Presentation on theme: "Kiwoon Choi PQ-invariant multi-singlet NMSSM"— Presentation transcript:
1Kiwoon Choi PQ-invariant multi-singlet NMSSM with anomalous U(1) gauge symmetryKiwoon ChoiThe IBS Center for Theoretical Physics of the UniverseKIAS-NCTS Workshop 2014
2Outline 2. Singlet extension of the MSSM with U(1)PQ originating from 1. Introduction and motivation2. Singlet extension of the MSSM with U(1)PQ originating froman anomalous U(1) gauge symmetry:* 126 GeV Higgs boson with a minimal fine tuning* Generation of an intermediate PQ scale:* Natural solution to- SUSY flavor problem- μ problem- Cosmological moduli problem3. A specific form of the minimal model with two singlets4. Conclusion
3Introduction and motivation The Standard Model (SM) of particle physics is now completed, howeverit is certain that the SM is not the final story, but merely a low energyeffective theory of certain form of more fundamental theory.Empirical evidences for physics beyond the SM (BSM physics):* Non-baryonic dark matter* Matter-antimatter asymmetry in our Universe* Neutrino masses* Inflation in the early UniverseIncomplete or unnatural features of the SM:* Lack of the unification & quantum gravity* Fine-tuning problems:- Gauge hierarchy problem:- Strong CP problem:
4What is the next energy scale of BSM physics? Unfortunately, empirical evidences for BSM physics do not provide yet a usefulhint to this question. Either there are so many different possibilities, orthe suggested scale of BSM physics is too high to be experimentally probed.* Dark matter:10-22 eV (Clumping within galaxy) < mDM < 1060 eV (MACHO search)Long list of the candidates with a vast range of the interaction rate:WIMP, Axions, Fuzzy CDM, Gravitinos, Axinos, Higgs-portal,Q-balls, WIMPzillas, Branons, Primordial Black Holes, ….* Neutrino masses: ΛBSM ≤ 1015 GeV* Matter-antimatter asymmetry: ΛBSM ≤ 1016 GeV* Early Universe inflation: ΛBSM ≤ 1016 GeV
5What to do?* Search for the rare signals of the SM particles, reflectingthe next BSM scale:Precision measurement of the Higgs and EW gauge bosons:EDM and (g-2):Flavor changing processes:* Search for new particlesThis requires a guideline, and at the moment, the best motivated new particlesare those associated with the solutions of the fine tuning problems of the SM:Gauge hierarchy problem and Strong CP problem SUSY particles (including the WIMP DM) and axion DM
6Gauge hierarchy problem: * 𝑆𝑈 5 ⊃𝑆𝑈(3)×𝑆𝑈(2)×𝑈 1 Grand unification at MGUT ~ 1014 – 1016 GeV* Non-renormalizable gravitational interactions: Quantum gravity at scales around MPlanck ~ 1018 GeVRadiative corrections to the Higgs boson mass when nothing happensbetween mH and MGUT :This requires a fine-tuning of UV physicsH at the level ofThen why mH << MGUT , MPlanck ?
8SUSY as a solution to the gauge hierarchy problem Supersymmetry SUSY particles Fermi-Bose cancellation in the Higgs boson self energy:mSUSY = SUSY particle masses, particularly mstop and mgluinoWith SUSY, the Higgs boson mass can be as light as mSUSY withouta fine-tuning of UV physics.
9Implications of the recent LHC results for SUSY * Discovery of the SM-like 126 GeV Higgs boson* No sign of SUSY yet
10* EWSB condition in SUSY model: mSUSY = SUSY-breaking mstop or mgluinoμ = SUSY-preserving mhiggsinomstop,gluino ≫ MZ , so even with SUSY, we need a fine-tuning of parametersat the level of , which is at least about a few % fine-tuning.To minimize this fine-tuning, mstop and mgluino need to be close tothe present LHC limit ~ 1 TeV.
11* Physical Higgs boson mass in SUSY model: MSSM:mstop ~ TeV, which requires a fine tuning of O(10-4−10-6)Singlet extension of the MSSM:With λ ~ 1 and tanβ ~ 1, this can be large enough for the observedHiggs boson mass to be compatible with mstop ~ 1 TeV.Fine-tuning can be ameliorated to the minimal level ~ few %,which is a point strongly motivates this type of singlet extensionof the MSSM.
