[Isac-journal-club] Journal club paper for this week

[Ragnar Stroberg]

Hi all,
There's been a slight change of plan and so I'll be leading the journal
club discussion this Wednesday. The paper I've selected is

"Large-Scale Shell-Model Analysis of the Neutrinoless ββ Decay of 48Ca"
http://link.aps.org/doi/10.1103/PhysRevLett.116.112502


*Questions to help you along in your reading:*
1) Why is the neutrinoless double beta decay matrix element an interesting
thing to calculate?
2) What is the "new" thing that is done in this paper?
3) What is the difference between the (beautifully named) SDPFMU and
SDPFMU-DB interactions?
4) In simple language, what does it mean for an operator to be "quenched"?
5) What is their explanation for why they get the energy of the second 0+
in Ti48 wrong by 1MeV?
5) What is the main finding of the paper?


*Questions for discussion:*
1) Is the adjustment made to the interaction justified or is it
over-fitting?

2) Do they have a convincing handle on their theoretical uncertainties?

3) Should the 0vBB operator be quenched? If so, how will we know it was
done correctly?


*Jargon that's not explained because PRL has length limits:*
* 2hw excitation - In a harmonic oscillator basis, the energy to excite
from one major shell to another (in this case sd -> pf ), is equal to hw,
where w is the oscillator frequency. So exciting two particles will naively
cost 2hw of energy.
* Seniority - Like nucleons tend to form pairs with spin-parity 0+.
Seniority is the number of un-paired nucleons.
* Short range correlations (SRC) - Most realistic nuclear interactions are
strongly repulsive at short distances, and so the SRCs try to account for
this phenomenologically by suppressing the nucleon wave functions at short
relative distances.


Happy reading,

-Ragnar


-- 
Ragnar Stroberg
Postdoctoral research associate
Theory Department
TRIUMF
(604)-222-1047 x 6446
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.triumf.ca/pipermail/isac-journal-club/attachments/20160724/26d1a17a/attachment.html>