The Sextet Model Conformal Symmetry vs. Chiral Symmetry Breaking. Martin Hansen Claudio Pica, Vincent Drach, Ari Hietanen, Francesco Sannino

Transcription

1 The Sextet Model Conformal Symmetry vs. Chiral Symmetry Breaking Martin Hansen Claudio Pica, Vincent Drach, Ari Hietanen, Francesco Sannino

2 Outline Motivation Simulations Spectrum Mesons and baryons Chiral behavior Conformal symmetry Chiral symmetry breaking

3 Outline Motivation Simulations Spectrum Mesons and baryons Chiral behavior Conformal symmetry Chiral symmetry breaking PRELIMINARY

4 Motivation Minimally Walking Technicolor model Near the conformal window Possible walking behavior Might have a light scalar This would be the Higgs particle Small S parameter

5 Motivation Minimally Walking Technicolor model Near the conformal window Possible walking behavior Significance 3 0 Might have a light scalar arxiv: (b) This would be the Higgs particle Small S parameter Events / 00 GeV ATLAS - s = 8 TeV, 0.3 fb Data Background model.5 TeV Bulk G RS, k/m PI =.0 TeV Bulk G RS, k/m PI = Significance (stat) Significance (stat + syst) ZZ Selection 0 This class of models can explain the TeV ATLAS excess Significance [TeV] m jj (c)

6 Simulations Unimproved Wilson fermions Plaquette gauge action SU(3) gauge group Two flavors of sextet (-index symmetric) fermions

7 Simulations Phase space delineated on 4 lattice

8 Simulations β = different masses Lightest pion mass is am π = 0.3 β = different masses Lightest pion mass is am π = 0.4 Volumes are 4 3 x 40 or 3 3 x 48 Around 000 thermalized configurations per mass

9 Spectrum

10 Effective mass We extract the masses in two different ways Method : fit to constant plateau. 0.8 M EFF Time

11 Effective mass We extract the masses in two different ways Method : fit to decaying exponential. 0.8 M EFF Time

12 Baryons Young tableaux for sextet baryons (color) or = 3 The first tableau is a singlet =

13 Baryons Young tableaux for sextet baryons (flavor) = Two doublets and a quadruplet = 4

14 Baryons The quadruplet contains the spin-3/ particles h 3, 3 = uuu h 3, uud + udu + duu = p 3 h 3, ddu + dud + udd = p 3 h 3, 3 = ddd Two doublets contain the spin-/ particles h, = udd p dud h, udd + dud = duu h, = udu duu p h, = p 6 duu + udu uud p 6

15 Spectrum Meson and baryon spectrum for β = Mass Baryon 3/ 0.4 Baryon / Axial 0. Vector Pseudoscalar M PCAC

16 Spectrum Meson and baryon spectrum for β = Mass Baryon 3/ 0.4 Baryon / Axial 0. Vector Pseudoscalar M PCAC

17 Chiral behavior

18 Chiral behavior Conformal fits Chiral fits Leading order pion mass and log term

19 Chiral behavior Conformal fits Chiral fits Fixed in continuum Leading order pion mass and log term

20 Conformal fits Combined fit to 6 different channels FPS MPS FV MV MA MB=/ F PS M PCAC

21 Conformal fits Combined fit to 6 different channels FPS MPS FV MV MA MB=/ M PS M PCAC

22 Conformal fits Combined fit to 6 different channels FPS MPS FV MV MA MB=/ F V M PCAC

23 Conformal fits Combined fit to 6 different channels FPS MPS FV MV MA MB=/ M V M PCAC

24 Conformal fits Combined fit to 6 different channels FPS MPS.6.4 FV MV MA MB=/ M A M PCAC

25 Conformal fits Combined fit to 6 different channels FPS MPS FV MV MA MB=/ χ /dofs =.8 /.3 dofs = γ = 0.9 / 0.3 M B M PCAC

26 Chiral fits Fit at NLO with free logs F PS 0.3 M PS M PCAC M PCAC χ /dofs = 3.5 dofs = 6

27 Chiral fits Fit at NNLO with continuum logs F PS 0.3 M PS NNLO NLO LO M PCAC 0. NNLO NLO M PCAC χ /dofs = 3.8 dofs = 4

28 Conformal or not? The results for β = 5.5 show similar behavior Both ChPT and Conformal fits can work We need lighter masses Things to consider includes: Scalar mass Renormalization constants Scale setting Spectrum of dirac operator

29 Thank you!

30 Backup slides

31 Topological freezing For light masses topological freezing is a problem 8 6 Q m 0 = MDU Q m 0 = MDU

32 Topological freezing Effect on observables m V m PS f V f PS 0.35 Observable Q

33 Mass ratios Ratio MV/MPS for β = 3.0 (left) and β = 5.4 (right).5.4. M V /M PS.3.. M V /M PS M PCAC M PCAC

34 Baryon effective mass Effective mass for heavy (left) and light (right) baryon 3 M EFF Time M EFF Time