The Higgs Particle and the Lattice KMI 2013 Julius Kuti University - PowerPoint PPT Presentation

The Higgs Particle and the Lattice KMI 2013 Julius Kuti University of California, San Diego KMI International Symposium 2013 Nagoya, December 11-13, 2013 1

Outline Lattice BSM after the Higgs discovery Light Higgs near conformality light scalar (dilaton-like?) close to conformal window EW precision and S-parameter scale setting and spectroscopy Running coupling running (walking?) coupling from gradient flow Chiral condensate new stochastic method for spectral density near-conformal sextet theory large anomalous dimension Early universe EW phase transition dark matter Summary and Outlook

Large Hadron Collider - CERN primary mission: - Search for Higgs particle - Origin of Electroweak symmetry breaking • A Higgs-like particle is found Is it the Standard Model Higgs? or • Near-conformal strong dynamics? • Composite PNGB-like Higgs? • SUSY? • 5 Dim? ... Primary focus of BSM lattice effort and this talk 3

LATTICE GAUGE THEORIES AT THE ENERGY FRONTIER Thomas Appelquist, Richard Brower, Simon Catterall, George Fleming, Joel Giedt, Anna Hasenfratz, Julius Kuti, Ethan Neil, and David Schaich (USQCD Collaboration) (Dated: March 10, 2013) USQCD BSM White Paper - community based effort input into US Snowmass 2013 planning: ++ correlators Triplet and singlet masses from 0 M t/s = a t/s + b t/s m (fitting functions) � =3.2 32 3 × 64 USQCD and the composite Higgs at the Energy Frontier 0.6 triplet and singlet masses F = 0.0279 (4) setting the EWSB scale The recent discovery of the Higgs-like particle at 126 GeV is the beginning of the experimental 0.5 M H /F ~ 1 − 3 range search for a deeper dynamical explanation of electroweak symmetry breaking beyond the Standard 0.4 Model (BSM). The USQCD collaboration has developed an important BSM research direction 0 ++ triplet state 0.3 (connected) with the primary focus on the composite Higgs mechanism as outlined in our recent USQCD BSM 0.2 white paper [1] and in this short report. Deploying advanced lattice field theory technology, we are 0.1 investigating new strong gauge dynamics to explore consistency with a composite Higgs particle 0 ++ singlet state (disconnected) at 126 GeV which will require new non-perturbative insight into this fundamental problem. The 0 0 0.005 0.01 0.015 fermion mass m organizing principle of our program is to explore the dynamical implications of approximate scale FIG. 1. This plot is unpublished and for illustration only. Some of the flavor singlet scalar data points are expected invariance and chiral symmetries with dynamical symmetry breaking patterns that may lead to the to remain in flux before final analysis and publication [3]. The ongoing work indicates the emergence of a light flavor singlet scalar state (red) with 0 ++ quantum numbers in the sextet rep of a fermion doublet with the minimal composite Higgs mechanism with protection of the light scalar mass, well separated from predicted realization of the composite Higgs mechanism. Annihilation diagrams driven by strong gauge dynamics downshift the new resonances, which maybe on the 1-2 TeV scale. Based on an underlying strongly-coupled mass of the flavor singlet state close to the EWSB scale. Turning on a third massive EW singlet in the model might bring the β -function even closer to zero with minimal tuning. The fermion mass dependence of the isotriplet meson theory, lattice calculations provide the masses and decay constants of these new particles, enabling (blue) is also shown, not e ff ected by disconnected annihilation diagram. In the chiral limit it is a heavy resonance concrete predictions for future experimental results at colliders and in dark matter searches. above 1 TeV. The model predicts several resonances in the 1-2 TeV range. On the other hand, if the higher resonances are too heavy to be directly probed at the LHC, indirect evidence for Higgs compositeness may appear for example as altered rates for electroweak gauge boson scattering, changes to the Higgs coupling constants, or the presence of additional light Higgs-like resonances. Here lattice calculations are used to derive the low energy constants in an E ff ective Field Theory description to predict departures of a composite Higgs dynamics from the standard model predictions. Of course as new experimental evidence from the LHC is forthcoming, BSM lattice simulations will be focused on an increasingly narrower class of candidate theories, consistent with experimental constraints, increasing its power as a theoretical tool in the search for BSM physics. Two major components of our BSM lattice program are carefully planned and coordinated, as summarized below. FIG. 2. From [11], lattice simulation results for the S -parameter per electroweak doublet, comparing SU(3) gauge theories with N f = 2 (red triangles) and N f = 6 (blue circles) degenerate strongly-coupled fermions in the funda- mental representation. The horizontal axis is proportional to the pseudoscalar Goldstone boson mass squared, or equivalently the input fermion mass m . The N f = 2 value of S is in conflict with electroweak precision measure- 4 ments, but the reduction at N f = 6 indicates that the value of S in many-fermion theories can be acceptably small, in contrast to more na¨ ıve scaling estimates [13].

