Beyond the Standard Model with SUSY and Axions Kiwoon Choi (KAIST) PLANCK 2013 May 24, Bonn

the best motivated and perhaps the most promising candidates for Beyond the SM physics Although more than 30 years old now, SUSY and axions are still the best motivated and perhaps the most promising candidates for BSM physics. Introduced to solve the two major fine-tuning problems of the SM: * Gauge hierarchy problem  SUSY around the weak scale * Strong CP problem  QCD axion and provide attractive DM candidate. In this talk, I will discuss the present status of these two compelling candidates for BSM physics in light of recent progress, as well as the prospect for experimental discoveries in the future. Cf: BSM in cosmology (L. Covi), flavor physics (A. Masiero) and string theory (L. Ibanez)

1) Implications of the 126 GeV Higgs boson for SUSY Outline 1) Implications of the 126 GeV Higgs boson for SUSY Where is SUSY ? mSUSY * MSSM: Maximal stop-mixing, Minimally split SUSY, High scale SUSY * Natural NMSSM as a model for minimal fine-tuning & Warped NMSSM as its UV completion 2) QCD Axion Where is axion ? fa * EDM, Axion dark matter, Axion dark radiation, … 3) Conclusion

* 126 GeV Higgs boson A new boson with mh = 126 GeV has been discovered at the LHC, which looks very much like the SM Higgs boson: pp  h + X & h  ZZ, WW, γγ, bb, ττ Although the data fit very well to the minimal SM Higgs boson, a variety of BSM physics models are also compatible with the data: Modification of Higgs boson couplings by BSM physics:

* Current LHC limits on SUSY (colored superparticles) mstop > 600 GeV mgluino > 1.3 TeV mgluino ~ msquark > 1.5 TeV

as a mechanism for natural EWSB, in particular for models with high Direct search limits begin to threaten the original motivation for SUSY as a mechanism for natural EWSB, in particular for models with high mediation scale of SUSY breaking. EWSB in SUSY model: ( Λ = mediation scale of SUSY breaking ) High mediation scale, e.g. Λ ~ MGUT:  fine-tuning of < 1 % (mstop > 600 GeV, mgluino > 1.3 TeV ) Low mediation scale, e.g. Λ ~ 10 - 102 TeV, Fine-tuning can be ameliorated to be about 10 %.

 

 

Can arise naturally from many SUSY breaking scheme * Minimally Split SUSY : mgaugino ~ msfermion/8π2 Can arise naturally from many SUSY breaking scheme 1) SUSY breaking F-component: FZ ~ m3/2MPl (for vanishing C.C) 2) Sfermion masses by gravity mediation:  msfermion ~ FZ/MPl ~ m3/2 3) Gauge multiplet can be easily sequestered from the SUSY breaking by Z: : No gaugino mass from FZ (Approximate symmetry, Geometric separation, …) However, usually there exists a gauge coupling modulus fa = T whose F-component contributes to the gaugino masses.

 

* High scale SUSY with shift symmetry tanβ = 1  Highest SUSY scale compatible with mh = 126 GeV Shift symmetry at compactification scale mcom: at mcom Pseudo-Goldstone Higgs model: Inoue et al (1986) Heterotic string orbifold: Antoniadis et al (1994); Lopes Cardoso et al (1994) Gauge-Higgs unification model: KC et al (2004); Hebecker et al (2009) Shift symmetry is broken by the top Yukawa coupling, but still tanβ at SUSY breaking scale can be close to 1:  mSUSY ~ 109 – 1011 GeV Hebecker, Knochel, Weigand (2012) Theoretically interesting in principle, however huge fine-tuning for EWSB and no hope to see SUSY at the LHC.

