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SUMMARY:Ultralight Dark Matter Background: Waking\, Shaking\, and Detectin
 g
DTSTART:20260915T110000Z
DTEND:20260915T120000Z
DTSTAMP:20260921T062000Z
UID:indico-event-5894@agenda.irmp.ucl.ac.be
DESCRIPTION:Speakers: Xucheng Gan (DESY)\n\nUltralight dark matter (ULDM) 
 that induces variations of fundamental constants is well motivated by a va
 riety of UV models and provides an excellent target for rapidly advancing 
 precision measurements. While linear interactions have been extensively st
 udied\, quadratic scalar couplings remain much less constrained and arise 
 naturally in many theories. Importantly\, they can generate qualitatively 
 new signatures through background-induced effects.\nIn this talk\, I will 
 introduce two major classes of background-induced effects: wake forces and
  oscillatory forces. For wake forces\, I will present a complete framework
  that unifies previous approaches developed for different regions of param
 eter space. I will then apply this framework to the MICROSCOPE satellite\,
  a leading space-based test of the equivalence principle. The Earth's scre
 ening effect redistributes the directional dark matter wind\, while the sa
 tellite's orbital motion modulates the resulting signal\, imprinting a cha
 racteristic frequency-band structure with annual modulation that provides 
 a distinctive fingerprint and substantially improves the sensitivity. For 
 oscillatory forces\, I will discuss two distinct signatures in gravitation
 al-wave observatories: a coherent signal at the second harmonic of the ULD
 M oscillation and a stochastic beat signal arising from interference among
  different ULDM modes. I will focus on pulsar timing arrays (PTAs)\, which
  currently provide leading sensitivity\, and the future flagship space-bas
 ed observatory\, the Laser Interferometer Space Antenna (LISA)\, where scr
 eening is absent. Together\, these two classes of background-induced effec
 ts provide complementary precision probes of quadratically coupled ultrali
 ght dark matter through late-Universe measurements.\nZoom: https://cern.z
 oom.us/j/62591938215?pwd=qSqjURfb693pfZR7aFvYR2vJw3YnuD.1 \n\nhttps://age
 nda.irmp.ucl.ac.be/event/5894/
LOCATION:E/3rd floor-E.349 - Seminar room (E.349) (Marc de Hemptinne (chem
 in du Cyclotron\, 2\, Louvain-la-Neuve))
URL:https://agenda.irmp.ucl.ac.be/event/5894/
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