Dark matter annual modulation analysis with combined nuclear and electron recoil channels

After decades of experimental efforts, the DAMA/LIBRA(DL) annual modulation (AM) analysis on the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>χ</a:mi><a:mi mathvariant="normal">N</a:mi></a:math> (WIMP dark matter interactions on nucleus) channel remains the only one which can be interpreted as positive signatures. This has been refuted by numerous time-integrated (TI) and AM analysis. It has been shown that <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mi>χ</d:mi><d:mi mathvariant="normal">e</d:mi></d:math> (WIMP interactions with electrons) alone is not compatible with the DL AM data. We expand the investigations by performing an AM analysis with the addition of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>χ</g:mi><g:mi mathvariant="normal">e</g:mi></g:math> long-range and short-range interactions to <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mi>χ</j:mi><j:mi mathvariant="normal">N</j:mi></j:math>, derived using the frozen core approximation method. Two scenarios are considered, where the <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mi>χ</m:mi><m:mi mathvariant="normal">N</m:mi></m:math> and <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mi>χ</p:mi><p:mi mathvariant="normal">e</p:mi></p:math> processes are due to a single <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:mi>χ</s:mi></s:math> (<u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:mrow><u:msubsup><u:mrow><u:mi mathvariant="normal">Γ</u:mi></u:mrow><u:mrow><u:mi>tot</u:mi></u:mrow><u:mrow><u:mn>1</u:mn><u:mi>χ</u:mi></u:mrow></u:msubsup></u:mrow></u:math>) or two different <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:mi>χ</x:mi></x:math>’s (<z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"><z:mrow><z:msubsup><z:mrow><z:mi mathvariant="normal">Γ</z:mi></z:mrow><z:mrow><z:mi>tot</z:mi></z:mrow><z:mrow><z:mn>2</z:mn><z:mi>χ</z:mi></z:mrow></z:msubsup></z:mrow></z:math>). The combined fits with <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mi>χ</cb:mi><cb:mi mathvariant="normal">N</cb:mi></cb:math> and <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:mi>χ</fb:mi><fb:mi mathvariant="normal">e</fb:mi></fb:math> provide stronger significance to the DL AM data which are compatible with the presence of additional physical effects beyond <ib:math xmlns:ib="http://www.w3.org/1998/Math/MathML" display="inline"><ib:mi>χ</ib:mi><ib:mi mathvariant="normal">N</ib:mi></ib:math> alone. This is the first analysis which explores how <lb:math xmlns:lb="http://www.w3.org/1998/Math/MathML" display="inline"><lb:mi>χ</lb:mi><lb:mi mathvariant="normal">e</lb:mi></lb:math> AM can play a role in DL AM. The revised allowed regions as well as the exclusion contours from the other null AM experiments are presented. All DL AM allowed parameter spaces in <ob:math xmlns:ob="http://www.w3.org/1998/Math/MathML" display="inline"><ob:mi>χ</ob:mi><ob:mi mathvariant="normal">N</ob:mi></ob:math> and <rb:math xmlns:rb="http://www.w3.org/1998/Math/MathML" display="inline"><rb:mi>χ</rb:mi><rb:mi mathvariant="normal">e</rb:mi></rb:math> channels under both <ub:math xmlns:ub="http://www.w3.org/1998/Math/MathML" display="inline"><ub:mrow><ub:msubsup><ub:mrow><ub:mi mathvariant="normal">Γ</ub:mi></ub:mrow><ub:mrow><ub:mi>tot</ub:mi></ub:mrow><ub:mrow><ub:mn>1</ub:mn><ub:mi>χ</ub:mi></ub:mrow></ub:msubsup></ub:mrow></ub:math> and <xb:math xmlns:xb="http://www.w3.org/1998/Math/MathML" display="inline"><xb:mrow><xb:msubsup><xb:mrow><xb:mi mathvariant="normal">Γ</xb:mi></xb:mrow><xb:mrow><xb:mi>tot</xb:mi></xb:mrow><xb:mrow><xb:mn>2</xb:mn><xb:mi>χ</xb:mi></xb:mrow></xb:msubsup></xb:mrow></xb:math> are excluded at the 90% confidence level by the combined null AM results. It can be projected that DL-allowed parameter spaces from generic models with interactions induced by two-WIMPs are ruled out.