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BEGIN:VEVENT
SUMMARY:Seminar\, Yaoduo Wang (TDLI)
DTSTART;VALUE=DATE-TIME:20260716T043000Z
DTEND;VALUE=DATE-TIME:20260716T053000Z
UID:578785351489
DESCRIPTION:Title : Non-thermal Particle Production via Super-cooled Phase
  Transitions\n\nAbstract : We investigate non-thermal particle production 
 during first-order phase transitions in the presence of ultra-relativistic
  thick bubble walls with non-trivial internal structure. Extending the fra
 mework of bubble-expansion particle production\, we consider bubble walls 
 containing multiple ripples and study how such spatial modulations affect 
 the production of heavy particles coupled to the order parameter field. By
  modeling an oscillatory thick-wall profile\, we derive the transition pro
 bability for particle splitting processes in the wall background\, and ide
 ntify a new contribution associated with momentum transfer from the wall m
 icrostructure. In addition to the conventional channel\, we find an enhanc
 ed production mode arising from resonant momentum exchange with the ripple
 s. For sufficiently large numbers of ripples\, the new contribution can do
 minate the production rate and significantly increase the abundance of par
 ticles much heavier than the phase-transition scale. Our results demonstra
 te that the internal structure of expanding bubble walls can play an impor
 tant role in particle production and should be taken into account when ass
 essing the cosmological implications of strongly first-order phase transit
 ions.
LOCATION:721
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar\, Junxuan Xu (TDLI)
DTSTART;VALUE=DATE-TIME:20260723T043000Z
DTEND;VALUE=DATE-TIME:20260723T053000Z
UID:169747849415
DESCRIPTION:Seminar\, Junxuan Xu (TDLI)
LOCATION:721
END:VEVENT
BEGIN:VEVENT
SUMMARY:Seminar\, Ziwen Yin (TDLI)
DTSTART;VALUE=DATE-TIME:20260730T043000Z
DTEND;VALUE=DATE-TIME:20260730T053000Z
UID:127391149246
DESCRIPTION:Titile :\nProbe exotic energy injection from dark sectors thro
 ugh cosmic reionization\n\nAbstract :\nAxions and primordial black holes (
 PBHs) are well-motivated dark matter candidates that can inject energy int
 o the intergalactic medium (IGM) via decay or evaporation over cosmic hist
 ory\, leaving imprints on the cosmic microwave background (CMB). In recent
  work\, we have derived a model-independent ionization history after recom
 bination from CMB power spectra using a Gaussian process approach\, allowi
 ng new physics to be constrained directly from the high-redshift optical d
 epth. Applying this framework\, we investigate the decay of multi-string a
 xions and place the first constraints on the corresponding geometrical par
 ameter space. We also compute the redshift-dependent energy injection from
  Hawking evaporation using BlackHawk\, we obtain upper limits on the initi
 al PBH abundance that are robust against reionization modeling uncertainti
 es and systematically more conservative than existing bounds. Our results 
 demonstrate the power of reionization observables as a precise probe of PB
 H evaporation and other late-time energy-injection scenarios.
LOCATION:721
END:VEVENT
END:VCALENDAR