Dark matter-electron scattering and freeze-in scenarios in the light of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>Z</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>′</mml:mo> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> mediation

Abstract

We investigate dark matter (DM-)electron scattering in a minimal <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>U</a:mi> <a:mo stretchy="false">(</a:mo> <a:mn>1</a:mn> <a:msub> <a:mo stretchy="false">)</a:mo> <a:mi>X</a:mi> </a:msub> </a:math> extension of the Standard Model (SM), where the DM can appear as a Majorana fermion, a complex singlet scalar, or a Dirac fermion. To study bounds on the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi>U</e:mi> <e:mo stretchy="false">(</e:mo> <e:mn>1</e:mn> <e:msub> <e:mo stretchy="false">)</e:mo> <e:mi>X</e:mi> </e:msub> </e:math> gauge coupling <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mo stretchy="false">(</i:mo> <i:msub> <i:mi>g</i:mi> <i:mi>X</i:mi> </i:msub> <i:mo stretchy="false">)</i:mo> </i:math> and new gauge boson mass <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mo stretchy="false">(</m:mo> <m:msub> <m:mi>M</m:mi> <m:msup> <m:mi>Z</m:mi> <m:mo>′</m:mo> </m:msup> </m:msub> <m:mo stretchy="false">)</m:mo> </m:math> , from DM-electron scattering, we consider several direct search experiments like CDMS, DAMIC, SENSEI, PandaX-II, DarkSide-50, and XENON1T-S2 for different <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:mi>U</q:mi> <q:mo stretchy="false">(</q:mo> <q:mn>1</q:mn> <q:msub> <q:mo stretchy="false">)</q:mo> <q:mi>X</q:mi> </q:msub> </q:math> charges. In this setup, we consider DM production via freeze-in in both radiation-dominated and modified cosmological background to project sensitivities onto <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"> <u:msub> <u:mi>g</u:mi> <u:mi>X</u:mi> </u:msub> <u:mo>−</u:mo> <u:msub> <u:mi>M</u:mi> <u:msup> <u:mi>Z</u:mi> <u:mo>′</u:mo> </u:msup> </u:msub> </u:math> plane satisfying observed relic abundance. DM-electron scattering could provide comparable, or even stronger, bounds compared to those obtained from the electron/muon ( <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"> <w:mrow> <w:mi>g</w:mi> <w:mo>−</w:mo> <w:mn>2</w:mn> </w:mrow> </w:math> ), low-energy scattering, and intensity frontier experiments within <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"> <y:mrow> <y:mn>0.01</y:mn> <y:mtext> </y:mtext> <y:mtext> </y:mtext> <y:mi>GeV</y:mi> <y:mo>≲</y:mo> <y:msub> <y:mi>M</y:mi> <y:msup> <y:mi>Z</y:mi> <y:mo>′</y:mo> </y:msup> </y:msub> <y:mo>≲</y:mo> <y:mn>0.1</y:mn> <y:mtext> </y:mtext> <y:mtext> </y:mtext> <y:mi>GeV</y:mi> </y:mrow> </y:math> . Constrains from freeze-in could provide stronger sensitivities for <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"> <ab:msub> <ab:mi>M</ab:mi> <ab:msup> <ab:mi>Z</ab:mi> <ab:mo>′</ab:mo> </ab:msup> </ab:msub> <ab:mo>≳</ab:mo> <ab:mi mathvariant="script">O</ab:mi> <ab:mo stretchy="false">(</ab:mo> <ab:mn>1</ab:mn> <ab:mo stretchy="false">)</ab:mo> <ab:mtext> </ab:mtext> <ab:mtext> </ab:mtext> <ab:mi>GeV</ab:mi> </ab:math> ; however, these limits are comparable to those obtained from LHCb and LEP experiments for <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"> <fb:mrow> <fb:mi mathvariant="script">O</fb:mi> <fb:mo stretchy="false">(</fb:mo> <fb:mn>10</fb:mn> <fb:mo stretchy="false">)</fb:mo> <fb:mtext> </fb:mtext> <fb:mtext> </fb:mtext> <fb:mi>GeV</fb:mi> <fb:mo>≲</fb:mo> <fb:msub> <fb:mrow> <fb:mi>M</fb:mi> </fb:mrow> <fb:mrow> <fb:msup> <fb:mrow> <fb:mi>Z</fb:mi> </fb:mrow> <fb:mrow> <fb:mo>′</fb:mo> </fb:mrow> </fb:msup> </fb:mrow> </fb:msub> <fb:mo>≲</fb:mo> <fb:mn>150</fb:mn> <fb:mtext> </fb:mtext> <fb:mtext> </fb:mtext> <fb:mi>GeV</fb:mi> </fb:mrow> </fb:math> . In the future, electron-muon scattering (MUonE), proton (FASER and DUNE), and electron/positron (ILC) beam-dump experiments could probe these parameters. Published by the American Physical Society 2024

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