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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-3478
DTSTART:20140923T200000Z
DTEND:20140923T210000Z
DTSTAMP:20240319T051657Z
LAST-MODIFIED:20140920T222539Z
LOCATION:5280 Chamberlin Hall
SUMMARY:The Goldstone Exception: Spontaneously broken global symmetry
\, i.e. the Goldstone theorem\, protects the Higgs from a Fine Tuning
(FT) Problem\, Theory Seminar (High Energy/Cosmology)\, Bryan Lynn\, U
niversity College London and Case Western University
DESCRIPTION:More than four decades ago\, B.W. Lee and K. Symanzik prov
ed that\, in the O(4) Gell-Mann Levy (GML) model with Partially Conser
ved Axial-vector Currents (PCAC)\, global Ward Takahashi Identities (W
TI) force all Ultra-Violet Quadratic Divergences (UVQD) into the renor
malized pseudo Nambu-Goldstone-Boson (NGB) pion mass-squared. Tadpole
renormalization is un-necessary.
\n
\nWe prove (to all-orders
perturbations) that all UVQD\, together with all other relevant operat
ors\, therefore vanish identically in GML’s spontaneous symmetry bro
ken (SSB) Goldstone-mode\, where pions are true NGB (i.e. exactly mass
less). A weak-scale Higgs mass is natural in SSB GML\, the Higgs mass
and vacuum expectation value (VEV) are stable against quantum correcti
ons and not FT: SSB GML has no Higgs FT problem. Neither do the SSB O(
4) Schwinger model (PCAC=0) or the Standard Model (SM). No-Higgs-FT i
s simply another (albeit unfamiliar) consequence of WTI and the Goldst
one Theorem.
\n
\nA huge class of high-mass-scale (M_{Heavy}>>
m_{Higgs}) extensions of GML\, Schwinger and SM also demonstrate natur
alness\, no-FT and heavy particle decoupling. We display two examples:
a heavy (M_S >> m_{Higgs}) real scalar field\; and a right-handed Typ
e 1 See-Saw Majorana neutrino with M_R >> m_{Higgs}. We prove that for
|q^2| << M_{Heavy}^2\, the heavy degrees of freedom contribute only i
rrelevant and marginal operators. Phenomenological consequences includ
e the renewed possibility of thermal lepto-genesis in the neutrino-MSM
. It is also easy to construct no-Higgs-FT models with very high-scale
SUSY breaking.
\n
\nWe conjecture that\, since classical Gene
ral Relativity (GR) couples democratically to spin=0\, ½ and 1 quantu
m particles\, GR+SM (and maybe certain quantum gravity theories) will
also retain naturalness\, avoiding FT problems. Absent a SM FT problem
\, there should be no expectation that LHC14 will discover physics bey
ond the SM which is unrelated to neutrino mixing\, the only known expe
rimental failure of the SM.
URL:https://www.physics.wisc.edu/events/?id=3478
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