USQCD lattice BSM project sites (a few years ago map was empty) BU Syracuse Yale FNAL RPI UoP Columbia U Colorado LLNL Argonne UCSD It is a world-wide effort ! 5

It is a world-wide effort (latKMI is playing important role!) 6

It is a world-wide effort (latKMI is playing important role!) Leading effort on spectrum of 0 ++ vacuum (Higgs) channel: latKMI and LHC group Lattice Higgs Collaboration: with Zoltan Fodor, Kieran Holland, Santanu Mondal, Daniel Nogradi, (Chris Schroeder) , Chik Him Wong 6

Congratulations latKMI for the excellent lattice BSM work !

Rational for BSM: • After the Higgs is found why bother with BSM? Nothing else was seen and perhaps no new physics below the Planck scale? • But Standard Model Higgs potential is parametrization rather than dynamical explanation ? λ ϕ 4 not a fundamental gauge force - consequences? • Built in cutoff from triviality with quadratic divergences leading to fine tuning and the hierarchy problem; vacuum instability • Standard Model is low energy effective theory with built in cut-off ? • Can new physics from compositeness hide within the LHC run2 reach ? • Isn’t compositeness dead anyway and we should not expect it in LHC run2 ? 8

Rational for BSM: v o i c e s : a l i g h t H i g g s - l i k e s c a l a r w a s f o u n d , c o n s i s t e n t w i t h S M w i t h i n e r r o r s , a n d c o m p o s i t e s t a t e s h a v e n o t b e e n s e e n b e l o w 1 T e V . S t r o n g l y c o u p l e d B S M g a u g e t h e o r i e s a r e H i g g s - l e s s w i t h r e s o n a n c e s b e l o w 1 T e V f a c t s : C o m p o s i t e n e s s a n d a l i g h t H i g g s s c a l a r a r e n o t i n c o m p a t i b l e ; s e a r c h f o r c o m p o s i t e s t a t e s w a s n o t b a s e d o n s o l i d p r e d i c t i o n s b u t o n n a i v e l y s c a l e d u p Q C D a n d u n a c c e p t a b l e o l d t e c h n i c o l o r g u e s s i n g g a m e s . R e s o n a n c e s , o u t o f L H C r u n 1 r e a c h , a r e i n t h e 2 - 3 T e V r a n g e i n t h e t h e o r y I w i l l d i s c u s s l a t t i c e B S M p l a n s : L H C r u n 2 w i l l s e a r c h f o r n e w p h y s i c s f r o m c o m p o s i t e n e s s a n d S U S Y , a n d t h e l a t t i c e B S M c o m m u n i t y i s p r e p a r i n g q u a n t i t a t i v e l a t t i c e b a s e d p r e d i c t i o n s t o b e r u l e d i n o r r u l e d o u t . W e b e t t e r g e t t h i s r i g h t ! 9