BEGIN:VCALENDAR VERSION:2.0 PRODID:-//chikkutakku.com//RDFCal 1.0//EN X-WR-CALDESC:GoogleカレンダーやiCalendar形式情報を共有シェ アしましょう。近所のイベントから全国のイベントま で今日のイベント検索やスケジュールを決めるならち っくたっく X-WR-CALNAME:ちっくたっく X-WR-TIMEZONE:UTC 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