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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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UID:UW-Physics-Event-3876
DTSTART:20151215T213000Z
DTEND:20151215T223000Z
DTSTAMP:20260419T051712Z
LAST-MODIFIED:20151214T135332Z
LOCATION:5280 Chamberlin
SUMMARY:Raymond Stora's last discovery: Hidden U(1)_Y symmetry and new
  Ward-Takahashi identities in the Abelian Higgs model\, Theory Seminar
  (High Energy/Cosmology)\, Bryan Lynn\, Visiting Professor
DESCRIPTION: The SSB AHM (the gauge theory of a scalar ϕ∝(H+iπ) an
 d a transverse vector A) has a massless pseudo-scalar π in Lorenz gau
 ge. Physical states have a conserved global current and Goldstone theo
 rem (GT)\, but no global charge. π contains a Nambu-Goldstone boson (
 NGB). Slavnov-Taylor identities force on-shell T-matrix elements to be
  independent of anomaly-free gauge\, and global\, U(1) transformations
 \, yielding towers of ϕ-sector Ward-Takahashi IDs (WTI)\, which sever
 ely constrain the dynamics\, and the effective potential\, of external
  ϕ. Ultraviolet quadratic divergences (UVQD) contribute only to the p
 seudo-NGB mass\, forced by the GT to 0 in the SSB mode\, so all UVQD v
 anish. Weak-scale renormalized gauge-independent Higgs pole-mass and V
 EV are therefore not technical-fine-tuned. The NGB is "eaten" and deco
 uples as usual\, hiding the U(1) WTI from observable particle physics.
  Our regularization-scheme-independent all-loop-orders results are unc
 hanged by the addition of certain heavy matter fields\, as the WTI and
  GT cause all relevant operators to vanish. We prove 5 new SSB decoupl
 ing theorems\, illustrating them with two examples: a Heavy (>>Weak) Z
 2-symmetric singlet real scalar field with 0 VEV\; and a heavy singlet
  right-handed type 1 see-saw Majorana neutrino. Including all loops we
  prove that these\, and certain other heavy degrees of freedom\, decou
 ple from the low-energy effective Lagrangian\, contributing only irrel
 evant operators. The NGB again decouples\, but our hidden SSB U(1) WTI
 \, and the resultant NGB shift symmetry\, protect the low-energy SSB A
 HM physics from loop contributions of heavy particles! Gauge-independe
 nt observable weak-scale Higgs pole mass and VEV <H> are not technical
 -fine-tuned.
URL:https://www.physics.wisc.edu/events/?id=3876
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