Supergravity gauge theories strike back: there is no crisis for SUSY but a new collider may be required for discovery

Baer, Howard; Barger, V.; Savoy, Michael

doi:10.1088/0031-8949/90/6/068003

Cited by 26 publications

(31 citation statements)

References 208 publications

(183 reference statements)

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“…Stated differently, we would agree with the authors of Ref. [52] that the fine-tuning measure reduces to ∆ EW in the RNS framework if we had a theory that fixed the a i to automatically give a small value of am 2 3/2 in Eq. (6).…”

Section: Fine-tuningsupporting

confidence: 73%

“…[52] where it is argued that ∆ EW , correctly used, is the appropriate measure of finetuning. These authors use the RNS framework to illustrate their argument.…”

Section: Fine-tuningmentioning

confidence: 99%

“…[52], however, the coefficients a i are fixed in terms of the parameters of the hidden sector superpotential, Kähler potential and gauge kinetic functions. In the absence of an underlying theory of hidden sector physics, we regard Eqs.…”

Section: Fine-tuningmentioning

confidence: 99%

“…(31-35) of Ref. [52] simply as a re-parametrization of the MSSM SSB parameters, which cannot alter any conclusions as to whether or not the theory is fine-tuned! Stated differently, we would agree with the authors of Ref.…”

Section: Fine-tuningmentioning

confidence: 99%

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Supersymmetry: aspirations and prospects

Tata

2015

Phys. Scr.

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The realization in the early 1980s that weak scale supersymmetry stabilizes the Higgs sector of the spectacularly successful Standard Model led several authors to explore whether low energy supersymmetry could play a role in particle physics. Among these were Richard Arnowitt, Ali Chamseddine and Pran Nath who constructed a viable locally supersymmetric Grand Unified Theory (GUT), laying down the foundation for supergravity GUT models of particle physics. Supergravity models continue to be explored as one of the most promising extensions of the Standard Model. After a quick overview of some of the issues and aspirations of early researchers working to bring supersymmetry into the mainstream of particle physics, we re-examine early arguments that seemed to imply that superpartners would be revealed in experiments at LEP2 or at the Tevatron. Our purpose is to assess whether the absence of any superpartners in searches at LHC8 presents a crisis for supersymmetry. Toward this end, we re-evaluate fine-tuning arguments that lead to upper bounds on (some) superpartner masses. We conclude that phenomenologically viable superpartner spectra that could arise within a high scale model tuned no worse than a few percent are perfectly possible. While no viable underlying model of particle physics that leads to such spectra has yet emerged, we show that the (supergravity-based) Radiatively-driven Natural Supersymmetry (RNS) framework serves as a surrogate for a phenomenological analysis of an underlying theory with modest fine-tuning. We outline the phenomenological implications of this framework, with emphasis on those LHC and electron-positron collider signatures that might point to the underlying natural origin of gauge and Higgs boson masses. We conclude that the supergravity GUT paradigm laid down in 1982 by Arnowitt, Chamseddine and Nath, and others, remains a vibrant possibility. *

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Section: Fine-tuningsupporting

confidence: 73%

“…[52] where it is argued that ∆ EW , correctly used, is the appropriate measure of finetuning. These authors use the RNS framework to illustrate their argument.…”

Section: Fine-tuningmentioning

confidence: 99%

Section: Fine-tuningmentioning

confidence: 99%

Section: Fine-tuningmentioning

confidence: 99%

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Supersymmetry: aspirations and prospects

Tata

2015

Phys. Scr.

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“…By writing the soft terms in Eq. 6 as suitable multiples of m 2 3/2 , then large positive and negative contributions can be combined/cancelled and one arrives at the simpler expression [21,46]:…”

Section: Bg Fine-tuning and Independent Model Parametersmentioning

confidence: 99%

Upper bounds on sparticle masses from naturalness or how to disprove weak scale supersymmetry

2016

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While it is often stated that the notion of electroweak (EW) naturalness in supersymmetric models is subjective, fuzzy and model-dependent, here we argue the contrary: electroweak naturalness can be elevated to a principle which is both objective and predictive. We demonstrate visually when too much fine-tuning sets in at the electroweak scale which corresponds numerically to the measure ∆ BG ∼ ∆ EW > ∼ 30. While many constrained SUSY models are already excluded by this value, we derive updated upper bounds on sparticle masses within the two-extra parameter non-universal Higgs model (NUHM2). We confirm the classic Barbieri-Giudice (BG) result that ∆ BG < 30 implies µ < 350 GeV. However, by combining dependent soft terms which appear as multiples of m 3/2 in supergravity models, then we obtain mg < ∼ 4 TeV as opposed to the BG result that mg < ∼ 350 GeV. We compare the NUHM2 results to a similar scan in the pMSSM with 19 weak scale parameters. In the pMSSM with complete one-loop scalar potential plus dominant two-loop terms, then a mg < 7 TeV bound is found. Our tabulation of upper bounds provides a target for experimenters seeking to discover or else falsify the existence of weak scale supersymmetry. In an Appendix, we show contributions to the naturalness measure from one-loop contributions to the weak scale scalar potential. *

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Higgs and superparticle mass predictions from the landscape

Baer

Barger

Serce

et al. 2018

J. High Energ. Phys.

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Predictions for the scale of SUSY breaking from the string landscape go back at least a decade to the work of Denef and Douglas on the statistics of flux vacua. The assumption that an assortment of SUSY breaking F and D terms are present in the hidden sector, and their values are uniformly distributed in the landscape of D = 4, N = 1 effective supergravity models, leads to the expectation that the landscape pulls towards large values of soft terms favored by a power law behavior P (m sof t ) ∼ m n sof t . On the other hand, similar to Weinberg's prediction of the cosmological constant, one can assume an anthropic selection of weak scales not too far from the measured value characterized by m W,Z,h ∼ 100 GeV. Working within a fertile patch of gravity-mediated low energy effective theories where the superpotential µ term is m 3/2 , as occurs in models such as radiative breaking of Peccei-Quinn symmetry, this biases statistical distributions on the landscape by a cutoff on the parameter ∆ EW , which measures fine-tuning in the m Z -µ mass relation. The combined effect of statistical and anthropic pulls turns out to favor low energy phenomenology that is more or less agnostic to UV physics. While a uniform selection n = 0 of soft terms produces too low a value for m h , taking n = 1 and 2 produce most probabilistically m h ∼ 125 GeV for negative trilinear terms. For n ≥ 1, there is a pull towards split generations with mq ,˜ (1, 2) ∼ 10 − 30 TeV whilst mt 1 ∼ 1 − 2 TeV. The most probable gluino mass comes in at ∼ 3 − 4 TeV-apparently beyond the reach of HL-LHC (although the required quasi-degenerate higgsinos should still be within reach). We comment on consequences for SUSY collider and dark matter searches. *

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Supergravity gauge theories strike back: there is no crisis for SUSY but a new collider may be required for discovery

Cited by 26 publications

References 208 publications

Supersymmetry: aspirations and prospects

Supersymmetry: aspirations and prospects

Upper bounds on sparticle masses from naturalness or how to disprove weak scale supersymmetry

Higgs and superparticle mass predictions from the landscape

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