126 GeV Higgs boson in NMSSM EWSB and mh = 126 GeV can be achieved in NMSSM with less fine-tuning: Hall et al (2012), Ross et al (2012), King et al (2012), Kang et al (2012), Gherghetta et al (2012), … Natural NMSSM: Hall, Pinner, Ruderman (2012); Gherghetta, Harling, Medina, Schmidt (2012) * Small tanβ ~ 2, Large λ = 1-2 , Low mediation scale Λ ~ 10-100 TeV, * mstop < 1.2 TeV, mgluino < 3 TeV, mhiggsino < 300 GeV, mS < 1 TeV  : About 10% tuning So, there still exists a sizable room for SUSY to provide a good solution to the hierarchy problem in the NMSSM.

* Warped NMSSM * Fine-tuning for EWSB in NMSSM Fine-tuning for Λ ~ 10 TeV Hall, Pinner, Ruderman (2012) Natural NMSSM: NMSSM with large λ=1-2 and low cutoff scales for UV completion well below MGUT: * Composite (Fat) Higgs with nearly conformal new strong dynamics Harnic, Kribs, Larson, Murayama (2004) * Warped NMSSM Birkedal, Chacko, Numura (2004); Gherghetta, Harling, Setzer (2011)

* Warped NMSSM with Higgs sector at IR brane Slice of AdS5 UV Birkedal, Chako, Nomura (2004); Gherghetta, Harling, Setzer (2012) Slice of AdS5 IR k = AdS curvature SUSY breaking Z Gauge multiplets & Radion T Higgs (Hu, Hd, S) at UV boundary in bulk at IR boundary Light fermions Moduli Top quark multiplets quasi-localized near stabilization quasi-localized near the UV boundary yielding the IR boundary (Small Yukawa couplings, FT << FZ (Large Yukawa couplings, Large soft masses) Small soft masses) * Low cutoff scale ΛIR ~ e-kπRMPl for the Higgs and stops * Effective SUSY with heavy 1st & 2nd generation sfermions, and light Higgs, stops, gauginos & Higgsinos

 

* Higgs mixing in natural NMSSM KC, Im, Jeong, Yamaguchi, arXiv:1211.0875; Cheung, McDermott, Zurek , arXiv:1302.0314; Barbieri, Buttazzo, Kannike, Sala, Tesi, arXiv:1304.3670; Badziak, Olechowski, Pokorski, arXiv:1304.5437 For λ = 1-2, all Higgs boson masses may not be so different from each other, which would result in a sizable Higgs mixing. 126 GeV Higgs boson:  with sizable θ1 and/or θ2 Such mixing results in a modification of the low energy couplings of the (Singlet-doublet mixing & Higgsino Loop)

KC, Im, Jeong, Yamaguchi, arXiv:1211.0875 The mixing between the 126 GeV Higgs and the singlet S is not severely constrained, so sin2θ2 can be as large as O(10)%. KC, Im, Jeong, Yamaguchi, arXiv:1211.0875 Significantly enhanced γγ rate ~ 1.5 x SM-rate, SM-like WW & ZZ events, and depleted bb & ττ rates ~ 0.7 x SM-rate can be obtained with = 1-2 & sin2θ2 = O(10) % which can be tested by the next round of LHC experiments.

(no anthropic reasoning) QCD axion * Strong CP problem : Neutron EDM  (no anthropic reasoning) * Axion solution: Non-linearly realized U(1)PQ broken by the QCD anomaly U(1)PQ: a  a + constant   Dynamical relaxation of θ

Generically the dynamical relaxation is not complete. Small shift of axion VEV by 1) CP-Violation 2) Additional PQ-breaking by UV dynamics (quantum gravity effects such as stringy instantons, gravitational wormholes, …) * SM CPV  * BSM CPV around TeV  * Stringy instantons   Even with axions, regardless of the existence of BSM physics near TeV, can take any values below the experimental bound ~ 10-10.

* EDM as a probe for BSM physics < 10-25 e-cm Future experiments may be able to measure some EDMs ~ 10-29 e-cm: Storage ring experiment for charged particle EDM: Y.K. Semertzidis (http://www.bnl.gov/edm) Sensitivity: dproton, ddeutron ~ 10-29 e-cm  BSM physics at scales up to 10-100 TeV However, for a proper interpretation of the experimentally measured EDM, it is necessary to have an accurate theoretical computation of the EDMs from .

