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SUSY Phenomenology Circa 2020 SUSY phenomenology circa 2020 Howie Baer (baer at ou dot edu), Pheno2020 University of Oklahoma May 4, 2020 m(higgs) finetuned in SM for cuto↵ m(weak) • 120 cosmological constant 10− expected • 10 ✓¯ 10− (strong CP/QCD) • ⇠ ``The appearance of fine- tuning in a scientific theory is like a cry of distress from nature, complaining that something needs to be better explained’’ virtual Pitt PACC meeting 1 SUSY phenomenology of 20th century mediation: gravity (mSUGRA/CMSSM), gauge, anomaly • naturalness: sparticles 100 GeV scale • ⇠ dark matter: WIMP/neutralino via stau-co, A-funnel or FP • 2 21 century experiments meet 20th century theory m = 125.18 0.16 GeV • h ± m > 2.1 TeV • g˜ m˜ > 1.1 TeV • t1 no sign of WIMPs (via DD) • These values/limits lead to impression that Weak Scale SUSY largely excluded except for few remote regions of p-space 3 21 century physics 1. discrete R-symmetries: mu-problem,p-decay, R-parity, gravity-safe global PQ symmetry 2. naturalness: BG, HS, EW 3. DM: need axion for strong CP, SUSY mu-problem: mainly DFSZ axion plus higgsino-like WIMP 4. string landscape: solves CC problem, role in hierarchy problem? Yes 4 SUSY mu problem: The SUSY preserving mu-parameter is usually tuned within spectrum calculator computer codes and otherwise ignored. But more basically, it should be ~m(Planck), or else in string theory=0 (no arbitrary mass scales) But: phenomenologically, need mu~m(weak)~100-300 GeV (practical naturalness: independent contributions to observables should be of order of or less than the measured value). Recent review: summarize 20 solutions 5 6 Recent mu solution: Discrete R symmetries: can arise from string compactification • Anomaly-free, GUT consistent (Lee et al.) ZR arXiv:1102.3595 • 4,6,8,12,24 R-parity, forbid µ,suppressp-decay, allow m(⌫) • ) R strongest: Z24: gravity-safe PQ symmetry arises as accidental, approx- • imate global symmetry! which solves strong CP via DFSZ axion! BBS, arXiv:1810.03713 R-parity and global PQ arise from same7 source: Z24^R 8 Developments in naturalness 2 @ log mZ EENZ/BG: ∆BG maxi • ⌘ | @ log pi | highly parameter dependent: for same spectra, • changes radically depending on model parameters may be correlated: top-down string models • parameters may be selected for: landscape • 2 δmHu ∆HS = m2 • h implies three 3rd gen squarks m˜ ˜ < 500 GeV • t1,2,b1 back-of-envelope cal’n sets • numerous terms 0inRGE ! this then ignores dependent contributions m2 , δm2 : • Hu Hu HB, Barger, Huang, violates practical naturalness Mustafayev, Tata: arXiv:1207.3343 2 2 d 2 u 2 m mH +⌃d (mH +⌃u)tan β Z = d − u µ2 m2 ⌃u(t˜ ) µ2 2 tan2 β 1 Hu u 1,2 • − − ⇠ − − ∆ max contribution on RHS /(m2 /2) • EW ⌘ | | Z model independent • ∆ ∆ for correlated soft terms • BG ! EW ∆ ∆ for combined dependent contibutions 9 • HS ! EW Whereas (artificial) CMSSM/mSUGRA is now excluded as natural, there is plenty of natural p-space in non-artificial models such as NUHM2,3 Typical spectrum for low ∆EW models mSUGRA with A0 =0 first/second generation 4 10 matter scalars ˜b1 t˜2 stops, sbottoms, gluinos t˜1 g˜ 3 10 (GeV) W˜ ± 2 Z˜4 wino m ˜ Z3 bino Z˜2 h W˜ ± Higgs,higgsinos ˜ 1 2 Z1 10 Z0 gauge bosons W ± 0 5 10 10 15 Dark matter from SUSY with radiatively-driven naturalness Short answer: both axion and (thermally-underproduced) higgsino-like WIMP Typically 80-90% axions; 10-20% WIMPs Should ultimately see WIMPs Axion coupling suppressed by presence of higgsinos- axion detection much tougher :( 11 DM production in SUSY DFSZ: solve eight coupled Boltzmann equations wimp Bae, HB, Chun; Bae, HB, Lessa, Serce radiation gravitino saxion axino a(CO) re-heat 12 Direct higgsino detection rescaled for minimal local abundance ⇠ ⌦TPh2/0.12 ⌘ χ Bae, HB, Barger,Savoy,Serce Xe-1-ton now operating! natural SUSY Can test completely with ton scale detector or equivalent (subject to minor caveats) 13 It is sometimes invoked that maybe we should abandon naturalness: after all, isn’t the cosmological constant (CC) fine-tuned? In a multiverse with 10^500 vacua with different CCs, then the value of the CC may not be surprising since larger values would lead to runaway pocket universes where galaxies wouldn’t condense- anthropics: no observers in such universes (Weinberg) The CC is as natural as possible subject to the condition that it allows for galaxy condensation (structure principle) 14 To handle string landscape and concomitant multiverse, Douglas introduced concept of stringy naturalness (anthropics hides here) This embodies Weinberg’s prediction of CC Can we apply similar reasoning to magnitude of weak scale? m(weak)~=m(W,Z,h)~100 GeV see talk by S. Salam in Theory session 15 dP/d f f O ⇠ prior · selection What is f(prior) for SUSY breaking scale? In string theory, usually multiple (~10) hidden