1 Updates on RICH analysis - High Field Runs Paweł Staszel Jagiellonian University

2 Why high field (3450) runs? 1. Spectra start at ~18GeV – well above the proton threshold, thus only geometrical effect plays a role. 2. Additional control of specie dependence by comparing A (less protons) and B (more protons) polarities. 3. Analysis is extremely easy: ineffic = veto/all 4. We can look at high field runs – the apposite case to low field runs where more complicated analysis utilizing tof2 is possible.

3 Inefficiency: 2A3450

4 Inefficiency vs d and dax: 2A3450 At small track separation (d ->0) inefficiency reaches value of 50% which means that one track (out of two tracks) is always lost. For dax it is only about 40%, because dax=0 might coincide with separation in day. Note, that for low filed settings analysis this representation would be very difficult due to low statistics of 2 track events. Low field analysis requires pion/kaon separation which is not in the full ax,p range. (d is not correlated with pid ability).

5 Inefficiency: 2B3450

6 Inefficiency (d and dax) : 2B3450

7 The rest of presentation documents results for other settings, namely: 3A3450, 3B3450, 4A3450 and 4B3450

8 Inefficiency: 3A3450

9 Inefficiency (d and dax) : 3A3450

10 Inefficiency: 3B3450

11 Inefficiency (d and dax) : 3B3450

12 Inefficiency: 4A3450

13 Inefficiency (d and dax) : 4A3450

14 Inefficiency: 4B3450

15 Inefficiency (d and dax) : 4B3450

16 Summary 1. For A polarity 2,3,4 deg setting are consistent showing averaged inefficiency from 2.5% to 3%. 2. For B polarity 2 and 3 deg are consistent (4.5-5%) but 4 deg. shows inefficiency on the level of 10%. Issues: a) is the 2% larger inefficiency for B polarity (is respect to A polarity) due to the larger contribution from protons??? b) how to explain the 10% inefficiency in 4B3450? Maybe some runs suffer from a bad rich performance? Has to be checked out. This is now fixed – discovered that two runs (10464 and 10465) have no signal in rich

17 Inefficiency (d_1 and d_2) : 2A3450