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Oleg Antipin "Revisiting the decoupling effects in the running of the Cosmological Constant"

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SEENET-MTP Balkan Workshop BW2018
10 - 14 June 2018, Niš, Serbia

Published in: Science
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Oleg Antipin "Revisiting the decoupling effects in the running of the Cosmological Constant"

  1. 1. BSW, Nis, June12, 2018 Revisiting the decoupling effects in the running Cosmological Constant Oleg Antipin (IRB, Zagreb) Based on: arxiv 1703.10967 in collaboration with Blazenka Melic
  2. 2. Outline • RG running of the Cosmological Constant • Case study: Standard Model • Applications • Conclusions
  3. 3. Vacuum energy density Induced vacuum energy density Experimentally measured value at Cosmological constant
  4. 4. Vacuum energy density Induced vacuum energy density Cosmological constant This represents “mathematical” scaling introduced during renormalization which sometimes can be used to trace the scaling dependence with a physical quantities The physical running (if there is at all) is not with µ but with some physical external momentum q or some dynamical property of the background metric, e.g. Hubble scale The physical scaling of the CC is unknown and we concentrate on its µ-dependence
  5. 5. But fine-tuning However CC experimentally measured value at need to RG run to this low scale taking into account decoupling of the heavy particles Cosmological constant problem
  6. 6. Decoupling effects On dimensional grounds and for Decoupling does not hold in the mass-independent schemes like MS-bar to analyze decoupling we need to work in a mass-dependent schemes Appelquist-Carazzone theorem
  7. 7. Cosmological Perspective ⇢⇤(H) = ⇢0 ⇤ + const ⇥ M2 P (H2 H2 0 ) + O(H4 ) Sola,Shapiro,…. Running vacuum models (subclass of dynamical vacuum models) Instead, our goal is to learn how CC problem can provide constraints on the particle physics models… µ = H The physical running of the CC (not derived from the first principles) and test it using current data…
  8. 8. Case study: Real scalar field One-loop effective potential: So far we had only classical parameters... now quantum Toy model :
  9. 9. Case study: Real scalar field Various pieces satisfy RG equations: - scheme
  10. 10. Vacuum and induced CC running Valid only in the UV regime !
  11. 11. Case study: Real scalar field in Need a mass-dependent scheme, but first :
  12. 12. Case study: Real scalar field in MOM
  13. 13. Vacuum and induced CC running in MOM Valid in the UV and IR regime !
  14. 14. Case study: Standard Model in
  15. 15. Valid in the UV regime only ! Case study: Standard Model in
  16. 16. Valid in the UV and IR regimes ! Case study: Standard Model in MOM
  17. 17. Applications : SM Responsible for CC tuningGoldstone terms canceled in the sum !
  18. 18. Applications: Massless theories generalized Veltman condition In massless models fine-tuning of Higgs mass and CC are linked
  19. 19. Massless theories : SM + real scalar One-loop induced (Coleman-Weinberg) Higgs mass: Example of how running of the CC may be connected to BSM physics prediction!
  20. 20. Applications: SM in constant curvature space
  21. 21. Conclusions • We considered the RG running of the Cosmological Constant • We showed that only RG running of the total (induced + vacuum) CC exhibits behaviour consistent with the decoupling theorem • We provided a simple extension of the SM with addition of one massless real scalar where condition of absence of leading RG effect allowed us to predict the radiative Higgs mass correctly • We also provided generalization to the constant curvature space
  22. 22. 018.irb.hr http://hvar2018.irb.hr The workshop aims at discussing the subject of asymptotic safety from both perturbative and non-perturbative perspectives, including modern developments in gravity and ordinary gauge theories.

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