((2S)+,4 charged tracks) < 9.16 x B ((3S)+,4 charged tracks) < 9.69 x B ((4S)+,4 charged tracks) < 1.21 x If more restrictive in M  1.5GeVM   5GeV we do better. Result Summary (1)

15 OCT 21, 2006 B ((1S)+,4 charged tracks) < 1.78 x B ((2S)+,4 charged tracks) < 1.95 x B ((3S)+,4 charged tracks) < 2.20 x B ((4S)+,4 charged tracks) < 5.34 x We report these upper limits as a function of recoiling mass M  B.R.’s are all ~10 -4 :unlikely to impact decays in gg analysis Result Summary (2)

Systematic Matters We currently assess the following systematics: Exclusive decay channel uncertainty: we take the worst correction imaginable Luminosity uncertainty: for continuum measurements, we assess a uniform 1% correction (determined in gg analysis) Total # events uncertainty: we take the total number of  events to be N events () -1 events Systematic fitting uncertainty: We bin our fitted spectra in 5 bins/signal width and use a 4 th order Chebyschev, based on studies of our procedure applied to continuum. No impact of polynomial order or binning. 16 OCT 21, 2006

17 OCT 21, 2006 Method (Efficiency Subtleties) To be conservative, 2 restrictions on the mode we obtain our M-dependent  correction function from: We only consider modes with 4 charged tracks in the final state (should have lowest ’s due to multiplicity cut) We take as our  the worst plausible We generate 5K events dedicated to each mode, and average the efficiency from 1.0 GeV < E  < 4.5 GeV (backup #1)

18 OCT 21, 2006 Efficiencies ( *+,  → ?) 60  2%460460 54  5%2p2  0 57  2%440440 65  2%4p  0 54  3%2  2K2  0 48  2%4K  0 57  2%2p2K2  0 60  2%4  0 63  5%2p2  2  0 53  3%2  2K 63  2%4p2  0 56  2% 2p2K 52  4% 6p 49  2%4K2  0 62  3%2p2  68  4% 6K 59  1%420420 67  2% 4p 74  3%66 53  2%2  2K  0 50  2% 4K 60  2%480480 50  5%2p2K  0 59  2%44 Worst  Phase Space High Mult.

19 OCT 21, 2006 Worst possible efficiency vs. E