Expanding W region to elastic (hsdelta<8% to hsdelta<12%) caused slope around elastic peak and a peak around 1.1 GeV. It looked like the small shift of W can solve the problem, because the dilution factor peak is not exactly consistent with elastic peak. But W shifts cannot solve it.

A180_72999_73041_no_W_shift.gif
A180_72999_73041_m5MeV_W_shift.gif
A180_72999_73041_m10MeV_W_shift.gif
A180_72999_73041_m15MeV_W_shift.gif

The peak at 1.1 GeV is like an island. The evolution of the peak is the following:

A_raw_72999_73041.gif
A_PbPt_72999_73041.gif
A_PbPtdf_72999_73041.gif

The dilution factor of this region is relatively small and it makes small fluctuation bigger.

df_73014.gif

Probably, the Monte Carlo result does not match data well in this region. There is big fluctuation of ratio of data to MC, even though stable W ~ 1.2GeV region has been selected for packing fraction.

Wdamc_73014_pf58.50_full.gif

Applying HMS tracking efficiency shows no good sign.