sectors containing a variety of F- and D- breaking fields For comparable <Fi> and <Dj> values, then expect 2n +n 1 f m F D − prior ⇠ soft Douglas ansatz arXiv:0405279 Under single F-term SUSY breaking, expect linear increasing statistical selection of soft terms 16 What about f(selection)? Originally, people adopted to penalize soft terms straying too far from weak scale This doesn’t work for variety of cases • Too big soft terms can lead to CCB minima: must veto such vacua • Bigger m(Hu)^2 leads to more natural value at weak scale • Bigger A(t) trilinear suppresses t1, t2 contribution to weak scale Adopt mu solution which leads to natural, weak scale value of mu~100-350 GeV Then for statistically selected soft terms, m(weak) is output, not input Must veto too large m(weak) values: nuclear physics screwed up (Agrawal, Barr, Donoghue, Seckel, 1998) Factor four deviation of weak scale17 from measured value => ∆EW < 30 Agrawal, Barr, Donoghue, Seckel result (1998): weak scale cannot deviate by more than factor 2-5 from its measured value lest disasters occur in nuclear physics Our Domain ++ p, Δ stable 20 10 0 ) 0 -10 ++ Δ stable τB < tchem -20 Log (v/v -30 no stable nuclei no light nuclei ? -40 stellar evolution ? -18 -15 -12 -9 -6 -3 0 3 6 9 12 15 18 2 2 2 1/2 sgn(µ ) Log(1+|µ |/fπ ) 18 mHu =1.3m0 statistical draw to large soft terms balanced by anthropic draw toward red (m(weak)~100 GeV): then m(Higgs)~125 GeV and natural SUSY spectrum! Denef, Douglas, JHEP0405 (2004) 072 Giudice, Rattazzi, NPB757 (2006) 19; Dutta, Mimura, PLB648 (2007) 357 HB, Barger, Savoy, Serce,19 PLB758 (2016) 113 Under stringy naturalness, a 3 TeV gluino is more natural than a 300 GeV gluino! higher density of dots => more stringy natural! n=4 draw n=1 draw HB, Barger, Salam: arXiv:1906.07741, HB, Barger, Sengupta:arXiv:1912.01672 20 Making the picture more quantitative: dN [m2 ,m , ⇤]=f (m2 ) f f dm2 vac hidden weak SUSY hidden · EWFT · cc hidden m(h)~125 most favored for n=1,2 HB,Barger, Serce, Sinha: arXiv:1712.01399 21 What is corresponding distribution for gluino mass? typically beyond LHC 14 reach (may need HE-LHC) 22 and m(t1)? 23 first/second generation sfermions pulled to common bound 20-40 TeV thus solving SUSY flavor/CP problems: Sengupta talk 24 Conclusions: • SUSY very much alive: natural for mu~100-300 GeV • EW naturalness: higgsino-like WIMP • QCD naturalness: axion • SUSY mu problem/Little Hierarchy: SUSY DFSZ axion-PQ gravity-safe • DM=higgsino-like WIMP+DFSZ axion admixture? • multi-ton SI noble liquid detectors should probe all p-space • string landscape: pull mh->125 and sparticles beyond LHC/Run2 reach • (HL)-LHC: direct higgsino pair prod => SDLJMET signature! • HE-LHC27 TeV may be required for gluinos/stops • ILC500 is ideal for light higgsinos 25 SUSY DFSZ axion: large range in m(a) but coupling reduced may need to probe broader and deeper! 26 Mainly higgsino-like WIMPs thermally underproduce DM green: excluded; red/blue:allowed HB, Barger, Mickelson IsaReD Factor of 10-15 too low 27 But so far we have addressed only Part 1 of fine-tuning problem: In QCD sector, the term must occur But neutron EDM says it is not there: strong CP problem (frequently ignored by SUSY types) Best solution after 35 years: PQWW/KSVZ/DFSZ invisible axion In SUSY, axion accompanied by axino and saxion Changes DM calculus: expect mixed WIMP/axion DM (2 particles) 28 mixed axion-neutralino production in early universe neutralinos: thermally produced (TP) or NTP viaa ˜, s or G˜ decays • s,a˜ – re-annihilation at TD axions: TP, NTP via s aa, bose coherent motion (BCM) • → saxions: TP or via BCM • – s gg: entropy dilution → – s SUSY : augment neutralinos → – s aa: dark radiation (∆N < 1.6) → eff axinos: TP • – a˜ SUSY augments neutralinos → gravitinos: TP, decay to SUSY • 29 => 30 higgsino abundance axion abundance mainly axion CDM for fa<~10^12 GeV; for higher fa, then get increasing wimp abundance Bae,31 HB,Lessa,Serce Prospects for SD WIMP searches: 32 Prospects for IDD WIMP searches: suppressed by square of diminished WIMP abundance 33 Prospects for discovering SUSY with radiatively-driven naturalness at LHC and ILC 34 Sparticle prod’n along RNS model-line at LHC14: higgsinos gauginos gluinos higgsino pair production dominant-but only soft visible energy release from higgsino decays largest visible cross section: wino pairs gluino pairs sharply dropping35 gluino pair cascade decay signatures will need HE-LHC (27 TeV) to36 probe unified SUSY models Top squark searches: HE-LHC can see entire natural p-space: discover or falsify natural SUSY! 37 Distinctive new same-sign diboson (SSdB) signature from SUSY models with light higgsinos! (soft) (soft) wino pair production This channel offers added reach of LHC14 fornSUSY; it is also indicative of wino-pair prod’n followed
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