VACUUM STABILITY AND NEW PHYSICS · vacuum stability and new physics ... the future of our physics...
Transcript of VACUUM STABILITY AND NEW PHYSICS · vacuum stability and new physics ... the future of our physics...
VACUUM STABILITY
AND
NEW PHYSICS
Emanuele Messina
University of Catania
INFN Sez. di Catania
INTERNATIONAL SCHOOL OF SUBNUCLEAR PHYSICS 53° Course: THE FUTURE OF OUR PHYSICS INCLUDING NEW FRONTIERS
Erice, 24 June – 3 July 2015
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References:
V. Branchina, E. Messina, Phys. Rev. Lett. 111, 241801 (2013) (arXiv:1307.5193);
V. Branchina, arXiv:1405.7864, Moriond 2014;
V. Branchina, E. Messina, A. Platania, JHEP 1409 (2014) 182 (arXiv:1407.4112);
V. Branchina, E. Messina, M. Sher, Phys. Rev.D91 (2015) 1, 013003 (arXiv:1408.5302);
V. Branchina, E. Messina, in preparation;
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The vacuum is unstable !!
INSTABILITY
SM interactions only
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CRITICAL CONDITION
STABLE
CRITICAL LINE
‘UNSTABLE’
(SM interactions only)
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EW EW EW
Planck Scale
new physics
MESTABILITY SCENARIO
METASTABLE
CRITICAL LINE
UNSTABLE (tout-court)
ASSUMPTION: NEW PHYSICS AT HIGH ENERGY SCALES CAN NOT HAVE AN IMPACT ON THE EW
VACUUM STABILITY.
STABILITY MESTABILITY
but
INSTABILITY
Buttazzo, Degrassi, Giardino, Giudice, Sala, Salvio, Strumia, JHEP 1312 (2013) 089.
STABILITY DIAGRAM
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(?)
NEGLECTING NEW PHYSICS…
Euclidean equation of motion with O(4) symmetry
BOUNCE SOLUTION FOR THE
CENTRAL VALUES…
COMPUTATION OF τ
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METASTABLE
NEGLECTING NEW PHYSICS…
Classical degeneracy
broken by quantum fluctuations
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A TOY UV COMPLETION High energy
couplings
Integrate out heavy d.o.f.
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Impose threshold cond.
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THRESHOLD SCALE
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ADDING NEW PHYSICS (our approach)
SCALE INVARIANCE IS
BROKEN !!
NEW BOUNCE SOLUTION!!!!
DEPENDS ON THE
THRESHOLD SCALE
COMPUTATION OF τ
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UNSTABLE !!! (not universal)
Neglecting the effects of New
Physics ….
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To be compared with
Consider different Standard
Model extensions
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SUMMARY AND PERSPECTIVES
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THANK YOU
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Backup - Slides
IN FAVOR OF UNIVERSALITY
COMMON (AND INCORRECT) ARGUMENTS …
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BUT…
• QFT has an infinite number of d.o.f.
The Potential Energy is
• Vacuum - decay is a non-perturbative
phenomenon
ES. HIGGS DECAY
IS PERTURBATIVE
TUNNELING: NON - PERTURBATIVE
n. neighbour interactions
Tunneling in QFT like a
Nucleation process
FALSE
VACUUM TRUE
VACUUM
The transition
amplitude is
dominated by a non
local configuration
R
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WARNING 1: NEW PHYSICS IS NECESSARY (RESCUES THE POTENTIAL)
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