TY - JOUR

T1 - Loop effects in direct detection

AU - Bell, Nicole F.

AU - Busoni, Giorgio

AU - Sanderson, Isaac W.

N1 - Publisher Copyright:
© 2018 IOP Publishing Ltd and Sissa Medialab.

PY - 2018/8/13

Y1 - 2018/8/13

N2 - We consider loop level contributions to dark matter - nucleon scattering in cases where the spin independent scattering cross section is absent or suppressed at tree level. In the case of a pseudoscalar interaction, for which the tree level cross section is both spin-dependent and suppressed by 4 powers of the exchanged momentum, loop diagrams give rise to a non-zero spin independent cross section. We show that if the pseudoscalar interaction is formulated using a gauge invariant framework, loop effects generate an effective χ h vertex and result in a scattering cross section that is within reach of current or forthcoming experiments. We also consider the case of inelastic dark matter, for which the dominant interaction terms have an off diagonal χ1-χ2 structure. In this case, the tree-level direct detection cross section is negligible when the inelastic χ1 N → χ2 N process is kinematically suppressed. However, loop diagrams generate a diagonal χ1-χ1 interaction and hence permit measurable, spin independent, χ1 N → χ1 N elastic scattering. As such, we are able to probe parameter space that was previously considered inaccessible to direct detection.

AB - We consider loop level contributions to dark matter - nucleon scattering in cases where the spin independent scattering cross section is absent or suppressed at tree level. In the case of a pseudoscalar interaction, for which the tree level cross section is both spin-dependent and suppressed by 4 powers of the exchanged momentum, loop diagrams give rise to a non-zero spin independent cross section. We show that if the pseudoscalar interaction is formulated using a gauge invariant framework, loop effects generate an effective χ h vertex and result in a scattering cross section that is within reach of current or forthcoming experiments. We also consider the case of inelastic dark matter, for which the dominant interaction terms have an off diagonal χ1-χ2 structure. In this case, the tree-level direct detection cross section is negligible when the inelastic χ1 N → χ2 N process is kinematically suppressed. However, loop diagrams generate a diagonal χ1-χ1 interaction and hence permit measurable, spin independent, χ1 N → χ1 N elastic scattering. As such, we are able to probe parameter space that was previously considered inaccessible to direct detection.

KW - dark matter experiments

KW - dark matter theory

UR - http://www.scopus.com/inward/record.url?scp=85053013207&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2018/08/017

DO - 10.1088/1475-7516/2018/08/017

M3 - Article

SN - 1475-7516

VL - 2018

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

IS - 8

M1 - 017

ER -