1 Review of the n-H analysis Zelimir Djurcic (ANL) Pau Novella (APC/CNRS)

2 Overview Analysis is good enough for a publication whose goal is to demonstrate that we can search for  13 with H captures. Several comments and concerns have been already addressed in latest version of the tech notes (see next slides). Typos and minor issues have also been fixed. There are still some open issues which are being addressed (marked in red in next slides).

3 Chapter 2: ν selection The justification of the neutrino selection cuts used to be very poor in previous versions. The rationale for each one of the cuts has been added/extended in the latest version, although claiming the cut values are not optimized. Optimizing the cuts might take few months. We think this is good enough for the scope of the first paper.

4 Chapter 3: Detection efficiency Some clarification on how the systematics were computed in DC2ndPub needs to be done, as current description is not accurate.  Kazu is addressing this Some references were missing, but they are in place now:  Study of the correlation among the selection cuts (DocDB 3667).  dedicated note for the Spill In/out study (DocDB 4156).  appendix about the LN cuts inefficiency.

H capture fraction in Target: analysis was not clear, and used to describe techniques not actually used in the H analysis.  It has been re-written: the DC2ndPub value is assumed. H capture fraction in GC: sample used, so there might be contamination nGd captures in the target  A dedicated study shows negligible effect (added to tech note).  Bernd agreed to perform a new x-check with 252Cf: dT>200ms. 5

6 Chapter 4: Detector systematics Further x-checks on E scale systematics?  Conservative approach: outer most GC calibration data point, where the data-MC discrepancy is biggest  Work in parallel (not a stopper for the paper) in some BiPo/B12 x-check to prove the current approach is actually conservative –planned to study Bi-Po and Boron-12 for the 2nd publication involving n-H

7 Chapter 6: 9 Li Some justification about why the Li9-reduced cut is not used is missing in the note  Will be added, although there may be no case for this cut The Li9 rate analysis depends deeply on the MC. Has the MC been validated somehow?  Same approach as in DC2ndPub, which yiels compatible results with official rate x-check "a la DC2ndPub", i.e., using only the DT and not the MC:  Analysis by Michi yields compatible Li9 rate (DocDB 4314)  Results from 4 different analysis are consistent within errors

IV tracking efficiency taken into account somehow, but not described in the tech note:  Some description will be added. A systematic in the Li9 rate accounts for the Off-time subtraction: difference in the rate w/ and w/o subtraction. The systematic can't be that large if the subtraction needs to be done for sure.  As Off-time subtraction is delicate, this approach is adopted as a very conservative one  The contribution of this systematic to the overall error in the rate is small 8

9 Spill In/Out tech note spill events might affect the shape of the prompt energy in n selection  Bernd is addressing this (1st approach: negligible, as in Gd) The way in which the efficiency systematics are computed does not seem to be robust. Artifacts like the "Safety factors" need to be avoided.  Bernd and Kazu are currently working on this The method used to compute the overall detection efficiency and systematics (by combining the volume classes) may depend on the MC model. Different models might predict different ratios of events among the different volume classes in spill regions. This should be accounted for.  Bernd and Kazu are currently working on this