19/09/22 meeting

To do list (based on discussions in meeting)

Item	Theory or exp input	Notes

Item	Theory or exp input	Notes
Section 2
Detector response	Exp	Include threshold, efficiency, QF, resolution (and recommendation for how they should be modelled)
Energy range/region/binning	Exp	Discuss possibility of unbinned analysis?
Mass and geometry description	Exp	All detectors (crys, LS, muons)
Section 3
Toy energy spectrums	Exp (Maddy)	Test with low and high mass spin dependent and independent, as well as a vel dep model
Interesting/physical velocity dep model	Theory (Ciaran)	Which EFT operator will demonstrate largest dependence/change on vel dist
Section 4
Methodology and assumptions for produced limit plot	Theory (Dipan)	e.g., energy ROI, background model for SABRE etc
Inclusion of DAMA in limit plot	Theory (Dipan)	If possible
Investiage crystal effects noted by DAMA and CUORE	Theory (Dipan?)	Try to understand if there are paradigms that would relax the Xe limits
Simulations of MIDM-like events	Exp	Want to redo existing plots w/ the updates to geant4
PMT characterisation	Exp	Currently planned, and should be done in November-ish
LS characterisation	Exp	Need to know realistic energy thresholds (this can be fed a bit by sims)
Section 5
Simulations of the decay process in SABRE	Exp	Ideally need more info about the exact signal, e.g., energy and direction of produced e-e+ pairs
Include summary/description of process in overleaf doc	Theory (Xuangong)	How the signal is generated, what it looks like, how we would assess sensitivity
Section 6
Input CSL limits in overleaf doc	Exp (Francesco)
Description of PEP processes	Theory (Cedric)

Meeting details

Zoom: https://unimelb.zoom.us/j/952735561?pwd=S2JQTmpqaUVLZEwzUnZiR2RiWWhBUT09

p/w: 271311

Section 2: Experimental overview

Authors:

Done to date:

Assessment of relevance: Useful to provide a citable, single source of truth for theorists who might want to conduct studies with SABRE or SABRE-like setups.

To do/open questions: Most existing experimental overview/description (background paper, TDR) are more engineering focused (dimension, material etc.). Should this focus more on things relevant for physics test, e.g., backgrounds, thresholds, resolutions for all the detector components?

Section 3: Dark matter halo

Authors: Ciaran and Maddy

Done to date: Theoretical overview of annual modulation and various halo models, brief description of how target choice impacts sensitivity to modulation fraction.

Assessment of relevance: Can make basic arguments for model independent mass restrictions based on a positive or negative modulation. This can then also be used to make predictions as to what other complementary experiments should see in modulation searches.

To do/open questions:

Compute basic model energy spectrums at SABRE

Impact of changing velocity distribution

Given time constraints, are there certain distributions or DM models that are better motivated than others? In theory, the biggests changes we would get are for velocity dependent form factors, but are these physical? Otherwise may just consider spin independent, dependent, and then either EFT operator 5 or 7 to show the basic effects.

Section 4: Low energy DM

Authors: Matt (Dolan), Irene, Lindsey

Low velocity Dark Matter - single interaction (Dipan and Irene):

Done to date:

The plot below shows a raw estimate of Sabre sensitivity to axions taking into account SABRE South final mass (50 kg) and 3 years of data taking.

“Cosine-full” line has been calculated by rescaling the Cosine one reported in the paper for all the months of data taking.

Assessment of relevance:

SABRE is not more competitive than Cosine since the full mass and the years of data taking play an important role in the model. SABRE background is lower than Cosine but it is not able to compensate the higher data taking period and the overall mass.

To do/open questions:

Xenon 1T and Xenon nT have not published their results below 1 keV; thus it is not possible to make a guess because the detector and background levels below 1 keV.
SABRE North can be taken into account to increase the mass in the model but they probably don't have an updated background model and this will lead to delays paper.
Verify the final mass of Cosine (106 kg vs approx. 60 kg).

Multiply Interacting Dark Matter

Done to date: Assessment of potential sensitivity is outlined here: Multiply-interacting Dark Matter .

Assessment of relevance: Owing to our large veto we may set competitive limits for a MIDM search, depending on the liquid scintillator light yield (veto threshold) and the veto PMT dark count rate.

To do/open questions:

Measurements of the dark count rate in the veto PMTs are due by November 2022 – these will permit better estimates of the background rates for a MIDM search.
MIDM requires a challenging trigger condition, which the SABRE trigger may or may not be able to continuously accommodate. The trigger condition is noted in our plans here: https://darkmatteraustralia.atlassian.net/wiki/spaces/SABRE/pages/1489829889
Simulations of MIDM ‘tracks’ in the veto. If the optical photon propagation time << MIDM crossing time then we can probably get away with using a Geant4-produced map of the photon detection efficiency in the veto. These simulations may help refine what a signal event looks like (beyond N-fold coincidence of veto PMTs within veto crossing time), and could be used to define more detailed limit calculations.

Section 5: Boosted DM

Authors: Xuangong and Matt (Gerathy)

Done to date:

Assessment of relevance:

To do/open questions:

Section 6: QM tests

Authors: Ray and Francesco

Done to date: Overview of continuous spontaneous localisation models and how it can be tested.

Assessment of relevance:

To do/open questions: Existing experimental bounds and projected SABRE sensitivity.