12Axion as a solution to the strong CP problem With a spontaneously broken anomalous global U(1) symmetry(Peccei-Quinn symmetry), θQCD becomes a dynamical field “axion”= Goldstone boson of the spontaneously broken U(1)PQ( vPQ = PQ scale = Scale of the spontaneous breaking of U(1)PQ )Dynamical relaxation of θQCD+ Arg Det(yq) = < a > / vPQLow energy QCD dynamics develops an axion potential minimizedat <a > = 0:a/vPQ
13Most of the axion physics is determined by the PQ scale vPQ: Axion mass:Axion-photon couplings:(Astrophysical bound on gaγγ : vPQ > 109 GeV )Cosmological relic axion mass density:Hiramatsu et al (2012)(PQ phase transition after the primordial inflation)PQ scale and the axion mass for axion DM:vPQ ~ 1010 − 1011 GeVma ~ 5×10-5 − 5×10-4 eV
14Axion search experiments are approaching to this region for axion DM. The new Center for Axion and Precision Physics (CAPP) in theInstitute for Basic Science (IBS) of Korea will join soon this gamesearching for the axion DM!
15ADMX (Axion Dark Matter eXperiment) vs CAPP (Y. Semertzidis) CurrentplanB-fieldHigh-QB-fieldDM axion mass
16* Low scale SUSY and the QCD axion are still the most compelling & interesting candidates for BSM physics.* They are introduced to understand some of the highly nontrivialhierarchical structures of the SM parameters:Scale hierarchy: (Gauge hierarchy problem)CP-angle hierarchy: (Strong CP problem)* They shed a light also on different questions such as the dark matter& unification.* They provide concrete predictions which can be tested experimentallyin the foreseeable future.* There are many virtues of having them together!
17Questions about the axion solution to the strong CP problem: Difficulties of low scale SUSY:* μ-problem* SUSY flavor problem* Cosmological moduli problemQuestions about the axion solution to the strong CP problem:* Origin of U(1)PQ whose explicit breaking other than the QCD anomalyis extremely suppressed:Axion potential induced by generic high scale dynamics:* Origin of the intermediate PQ scale 109 GeV < vPQ < 1011 GeVHaving SUSY together with U(1)PQ that originates from ananomalous U(1) gauge symmetry, all of these problems can besolved in a natural manner.
18EWSB condition in SUSY model: * μ-problemEWSB condition in SUSY model:mSUSY = SUSY-breaking mstop or mgluinoμ = SUSY-preserving mhiggsinoThen why μ ≈ mSUSY, rather than μ ≈ MPlanck ?There may exist a symmetry, e.g. U(1)PQ or an R-symmetry, which forbidsa bare μ ≈ MPlanck , but is spontaneously broken in a specific way to generateμ ≈ mSUSY . Kim, Nilles
19* SUSY flavor problemNon-observation of any BSM flavor-changing process= Deviation from flavor-degenerate sfermion masses Nearly flavor-degenerate sfermion massesor heavy ( ≥ 100 TeV) sfermions* Cosmological moduli problemGeneric SUGRA or string models involve moduli fields with mmoduli ≤ mSUSY.Moduli-dominated Universe followed by late moduli decays: mSUSY ≥ 100 TeV Cosmological mechanism to wash out the moduli in the early universe
20Two possible scenarios for SUSY: 1) msfermion (∋ mstop) ~ 100 TeV: fine-tuning of O(10-6),with a mechanism to generate μ ~ msfermion(Still the gauginos may be around TeV: Minimally split-SUSY)2) msfermion ~ mgaugino ~ 1 TeV: fine-tuning of O(few %),Price for the reduced fine-tuning:* singlet-extension in order to be compatible with mhiggs = 126 GeV * flavor-degenerate sfermion masses in order to be compatible withthe non-observation of BSM flavor-changing process* cosmological mechanism to wash out the moduli in the early universe
21SUSY models with an anomalous U(1) gauge symmetry can explain * the origin of U(1)PQ,* the origin of the intermediate PQ-scale 109 GeV < vPQ < 1011 GeV,* why μ ≈ mSUSY , rather than μ ≈ MPlanck ?and also provide a natural mechanism to* wash out the cosmological moduli,* generate flavor-degenerate sfermion masses. KC, S.H. Im, M.S. Seo (in preparation)We are interested in such SUSY models yielding a singlet-extensionof the MSSM in the low energy limit:* compatible with mhiggs = 126 GeV with a minimal fine tuning of O(few %)