To make sure the existence of BSM physics, we need to measure EDMs from Bsaisou, Hanhart, Liebig, Meiβner, Nogga, Wirzba, arXiv:1209.6306; Guo, Meiβner, arXiv:1210.5887 (χPT + Lattice) To make sure the existence of BSM physics, we need to measure both dn & dp, together with an improvement of the theoretical computation of dn(θ) & dp(θ). Although the electron EDM by itself can probe BSM physics directly, the observable most sensitive to de is the EDM of paramagnetic atoms, which are affected by θ even more complicate way: ( )

 

 

* QCD axion from closed string modes Axion scales suggested by theory * QCD axion from closed string modes KC, Kim (1985); Svrcek, Witten (2006) (U(1)PQ is non-linearly realized during inflation) * Axion scale generated by SUSY breaking effects  Kim, Nilles (1984) (PQ phase transition after primordial inflation)

* PQ phase transition after inflation: Axion DM * PQ phase transition after inflation:  (fa can be larger in case with late entropy production) Axion DM search with resonant cavity: may be here!

 

Stringy realization: U(1)PQ from anomalous U(1) gauge symmetry with Axions with SUSY 1) Nearly inevitable component of string theory 2) Natural generation of an intermediate axion scale Stringy realization: U(1)PQ from anomalous U(1) gauge symmetry with FI=0 in SUSY limit KC, Jeong, Okumura, Yamaguchi (2011) 3) Interesting cosmology due to axino & saxion * Axino DM: Covi, Kim, Roszkowski (1999) See J. E. Kim’s talk * Axion dark radiation: KC, Chun, Kim (1997) Late decaying saxions (moduli)  (Nearly generic feature of SUSY axion models) See J. Conlon’s talk

SUSY may be here! Then we will discover her in the next round Conclusion Where is SUSY ? * Natural NMSSM still provides a good solution to the fine-tuning problem in EWSB, and the natural parameter region (~ 10% fine-tuning) can be extended to mstop = 1.2 TeV, mgluino = 3 TeV. Stop Gluino 1.2 TeV 3 TeV SUSY may be here! Then we will discover her in the next round of LHC experiments.

* Sizable modification (~ O(10)%) of the low energy couplings of 126 GeV Higgs boson is a plausible possibility in natural NMSSM. Expected 1-σ precision Higgs measurements at LHC (14 TeV, 300 fb-1) Deviation Peskin, of arXiv:1207.2516 Higgs couplings We may be able to see some deviations from the SM in the next round of LHC experiments.

* With the proposed level of sensitivity, EDMs will make it possible to access BSM physics even at scales above the LHC scale. Storage ring experiment for charged particle EDM: Sensitivity of dproton, ddeutron ~ 10-29 e-cm To utilize this exciting possibility, we will need a more precise theoretical computation of the EDMs from .

Where is axion? * In near future, detection of axion DM with fa ~ few x (1011 – 1012) GeV will be a real possibility. On the other hand, we will need new technique to reach the region fa ~ 3 x 1010 GeV, giving Ωah2 ~ 0.1 in a minimal cosmological scenario. It may be possible to test fa ~ 1016 GeV with molecular interferrometry or a tensor mode in density perturbation.

Flavor, Neutrino CMB, LSS, Cosmic Rays In summary, to make a further progress, we will need a guide from experiments. It may come soon from some of our on-going (or planned) efforts to search for BSM physics with LHC, flavors, DM, CMB, EDM, …. Dark matter, Inflation, Baryon Asymmetry,  BSM Physics Naturalness, Unification Quantum Gravity, … Flavor, Neutrino CMB, LSS, Cosmic Rays p-decays, EDM, LHC, DM, … (Higgs, MET, …) (WIMP, Axion,…) Exciting discoveries may be waiting for us!

Thank you for your attention!