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SUMMARY:Gauge-Independent Gravitational Waves from a Minimal Dark U(1) Sec
 tor
DTSTART;VALUE=DATE-TIME:20260512T010000Z
DTEND;VALUE=DATE-TIME:20260512T020000Z
DTSTAMP;VALUE=DATE-TIME:20260521T004300Z
UID:indico-event-5000@indico-tdli.sjtu.edu.cn
DESCRIPTION:Speakers: Wan-Zhe Feng (Tianjin University)\n\nAbstract: First
 -order phase transitions in hidden gauge sectors can generate stochastic g
 ravitational wave backgrounds\, providing a powerful new probe of dark sec
 tor physics. In this talk\, I will present a gauge-independent analysis of
  gravitational waves from a minimal dark U(1) sector containing a dark Hig
 gs and a dark photon\, with the possible inclusion of a vectorlike dark fe
 rmion as a dark matter candidate. Particular emphasis will be placed on lo
 w-temperature phase transitions. By combining the Nielsen identity with a 
 controlled derivative expansion and gauge coupling power-counting framewor
 k\, one can construct a gauge-independent effective action in both the hig
 h-temperature and low-temperature regimes. This allows for robust predicti
 ons of bubble nucleation dynamics and the resulting gravitational wave sig
 nals. The results show that low-temperature phase transitions generally pr
 oduce stronger and more readily detectable gravitational wave signals. Our
  analysis provides a reliable and concrete prediction framework for gravit
 ational waves from the minimal U(1) dark sector. Biography: Dr. Wan-Zhe F
 eng is a tenured Associate Professor at the School of Science\, Tianjin Un
 iversity. He received his B.S. degree in physics from Peking University an
 d his Ph.D. degree in theoretical physics from Northeastern University in 
 the United States. He subsequently held postdoctoral positions at the Depa
 rtment of Physics and the Institute for Advanced Study at the Hong Kong Un
 iversity of Science and Technology\, the Max Planck Institute for Physics 
 in Munich\, and the Arnold Sommerfeld Center for Theoretical Physics at Lu
 dwig Maximilian University of Munich. He also held a visiting scientist po
 sition at Northeastern University. Dr. Feng joined Tianjin University in N
 ovember 2018.Following his early research in string theory during his Ph.D
 . and postdoctoral period\, Dr. Feng shifted his focus to particle physics
  phenomenology\, with particular emphasis on dark matter and dark sector d
 ynamics. His research has covered low-energy supersymmetry\, the origin of
  the matter-antimatter asymmetry\, Higgs physics\, flavor physics\, and ne
 utrino physics. His recent work focuses on the role of dark sector dynamic
 s in the cosmological evolution of dark matter\, as well as gravitational 
 waves from cosmological phase transitions. Online Link: Join Zoom Meeting
 https://umass-amherst.zoom.us/j/9432601370?pwd=V0d6dVUzT3NXaGxvWDBhekdhOFk
 5UT09&omn=93787572123Meeting ID: 943 260 1370Passcode: Saguaro\n\nhttps://
 indico-tdli.sjtu.edu.cn/event/5000/
URL:https://indico-tdli.sjtu.edu.cn/event/5000/
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