22compactification, and it is broken often by the Stuckelberg mechanism: * Origin of U(1)PQ :Anomalous U(1)A gauge symmetry is a nearly generic feature of realistic stringcompactification, and it is broken often by the Stuckelberg mechanism:-Stuckelberg mechanism:Gauge boson gains a heavy mass without breaking the global part of U(1)A.U(1)PQ = Unbroken global part of U(1)A* Origin of the intermediate PQ-breaking scale:Spontaneous PQ-breaking by a balance between SUSY-breaking effect(by the D-term of U(1)A) and Planck-scale suppressed effect:Murayama, Suzuki, Yanagida ( )
23* μ-problem:Bare μ ≈ MPlanck is forbidden by U(1)PQ , but a correct value of μ ≈ mSUSYis generated by the spontaneous PQ-breaking: Kim, Nilles( )* Cosmological mechanism to wash out the moduliPQ phase transition takes place at T ~ mSUSY , rather than T ~ vPQ.Vacuum-energy dominated universeat a temperaturePresent universe withbroken PQ-symmetry Thermal inflation to wash out the cosmological moduliLyth, Stewart; KC, Chun, Kim
24* Flavor-degenerate sfermions masses SUSY breaking in models with anomalous U(1)A gauge symmetry:KC, Jeong, Okumura, Yamaguchi(Flavor-degenerate DA always dominates over the potentially dangerousflavor-non-degenerate gravity mediation.)There can be additional gauge-mediated SUSY breaking induced by thePQ-breaking sector, which is comparable to DA. Sfermion masses are determined mostly by the flavor-degenerateU(1)A D-term and gauge mediation.and
25 Just two minimal models whose low energy limits at the TeV scale * Singlet extension of the MSSM with U(1)PQ originating froman anomalous U(1) gauge symmetryMost general singlet extension of the MSSM around the TeV scale:Generalized μ-problem: Why μ , μij , ξi1/2 ~ mSUSY (or smaller)?All mass parameters in this effective superpotential should be generatedby the spontaneous breaking of U(1)PQ .Attempts to get phenomenologically viable singlet-extension with a reasonablysimple PQ-breaking sector and tanβ ~ 1: KC, S.H. Im, M.S. Seo, arXiv:1402.xxxx Just two minimal models whose low energy limits at the TeV scaleare described by
26Among those two models, the one with is particularly interesting as it allows a limit where the singlet sector isparametrically lighter than the MSSM sector without causing any furtherfine-tuning:For instance, we can consider a limitwhich has a variety of interesting implications for the Higgs and DM physics,as well as the collider signatures of the model. KC, S.H. Im, M.S. Seo (in preparation)
27candidate for BSM physics: Conclusion1. Low scale SUSY and the QCD axion are still the most compellingcandidate for BSM physics:-Solve the gauge hierarchy problem & the strong CP problem-Provide attractive DM candidates: axions and/or neutralinos-Fit nicely with the unification and also with string theory-Phenomenological consequences which are within the reach ofexperimental tests in the foreseeable future2. Singlet-extension of the MSSM at the TeV scale is well motivatedby the observed Higgs boson mass mhiggs=126 GeV and a requestfor the minimal fine-tuning.
283. Attempts to understand - the origin of the PQ-symmetry - the origin of the intermediate PQ-breaking scale- the μ-problem: why μ ≈ mSUSY, rather than μ ≈ Mplanck ?- flavor-degenerate sfermion masses- the cosmological moduli problempoint to SUSY models with an anomalous U(1) gauge symmetryat high scales.4. Attempt to get phenomenologically viable singlet-extensionof the MSSM from such high scale models yields a specificform of two-singlet NMSSM at the TeV scale, which can haveinteresting implications for the Higgs and DM physics, as wellas the collider signatures of SUSY particles.